alphabetical list of all turing elements · typespec - type specification unchecked - compiler...

AlphabeticalListofAllTuringElements

abs-absolutevaluefunctionaddr-addressofavariableaddressint-typeall-allmembersofasetand-operatoranyclass-theancestorofallclassesarctan-arctangentfunction(radians)arctand-arctangentfunction(degrees)array-typeassert-statementassignability-ofexpressiontovariableassignment-statementbegin-statementbind-declarationbits-extractionbody-declarationboolean-true-falsetypebreak-debuggerpausestatementbuttonchoose-switchmousemodesbuttonmoved-hasamouseeventoccurredbuttonwait-getamouseeventprocedurecase-selectionstatementcatenation(+)-joiningtogetherstringsceil-real-to-integerfunctionchar(n)-typechar-typecheat-typecheatingchecked-compilerdirectivechr-integer-to-characterfunctionclass-declarationclock-millisecsusedprocedureclose-filestatement

cls-clearscreengraphicsprocedurecollection-declarationcolor-textcolorgraphicsprocedurecolorback-backgroundcolorprocedurecolour-textcolorgraphicsprocedurecolourback-backgroundcolorprocedurecomment-remarkstatementcomparisonOperatorConcurrencyConcurrency.emptyConcurrency.getpriorityConcurrency.setpriorityConcurrency.simutimecondition-declarationConfigConfig.DisplayConfig.LangConfig.Machineconst-constantdeclarationconstantReference-useofaconstantcos-cosinefunction(radians)cosd-cosinefunction(degrees)date-proceduredeclaration-createavariabledeferred-subprogramdeclarationdelay-procedureDirDir.ChangeDir.CloseDir.CreateDir.CurrentDir.DeleteDir.GetDir.GetLongDir.Opendiv-integertruncatingdivisionoperatorDrawDraw.ArcDraw.Box

Draw.ClsDraw.DotDraw.FillDraw.FillArcDraw.FillBoxDraw.FillMapleLeafDraw.FillOvalDraw.FillPolygonDraw.FillStarDraw.LineDraw.MapleLeafDraw.OvalDraw.PolygonDraw.StarDraw.Textdrawarc-graphicsproceduredrawbox-graphicsproceduredrawdot-graphicsproceduredrawfill-graphicsproceduredrawfillarc-graphicsproceduredrawfillbox-graphicsproceduredrawfillmapleleaf-graphicsproceduredrawfilloval-graphicsproceduredrawfillpolygon-graphicsproceduredrawfillstar-graphicsproceduredrawline-graphicsproceduredrawmapleleaf-graphicsproceduredrawoval-graphicsproceduredrawpic-graphicsproceduredrawpolygon-graphicsproceduredrawstar-graphicsprocedureempty-conditionfunctionenum-enumeratedtypeenumeratedValue-enumeratedvalueeof-end-of-filefunctionequivalence-oftypeserealstr-real-to-stringfunctionErrorError.Last

Error.LastMsgError.LastStrError.MsgError.StrError.TripErrorNumExceptionsexit-statementexp-exponentiationfunctionexplicitCharConstant-characterliteralexplicitConstant-literalexplicitIntegerConstant-integerliteralexplicitRealConstant-realliteralexplicitStringConstant-stringliteralexplicitTrueFalseConstant-booleanliteralexpn-expressionexport-listexternal-declarationfalse-booleanvalue(nottrue)fetcharg-fetchargumentfunctionFileFile.CopyFile.DeleteFile.DiskFreeFile.ExistsFile.RenameFile.Statusflexible-arrayinitializationfloor-real-to-integerfunctionFontFont.DrawFont.FreeFont.GetNameFont.GetSizeFont.GetStyleFont.NameFont.NewFont.SizesFont.StartName

Font.StartSizeFont.Widthfor-statementfork-statementforward-subprogramdeclarationfrealstr-real-to-stringfunctionfree-statementfunction-declarationfunctionCallget-filestatementgetch-getcharacterproceduregetchar-getcharacterfunctiongetenv-getenvironmentfunctiongetpid-getprocessidfunctiongetpriority-functionGUIGUI.AddLineGUI.AddTextGUI.AlertGUI.Alert2GUI.Alert3GUI.AlertFullGUI.ChooseGUI.ChooseFullGUI.ClearTextGUI.CloseWindowGUI.CreateButtonGUI.CreateButtonFullGUI.CreateCanvasGUI.CreateCanvasFullGUI.CreateCheckBoxGUI.CreateCheckBoxFullGUI.CreateFrameGUI.CreateHorizontalScrollBarGUI.CreateHorizontalScrollBarFullGUI.CreateHorizontalSliderGUI.CreateLabelGUI.CreateLabelFullGUI.CreateLabelledFrame

GUI.CreateLineGUI.CreateMenuGUI.CreateMenuItemGUI.CreateMenuItemFullGUI.CreatePictureGUI.CreatePictureButtonGUI.CreatePictureButtonFullGUI.CreatePictureRadioButtonGUI.CreatePictureRadioButtonFullGUI.CreateRadioButtonGUI.CreateRadioButtonFullGUI.CreateTextBoxGUI.CreateTextBoxFullGUI.CreateTextFieldGUI.CreateTextFieldFullGUI.CreateVerticalScrollBarGUI.CreateVerticalScrollBarFullGUI.CreateVerticalSliderGUI.DisableGUI.DisposeGUI.Draw...GUI.EnableGUI.FontDrawGUI.GetCheckBoxGUI.GetEventTimeGUI.GetEventWidgetIDGUI.GetEventWindowGUI.GetHeightGUI.GetMenuBarHeightGUI.GetScrollBarWidthGUI.GetSliderValueGUI.GetTextGUI.GetVersionGUI.GetWidthGUI.GetXGUI.GetYGUI.HideGUI.HideMenuBarGUI.OpenFile

GUI.OpenFileFullGUI.Pic...GUI.ProcessEventGUI.QuitGUI.RefreshGUI.SaveFileGUI.SaveFileFullGUI.SelectRadioGUI.SetActiveGUI.SetBackgroundColorGUI.SetBackgroundColourGUI.SetCheckBoxGUI.SetDefaultGUI.SetDisplayWhenCreatedGUI.SetKeyEventHandlerGUI.SetLabelGUI.SetMouseEventHandlerGUI.SetNullEventHandlerGUI.SetPositionGUI.SetPositionAndSizeGUI.SetScrollAmountGUI.SetSelectionGUI.SetSizeGUI.SetSliderMinMaxGUI.SetSliderReverseGUI.SetSliderSizeGUI.SetSliderValueGUI.SetTextGUI.SetXORGUI.ShowGUI.ShowMenuBarhandler-exceptionhandlerhasch-hascharacterfunctionid-(identifier)nameofaniteminaprogram#if-usedforconditionalcompilationif-statementimplementby-clauseimplement-clauseimport-list

in-memberofasetinclude-sourcefilesindex-findpatterninstringfunctionindexTypeindirection-operator(@)infix-operatorinherit-inheritanceclauseinit-arrayinitializationInputInput.getchInput.getcharInput.haschInput.KeyDown-getkeyboardstateInput.Pause-pauseforkeystrokeint-integertypeintn-n-byteintegertypeintreal-integer-to-realfunctionintstr-integer-to-stringfunctioninvariant-assertionJoystickJoystick.GetInfoKeyboardlength-ofastringfunctionLimitsln-naturallogarithmfunctionlocate-procedurelocatexy-graphicsprocedureloop-statementlower-boundMathmax-maximumfunctionmaxcol-maximumcolumnfunctionmaxcolor-graphicsfunctionmaxcolour-graphicsfunctionmaxint-maximumintegerfunctionmaxnat-maximumnaturalnumberfunctionmaxrow-maximumrowfunctionmaxx-graphicsfunctionmaxy-graphicsfunction

min-minimumfunctionminint-minimumintegerfunctionminnat-minimumnaturalnumberfunctionmod-modulooperatormodule-declarationmonitor-declarationMouseMouse.ButtonChooseMouse.ButtonMovedMouse.ButtonWaitMouse.WheremousewhereMusicMusic.PlayMusic.PlayFileMusic.PlayFileStopMusic.SoundMusic.SoundOffnamed-typenargs-numberofargumentsnat-naturalnumbertypenatn-n-bytenaturalnumbertypenatreal-naturalnumbertorealfunctionnatstr-natural-number-to-stringfunctionNetNet.BytesAvailableNet.CharAvailableNet.CloseConnectionNet.HostAddressFromNameNet.HostNameFromAddressNet.LineAvailableNet.LocalAddressNet.LocalNameNet.OpenConnectionNet.OpenURLConnectionNet.TokenAvailableNet.WaitForConnectionnew-statementnil-pointertoacollection

not-true/false(boolean)operatorobjectclass-ofapointeropaque-typeopen-filestatementor-operatorord-character-to-integerfunctionparallelget-parallelportfunctionparallelput-parallelportprocedureparamDeclaration-parameterdeclarationpause-statementPCPC.ParallelGetPC.ParallelPutpervasive-declarationmodifierPicPic.BlendPic.BlurPic.DrawPic.DrawFramesPic.DrawFramesBackPic.DrawSpecialPic.DrawSpecialBackPic.FileNewPic.FileNewFramesPic.FlipPic.FramesPic.FreePic.HeightPic.MirrorPic.NewPic.RotatePic.SavePic.ScalePic.ScreenLoadPic.ScreenSavePic.SetTransparentColorPic.SetTransparentColourPic.Widthplay-procedure

playdone-functionpointer-typepost-assertionpre-assertionprecedence-ofoperatorspred-predecessorfunctionprefix-operatorprocedure-declarationprocedureCall-statementprocess-declarationprogram-a(main)programput-statementquit-failstatementRandRand.IntRand.NextRand.RealRand.ResetRand.SeedRand.Setrand-randomrealnumberprocedurerandint-randomintegerprocedurerandnext-procedurerandomize-procedurerandseed-procedureread-filestatementreal-therealnumbertyperealn-n-byterealnumbertyperealstr-real-to-stringfunctionrecord-typeregister-usemachineregisterrem-remainderoperatorrepeat-makecopiesofstring:functionresult-statementreturn-statementRGBRGB.AddColorRGB.AddColourRGB.GetColor

RGB.GetColourRGB.maxcolorRGB.maxcolourRGB.SetColorRGB.SetColourround-real-to-integerfunctionscalar-typeseek-(file)statementself-pointertocurrentobjectseparator-betweentokensinaprogramset-typesetConstructorsetpriority-proceduresetscreen-graphicsprocedureshl-shiftleftoperatorshr-shiftrightoperatorsign-functionsignal-wakeupaprocessstatementsimutime-simulatedtimefunctionsin-sinefunction(radians)sind-sinefunction(degrees)sizeof-sizeofatypesizepic-graphicsfunctionskip-usedingetstatementskip-usedinputstatementsound-statementSpriteSprite.AnimateSprite.ChangePicSprite.FreeSprite.HideSprite.NewSprite.SetFrameRateSprite.SetHeightSprite.SetPositionSprite.Showsqrt-squarerootfunctionstandardTypestatement

statementsAndDeclarationsStrStreamStream.eofStream.FlushStream.FlushAllstring-typestring-comparisonstrint-string-to-integer:functionstrintok-string-to-integer:functionstrnat-stringtonaturalnumberfunctionstrnatok-stringtonaturalnumberfunctionstrreal-string-to-realfunctionstrrealok-string-to-realfunctionsubprogramHeadersubprogramTypesubrangeTypesubstring-ofanotherstringsucc-successorfunctionSysSys.ExecSys.FetchArgSys.GetComputerNameSys.GetEnvSys.GetPidSys.GetUserNameSys.Nargssysclock-millisecsusedproceduresystem-statementtag-statementtakepic-graphicsproceduretell-filestatementTextText.ClsText.ColorText.ColorBackText.ColourText.ColourBackText.Locate

Text.LocateXYText.maxcolText.maxrowText.WhatColText.WhatColorText.WhatColorBackText.WhatColourText.WhatColourBackText.WhatRowTimeTime.DateTime.DateSecTime.DelayTime.ElapsedTime.ElapsedCPUTime.PartsSecTime.SecTime.SecDateTime.SecPartstime-timeofdayasastringproceduretoken-ininputtrue-booleanvalue(notfalse)type-declarationTypeConvtypeSpec-typespecificationunchecked-compilerdirectiveunion-typeunit-filecontainingmodule,monitor,orclassunqualified-exportupper-boundvar-declarationvariableReference-useofavariableViewView.ClipAddView.ClipOffView.ClipSetView.maxcolorView.maxcolourView.maxx

View.maxyView.SetView.Update-flicker-freeanimationView.WhatDotColorView.WhatDotColourwait-blockaprocessstatementwallclock-secondssince1/1/1970procedurewhatcol-cursorpositionfunctionwhatcolor-textcolorgraphicsfunctionwhatcolorback-colorofbackgroundfunctionwhatcolour-textcolorgraphicsfunctionwhatcolourback-colorofbackgroundfunctionwhatdotcolor-graphicsfunctionwhatdotcolour-graphicsfunctionwhatrow-cursorpositionfunctionWindowWindow.CloseWindow.GetActiveWindow.GetPositionWindow.GetSelectWindow.HideWindow.OpenWindow.SelectWindow.SetWindow.SetActiveWindow.SetPositionWindow.ShowWindow.Updatewrite-filestatementxor-exclusive"or"operator

abs absolutevaluefunction

Syntax abs(expn)

DescriptionTheabsfunctionisusedtofindtheabsolutevalueofanumber(theexpn).Forexample,abs(-23)is23.

Example

Thisprogramoutputs9.83.

varx:real:=-9.83

putabs(x)%Outputs9.83

Execute

Details

Theabsfunctionacceptsnumbersthatareeitherint'sorreal's.Thetypeoftheresultisthesametypeastheacceptednumber.Theabsfunctionisoftenusedtoseeifonenumberxiswithinagivendistancedofanothernumbery;forexample:

ifabs(x-y)<=dthen…

Seealso predefinedunitMath.

addr addressofavariable

Syntax addr(reference)

Description

Theaddrattributeisusedtofindtheintegeraddressofavariableornonscalarconstant.Thisisimplementation-dependent.Thisaddressmaybeusedinanindirectionoperation@.

Example

Setatobetheaddressofx.

varx:real

vara:addressint:=addr(x)

Details

Thevalueoftheaddressproducedbyaddrisoftypeaddressint,anintegertypewhoserangeisthatoftheunderlyingmemoryaddresses.

Theconceptofanaddressisimplementation-dependent.Forexample,anoptimizingcompilercoulddeterminethatavariabledoesnotrequirespacebecausetheprogramcouldbecomputedwithoutthevariablewithnochangeinoutput.However,inmostimplementations,typeshaveapredictablesizeandvariablesofthattypeoccupythatnumberofbytesinmemory.

Seealso

theindirectionoperator@,cheat,explicitIntegerConstant(howtowritehexadecimalconstants),andpointertype(inparticularuncheckedpointertype).Seealsosizeof,whichreturnsthesizeofavariable.

addressint type

Syntax addressint

Description

Theaddressint(addressinteger)typeisanintegertypewhoserangeofvalueisthesameasthatoftheunderlyingcomputer.Thisrangeis,byitsnature,implementation-dependent.On32-bitarchitectures,itiscommonlythesamerangeasnat4(4-bytenaturalnumber).

Example

Recordrcontainsthreefields,oneofwhichhastypechar(28).Variableaisanintegerwhoserangeofvaluesisthesameastheaddressesoftheunderlyingcomputer.ThisassignsBtotheseventhcharacterofarecordoftyperwhichisassumedtobelocatedatabsoluteaddress

typer:

record

c28:char(28)

c11:char(11)

endrecord

vara:addressint%Aninteger

…%aisassignedanintegervalue

r@(a).c28(7):='B'%Useindirectionoperator

Details

Althoughaddressintiscalledanintegertype,itiscommonlyequivalenttoanaturaltypesuchasnat4(for32-bitmachines).

Becarefulnottoconfuseaddressintwithpointertypes.InlowlevellanguagessuchasassemblerandC,addressesandpointersarethesame.InTuring,however,apointerisahighlevelconceptthatismoreabstractthanamachineaddress.ATuringpointerisareferencetoanobject,andtherepresentationofthisreferencedependsupontheimplementation.IncurrentTuringimplementations,pointers(whicharebydefaultchecked)arerepresentedasatimestamp(auniquenumber)togetherwithanaddress.Thetimestampisusedtomakesurethatthepointeractuallylocatesanobject.Therearealsouncheckedpointers.Anuncheckedpointer'sinternalrepresentationisamachineaddress.Youcanusetypecheats(adangerousfeature)totranslatebetweenaddressintanduncheckedpointers.Thisismeaningfulincurrent

implementations.

Seealso

theindirectionoperator@,cheat,explicitIntegerConstant(howtowritehexadecimalconstants),andpointertype(inparticularuncheckedpointertype).Seealsoaddr,whichreturnstheaddressofavariable.

all allmembersofaset

Syntax setTypeName(all)

DescriptionGivenasettypenamedS,thesetofallofthepossibleelementsofSiswrittenS(all).

ExampletypesmallSet:setof0..2

varx:smallSet:=smallSet(all)

%Setxcontainselements0,1and2

Seealso settypefordetailsaboutsets.

and operator

Syntax AandB

Description

Theand(boolean)operatoryieldsaresultoftrueif,andonlyif,bothoperandsaretrue.Theandoperatorisashortcircuitoperator.Forexample,ifAisfalseinAandBthenBisnotevaluated.

Examplevarsuccess:boolean:=false

varcontinuing:=true%Thetypeisboolean

continuing:=continuingandsuccess

Details

Thecontinuingvariableissettotrueif,andonlyif,bothcontinuingandsuccessaretrue.SinceTuringusesshortcircuitoperators,oncecontinuingisfalse,successwillnotbelookedat.

Theandoperatorcanalsobeappliedtonaturalnumbers.Theresultisthenaturalnumberthatisthebit-wiseandoftheoperands.Seenat(naturalnumber).

Example

Thismasksouttheeverythingbutthelowertwobytesofnumber.

varnumber:nat:=16#ABCD

varmask:nat:=16#FF

putnumberandmask%Outputs205(CD16)

Seealso

boolean(whichdiscussestrue/falsevalues),explicitTrueFalseConstant(whichdiscussesthevaluestrueandfalse),precedenceandexpn(expression).

anyclass theancestorofallclasses

Syntax anyclass

Description

Thereisapredefinedclasscalledanyclass,whichistherootoftheexpansiontree.AllclassesthatdonothaveinheritlistsareconsideredtobeexpansionsofThemainpurposeofanyclassistoallowpointersthatcanlocateobjectsofanyclass.

Example

Hereisthedeclarationofapointerpthatcanlocateanobjectofanyclass.

varp:pointertoanyclass%Shortform:varp:^anyclass

varq:pointertostack%Shortform:varq:^stack

newq%Createastackobject

p:=q%Legalbecausep'sclass

%isanancestorofq'sclass

Assumingstackisaclass,thiscreatesastackobjectandplacesitslocationinThecompilerwillnotallowacalltostack'sexportedsubprogramsusingin:

p->push(14)%ILLEGAL!anyclasshasnooperations

Anassignmentfromptoqislegal,asin:

q:=p%Checksthatplocatesastackobject(ordescendant)

Thisimpliesaruntimechecktomakesurethatplocatesanobjectthatisadescendantofastack).

Hereisawaytocallasubprogramexportedfromstackusingp:

stack(p).push(14)%Checksthatplocatesastackobject

Thischeckstoseethatplocatesastackobject(oradescendant)beforecallingthestackoperationpush.

Details

Itislegaltocreateobjectsoftheclasscalledanyclass,butthisisnotofmuchuse,becausethereisnothingyoucandowiththeseobjects(theyhavenooperations).Itislegaltoassigntheseobjectstootherobjectsofthesameclass(anyclassthisaccomplishesnothing.

Seealso

objectclass,whichtakesaclasspointerandproducestheclassoftheobjectlocatedbythepointer.Thisisusedfortestingtodeterminetheclassoftheobjectlocatedbyapointer.

Seealsoclass.Seealsoexportlist,importlist,inheritlist,implementimplementbylist.

arccos arccosinefunction(radians)

Syntax arccos(r:real):real

DescriptionThearccosfunctionisusedtofindthearccosineofavalue.Theresultisgiveninradians.Forexample,arccos(0.5)isp/3.

Example

Thisprogramprintsoutthearccosineof-1through1inradians.

fori:-4..4

constarg:=i/4

put"Arccosineof",arg,"is",

arccos(arg),"radians"

endfor

Execute

Seealso

thearcsinandarctanfunctionsforcalculatingarcsineandarctangent.

thearccosdfunctionwhichfindsthearccosineofavaluewiththeresultgivenindegrees.(2pradiansarethesameas360degrees.)

SeealsopredefinedunitMath.

arccosd arccosinefunction(degrees)

Syntax arccosd(r:real):real

DescriptionThearccosdfunctionisusedtofindthearccosineofananglegivenindegrees.Forexample,arccosd(0.5)is60.

Example

Thisprogramprintsoutthearccosineofvaluesfrom-1to1indegrees.

fori:-4..4

constarg:=i/4

put"Arccosineof",arg,"is",

arccosd(arg),"degrees"

endfor

Execute

Seealso

thearcsindandarctandfunctionsforcalculatingarcsineandarctangent

thearccosfunctionwhichfindsthearccosineofavaluewiththeresultgiveninradians.(2pradiansarethesameas360degrees.)

arcsin arcsinefunction(radians)

Syntax arcsin(r:real):real

DescriptionThearcsinfunctionisusedtofindthearcsineofavalue.Theresultisgiveninradians.Forexample,arcsin(0.5)isp/6.

Example

Thisprogramprintsoutthearcsineof-1through1inradians.

fori:-4..4

constarg:=i/4

put"Arcsineof",arg,"is",

arcsin(arg),"radians"

endfor

Execute

Seealso

thearccosandarctanfunctionsforcalculatingarccosineandarctangent.

thearcsindfunctionwhichfindsthearcsineofavaluewiththeresultgivenindegrees.(2pradiansarethesameas360degrees.)

arcsind arcsinefunction(degrees)

Syntax arcsind(r:real):real

DescriptionThearcsindfunctionisusedtofindthearcsineofananglegivenindegrees.Forexample,arcsind(0.5)is30.

Example

Thisprogramprintsoutthearcsineofvaluesfrom-1to1indegrees.

fori:-4..4

constarg:=i/4

put"Arcsineof",arg,"is",

arcsind(arg),"degrees"

endfor

Execute

Seealso

thearccosdandarctandfunctionsforcalculatingarccosineandarctangent

thearcsinfunctionwhichfindsthearcsineofavaluewiththeresultgiveninradians.(2pradiansarethesameas360degrees.)

arctan arctangentfunction(radians)

Syntax arctan(r:real):real

DescriptionThearctanfunctionisusedtofindthearctangentofavalue.Theresultisgiveninradians.Forexample,arctan(1)isp/4.

Example

Thisprogramprintsoutthearctangentof0through3inradians.

fori:0..12

constarg:=i/4

put"Arctangentof",arg,"is",

arctan(arg),"radians"

endfor

Execute

Seealso

thearcsinandarccosfunctionsforcalculatingarcsineandarccosine

thearctandfunctionwhichfindsthearctangentofavaluewiththeresultgivenindegrees.(2pradiansarethesameas360degrees.)

arctand arctangentfunction(degrees)

Syntax arctand(r:real):real

DescriptionThearctandfunctionisusedtofindthearctangentofananglegivenindegrees.Forexample,arctand(0)is0.

Example

Thisprogramprintsoutthearctangentofvaluesfrom0to3indegrees.

fori:0..12

constarg:=i/4

put"Arctangentof",arg,"is",

arctand(arg),"degrees"

endfor

Execute

Seealso

thearcsindandarccosdfunctionsforcalculatingarcsineandarccosine

thearctanfunctionwhichfindsthearctangentofavaluewiththeresultgiveninradians.(2pradiansarethesameas360degrees.)

array type

Syntax arrayindexType{,indexType}oftypeSpec

Description

Anarrayconsistsofanumberofelements.ThetypeSpecgivesthetypeoftheseelements.Thereisoneelementforeachiteminthe(combinationsof)range(s)oftheindexType(s).Inthefollowingexample,thearraycalledmarksconsistsof100elements,eachofwhichisaninteger.

Example

varmarks:array1..100ofint

varsum:int:=0

fori:1..100%Adduptheelementsofmarks

sum:=sum+marks(i)

endfor

Execute

Details

Intheaboveexample,marks(i)isthei-thelementofthemarksarray.Wecallorsubscriptofmarks.InTuring,asubscriptissurroundedbyparentheses,notbysquarebracketsasisthecaseinthePascalorC-likelanguages.

Example

Thepricesarrayshowshowanarraycanhavemorethanonedimension.Thisarrayhasonedimensionfortheyear(1988,1989or1990)andanotherforthemonth(1..12).Thereare36elementsofthearray,oneforeachmonthofeachyear.

varprice:array1988..1990,1..12ofint

varsum:int:=0

foryear:1988..1990%Foreachyear

formonth:1..12%Foreachmonth

sum:=sum+price(year,month)

endfor

Execute

Details

EachindexTypemustcontainatleastoneitem.Therange1..0,forexample,wouldnotbeallowed.Eachindextypemustbeasubrangeoftheintegers,characters(thetype),orofanenumeratedtype,an(entire)enumeratedtype,thechartype,oranamedtypewhichisoneofthese.

Arrayscanalsobedeclaredintheform

vara:array1..*oftypeSpec:=init(…)

Theupperboundofawillbecomputedfromthecountoftheinitializingvalues.Bothvarandconstarrayscanbedeclaredthisway.Anarrayvariable/constantdeclaredwith"*"asanupperboundmusthaveaninitializinglist.Onlyonedimensionalarraysmaybedeclaredinthisform.

Arrayscanbeassignedasawhole(toarraysofanequivalenttype),buttheycannotbecompared.

Anarraycanbeinitializedinitsdeclarationusinginit.Fordetails,seedeclarations.

Example

Inthisexample,thesizeofthearrayisnotknownuntilruntime.

varhowMany:int

gethowMany

varheight:array1..howManyofreal

…readinalltheelementsofthisarray…

functiontotal(a:array1..*ofreal):real

varsum:real:=0

fori:1..upper(a)

sum:=sum+a(i)

endfor

resultsum

endtotal

put"Sumoftheheightsis",total(height)

Execute

Details

Theendsoftherangeofasubscriptarecalledtheboundsofthearray.Ifthesevaluesarenotknownuntilruntime,thearrayissaidtobedynamic.Intheaboveexample,heightisadynamicarray.Dynamicarrayscanbedeclaredasvariables,asinthecaseforheight.However,dynamicarrayscannotappearinsideothertypessuchasrecords,andcannotbenamedtypes.Dynamicarrayscannotbeassignedandcannotbeinitializedusinginit.

Intheaboveexample,upper(a)returnsthesizeofa.Seealsoupper

Inthedeclarationofanarrayparameter,theupperboundcanbegivenasanasterisk(asisdoneintheaboveexample.Thismeansthattheupperboundistakenfromthatofthecorrespondingactualparameter(fromheightinthisexample).

Youcanhavearraysofothertypes,forexamplearraysofrecord.Ifrecords,thenR(i).fisthewaytoaccesstheffieldofthei-thelementofarray

Details

Arrayscanalsobemaderesizeable.Thisisdoneusingtheflexibledeclarationsyntaxis:

varname:flexiblearrayindexType{,indexType

Theindicesmayhavecompile-timeorrun-timeupperbounds(thelowerboundmustbecompile-time).Theupperboundscanbechangedbyusing:

newname,newUpper1{,newUpper2}

Theexistingarrayentrieswillretaintheirvalues,exceptthatanyindexmadesmallerwillhavethecorrespondingarrayentrieslost.Anyindexmadelargerwillhavethenewarrayentriesuninitialized(ifapplicable).

Additionally,theupperbound(bothinthedeclarationandthenewstatement)canbemadeonelessthanthelowerbound.Thiseffectivelymakesanarraythatcontains0

elements.Itcanlaterbeincreasedinsizewithanothernew.

Inthecurrentimplementation(2002),withamulti-dimensionalarraywithanon-zeronumberoftotalelements,itisarun-timeerrortochangeanybutthefirstdimension(unlessoneofthenewupperboundsisonelessthanthecorrespondinglowerbound,giving0elementsinthearray)asthealgorithmtorearrangetheelementmemorylocationshasnotyetbeenimplemented.

Currently,onlyvariablescanbedeclaredinthisform.Thereisnoflexiblearrayparametertype,althoughaflexiblearraycanbepassedtoanarrayparameterwith“astheupperbound.

Example

Inthisexample,thearrayisresizedtofitthenumberofelementsinthefile.

functiongetLines(fileName:string):int

varf,numLines:int

varline:string

open:f,fileName,get

numLines:=0

exitwheneof(f)

get:f,line:*

numLines+=1

endloop

close:f

resultnumLines

endgetLines

procedurereadFile(varlines:array1..*ofstring

varf:int

varline:string

open:f,fileName,get

fori:1..upper(lines)

get:f,lines(i):*

endfor

close:f

endreadFile

varlines:flexiblearray1..0ofstring

newlines,getLines("text.dat")

readFile(lines,"text.dat")

fori:1..upper(lines)

putlines(i)

endfor

Execute

Seealsoinittoinitializearrays,flexibletodeclareresizablearraysandindexTypeindexofanarray.

assert statement

Syntax asserttrueFalseExpn

Description

Anassertstatementisusedtomakesurethatacertainrequirementismet.ThisrequirementisgivenbythetrueFalseExpn.ThetrueFalseExpnisevaluated.Ifitistrue,alliswellandexecutioncontinues.Ifitisfalse,executionisterminatedwithanappropriatemessage.

ExampleMakesurethatnispositive.

assertn>0

Example

ThisprogramassumesthatthetextFileexistsandcanbeopened,inotherwords,thattheopenwillsetthefileNumbertoapositivestreamnumber.Ifthisisnottrue,theprogrammerwantstheprogramhaltedimmediately.

varfileNumber:int

open:fileNumber,"textFile",read

assertfileNumber>0

Details

InsomeTuringsystems,checkingcanbeturnedoff.Ifcheckingisturnedoff,assertstatementsmaybeignoredandasaresultnevercausetermination.

assignability ofexpressiontovariable

Description

Avalue,suchas24,isassignabletoavariable,suchasi,ifcertainrulesarefollowed.Theserules,givenindetailbelow,arecalledtheassignabilityrules.Theymustbefollowedinassignmentstatementsaswellaswhenpassingvaluestonon-varparameters.

Example

vari:int

i:=24%24isassignabletoi

varwidth:0..319

width:=3*i%3*iisassignabletowidth

vara:array1..25ofstring

a(i):="Ralph"%"Ralph"isassignabletoa(i)

varname:string(20)

name:=a(i)%a(i)isassignabletoname

varb:array1..25ofstring

b:=a%Arrayaisassignabletob

typepersonType:

record

age:int

name:string(20)

endrecord

varr,s:personType

s:=r%Recordrisassignabletos

Theexpressionontherightof:=mustbeassignabletothevariableontheleft.Anexpressionpassedtoanon-varparametermustbeassignabletothecorrespondingparameter.

Anexpressionisdefinedtobeassignabletoavariableifthetworoottypesareequivalentorifanintegervalueisbeingassignedtoarealvariable(inwhichcasetheintegervalueisautomaticallyconvertedtoreal).Twotypesareconsideredtobeequivalentiftheyareessentiallythesametype(seeequivalenceforthedetaileddefinitionofthisterm).

Details

Inmostcasesaroottypeissimplythetypeitself.Theexceptionsaresubrangesandstrings.Theroottypeofasubrange,suchas0..319,isthetypeofitsbounds(inttypeinthisexample).Theroottypeofastring,suchasthetypestring(9),isthemostgeneralstringtype,namelystring.

Whenasubrangevariable,suchaswidth,isusedasanexpression,forexampleontherightsideofanassignmentstatement,itstypeisconsideredtobetheroottype(integerinthiscase)ratherthanthesubrange.Whenanexpressionisassignedtoasubrangevariablesuchaswidth,thevalue(3*iinthisexample)mustlieinthesubrange.Analogously,anystringvariableusedinanexpressionisconsideredtobeofthemostgeneraltypeofstring.Whenastringvalueisassignedtoastringvariable,itslengthmustnotexceedthevariable'smaximumlength.

Turing'sassignabilityruleappliestocharactersandstringsinthisway.Acharvaluecanbeassigned(orpassedtoannonvarparameter)withautomaticconversiontoachar(1)variableandviceversa.Stringvaluesoflength1canbeassignedtocharvariables.Character,thatischar,valuescanbeassignedtostringvariables,yieldingastringoflength1.Stringvaluesoflengthnareassignablewithautomaticconversiontochar(n)variables.Valuesoftypechar(n)canbeassignedwithautomaticconversiontostringvariables.

Turing'sassignabilityruleappliestopointerstoclassesinthisway.ApointerthatlocatesanobjectcreatedasclassE,canbeassignedtoapointertoclassBonlyifBisanancestorof(orthesameas)E.Forexample,apointertoanobjectthatisastackWithDepthcanbeassignedtoapointertostack,wherestackWithDepthisachildofstack,butnotviceversa.Thepointernilcanbeassignedtoanypointervariable,butthevaluenil(C)canonlybeassignedtoapointertoanancestorofC.

Objectsofclassescanbeassignedtoeachotheronlyifbothwerecreatedasthesameclass.

assignment statement

Syntax

AnassignmentStatementis:

variableReference:=expn

DescriptionAnassignmentstatementcalculatesthevalueoftheexpression(expnassignsthatvaluetothevariable(variableReference).

Example

vari:int

i:=24%Variableibecomes24

vara:array1..25ofstring

a(i):="Ralph"%Thei-thelementofabecomes

b:=a%Arraybbecomes(isassigned)arraya

Details

Theexpressionontherightof:=mustbeassignabletothevariableontheleft.Forexample,intheabove,anyintegervalue,suchas24,isassignabletoi,butarealvaluesuchas3.14wouldnotbenotassignabletoi.Entirearrays,recordsandunionscanbeassigned.Forexample,intheabove,arrayaisassignedtoarrayb.Seeassignabilityfortheexactrulesofallowedassignments.

Youcannotassignanewvaluetoaconstant(const).

Thereareshortformsthatallowyoutowriteassignmentstatementsmorecompactly.Forexample,

i:=i+1

canbeshortenedto

InTuring,thereareshortformsforcombining+,=and*withassignment.Forexample,i*=2doublesi.

Therearealsoshortformstoallowanybinaryoperatortobecombined

withassignment.Forexample,ishl=2shiftsiby2totheleft.

begin statement

Syntax

AbeginStatementis:

begin statementsAndDeclarations end

Description

Abeginstatementlimitsthescopeofdeclarationsmadewithinittotheconfinesofthebegin/endblock.InTuring,beginisrarelyused,becausedeclarationscanappearwhereverstatementscanappear,andbecauseeverystructuredstatementsuchasifendswithanexplicitend.

Examplebegin

varbigArray:array1..2000ofreal

…bigArraywillexistonlyinsidethisbeginstatement…

Details

InPascalprograms,beginstatementsarequitecommonbecausetheyarerequiredforgroupingtwoormorestatements,forexample,togroupthestatementsthatfollowthen.ThisisnotnecessaryinTuringaswhereeveryoucanwriteasinglestatement,youcanalsowriteseveralstatements.

bind declaration

Syntax

AbindDeclarationis:

bind[var]idtovariableReference {,[var]idtovariableReference}

Description

Thebinddeclarationcreatesanewname(ornames)foravariablereference(orreferences).Youareallowedtochangethenameditemonlyifyouspecifyvar.Youcanalsobindtonamednonscalarconstants.

WhilevariableReferenceisbounditdoesnotdisappearinthescope.

Example

Renamethen-thelementofarrayAsoitiscalleditemandthenchangethiselementto15.

bindvaritemtoA(n)

item:=15

Details

Thescopeoftheidentifier(itemabove)beginswiththebinddeclarationandlaststotheendofthesurroundingprogramorstatement(ortotheendofthesurroundingpartofacaseorifstatement).Duringthisscope,achangetoasubscript(nabove)thatoccursinthevariablereferencedoesnotchangetheelementtowhichtheidentifierrefers.

Youarenotallowedtousebindattheoutermostlevelofthemainprogram(exceptnestedinsidestatementssuchasif)orattheoutermostlevelinamodule.

Youcanalsooptionallyusetheregisterkeywordtorequestthatthebindbedoneusingamachineregister.ThesyntaxforbindDeclarationisactually:

bind[var][register]idtovariableReference {,[var][register]idtovariableReference}

Inthecurrent(2002)implementation,programsareruninterpretivelyusingpseudo-codeandtheregisterkeywordisignored.

bits extraction

Syntax bits(expn,subrange)

Description

Thebitsoperatorisusedtoextractasequenceofbitsfromanatural(non-negative)numberexpression.Thebitsarenumberedfromrighttoleftas0,1,2…

Example

Setbits2and1(thirdandsecondfromtheright)inthevariabledtobe01.Wefirstsetbtobethebitstring1100.

typeT12:1..2%Usetospecifybitrange

vard:nat2:=2#1100%Twobytenaturalnumber

%Atthispointbits(d,T12)=2#10

bits(d,T12):=2#01

%Atthispointd=2#1010

Example

Setbit7invariablentobe1.Asaresult,nwillequal2#10000000.

varn:nat1:=0%Aonebytevariablesettozero

bits(n,7):=1%nnowcontainsthepattern10000000

Details

Theformofsubrangemustbeoneof:

(a) typeSpec %Subrangetype (b) compileTimeIntegerExpression

Inform(a)thesubrangetypespecifiesarangefromLtoM(forleastmostsignificant).ThisisalittleconfusingbecausethesubrangeiswrittenMwithLontheleftandMontheright,butinanumber,theleastsignificantbitisontherightandthemostsignificantisontheleft.Thesubrangetypecanbeeitherthenameofatype,forexampleT12,oranexplicitsubrange,forexample3..7.Thevaluesintheexplicitsubrangemustbecompiletimevalues.

Form(b)representstherangen..nwherenisthenon-negativevalueoftheexpression.Inotherwords,bothLandMequaln.Theexpressioncanbeanynon-negativeintegervalueornaturalnumbervalue.

Iftheexpressionexpnisavariablereference,thebitsoperationcanbeassignedto,butcannotbepassedto,avarparameter.Forexample,intheabove,bits(d,T12)hasthevalue2#01assignedtoit.Forthisassignmenttobeallowed,theexpressionexpnmustbeanaturalnumbertype(natnat2ornat4).

Seealso

explicitIntegerConstant(fordescriptionofconstantssuchas16#FFFF)andthefollowingfunctionsthatconvertonetypetoanotherinamachine-independentmanner:ord,chr,intstr,strint,natstr,andstrnat.Seealsoandshl(shiftrightandleft).

body declaration

Syntax

AbodyDeclarationisoneof:

(a) bodyprocedureprocedureId statementsAndDeclarations endprocedureId (b) bodyfunctionfunctionId statementsAndDeclarations endfunctionId (c) bodyprocedureid[(paramDeclaration {,paramDeclaration})] statementsAndDeclarations endid (d) bodyfunctionid[([paramDeclaration{, paramDeclaration}])]:typeSpec statementsAndDeclarations endid

Description

Abodydeclarationisusedtoresolveeitheraforwardsubprogramoradeferredsubprogram.

Youdeclareaprocedureorfunctionforwardwhenyouwanttodefineitsheaderbutnotitsbody.Thisisthecasewhenoneprocedureorfunctioncallsanother,whichinturncallsthefirst.Thissituationiscalledmutualrecursion.Theuseofforwardisnecessaryinthiscasebecauseeveryitemmustbedeclaredbeforeitcanbeused.Theforwarddeclarationmustbefollowedbyabodydeclarationforthesameprocedureorfunction.Fordetails,seeforwarddeclarations.

Whenaprocedureorfunctioninaclassisdeclaredtobedeferred(orsimplyexportedfromtheclass),itcanberesolved

oroverriddenafterwardbygivingitsbodyfurtherdowninthatclassorindescendantclasses.Theoverridingproceduremustusethekeywordbody.Seeclassor"implementby"forexamples.

Details

Youcanspecifytheparameterandreturnvaluesofthesubprograminthebodydeclaration.However,thenamesandtypesoftheparametersandreturnvaluesmustmatchtheinitialdeclarationexactly,orawarningresultsandtheparameterlistandreturnvaluesfromthebodydeclarationareignored.

Example

TheexamplegivenhereispartofacompleteTuringprogramthatincludesanexplanationofforwarddeclarations.

vartoken:string

forwardprocedureexpn(vareValue:real)

importforwardterm,vartoken

…otherdeclarationsappearhere…

bodyprocedureexpn

varnextValue:real

term(eValue)%Evaluatet

loop%Evaluate{+t}

exitwhentokennot="+"

gettoken

term(nextValue)

eValue:=eValue+nextValue

endloop

endexpn

Execute

ThesyntaxofabodyDeclarationpresentedabovehasbeensimplifiedbyomittingtheoptionalresultidentifier,importlist,preandpostconditionandinitclause.Seeprocedureandfunctiondeclarationsfordescriptionsoftheseomissions.

The"function"or"procedure"tokeninthedeclarationisnow

Details optional.Inotherwordsthefollowingcodefragmentislegal

forwardprocedurep

Seealso class,forwardandimplementby

boolean true-falsetype

Syntax boolean

Description

Thebooleantypeisusedforvaluesthatareeithertrueorfalse.Thesetrue-falsevaluescanbecombinedbyvariousoperatorssuchasorandand.

Example

varsuccess:boolean:=false

varcontinuing:=true%Thetypeisboolean

success:=mark>=60

continuing:=successandcontinuing

ifcontinuingthen…

Details

ThistypeisnamedaftertheBritishmathematician,GeorgeBoole,whoformulatedlawsoflogic.

Theoperatorsfortrueandfalseareand,or,xor,=>,andnot.Fortwotrue/falsevaluesAandB,theseoperatorsaredefinedasfollows:

AandBistruewhenbotharetrue AorBistruewheneitherorbotharetrue AxorBistruewheneitherbutnotbotharetrue

A=>B(AimpliesB)istruewhenbotharetrueorwhenAisfalse

notAistruewhenAisfalse

Theandoperatorhashigherprecedencethanor,soAorBandCmeansAor(BandC).

Theoperatorsor,andand=>areshortcircuitoperators.Forexample,ifAistrueinAorB,Bisnotevaluated.

Details Thebooleantypecanbeusedasanindextoanarray.

Declarationofanarraywithbooleanindex.

Examplevara:arraybooleanofint

a(false):=10

a(true):=20

Details

Theputandgetsemanticsallowput'sandget'sofbooleanvalues.truevalueswillbeoutputas"true"andfalsevalueswillbeoutputas"false".Theonlylegalinputvaluesare"true"and"false",whicharecasesensitive.

SeealsoexplicitTrueFalseConstant(whichdiscussesthevaluestrueandfalse),precedenceandexpn(expression).

break debuggerpausestatement

Syntax break

Description

Onsystemswithadebugger,theenvironment"pauses"whenexecutionreachesthebreakstatement.While"pausing"isenvironmentspecific,ingeneral,theprogramstopsexecutionuntiltheuserpressesthe"Resume"or"Continue"button.Whilepaused,theprogramvariablescanbeinspected,stacktracesdone,etc.

Examplefori:1..100

endfor

buttonchoose switchmousemodes

Syntax buttonchoose(choice:string)

Description

Thebuttonchooseprocedureisusedtochangethemodeofthemouse.InTuring,themousecaneitherbein"single-buttonmode"orin"multi-buttonmode".In"single-buttonmode"themouseistreatedasaonebuttonmouse.Abuttonisconsideredpressedwhenanybuttonispressedandreleasedonlywhenallbuttonshavebeenreleased.

InTuring,themousestartsin"single-buttonmode".

Theparameterchoicecanbeoneof"singlebutton","onebutton"(whichswitchthemouseinto"single-buttonmode")or"multibutton"(whichswitchesthemouseinto"multi-buttonmode").

Example

Aprogramthatdisplaysthestatusofthemouseatthetopleftcornerofthescreen.

buttonchoose("multibutton")

varx,y,button,left,middle,right:int

mousewhere(x,y,button)

left:=buttonmod10%left=0or1

middle:=(button-left)mod100%middle=0or10

right:=button-middle-left%right=0or100

ifleft=1then

put"leftbuttondown"

ifmiddle=10then

put"middlebuttondown"

ifright=100then

put"rightbuttondown"

Execute

Seealso

buttonmovedandbuttonwaittogetmouseeventssavedinaqueue.Seealsomousewheretogetthecurrentstatusofmousebutton(s).

SeealsopredefinedunitMouse.

buttonmoved hasamouseeventoccurred

Syntax buttonmoved(motion:string):boolean

Description

Thebuttonmovedfunctionindicateswhetherthereisamouseeventoftheappropriatetypeonthemousequeue.Eventsareeither"up","down","updown"or"downup"events(althoughthe"downup"and"updown"arethesameevent).

Theparametermotionmustbeoneof"up","down","updown"or"downup".Ifaneventofthetyperequestedisinthequeue,buttonmovedreturnstrue.Iftheeventisnotinthequeue,thenbuttonmovedreturnsfalse.

In"single-buttonmode"(wherethemouseistreatedlikeaone-buttonmouse),a"down"eventoccurswheneverallthebuttonsareupandabuttonispressed.An"up"eventtakesplacewhenthelastbuttonisreleasedsothatnobuttonsremainpressed.

In"multi-buttonmode",a"down"eventoccurswheneveranybuttonispressed,andan"up"eventoccurswheneveranybuttonisreleased.

Example

Thisprogramdrawsrandomcirclesonthescreenuntiltheuserclicksthemousebutton,whereuponisstartsdrawingrandomboxes.Clickingthemousebuttonswitchesbetweenthetwo.

varcircles:boolean:=true

varx,y,radius,clr:int

ifbuttonmoved("down")then

varbuttonnumber,buttonupdown:int

buttonwait("down",x,y,buttonnumber,

circles:=notcircles

randint(x,0,maxx)

randint(y,0,maxy)

randint(radius,0,100)

randint(clr,0,maxcolor)

ifcirclesthen

drawfilloval(x,y,radius,radius,clr)

drawfillbox(x,y,x+radius,y+radius

endloop

Execute

Example

Thisisanexampledemonstratinghowtocheckforbothcharacterandmouseinputatthesametime.

varch:string(1)

varx,y,btnnum,btnupdown:int

ifhaschthen

getch(ch)

locate(1,1)

put"Thecharacterenteredisa:",ch

buttonwait("down",x,y,btnnum,btnupdown

locate(1,1)

put"Thebuttonwasclickedatposition:",

endloop

Execute

Details

buttonmovedcanbethoughtofasthemouseequivalentofhaschinthattheybothcheckforsomethinginaqueueandbothreturnimmediately.

Seealso

buttonwaittogetmouseeventssavedinthequeue.Seealsobuttonchoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

buttonwait getamouseeventprocedure

Syntaxbuttonwait(motion:string, varx,y,buttonnumber,buttonupdown:int)

Description

Thebuttonwaitproceduregetsinformationaboutamouseeventandremovesitfromthequeue.

Theparametermotionmustbeoneof"up","down","updown"or"downup".Ifaneventofthetyperequestedisinthequeue,buttonwaitreturnsinstantly.Ifthereisn'tsuchanevent,buttonwaitwaitsuntilthereisoneandthenreturns(muchlikegetchhandleskeystrokes).

Theparametersxandyaresettothepositionofthemousecursorwhenthebuttonwaspressed.Theparameterbuttonnumberissetto1whenin"single-buttonmode".In"multi-buttonmode",itissetto1iftheleftbuttonwaspressed,2ifthemiddlebuttonwaspressed,and3iftherightbuttonwaspressed.Theparameterbuttonupdownissetto1,ifabuttonwaspressedand0ifabuttonwasreleased.

Example

Thisprogramdrawslines.Itstartsalinewheretheuserpressesdownandcontinuestoupdatethelinewhilethemousebuttonishelddown.Whenthebuttonisreleased,thelineispermanentlydrawandtheusercandrawanotherline.

varx,y,buttonnumber,buttonupdown,buttons:

varnx,ny:int

buttonwait("down",x,y,buttonnumber,buttonupdown

drawline(x,y,nx,ny,0)%Erasepreviousline

exitwhenbuttonmoved("up")

mousewhere(nx,ny,buttons)

drawline(x,y,nx,ny,1)%Drawlinetoposition

endloop

buttonwait("up",nx,ny,buttonnumber,buttonupdown

drawline(x,y,nx,ny,2)%Drawlinetofinalposition

endloop

Execute

Example

Inthepreviousexample,whenthemousemoves,thelineiserasedbydrawingitinwhite.Thiserasesanythingthatthelinewasdrawnontopof,includingpreviouslines.Amorecompleteexampleinvolvingtheclickinganddraggingoffilledrectanglesusingthemouseisavailable.Inthisexample,thebackgroundisfullyrestoredwhentherectangleismovedbyusing"xor".

Example

varch:string(1)

ifhaschthen

getch(ch)

locate(1,1)

buttonwait("down",x,y,btnnum,btnupdown

locate(1,1)

endloop

Execute

Details

buttonwaitcanbethoughtofasthemouseequivalentofgetchinthattheybothreadsomethinginaqueueandbothwaituntiltheygetthethingthey'relookingfor.

Seealso

buttonwaittoseeifanappropriateeventisinthequeue.Seealsobuttonchoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

case selectionstatement

Syntax

AcaseStatementis:

caseexpnof

{labelcompileTimeExpn{,compileTimeExpn}:

statementsAndDeclarations} [label: statementsAndDeclarations] endcase

Description

Acasestatementisusedtochooseamongasetofstatements(anddeclarations).Onesetischosenandexecutedandthenexecutioncontinuesjustbeyondendcase.

Theexpression(expn)followingthekeywordcaseisevaluatedandusedtoselectoneofthealternatives(setsofdeclarationsandstatements)forexecution.Theselectedalternativeistheonehavingalabelvalueequalingthecaseexpression.Ifnoneareequalandthereisafinallabelwithnoexpression,thatalternativeisselected.

Example

Outputamessagebasedonvalueofmark.

casemarkof

label9,10:put"Excellent"

label7,8:put"Good"

label6:put"Fair"

label:put"Poor"

endcase

Execute

Example

Outputamessagebasedonvalueofname.

casenameof

label"horse","cow":put"Farmanimal"

label"tiger","lion":put"Jungleanimal"

label"cat","dog":put"Pet"

label:put"Unknownanimal"

endcase

Execute

Details

Thecaseexpressionisrequiredtomatchoneofthelabels.Ifitdoesnot,theremustbeafinallabelwithnoexpression.Labelexpressionsmusthavevaluesknownatcompiletime.Alllabelvaluesmustbedistinct.Thecaseexpressionandthelabelvaluesmusthavethesameequivalenttype,whichmustbeaninteger,char,boolean,anenumtypeorstrings.

Notethatthereisnowaytoexpressarangeofvalues(forexamplefrom5to10)inalabel.Eachindividualvaluemustbeexpressedinthelabel.

catenation(+) joiningtogetherstrings

Syntax

Acatenationis:

stringExpn+stringExpn

DescriptionTwostrings(stringExpns),charorchar(n)valuescanbejoinedtogether(catenated)usingthe+operator.

Example

varlastName,wholeName:string

lastName:="Austere"

wholeName:="Nancy"+""+lastName

%ThethreestringsNancy,ablankandAustere

%catenatedtogethertomakethestring

%"NancyAustere".Thisstringbecomesthe

%valueofwholeName

Details

Thelengthofastringcatenationislimitedto255characters.

Catenationissometimescalledconcatenation.

Catenationcanalsobeappliedtocharandchar(n)values.Seecharandchar(n).Ifeitheroperand,sortins+t,isastringoradynamicchar(n)(lengthnotknownatcompiletime),theresulttypeisstring.Otherwise(whenbothsandtarecharornon-dynamicchar(n))theresulttypeischar(n).

Theresultofcatenationisconsideredtobeacompiletimevalueifbothoperandsarecompiletimevalues.

Ifbothoperandshavethetypecharorchar(n)neitherofwhichisadynamicchar(n),theresultisoftypechar(n),whichisalsoofanondynamictype.Thisallowsthecreationofverylongchar(n)valuesthatcaneffectivelyspanlineboundariesusingcatenationtojoinlines.Ifeitheroperandisadynamictypeorastringtype,thecatenationproducesastring,whoselengthislimitedto255characters.

substrings(forseparatingastringsintoparts),repeat(formaking

Seealso

repeatedcatenations),stringtype,length,andindex(todeterminewhereonestringislocatedinsideanother).

Seealsostring,char,char(n),explicitStringConstant,explicitCharConstant,substringandlength.

ceil real-to-integerfunction

Syntax ceil(r:real):int

Description Returnsthesmallestintegergreaterthanorequaltor.

Details

Theceil(ceiling)functionisusedtoconvertarealnumbertoaninteger.Theresultisthesmallestintegerthatisgreaterthanorequaltor.Inotherwords,theceilfunctionroundsuptothenearestinteger.Forexample,ceil(3)is3,ceil(2.25)is3andceil(-8.43)is-8.

Seealso Seealsothefloorandroundfunctions.

char(n) type

Syntax char(numberOfCharacters)

DescriptionEachvariablewhosetypeisachar(n)containsexactlyncharacters.

Example

Canadianpostalcodescontainsixcharacters,forexample,M4V1Y9.Thisisrepresentedinachar(6)variable:

varpostalCode:char(6):='M4V1Y9'

Explicitconstantsforthechar(n)typeusesinglequotesasin'M4V1Y9',asopposedtoexplicitstringconstantswhichusedoublequotes,asin"Nancy".Asinglecharactersinglequotedcharacter,suchas'A',isconsideredtohavethetypecharinsteadofchar(n),butsincethesetwotypescanbeassignedtoeachotherandcomparedtoeachother,thisfacthaslittleconsequence.

Thetypechar(n)isgenerallymoredifficulttousethanthestringtype,whichisfavoredformostsimpleprograms.Thetypechar(n)hastheadvantagethatitisefficientintermsofbothspaceandtime.Inparticular,itisrepresentedasnbytesinthecomputer'smemory.Bycontrast,thestringtypemustuseextraspace(atrailingzerobyteincurrentimplementations)torepresentthecurrentlengthandallocatesspaceforthemaximumvalueitcanhold.

TheformofnumberOfCharactersisoneof:

(a)expn %Integervalue (b)* %Onlyinsubprogramparameters

Thefirstformdeterminesn.Iftheexpressionisaruntimevalue,thetypeisconsideredtobedynamicchar(n).Thevalueofnmustbeatleast1.Thesecondformisusedonlyforsubprogramparametersandusesthelengthoftheactualparameter.Thistoo,isconsideredtobeadynamicchar(n)type.Dynamicchar(n)

Details

typescanonlybepassedtochar(*)parameters.Dynamicchar(n)typeshavethesamerestrictionsasdynamicarrays.Thisimpliestheycannotbeassignedasawholeandcannotappearinrecordanduniontypes.

Animplementationmayimposealimit,recommendedtobeatleast32767,onthelengthn.

Valuesofthechar(n)typecanbeassignedandtheycanbecomparedforbothequalityandforordering,butonlyiftheyhavethesamelengthandtheyarenotdynamic(i.e.thelengthmustbeknownatcompiletime).

Valuesofthechar(n)typecanbereadandwrittenbygetandputstatements.

Thechar(n)typeisanonscalar,whichimpliesthatitsparametersarealwayspassedbyreference(bymeansofanimplicitpointer).

Asistrueforthechartype,all256possiblevaluesofan8-bitbyteareallowedforeachcharacterinchar(n)type.Thereisnopatternlefttobeusedforthe"initializedvalue",sothereisnouninitializedcheckingforchar(n).

Ingeneral,youcanfreelyintermixthevaluesofthetypeschar,char(n)andstring.Thismeansthatcatenation(+),comparisons,lengthandsubstringscanbeappliedtoanyofthesetypes.Seecatenationandsubstring.Iftwonondynamicchar(n)values(orcharvalues)arecatenated,theresultisachar(n)value.Ifeitheraredynamic,itisastringvalue.Thisimpliesthatverylongchar(n)valuescanbecreatedbycatenatingthemtogether,forexampletoinitializeachar(n)variable.

Acharvaluecanbeassigned(orpassedtoannonvarparameter)withautomaticconversiontoachar(1)variableandviceversa.Stringvaluesoflength1canbeassignedtocharvariables.Character(char)valuescanbeassignedtostringvariables,yieldingastringoflength1.Stringvaluesoflengthnareassignablewithautomaticconversiontochar(n)variables.Valuesoftypechar(n)canbeassignedwithautomaticconversionto

stringvariables.

Whencomparingtwochar(n)values,asins>t,ifbotharenon-dynamicandofthesamelength,theyarecomparedwithoutconvertingtostrings.Ifeitheraredynamic,theyareconvertedtostringsandthencompared.

Seealsothechartypewhichismuchlikechar(1).Seealsothestringtype.

char type

Syntax char

DescriptionEachvariablewhosetypeisacharcontainsasinglecharacter,suchastheletterA,thedigit3orthespecialcharacter&.

Example

Countcharactersuntilaperiodisfound.Charactercisreadusingastatementandiscomparedtotheexplicitcharacterconstant'.'.

varc:char

varcounter:=0

exitwheneof

getc%Readasinglecharacter

exitwhenc='.'%Singlequotesforcharconstant

counter:=counter+1

endloop

putcounter,"charactersbeforetheperiod"

Execute

Example

Countcapitalletters.Thisexampleillustratestheuseofthechartypeasthesubscripttypeforthefrequencyarray,theuseofcharactervariablecasasubscript,andtheuseofdasaforcounterthatrangesacrossthelettersAtoZ.

varfrequency:array'A'..'Z'ofnat

ford:'A'..'Z'

frequency(d):=0

endfor

loop%Tabulateuseofcapitalletters

exitwheneof

varc:char

getc%Readonecharacter

ifc>='A'andc<='Z'then

frequency(c):=frequency(c)+1

endloop

ford:'A'..'Z'%Printfrequencyofcapitalletters

putd,"",frequency(d)

endfor

Execute

Details

Thetypestring(orchar(n))isusedinsteadofcharwhenmorethanonecharacterneedstobestored,suchasthestringofcharactersHenryUnlesstheprogramneedstobequiteefficient,itisusuallyeasiertousethestringtype.Seealsothechar(n)type,whichalwaysstoresexactlyncharacters.

Thechartypediffersfromthestring(1)typeinthefollowingway:charalwaysrepresentsexactlyonecharacter,whilestring(1)canrepresenteitherthenullstringorastringcontainingonecharacter.Thechartypeissimilartothechar(1)typeinthatbothcontainatmostonecharacter.

Thechartypeisanindextypeandcanbeused,forexample,assubscripts,forrangesandcaselabels.Forexample,thisdeclaration

varcharCounts:arraycharofint

createsanarraywhosesubscriptsarecharacters.

Thechartypeisascalartype,whichimpliesthatitsparametersarepassedbyvalue,insteadofbyreference(whichisthecaseforcharandstring).

Valuesofthechartypecanbeassignedandtheycanbecomparedforbothequalityandordering.Explicitcharconstantsarewrittenasacharactersurroundedbysinglequotes,forexample,'A'.Fordetails,

includinghowtowritecontrolcharacters,seeexplicitCharConstant

Characterscanbereadandwrittenbygetandputstatements.

Thereare256charvalues,correspondingtothedistinctpatternsinan8-bitbyte.Thisallowsthepatternseos(internalvalue0)anduninitchar(internalvalue128)tobecharvalues(thesepatternsarenotallowedinthestringtype;seethestringtype).All256patternsareused,sothereisnopatternlefttobethe"uninitializedvalue".Uninitializedcheckingisnotdoneforthechartype.

Theordandchrfunctionsconvertbetweenthecharvaluesandtheircorrespondingnumericrepresentationinabyte.Seeordandchr.

Ingeneral,youcanfreelyintermixthevaluesofthetypeschar,char(n)andstring.Thismeansthatcatenation(+),comparisons,lengthandsubstringscanbeappliedtoanyofthesetypes.Seecharfordetailsaboutconversionsbetweenchar,char(n)andstring.

Seealso

stringandchar(n)forrelatedtypes.SeeordandchrfunctionsforconversionfromandtoASCIIvalues.SeeexplicitCharConstantforinformationonspecialcharacterslikecaret(^)andbackslash(\).

cheat typecheating

Dangerous

Syntax

AtypeCheatisoneof:

(a) cheat(targetType,expn[:sizeSpec]) (b) #expn (c) id:cheattypeSpec

Description

Atypecheatinterpretstherepresentation(bits)ofonetypeasanothertype.Typecheatsaredirty(machine-dependent)andsometimesdangerous(arbitrarycorruption)andshouldbeusedonlybyprogrammerswhoknowtheunderlyingcomputerrepresentationofvalues.

Form(b)isashortformtypecheatinwhichthetargettypeisanaturalnumber.

Form(c)isusedasaparameterinasubprogramdeclaration.ItcauseswhateverispassedintotheparametertobeinterpretedastypeSpec

Example

Thecharacter'B'isassignedtovariablei,whosetypeisconsideredtobechar(althoughitisreallyint1).

vari:int1%Onebyteinteger

cheat(char,i):='B'

Thisassignmentisequivalent(onbyteorientedcomputers)toeitherofthefollowing:

i:=cheat(int1,'B')

i:=ord('B')

TheformoftargetTypemustbeoneof:

(a) [id.]typeId (b) int,int1,int2orint4

Details

(c) nat,nat1,nat2ornat4 (d) boolean (e) char[(numberOfCharacters)] (f) string[(maximumLength)] (g) addressint

Inform(a)thebeginningidentifieridmustbethenameofamodule,monitororclassthatexportsthetypeId.EachofnumberOfCharactersandmaximumLengthmustbecompiletimeintegerexpressions.

IftheexpninatypecheatisavariablereferenceandthesizeSpecisomitted,thetypecheatisconsideredtobeavariablewhosetypeistargetType.Thisallows,forexample,thetypecheattobeassignedto,asin:

cheat(char,i):='B'

Iftheexpnisavaluethatisnotavariablereference,orifsizeSpecispresent,thetypecheatisanexpressionvaluewhosetypeistargetType

ThesizeSpecisacompiletimeintegerexpressiongivingthesizeoftheexpn'svalue.Itcanbespecifiedonlyforintegerornaturalnumbervalues(whereitmustbe1,2or4)orrealvalues(whereitmustbe4or8).

Atypecheatiscarriedoutintwosteps.ThefirststepconvertsthevalueifnecessarytothesizegivenbysizeSpec.Thesecondstep,whichinvolvesnogeneratedcode,interpretsthevalueasthetargettype.

Theprefixoperator#isashortformforaclassoftypecheats.Itinterpretsitsargumentasanaturalnumber.Ingeneral,#expnisthesameascheat(natn,expn)wherenisdeterminedasfollows.Iftheexpnisavariableorexpressionofsize1,2or4,nisthesizeoftheitem,otherwisenis4.

Example

Setthesecondcharacterofdsoithasthenumericrepresentation24.Ingeneral,ifcisacharacter,then#c=ord(c).Notethat#ccanhaveanumbervalueassignedtoit,butord(c)cannot.

vard:char(3)

#d(2):=24%Sameasd(2):=chr(24)

Example

Thenotation16#FFFFmeansFFFFinbase16,whichis32767inbase10andis161'sinarowinbase2.Thissamepatternisthetwo'scomplementrepresentationofthevalue-1ina2-byteinteger.

vari:int2

#i:=16#FFFF%Equivalenttoi:=-1

Example

ThefollowingexampleprintsoutastringlocatedataddressintmyAddr

procedurePrintString(str:cheatstring)

putstr

endPrintString

varmyAddr:addressint

...%AssignedavaluetomyAddr

PrintString(myAddr)%myAddrwillbetreatedasastring

Details

Animplementationmayprohibitcertaintypecheats.Memoryalignmentrequirementsmayrendersometypecheatsunfeasible.ItisdangeroustoconsideravaluetohaveatargetTypelargerthanthevalue'stype.Animplementationmayprohibitcertaintypecheatsonregisterscalaritems.

Seealso

explicitIntegerConstant(fordescriptionofconstantssuchas16#FFFF)andthefollowingfunctionsthatconvertonetypetoanotherinamachine-independentmanner:ord,chr,intstr,strint,natstr,andstrnat.

checked compilerdirective

Description

Uncheckedmeansthatcertainruntimetests,whichtakeplacebydefault,canbeeliminated,usuallytomaketheprogrammoreefficientattheriskofunreliability.Thekeywordchecked,usedasastatement,requeststhatthedisablingofchecking,previouslyrequestedbythekeywordunchecked,bere-enabled.Seeuncheckedfordetailsandanexample.

chr integer-to-characterfunction

Syntax chr(i:int):char

Description

Thechrfunctionisusedtoconvertanintegertoacharacter.Thecharacteristhei-thcharacteroftheASCIIsequenceofcharacters(exceptontheIBMmainframe,whichusestheEBCDICsequence.)Forexample,chr(65)is"A".

Theordfunctionistheinverseofchr,soforanycharacterc,:

chr(ord(c))=c.

Execute

Details

Therearetwosetsofcharactersrepresentingvalues128-255:theANSIvalues(thedefaultvaluesforWindows),andtheMS-DOSOEMcharacterset,whichcontainsvariouslinedrawingcharacters.TousetheMS-DOScharacterset,youmustusethesetscreen("msdos")command.

Example

Anotherexampleisavailablethatdisplaystheentirecharactersset,boththeregularANSIcharactersetandtheMS_DOSOEMcharacterset.

Seealso ord,intstrandstrintfunctions.

class declaration

Pointerpisusedtolocateindividualobjectsoftheclass.Thenewstatementcreatesoneoftheseobjects.Thestatement

p->push("Harvey")

isashortformfor:

stackClass(p).push("Harvey")

ThisinsertsthestringHarveyintothestackobjectlocatedbyp.

Syntax

AclassDeclarationis:

[monitor] classid [inheritinheritItem] [implementimplementItem] [implementbyimplementByItem] [import[var]importItem{,[var]importItem [export[howExport]id{,[howExport]id}] statementsAndDeclarations endid

Description

Aclassdeclarationdefinesatemplateforapackageofvariables,constants,types,subprograms,etc.Thenameoftheclass(id)isgivenintwoplaces,justafterjustafterend.Itemsdeclaredinsidetheclasscanbeaccessedoutsideoftheclassonlyiftheyareexported.Itemsfromoutsidetheclassthataretobeusedintheclass,needtobeimported(unlesstheyarepredefinedorpervasive).Instances(objects)ofaclassarecreatedusingthenewstatement.Eachobjectisessentiallyamodulelocatedbyapointer.

Thisclassisatemplateforcreatingobjects,eachofwhichisastackofstrings.(Seethemoduledescriptionforthecorrespondingmodulethatimplementsasinglestackofstrings.)

Example

classstackClass%Templateforcreatingindividualstacks

exportpush,pop

vartop:int:=0

varcontents:array1..100ofstring

procedurepush(s:string)

top:=top+1

contents(top):=s

endpush

procedurepop(vars:string)

s:=contents(top)

top:=top-1

endpop

endstackClass

varp:pointertostackClass%Shortform:var

newstackClass,p%Shortform:newp

p->push("Harvey")

varname:string

p->pop(name)%ThissetsnametobeHarvey

Execute

Thenewstatementisusedtocreateobjectsofaclass.Manyinstancesofaclasscanexistatagiventime,eachlocatedbyapointer.Thefreestatementisusedtodestroyobjectsthatarenolongerofuse.Turingdoesnotsupportgarbagecollection(automaticrecoveryofspacebelongingtoinaccessibleobjects).

Seemodulesforadiscussionofimporting,exportingandrelatedconcepts.Whenanobjectiscreatedbynew,itsinitializationcodeisexecuted.Inthisexample,theobject'stopvariableissetto0.Asistrueinmodules,anexportedsubprogramofanobject'sclasscannotbecalleduntiltheobjectiscompletelyinitialized.

Youarenotallowedtocreatevariablesofaclass,asin:

vars:stack%Notlegal!

Details

Ifthemonitorkeywordispresent(justbeforeclass),theobjectsaremonitors.Thismeansthatonlyoneprocessatatimecanbeactiveintheobject.Seeprocess.

Inheritlistsareusedtospecifyinheritance.Seeinheritlist.Implementandimplement-bylistsprovideaspecialkindofexpansionwhichsupportstheseparationofaninterfacefromitsimplementation.Seeimplementlistandimplement-bycannotcontainbothaninheritandanimplementlist.

Classdeclarationscanbenestedinsidemodulesandmonitorsbutcannotbenestedinsideotherclassesorinsideproceduresorfunctions.Aclassmustnotcontainaasoneofits(outermost)declarations.Areturnstatementcannotbeusedasoneofthe(outermost)statementsinaclass.

Aclasscannotexportvariables(orruntimeconstants)asunqualifiedobjecthasadistinctsetofvariables).

ThesyntaxofaclassDeclarationpresentedabovehasbeensimplifiedbyleavingoutpre,invariantandpostclauses.Thefullsyntaxwhichsupportsprepostisthesameasthatformodules.Theinitializationofclassesisthesameasthatformodules.Seemodule.

Wewillgiveanexampleinwhichasubprograminoneclassoverridesthecorrespondingsubprograminaclassthatisbeinginherited.Theexampleisbasedonaprogramthatimplementsafilesysteminsideanoperatingsystem.Allfileshaveclose,readandwriteoperations.Somefiles,calledDevicefiles,alsohaveanoperationcalledioCtl(input/outputcontrol).Thekindoffiledeterminestheimplementationmethod.Hereistheexpansion(inheritance)hierarchyamongtheclassesoffiles.

TheclasscalledFilegivestheinterfacetoallpossiblekindsoffiles.Theimplementsfilesthataretext(ASCIIcharacters).TheDeviceclassgivestheinterface

Example

toallfilesthathavetheioCtloperationinadditiontoopen,close,readTapeandDiskclassesimplementfilesthatareactuallyphysicaltapesordisks.HereisthedeclarationoftheFileclass:

classFile

exportopen,close,read,write

deferredprocedureopen(…parametersforopen…)

deferredprocedureclose(…parametersforclose…)

deferredprocedureread(…parametersforread…)

deferredprocedurewrite(…parametersforwrite…)

endFile

TheTextFileclassimplementstheFileinterfacebygivingvariablesdeclarationsandprocedurebodiesforASCIIfiles:

classTextFile

inheritFile

varinternalTextFileData:

…internaldatafortextfiles…

bodyprocedureopen

…bodyforopenfortextfiles…

endopen

…bodiesforclose,readandwriteproceduresfortextfiles…

endTextFile

Objectstorepresentindividualtextfilesarecreatedusingthenewstatement:

vartextFilePtr:^TextFile

%Pointerwilllocateatextfileobject

newtextFilePtr%Createatextfileobject

textFilePtr->read(…actualparameters…)%Readtextfile

TheDeviceclassaddstheioCtlproceduretotheFileinterface.

classDevice

inheritFile

exportioCtl

deferredprocedureioCtl(…parametersforioCtl

endDevice

TheDiskclassprovidesdataandprocedurestoimplementafilethatisactuallyadisk(theTapeclassisanalogous):

classDisk

inheritDevice

varinternalDiskFileData:…internaldatafordiskfiles

bodyprocedureopen

…bodyforopen…

endopen

…bodiesforclose,read,writeandioCtlproceduresfordisk…

endDisk

ApointerthatcanlocateanykindofFileobjectisdeclaredthisway:

varfilePtr:^File

Thismaylocate,forexample,aTextFile:

filePtr:=textFilePtr

ThisassignmentisallowedbecausefilePtr'scorrespondingclass(FileoftextFilePtr'scorrespondingclass(TextFile).ItisguaranteedthattheobjectnowlocatedbyfilePtrsupportsaversionofalltheoperationsofaFile(andwrite).

WhenwecallaprocedureintheobjectlocatedbyfilePtr,theactualprocedurecalledwilldependupontheobject:

filePtr->read(…actualparameters…)

Forexample,iffilePtrcurrentlylocatesaDiskfile,thiswillcallthefromtheDiskclass.ThisisanexampleofdynamicbindinginwhichreadtobeusedisselectedatruntimeandthischoiceisbasedontheobjectlocatedbyfilePtr.Thisiscalledpolymorphism,becauseFileobjectscanhavemorethanoneform.

Asanotherexample,considerclassC,whichcontainsheadersandbodiesforfunctionsfandg.Cexportsfunctionsfandg.ThereisalsoaclassD,whichinheritsfromClassDcontainsabodythatoverridesthebodyforg.Dalsocontainsaheaderandbodyforfunctionh.Dexportsfunctionh.

PointerphasbeendeclaredtolocateanobjectofclassC,butatruntimeobjectofclassD.Whenpisusedtocallf,bymeansofp->f,thebodyofappearsinC,isinvoked.Whenpisusedtocallg,bymeansofp->bodyinDisinvoked.Anyattempttouseptocallhisillegalbecause

Example

usedtocallfunctionsthatareexportedfromC.

classC

exportf,g

proceduref

put"C'sf"

procedureg

put"C'sg"

classD

inheritC%Inheritfandg

bodyprocedureg%OverridesginC

put"***D'sg***"

procedureh

put"***D'sh***"

varp:pointertoC%pcanpointtoanydescendantofC

newD,p%plocatesanobjectofclassD

p->f%Outputs"C'sf"

p->g%Outputs"***D'sg***"

p->h%Causeserror"'h'isnotinexportlistof'C'"

Execute

Seealso

module,monitorandunit.Seealsoimportlist,exportlist,implementimplementbylist,andinheritlist.Seealsodeferredsubprogram.Seealsoandobjectclass.

clock millisecsusedprocedure

Syntax clock(varc:int)

Description

Theclockstatementisusedtodeterminetheamountoftimesinceaprogram(process)startedrunning.Variablecisassignedthenumberofmillisecondssincetheprogramstartedrunning.

Example

Thisprogramtellsyouhowmuchtimeithasused.

vartimeRunning:int

clock(timeRunning)

put"Thisprogramhasrun",timeRunning,"milliseconds"

Execute

DetailsOnAppleMacintoshes,thehardwareresolutionofdurationisinunitsof17milliseconds(1/60-thofasecond).

Seealsodelay,time,sysclock,wallclockanddatestatements.

SeealsopredefinedunitTime.

close filestatement

Syntax

AcloseStatementis:

close:fileNumber

Description

InTuring,filesarereadandwrittenusingafileNumber.Inmostcases,thisnumberisgivenavalueusingtheopenstatement,whichtranslatesafilename,suchas"Master",toafilenumber,suchas5.Whentheprogramisfinishedusingthefile,itdisconnectsfromthefileusingtheclosestatement.

Example

Thisprogramillustrateshowtoopen,readandthencloseafile.

varfileName:string:="Master"%Nameoffile

varfileNo:int%Numberoffile

varinputVariable:string(100)

open:fileNo,fileName,read

read:fileNo,inputVariable

close:fileNo

Details

InaTuringimplementation,therewillgenerallybealimitonthenumberofcurrentlyopenfiles.Thislimitwilltypicallybearound20.Toavoidexceedingthislimit,aprogramthatusesmanyfilesoneafteranothershouldclosefilesthatarenolongerinuse.

Ifaprogramdoesnotcloseafile,thefilewillbeautomaticallyclosedwhentheprogramfinishes.

Thereisanolderandstillacceptableversionofclosethathasthissyntax:

close(fileNumber:int)

Seealso theopen,get,put,read,write,seekandtellstatements.

cls clearscreengraphicsprocedure

Syntax cls

DescriptionThecls(clearscreen)procedureisusedtoblanktheoutputwindow.Thecursorissettothetopleft(torow1,column1).

Details

Theentireoutputwindowissettothecurrenttextbackgroundcolor(assetbycolorbackorText.ColorBack).

Theoutputwindowmustbein"graphics"mode.Seesetscreenfordetails.

Seealso SeealsopredefinedunitText.

collection declaration

Syntax

AcollectionDeclarationisoneof:

(a) varid{,id}:collectionoftypeSpec (b) varid{,id}:collectionofforwardtypeId

Description

Acollectiondeclarationcreatesanewcollection(orcollections).Acollectioncanbethoughtofasanarraywhoseelementsaredynamicallycreated(bynew)anddeleted(byfree).Elementsofacollectionarereferredtobythecollection'snamesubscriptedbyapointer.Seealsonew,freeandpointer.

Example

Createacollectionthatwillrepresentabinarytree.

vartree:collectionof

record

name:string(10)

left,right:pointertotree

endrecord

varroot:pointertotree

newtree,root

tree(root).name:="Adam"

Thestatement"newC,p"createsanewelementincollectionCandsetsptopointati.Ifthereisnomorememoryspacefortheelement,though,pissettonil(C),whichisthenullpointerforcollectionC.Thestatement"freeC,p"deletestheelementofCpointedtobypandsetsptonil(C).Ineachcase,pispassedasavarparameterandmustbeavariableofthepointertypeofC.

Thekeywordforward(formbabove)isusedtospecifythatthetypeIdofthecollectionelementswillbegivenlaterinthecollection'sscope.Thelaterdeclarationmustappearatthesamelevel(inthesamelistofdeclarationsandstatements)astheoriginaldeclaration.Thisallowscycliccollections,forexample,whenacollectioncontainspointerstoanothercollection,whichinturncontainspointerstothefirstcollection.Inthiscase,the

Details

typeIdisthenameofthetypethathasnotyetbeendeclared;typeIdcannotbeuseduntilitsdeclarationappears.Acollectionwhoseelementtypeisforwardcanbeusedonlytodeclarepointerstoituntilthetype'sdeclarationisgiven.

Supposepointerqisequaltopointerpandtheelementtheypointtoisdeletedby"freeC,p".Wesayqisadanglingpointerbecauseitseemstolocateanelement,buttheelementnolongerexists.Adanglingpointerisconsideredtobeanuninitializedvalue.Itcannotbeassigned,compared,usedasacollectionsubscript,orpassedtofree.

Collectionscannotbeassigned,compared,passedasparameters,boundto,ornamedbyaconstdeclaration.Collectionsmustnotbedeclaredinprocedures,functions,recordsorunions.

Thesameshortformsforclassescanbealsousedforcollections.Theseincludeomissionofthecollectionnameinnew,freeandniltogetherwiththe^and->notations.Pointerstotypes(seepointer)canalsobeused,whichareoftenmoreconvenienttousethancollections.

ThesyntaxofacollectionDeclarationpresentedabovehasbeensimplifiedbyleavingoutuncheckedcollections.Withthisfeature,acollectionDeclarationisoneof:

(a)varid{,id}:[unchecked]collectionoftypeSpec

(b)varid{,id}:[unchecked]collectionofforwardtypeId

Whenuncheckedisspecified,thecheckingtoverifythatpointersactuallylocateelementsisremoved.Thischeckingisdoneusinga"timestamp"attachedtoeachelementandpointer,andmakingsurethatthesematchwitheachother.Whenuncheckedisspecified,theexecutionisdangerous,butfasterandsmaller,andthepointersbecomesimplymachineaddresses(asinC).

color textcolorgraphicsprocedure

Syntax color(Color:int)

Description

Thecolorprocedureisusedtochangethecurrentlyactivecolor.Thisisthecolorofcharactersthataretobeputonthescreen.Thealternatespellingiscolour.

Example

Thisprogramprintsoutthemessage"Bravo"threetimes,eachinadifferentcolor.

setscreen("graphics")

fori:1..3

color(i)

put"Bravo"

endfor

Execute

Example

Thisprogramprintsoutamessage.Thecolorofeachletterisdifferentfromtheprecedingletter.Forletternumberithecolornumberisimodmaxcolor+1.Thiscyclesrepeatedlythroughalltheavailablecolors.

constmessage:="HappyNewYear!!"

fori:1..length(message)

color(imodmaxcolor+1)

putmessage(i)..

endfor

Execute

Details

Seemaxcolorforthenumberofcolorsavailableinthevarious"graphics"modes.Thebackgroundcolorthattextappearsuponcanbesetusingthecolorbackprocedure.

Thescreenmustbeina"graphics"modetousethecolorprocedure.Seesetscreenfordetails.

Seealsocolorback,whatcolorandmaxcolor.

SeealsopredefinedunitText.

colorback backgroundcolorprocedure

Syntax colorback(Color:int)

DescriptionThecolorbackprocedureisusedtochangethecoloruponwhichtextappears.Thealternatespellingiscolourback.

Example

Whenthemessage"Greetings"isoutput,thebackgroundsurroundingeachletterwillbeinred.

colorback(red)

put"Greetings"..

Execute

Details

Whenanewlineisoutput,suchaswhentheputstatementdoesnotcontaina..attheend,therestofthelineisclearedfromcursortotherightedgeoftheoutputwindowinthetextbackgroundcolor.

Example

Thisprogramwillresultintheword"Hello"beingdisplayedinredonagreenbackgroundfollowedbytheword"Again"displayedinredonayellowbackground.Theyellowbackgroundstretchesacrossthewindow.

color(red)

colorback(green)

put"Hello"..%The".."attheendoflinestopsthenewline

colorback(yellow)

put"Again"%Therestofthelineisclearedinyellow

Execute

Example

Thisprogramdisplaystheletter'X'in16differentcolorson16differentbackgrounds.Notethattheletterisnotvisiblewhenthetextcolorandthebacgroundcolorarethesame

forrow:0..15

colorback(row)

forcolumn:0..15

color(column)

locate(row,column)

put"X"..

endfor

Execute

Details

Seemaxcolorforthenumberofbackgroundcolorsavailable.Thecolorinwhichtextappearscanbesetusingthecolorprocedure.

Thescreenmustbeina"graphics"modetousethecolorprocedure.Seesetscreenfordetails.

Seealsocolorandwhatcolorback.

comment remarkstatement

Description

Acommentisaremarktothereaderoftheprogram,whichthecomputerignores.ThemostcommonformofcommentinTuringstartswithapercentsign(%)andcontinuestotheendofthecurrentline;thisiscalledanend-of-linecomment.Thereisalsothebracketedcomment,whichbeginswiththe/*andendswith*/andwhichcancontinueacrosslineboundaries.

Example

%Thisisanend-of-linecomment

varx:real%Hereisanotherend-of-linecomment

consts:="Hello"

/*Hereisabracketedcommentthat

lastsfortwolines*/

constpi:=3.14159

DetailsIntheBASIClanguage,commentsarecalledremarksandstartwiththekeywordREM.InPascal,commentsarebracketedby(*and*).

comparisonOperator

Syntax

AcomparisonOperatorisoneof:

(a) < %Lessthan (b) > %Greaterthan (c) = %Equal (d) <= %Lessthanorequal;subset (e) >= %Greaterthanorequal;superset (f) not= %Notequal

Description

Acomparisonoperatorisplacedbetweentwovaluestodeterminetheirequalityorordering.Forexample,7>2istrueandsois"Adam"<"Cathy".Thecomparisonoperatorscanbeappliedtonumbersaswellastoenumeratedtypes.Theycanalsobeappliedtostringstodeterminetheorderingbetweenstrings(seethestringtypefordetails).Arrays,records,unionsandcollectionscannotbecompared.Booleanvalues(trueandfalse)canbecomparedonlyforequality(=andnot=);thesameistrueofpointervalues.Setvaluescanbecomparedusing<=and>=,whicharethesubsetandsupersetoperators.Thenot=operatorcanbewrittenas~=.

Comparisonsamongclassesisalsosupported(seeclass).IfCandDareclasses,C<=DmeansDisadescendantof(inheritsfrom)C.Seeclass.

Seealso

Seealsoinfixoperatorsandprecedenceofoperators.Seealsotheint,real,string,set,booleanandenumtypes.Seealsostringcomparison.

Concurrency

Description

Thisunitcontainsthepredefinedproceduresthatdealwithconcurrency.Itcontainsonepredefinedfunction,althoughconceptuallyitcontainsthreeothersubprograms.

AllroutinesintheConcurrencymoduleareexportedunqualified.(Thismeansyoucancalltheentrypointsdirectly.)

EntryPoints

empty* Returnstrueifnoprocessesarewaitingontheconditionqueue.

getpriority* Returnsthepriorityofthecurrentprocess.setpriority* Setsthepriorityofthecurrentprocess.

simutime Returnsthenumberofsimulatedtimeunitsthathavepassed.

*Partofthelanguage,conceptuallypartoftheConcurrencyunit.

Concurrency.empty PartofConcurrencymodule

Syntax empty(variableReference):boolean

Description

Theemptyfunctionisusedinaconcurrentprogram.ItreturnstrueifthevariableReference,whichmustbeaconditionvariable,hasnoprocesseswaitingforit.Processesjointhequeueofaconditionvariablebyexecutingthewaitstatement,andareawakenedbythesignalstatement.

Status

PartofthelanguageandonlyconceptuallypartoftheConcurrencyunit.

Thismeansthatyoucanonlycallthefunctionbycallingempty,notbycallingConcurrency.empty.

Seealso condition,wait,signal,forkandmonitor.

Concurrency.getpriority PartofConcurrencymodule

Syntax getpriority:nat

Description

Thegetpriorityfunctionreturnsthepriorityofanexecutingprocessinaconcurrentprogram.Asmallervaluemeansafasterspeed.

Status

Thismeansthatyoucanonlycallthefunctionbycallinggetpriority,notbycallingConcurrency.getpriority.

Seealso setpriority,forkandmonitor.

Concurrency.setpriority PartofConcurrencymodule

Syntax setpriority(p:nat)

Description

Thesetpriorityprocedureisusedtosetthepriorityofaprocessinaconcurrentprogram.Thisprioritycannotbecountedontoguaranteecriticalaccesstosharedvariables.Asmallervalueofpmeansincreasedspeed.Theargumenttosetprioritymaybelimitedtotherange0to2**15-1.

Status

Thismeansthatyoucanonlycallthefunctionbycallingsetpriority,notbycallingConcurrency.setpriority.

Seealso getpriority,forkandmonitor.

Concurrency.simutime PartofConcurrencymodule

Syntax simutime:int

DescriptionThesimutimefunctionreturnsthenumberofsimulatedtimeunitsthathavepassedsinceprogramexecutionbegan.

Details

Simulatedtimeonlypasseswhenallprocessareeitherpausedorwaiting.ThissimulatesthefactthatCPUtimeiseffectivelyinfinitelyfasterthan"pause"time.

Example

Thisprintsoutthesimulatedtimepassingbetweentwoprocesses.Thiswillprintout3,5,6,9,10,12,15,15,18,20,21,...

processp(t:int)

pauset

putsimutime

endloop

forkp(3)

forkp(5)

Execute

Status

Exportedunqualified.

ThismeansthatyoucancallthefunctionbycallingsimutimeorbycallingConcurrency.simutime.

condition declaration

Syntax

AconditionDeclarationis:

varid{,id}:[arrayindexType{,indexType}of]

[conditionOption]condition

Description

Aconditionisessentiallyaqueueofsleepingprocesses.Itisusedinaconcurrentprogramtoallowprocessestoblockthemselves(bythewaitstatement)andlatertobeawakened(bythesignalstatement).Aconditionvariable,whichcanoccuronlyinsideamonitor(aspecialkindofmodulethathandlesconcurrency)ormonitorclass,isusedbythewaitandsignalstatementsforputtingprocessestosleepandlaterwakingthemup.

Example

Theprocessesusethismonitortogainexclusiveaccesstoaresource.Aprocesswantingtousetheresourcecallstherequestentrypointandisblockeduntiltheresourceisfree.Whentheprocessisfinishedwiththeresource,itcallsthereleaseentrypoint.Thismonitorisessentiallyabinarysemaphoreinwhichthesemaphore'sPoperationistherequestandtheVistherelease.

monitorresource

exportrequest,release

varavailable:boolean:=true

varnowAvailable:condition

procedurerequest

ifnotavailablethen

waitnowAvailable%Gotosleep

assertavailable

available:=false%Allocateresource

endrequest

procedurerelease

assertnotavailable%Resourceisallocated

available:=true%Freetheresource

signalnowAvailable%Wakeuponeprocess

%Ifanyaresleeping

endrelease

endresource

processworker

resource.request%Blockuntilavailable

…useresource…

resource.release

endloop

endworker

forkworker%Activateoneworker

forkworker%Activateanotherworker

Execute

AconditionOptionisoneof:

(a) priority (b) deferred (c) timeout

Thepriorityoptionrequiresthatthecorrespondingwaitstatementsincludepriorities.Options(b)and(c)declaredeferredconditions.Asignaltoadeferredconditioncausesthesignaledprocesstobecomereadytoenterthemonitorwhenthemonitorbecomesinactive.Thesignalingprocesscontinuesrunninginthemonitor.Asignaltoanimmediate(nondeferred)conditioncausesthesignaledprocesstobeginrunninginthemonitorimmediately.Thesignalingprocesswaitstore-enterthemonitorwhenthemonitorbecomesinactive.Allconditionsinadevicemonitormustbedeferred(ortimeout).

Atimeoutoptionmeansthesignalingisdeferredandthatan

Details extraparametertothewaitstatementmustgiveatimeoutinterval.Ifaprocesswaitslongerthanitsinterval,itisautomaticallysignaled.Bewarethattheemptyfunctioncanbenon-repeatablewhenappliedtotimeoutconditions.Forexample,empty(c)maynotbeequaltoempty(c)inasingleexpression.Inthecurrent(1999)versionofTuring,thetimefortimeoutsismeasuredinsimulationtimeratherthanrealtime.Seethepausestatement.

Conditionscannotbenamedastypes,cannotbecontainedinrecords,unionsorcollectionsandcannotbedeclaredinstatements(suchasbeginorloop)orinsubprograms.Theycanonlybedeclaredinmonitorsandmonitorclasses.

Thereisnoguaranteedorderofprogressamongawakeneddeferredprocesses,processessignalingimmediateconditions,andprocessesattemptingtoenteranactivemonitor.

NotethatconditionOptionmustprecedethekeywordcondition.

Seealsowaitandsignal.Seealsomonitorandfork.Seealsoempty.Seealsopause.

Config

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithgettingconfigurationinformationaboutthemachineandenvironmentonwhichtheprogramisbeingrun.Itexistsinordertoallowuserstoobtaininformationaboutthesystemthatmayonlybeavailableatruntime.

AllroutinesintheConfigmoduleareexportedqualified(andthusmustbeprefacedwith"Config.").

EntryPoints

Display Returnsinformationaboutthedisplaycurrentlyattached.

Lang Returnsinformationaboutthelanguageenvironmentthattheprogramiscurrentlyrunningwithin.

Machine Returnsinformationaboutthehardwareonwhichtheprogramisrunning.

Config.Display PartofConfigmodule

Syntax Config.Display(displayCode:int):int

Description

Config.Displayreturnsinformationaboutthedisplay(ordisplays)attachedtothecomputer.TheparameterdisplayCodedetermineswhatsortofinformationispassedback.displayCodehasanumberofpossiblevalues,allsummarizedbyasetofpredefinedconstants.

Atthetimeofthiswriting,thefollowingconstantsweredefined:

cdScreenHeight returntheheightofthescreeninpixels.cdScreenWidth returnthewidthofthescreeninpixels.

cdMaxNumColors returnthemaximumnumberofcolorssupportedbythedisplay.

cdMaxNumColours returnthemaximumnumberofcolorssupportedbythedisplay.

Execute

Example

Thisprogramprintsthescreenwidthandheight.

constwidth:int:=Config.Display(cdScreenWidth

constheight:int:=Config.Display(cdScreenHeight

put"Thescreenwidthis",width,"thescreenheightis",

Details

OntheMacintosh,it'spossibletohavemultipledisplaysattachedtoasinglecomputer.Togetinformationabouttheextradisplays,youcancallConfig.Displaywithanyofthefirstfourconstantsaboveplusone,two,three,etc.Thiswillreturntheheight,widthormaximumnumberofcolorsforthesecond,thirdandbeyonddisplays.

Example

ThisprogramprintsthescreenwidthandheightoftheseconddisplayonaMacintosh.

constwidth:int:=Config.Display(cdScreenWidth

constheight:int:=Config.Display(cdScreenHeight

put"Theseconddisplaysizeis",width,"x",

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingConfig.DisplaycallingDisplay.

Config.Lang PartofConfigmodule

Syntax Config.Lang(langCode:int):int

Description

Config.Langreturnsinformationaboutthelanguageandthelimitationsoftheimplementationthattheprogramiscurrentlyrunning.TheparameterlangCodedetermineswhatsortofinformationispassedback.langCodehasanumberofpossiblevalues,allsummarizedbyasetofpredefinedconstants.

clRelease returnthecurrentreleasenumberoftheenvironment(e.g.4.02=400).

clLanguageVersion returnthecurrentversionnumberofthelanguage(e.g.1.81=181).

clMaxNumStreams returnthemaximumnumberofI/Ostreams(usedbytheopenandclosestatements)thatcanbeopenedatonce.

clMaxNumDirStreams returnthemaximumnumberofdirectorystreamsthatcanbeopenedatonce.

clMaxNumRunTimeArgs returnthemaximumnumberofrun-timearguments.

Example

Thisprogramprintsthecurrentenvironmentversion.

constversion:int:=Config.Lang(clLanguageVersion

put"Thelanguageversionnumberis",version

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingConfig.LangnotbycallingLang.

Config.Machine PartofConfigmodule

Syntax Config.Machine(machineCode:int):int

Description

Config.Machinereturnsinformationaboutthemachinethattheprogramiscurrentlyrunningon.TheparametermachineCodedetermineswhatsortofinformationispassedback.machineCodehasanumberofpossiblevalues,allsummarizedbyasetofpredefinedconstants.

cmProcessor returnanencodingoftheprocessornumber.cmFPU return1ifthereisanFPUinstalled,0ifnot.

cmOS returnthecurrentversionnumberoftheoperatingsystem(e.g.6.07=607).

Example

ThisprogramprintswhetherthemachinehasanFPUornot.

ifConfig.Machine(cmFPU)=1then

put"ThemachinehasanFPUinstalled"

put"ThemachinedoesnothaveanFPUinstalled"

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingConfig.Machine,notbycallingMachine.

const constantdeclaration

Syntax

AconstantDeclarationis:

constid[:typeSpec]:=initializingValue

DescriptionAconstdeclarationcreatesanameidforavalue.

Example

constc:=3

consts:="Hello"%Thetypeofsisstring

constx:=sin(y)**2

consta:array1..3ofint:=init(1,2,3)

constb:array1..3ofint:=a

constc:array1..2,1..2ofint:=init(1,2,3,4)

%Soc(1,1)=1,c(1,2)=2,c(2,1)=3,c(2,2)=4

Details

Theinitializingvaluecanbeanarbitraryvalueorelsealistofitemsseparatedbycommasinsideinit(…).ThesyntaxofinitializingValueis:

a. expn b. init(initializingValue,initializingValue)

Eachinit(…)correspondstoanarray,recordorunionvaluethatisbeinginitialized.Thesemustbenestedforinitializationofnestedtypes.InthePascallanguage,constantsmusthavevaluesknownatcompiletime;Turinghasnosuchrestriction.

WhenthetypeSpecisomitted,thevariable'stypeistakentobethe(root)typeoftheinitializingexpression,forexample,intorstring.ThetypeSpeccannotbeomittedfordynamicarraysorwhentheinitializingvalueisoftheforminit(…).Thevaluesinsideinit(…)mustbeknownatcompiletime.

Thekeywordpervasivecanbeinsertedjustafterconst.Whenthisisdone,theconstantisvisibleinsideallsubconstructsoftheconstant'sscope.Withoutpervasiveisnotvisibleinsidemodules,monitorsorclassesunlessexplicitlyimported.Pervasiveconstantsneednotbeimported.Youcanabbreviatepervasiveasanasterisk(

Youcanalsooptionallyusetheregisterkeywordtorequestthattheconstantbeplacedinamachineregister.ThesyntaxforconstantDeclarationisactually:

const[pervasive][register]id[:typeSpec]:=

Inthecurrent(2002)implementation,programsareruninterpretivelyusingpseudo-code,whichhasnomachineregisters,andtheregisterkeywordisignored.Seealsoforrestrictionsontheuseofregisterconstants.

constantReference useofaconstant

Syntax

AconstantReferenceis:

constantId{componentSelector}

Description

InaTuringprogram,aconstantisdeclaredandgivenaname(constantId)andthenused.Eachuseiscalledaconstantreference.

Iftheconstantisanarray,recordorunion,itsparts(components)canbeselectedusingsubscriptsandfieldnames(usingcomponentSelectors).TheformofacomponentSelectorisoneof:

(a) (expn{,expn}) (b) .fieldId

Form(a)isusedforsubscripting(indexing)arrays.Thenumberofarraysubscriptsmustbethesameasinthearray'sdeclaration.Form(b)isusedforselectingafieldofarecordorunion.Componentselectorsareusedinthesamemannerasvariablereferences.SeevariableReferencefordetails.SeealsoconstdeclarationandexplicitConstant.

Example

varradius:real

constpi:=3.14159%Constantdeclaration

put"Areais:",pi*radius**2

%piisaconstantreference

cos cosinefunction(radians)

Syntax cos(r:real):real

DescriptionThecosfunctionisusedtofindthecosineofananglegiveninradians.Forexample,cos(0)is1.

Example

Thisprogramprintsoutthecosineofp/6,2p/6,3p/6,upto12p/6radians.

constpi:=3.14159

fori:1..12

constangle:=i*pi/6

put"Cosof",angle,"is",cos(angle)

endfor

Execute

Seealso

thesinandtanfunctionsforcalculatingsineandtangent.

thecosdfunctionwhichfindsthecosineofananglegivenindegrees.(2pradiansarethesameas360degrees.)

cosd cosinefunction(degrees)

Syntax cosd(r:real):real

DescriptionThecosdfunctionisusedtofindthecosineofananglegivenindegrees.Forexample,cosd(0)is1.

Example

Thisprogramprintsoutthecosineof30,60,90,upto360degrees.

fori:1..12

constangle:=i*30

put"Cosof",angle,"is",cosd(angle)

endfor

Execute

Seealso

thesindandtandfunctionsforcalculatingsineandtangent.

thecosfunctionwhichfindsthecosineofananglegiveninradians.(2pradiansarethesameas360degrees.)

date procedure

Syntax date(vard:string)

Description

Thedatestatementisusedtodeterminethecurrentdate.Variabledisassignedastringintheformat"ddmmmyy",wheremmmisthefirst3charactersofthemonth,e.g.,"Apr".Forexample,ifthedateisChristmas2002,dwillbesetto"25Dec02".

Example

Thisprogramgreetsyouandtellsyouthedate.

vartoday:string

date(today)

put"Greetings!!Thedatetodayis",today

Execute

Details

BewarnedthatTuringgetsthedatefromtheoperatingsystem.Ifthedateisisnotcorrectlysetintheoperatingsystem,thenthedateprocedurewillgiveincorrectresults.

Seealsodelay,clock,sysclock,wallclockandtimestatements.

declaration createavariable

Syntax

Adeclarationisoneof:

(a) variableDeclaration (b) constantDeclaration (c) typeDeclaration (d) bindDeclaration (e) procedureDeclaration (f) functionDeclaration (g) moduleDeclaration (h) classDeclaration (i) processDeclaration (j) monitorDeclaration (k) conditionDeclaration

Description

Adeclarationcreatesanewname(ornames)foravariable,constant,type,procedure,function,module,class,process,monitor,orcondition.Thesenamesarecalledidentifiers,whereidistheabbreviationforidentifier.

Example

varwidth:int%Variabledeclaration

constpi:=3.14159%Constantdeclaration

typerange:0..150%Typedeclaration

proceduregreet%Proceduredeclaration

put"Helloworld"

endgreet

Ordinarily,eachnewnamemustbedistinctfromnamesthatarealreadyvisible;thatis,redeclarationisnotallowed.Therearecertainexceptionstothisrule,forexample,namesofparametersandfieldsofrecordscanbethesameasexistingvisiblevariables.Variablesdeclaredinsideasubprogram(aprocedureandfunction)areallowedtobethesameasvariablesglobalto

Details

(outsideof)thesubprogram.

Theeffectofadeclaration(itsscope)laststotheendoftheconstructinwhichthedeclarationoccurs;thiswillbetheendoftheprogram,theendofthesurroundingprocedure,functionormodule,theendofaloop,for,caseorbeginstatement,ortheendofthethen,elsif,orelseclauseofanifstatement,ortheendofthecasestatementalternative.

Anamemustbedeclaredbeforeitcanbeused;thisiscalledtheDBU(DeclarationBeforeUse)rule.Theexceptionstothisruleusethekeywordforward,asinimportlistsandincollectiondeclarations.

Adeclarationcanappearanyplaceastatementcanappear.ThisdiffersfromthePascallanguage,inwhichdeclarationsareallowedonlyatthebeginningoftheprogramoratthebeginningofaprocedureorfunction.Eachdeclarationcanoptionallybefollowedbyasemicolon(;).

Therearecertainrestrictionsontheplacementofdeclarations.Proceduresandfunctionscannotbedeclaredinsideotherproceduresandfunctionsnorinsidestatements(forexample,notinsideanifstatement).Abinddeclarationcannotappearattheouterlevelofeitherthemainprogramoramodule.Aconditiondeclarationcanappearonlyinsideamonitor.Processescannotbedeclaredinsideprocedures,functions,monitorsorclasses.Classescannotbedeclaredinsideclasses.However,modulesandmonitorscanbedeclaredinsideclassesandviceversa.Monitorscanbedeclaredinsidemodules,notviceversa.

deferred subprogramdeclaration

Syntax

AdeferredDeclarationis:

deferredsubprogramHeader

Description

Aprocedureorfunctionisdeclaredtobedeferredwhenyouwanttobeabletooverridethesubprograminanexpansion.Theprocedureorfunctionmustbeinamodule,monitororclass.

Example

Thedisplayprocedureisdeferredinthisclassofstackstoallowvariouswaysofgraphicallydisplayingthestackonthescreen:

classstack

exportpush,pop

…localdeclarations…

…declarationsofthepushandpopprocedures…

deferredproceduredisplay(howbig:int)

endstack

Anexpansiontothestackclasscangiveabodyfordisplay,asin:

classstackWithSimpleDisplay

bodyproceduredisplay%(howbig:int)

…graphicallydisplaythestackonthescreen…

enddisplay

endstackWithSimpleDisplay

Thefollowingcreatesastackthatcanbedisplayedanddisplaysit:

varp:^stackWithSimpleDisplay

p->display(25)%Displaythestackonthescreen

Adeferredprocedureisresolvedbygivingitsbody.Thiscanbedoneinthescope(module,monitororclass)containingthedeferreddeclaration(followingthedeferreddeclaration)orinanyexpansionofthatscope.Onlyoneresolutionperscopeisallowed.Unresolvedsubprogramscanbecalled,buttheyimmediatelyabort.

Allexportedsubprogramsareimplicitlydeferredandcanbe

Details overriddeninexpansions.

Duringinitializationofamodule,monitororobjectofaclass,deferredsubprograms(includingexportedsubprograms)cannotbecalled.Thisrestrictionpreventsaccessinganobjectbeforeitisfullyinitialized.

Adeferreddeclarationmustnotappearinthemainprogram.

Seealsomodule,monitorandclass.Seealsoexportlist,importlist,inheritlist,implementlistandimplementbylist.

delay procedure

Syntax delay(duration:int)

DescriptionThedelaystatementisusedtocausetheprogramtopauseforagiventime.Thetimedurationisinmilliseconds.

Example

Thisprogramprintstheintegers1to10withaseconddelaybetweeneach.

fori:1..10

delay(1000)%Pausefor1second

endfor

Execute

Details

OnAppleMacintoshes,thehardwareresolutionofdurationisinunitsof17milliseconds(1/60thofasecond).Forexample,delay(500)willdelaytheprogrambyabouthalfasecond,butmaybeoffbyasmuchas17milliseconds.

Seealsosound,clock,sysclock,wallclock,timeanddatestatements.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithdirectories.Youcanusethesesubprogramstolistthecontentsofdirectories,createdirectories,changedirectoriesandreturnthecurrentdirectory.

AllroutinesintheDirmoduleareexportedqualified(andthusmustbeprefacedwith"Dir.").

EntryPoints

Open Opensadirectorystreaminordertogetalistingofthedirectorycontents.

Get Getsthenextfilenameinthedirectorylisting.

GetLong Getsthenextfilenameandotherinformationinthedirectorylisting.

Close Closesthedirectorystream.Create Createsanewdirectory.Delete Deletesadirectory(mustbeempty).Change Changesthecurrentexecutiondirectory.Current Returnsthecurrentexecutiondirectory.Exists Returnswhetheradirectoryexists.

Details

PathnamesinTuringcanbeexpressedusingeitherforwardslashesorbackslashes.Forexample,Dir.Change("d:\\turingfiles\\assignment3")orDir.Change("d:/turingfiles/assignment3")arebothlegal.Notethatbackslashesmustbedoubledinstringliterals.The"."directoryrepresentthecurrentdirectory(asinDir.Open(".")),andthe".."directoryrepresentstheparentdirectory.Forexample,ifthecurrentexecutiondirectoryis"d:/turingfiles/assignment3",thenDir.Change("..")changesthecurrentexecutiondirectoryto"d:/turingfiles".

Seealso

Fileunitformoreexplanationofthedifferentwaysofspecifyingapathnameofafileordirectoryunderthedifferentoperatingsystems.

Dir.Change PartofDirmodule

Syntax Dir.Change(directoryPathName:string)

Description

Dir.ChangechangestheexecutiondirectorytothatspecifiedbytheparameterdirectoryPathName.ThisistheequivalentofdoingacdinUNIX.

UnderMicrosoftWindows,specifyingadriveinthedirectoryPathNameparametercausesthedrivetobecomethedefaultdrive(unliketheDOScdcommand).

Details

IftheDir.Changecallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramchangestothedirectorycalled/usr/westandthenliststhecurrentdirectory.

Dir.Change("/usr/west")

ifError.Last=eNoErrorthen

put"Directorychanged"

put"Didnotchangethedirectory."

put"Error:",Error.LastMsg

put"Thecurrentexecutiondirectoryis",Dir.Current

Example

AnexampledemonstratingtheuseofseveraloftheDirsubprogramsisavailable.Inthisexample,adirectoryiscreated,afileiswrittentothedirectory,anattemptismadetodeletethedirectory,thefileisdeleted,andthenthedirectoryisdeleted.

ThisexampledemonstratestheuseofDir.Change,Dir.Current,Dir.Create,andDir.Delete.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.Change,notbycallingChange.

Dir.Close PartofDirmodule

Syntax Dir.Close(streamNumber:int)

Description

Dir.Closeispartofaseriesoffoursubprogramsthathelpusersgetdirectorylistings.Dir.CloseisusedtocloseadirectorystreamnumberopenedbyDir.Open.Afterthedirectorystreamnumberisclosed,itcannotbeusedwithDir.GetorDir.GetLong.

Details

IftheDir.Closecallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramprintsalistingofallthefilesinthedirectorydatafiles.

varstreamNumber:int

varfileName:string

streamNumber:=Dir.Open("datafiles")

assertstreamNumber>0

fileName:=Dir.Get(streamNumber)

exitwhenfileName=""

putfileName

endloop

Dir.Close(streamNumber)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.Close,notbycallingClose.

Dir.Create PartofDirmodule

Syntax Dir.Create(directoryPathName:string)

Description

Dir.CreateisusedtocreatethedirectoryspecifiedbytheparameterdirectoryPathName.ThisistheequivalentofdoingamkdirinDOSorUNIX.OntheMacintosh,itcreatesafolder.

Details

IftheDir.Createcallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramcreatesthedirectorycalledinformation.

Dir.Create("information")

put"Directorycreated"

put"Didnotcreatethedirectory."

Example

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingDir.Create,notbycallingCreate.

Dir.Current PartofDirmodule

Syntax Dir.Current:string

DescriptionDir.Currentreturnsthefullpathnameofthecurrentexecutiondirectory.ThisistheequivalentofdoingapwdinUNIX.

Details

IftheDir.Currentcallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramchangestothedirectorycalled/usr/westandthenliststhecurrentdirectory.

Dir.Change("/usr/west")

put"Directorychanged"

put"Didnotchangethedirectory."

put"Thecurrentexecutiondirectoryis",Dir.Current

Example

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingDir.Current,notbycallingCurrent.

Dir.Delete PartofDirmodule

Syntax Dir.Delete(directoryPathName:string)

Description

Dir.DeleteisusedtodeletethedirectoryspecifiedbytheparameterdirectoryPathName.ThisistheequivalentofdoingarmdirinDOSorUNIX.OntheMacintosh,itremovesafolder.

Dir.Deletewillfailifitattemptsdeleteadirectorythathasfilesinit.

Details

IftheDir.Deletecallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramdeletesthedirectorycalledinformation.

Dir.Delete("information")

put"Directorydelete"

put"Didnotdeletethedirectory."

Example

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.Delete,notbycallingDelete.

Dir.Exists PartofDirmodule

Syntax Dir.Exists(directoryPathName:string):boolean

Description

Dir.ExistsreturnstrueifadirectorybythenameofdirectoryPathNameexists.ItwillreturnfalseifdirectoryPathNameisafile.

Details

IftheDir.Existsreturnsfalse,youcanexamineError.LastorError.LastMsgformoreinformation(i.e.whetherthepathfailedorthedirectorywassimplynotfound).

Example

Thefollowingprogramdeterminesifthedirectory"d:/usr/west"exists,andoutputsanerrormessageifitdoesnot.

ifDir.Exists("d:/usr/west")then

put"Directoryexists"

put"Directorydoesnotexists:",Error.LastMsg

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.Exists,notbycallingExists.

Dir.Get PartofDirmodule

Syntax Dir.Get(streamNumber:int):string

Description

Dir.Getispartofaseriesoffoursubprogramsthathelpusersgetdirectorylistings.Dir.Getisusedtogetthefilenamesinthedirectory.Eachtimethefunctioniscalled,itreturnsthenextfilenameinthedirectory.Thenamesarenotsorted.Whentherearenomorefilenamesinthedirectory,Dir.Getreturnstheemptystring.

Details

IftheDir.Getcallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramprintsalistingofallthefilesinthedirectorydatafiles.

varstreamNumber:int

varfileName:string

exitwhenfileName=""

putfileName

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.Get,

notbycallingGet.

Dir.GetLong PartofDirmodule

SyntaxDir.GetLong(streamNumber:int,varentryName:string varsize,attribute,fileTime:int)

Description

Dir.GetLongispartofaseriesoffoursubprogramsthathelpusersgetdirectorylistings.Dir.GetLongisusedtogetthenamesandassortedinformationofthefilesinthedirectory.Eachtimethefunctioniscalled,itreturnsthenameandinformationofthenextfileinthedirectory.Thenamesarenotsorted.Whentherearenomorefilenamesinthedirectory,Dir.GetLongreturnstheemptystringintheentryNameparameter.

Thesizeparameteristhesizeofthefileinbytes.Theattributeparameterhasitsindividualbitssetasfollows(theindividualbitscanbeextractedusingthebitsoperator):

Bit0attrDirsetto1ifentryisadirectory.

Bit1attrReadsetto1iftheprogramcanreadthefile.

Bit2attrWritesetto1iftheprogramcanwritethefile.

Bit3attrExecutesetto1iftheprogramcanexecutethefile.

Bit4attrHiddensetto1iftheentryifahiddenfile(PC,Mac).

Bit5attrSystemsetto1iftheentryisasystemfile(PConly).

Bit6attrVolumesetto1iftheentryisavolumename(PConly).

Bit7attrArchivesetto1iftheentryhasarchivebitset(PConly).

Theattr...constantsaredefinedintheDirunit.Theycorrespondtothevaluesofattributeifaspecifiedbitisset.Forexample,attrSystemisthevalueoftheattributeparameterifbit5issetto1.Youcanandororconstantstogetcombinationsofspecificfileattributes.

ThefileTimeisthetimeoflastmodificationofthefile.Itisreturnedasthenumberofsecondssince00:00:00GMT1/1/1970.Toconvertthistoa

string,useTime.SecDate

Details

IftheDir.GetLongcallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramprintsalistingofallthefilesinthedirectorydatafiles

varstreamNumber:int

varfileName:string

varsize,attribute,fileTime:int

Dir.GetLong(streamNumber,fileName,size,attribute,fileTime

exitwhenfileName=""

putfileName,"",Time.SecDate(fileTime)

endloop

Example

Thisprogramprintsalistingoftheattributesofallthefilesinthecurrentdirectory.

varstreamNumber:int

varfileName:string

streamNumber:=Dir.Open(Dir.Current)

Dir.GetLong(streamNumber,fileName,size,attribute,fileTime

exitwhenfileName=""

putfileName,""..

if(attributeandattrDir)not=0then

put"Directory"..

if(attributeandattrRead)not=0then

put"Readable"..

if(attributeandattrWrite)not=0then

put"Writeable"..

if(attributeandattrExecute)not=0then

put"Executable"..

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDir.GetLongbycallingGetLong.

Dir.Open PartofDirmodule

Syntax Dir.Open(directoryPathName:string):int

Description

Dir.Openispartofaseriesoffoursubprogramsthathelpusersgetdirectorylistings.Dir.Openreturnsadirectorystreamnumberifthedirectorycouldbeopened.ThisstreamnumbercanbeusedtogetfilenamesandinformationusingtheDir.GetandDir.GetLongsubprograms.Aftergettingthelisting,theusershouldcallDir.Close.

Details

IftheDir.Opencallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramprintsalistingofallthefilesinthecurrentdirectory.

varstreamNumber:int

varfileName:string

streamNumber:=Dir.Open(Dir.Current)

exitwhenfileName=""

putfileName

endloop

Execute

Status

Exportedqualified.

Thismeansthatyoucanonlycallthefunctionbycalling

Dir.Open,notbycallingOpen.

div integertruncatingdivisionoperator

Syntax div

Description

Thedivoperatordividesonenumberbyanotherandproducestheintegerresult,truncatedinthedirectionofzero.Forexample,7div2produces3and-7div2produces-3.

Example

Inthisexample,eggCountisthetotalnumberofeggs.Thefirstputstatementdetermineshowmanydozeneggsthereare.Thesecondputstatementdetermineshowmanyextraeggstherearebeyondthelastdozen.

vareggCount:int

geteggCount

put"Youhave",eggCountdiv12,"dozeneggs"

put"Youhave",eggCountmod12,"leftover"

Execute

Seealso infixoperators,precedenceofoperatorsandthemodoperator.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithdrawingpixelgraphicstothescreen.

AllroutinesintheDrawunitareexportedqualified(andthusmustbeprefacedwith"Draw.").

EntryPoints

Cls Clearsthescreentocolor0.Dot Drawsadot.Line Drawsaline.DashedLine Drawsadashedordottedline.ThickLine Drawsathickline.Box Drawsabox.FillBox Drawsafilledbox.Oval Drawsanoval.FillOval Drawsafilledoval.Arc Drawsanarc.FillArc Drawsafilledarcorawedge.Polygon Drawsapolygon.FillPolygon Drawsafilledpolygon.MapleLeaf Drawsamapleleaf.FillMapleLeaf Drawsafilledmapleleaf.Star Drawsastar.FillStar Drawsafilledstar.Fill Doesafloodfill.Text Drawstextasgraphics

Draw.Arc PartofDrawmodule

SyntaxDraw.Arc(x,y,xRadius,yRadius:int, initialAngle,finalAngle,Color:int)

Description

TheDraw.Arcprocedureisusedtodrawanarcwhosecenterisat(x,y).ThisisjustlikeDraw.Oval,exceptthatyoumustalsogivetwoangles,initialAngleandfinalAngle,whichdeterminewheretostartandstopdrawing.Zerodegreesis"threeo'clock",90degreesis"twelveo'clock",etc.ThehorizontalandverticaldistancesfromthecentertothearcaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsaquartercirclewhosecenteris(midx,midy)thecenterofthescreen,usingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

View.Set("graphics")

constmidx:=maxxdiv2

constmidy:=maxydiv2

Draw.Arc(midx,midy,midx,midy,0,90,1)

Execute

DetailsThescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Arc,notbycallingArc.

SeealsoView.Set,maxx,maxyandthevariousproceduresintheDrawunit.

Draw.Box PartofDrawmodule

Syntax Draw.Box(x1,y1,x2,y2,Color:int)

Description

TheDraw.Boxprocedureisusedtodrawaboxonthescreenwithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.

Example

Thisprogramdrawsalargebox,reachingtoeachcornerofthescreenusingcolornumber12.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreenand(maxx,maxy)istherighttop.

Draw.Box(0,0,maxx,maxy,12)

Execute

Details

Thescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Box,notbycallingBox.

View.Set,maxx,maxyandthevariousproceduresintheDraw

Seealso unit.

Draw.Cls PartofDrawmodule

Syntax Draw.Cls

DescriptionTheDraw.Cls(clearscreen)procedureisusedtoblanktheoutputwindowThecursorissettothetopleft(torow1,column1).

Details

TheDraw.Clsproceduresetsallpixelsintheoutputwindowtocolor0.InthiswayitdiffersfromtheclsandText.Clsprocedureswhichsetthescreentothetextbackgroundcolor.

Thescreenmustbein"graphics"mode.SeeView.Setfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Cls,notbycallingCls.

Draw.DashedLine PartofDrawmodule

Syntax Draw.DashedLine(x1,y1,x2,y2,lineStyle,Color:int)

Description

TheDraw.DashedLineprocedureisusedtodrawadottedordashedlineonthescreenfrom(x1,y1)to(x2,y2)usingthespecifiedColor.

Therearefivepossiblelinestyles:drawSolidDrawsasolidline(sameasDraw.Line)drawDashDrawsadashedlinedrawDotDrawsadottedlinedrawDashDotDrawsalinethatalternatesdashesanddotsdrawDashDotDotDrawsalinethatalternatesdashanddot-dot

Example

ThisprogramdrawsalargeX,reachingtoeachcornerofthescreenintwodifferentcolors.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreen,(maxx,maxy)istherighttop,etc.

%Drawalineineachofthestyles.

Draw.DashedLine(0,50,maxx,50,drawSolid,brightred)

Draw.DashedLine(0,100,maxx,100,drawDash,brightred)

Draw.DashedLine(0,150,maxx,150,drawDot,brightred)

Draw.DashedLine(0,200,maxx,200,drawDashDot,brightred)

Draw.DashedLine(0,250,maxx,250,drawDashDotDot,brightred)

Execute

DetailsThescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.DashedLine,notbycallingDashedLine.

Seealso View.Set,maxx,maxyandthevariousproceduresintheDrawunit.

Draw.Dot PartofDrawmodule

Syntax Draw.Dot(x,y,Color:int)

Description

TheDraw.Dotprocedureisusedtocolorthedot(pixel)atlocation(x,y)usingthespecifiedColor.

Example

Thisprogramrandomlydrawsdotswithrandomcolors.Themaxx,maxyandmaxcolorfunctionsgivethemaximumx,yandcolorvalues.

varx,y,c:int

x:=Rand.Int(0,maxx)%Randomx

y:=Rand.Int(0,maxy)%Randomy

c:=Rand.Int(0,maxcolor)%Randomcolor

Draw.Dot(x,y,c)

endloop

Execute

DetailsThescreenmustbeina"graphics"mode.Ifthescreenisnotina

"graphics"mode,anerrorwilloccur.SeeView.Setfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Dot,notbycallingDot.

Draw.Fill PartofDrawmodule

Syntax Draw.Fill(x,y:int,fillColor,borderColor:int)

Description

TheDraw.Fillprocedureisusedtocolorinafigurethatisonthescreen.Startingat(x,y),thefigureisfilledwithfillColortoasurroundingborderwhosecolorisborderColor.

Example

Thisprogramdrawsanovalwithxandyradiusof10inthecenterofthescreeninbrightgreen.Thentheovalisfilledwithred.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

Draw.Oval(midx,midy,10,10,brightgreen)

Draw.Fill(midx,midy,red,brightgreen)

Execute

Details

Status

Exportedqualified.

Draw.Fill,notbycallingFill.

Draw.FillArc

SyntaxDraw.FillArc(x,y,xRadius,yRadius:int, initialAngle,finalAngle,Color:int)

Description

TheDraw.FillArcprocedureisusedtodrawafilledarcwhosecenterisat(x,y).Itthenfillsinthepie-shapedwedgeusingthespecifiedColor.Tooutlineafilledarc,useDraw.FillArcwiththeColorparametersettothefillcolorandthenDraw.ArcwiththeColorparametersettothebordercolor.ForinitialAngleandfinalAngle,whichdeterminetheedgesofthewedge,zerodegreesis"threeo'clock"and90degreesis"twelveo'clock",etc.ThehorizontalandverticaldistancesfromthecentertothearcaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsafilledsemicircle(actually,anapproximationtoasemicircle)whosecenteris(midx,0)thebottomcenterofthescreen,inbrightred.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

constmidx:=maxxdiv2

Draw.FillArc(midx,0,maxy,maxy,0,180,brightred

Execute

Thescreenmustbeina"graphics"mode.SeetheView.Set

Details procedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillArc,notbycallingFillArc.

Draw.FillBox

Syntax Draw.FillBox(x1,y1,x2,y2,Color:int)

Description

TheDraw.FillBoxprocedureisusedtodrawafilledboxonthescreenwithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)filledusingthespecifiedColor.Togetaboxoutlinedinadifferentcolor,useDraw.FillBoxwiththeColorparametersettothefillcolorandthencallDraw.BoxwiththeColorparametersettothebordercolor.

Example

Thisprogramwillfillthebottomhalfofthescreenwithcolor1andthenoutlineitincolor2.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreenand(maxx,maxy)istherighttop.

Draw.FillBox(0,0,maxx,maxydiv2,1)

Draw.Box(0,0,maxx,maxydiv2,2)

Execute

Details

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillBox,notbycallingFillBox.

Draw.FillMapleLeaf

Syntax Draw.FillMapleLeaf(x1,y1,x2,y2,Color:int)

Description

TheDraw.FillMapleLeafprocedureisusedtodrawafilledmapleleafonthescreenboundedbyarectanglewithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)andfilledusingthespecifiedColor.Togetamapleleafoutlinedinadifferentcolor,useDraw.FillMapleLeafwiththeColorparametersettothefillcolorandthencallDraw.MapleLeafwiththeColorparametersettothebordercolor.Ify1isgreaterthany2,thenthemapleleafisdrawnupsidedown.

Example

Thisprogramwilldrawtwomapleleavesbesideeachother.Thefirstwillbeoutlinedinblackandfilledinbrightred.Thesecondmapleleafwillbeupsidedownandbothfilledandoutlinedingreen.

Draw.FillMapleLeaf(0,0,100,100,brightred)

Draw.MapleLeaf(0,0,100,100,black)

Draw.FillMapleLeaf(150,100,250,0,green)

Execute

TheDraw.FillMapleLeafprocedureisusefulfordrawingthe

Details

Canadianflag.

Thescreenshouldbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,itwillautomaticallybesetto"graphics"mode.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillMapleLeaf,notbycallingFillMapleLeaf.

Draw.FillOval

Syntax Draw.FillOval(x,y,xRadius,yRadius,Color:int)

Description

TheDraw.FillOvalprocedureisusedtodrawafilledovalwhosecenterisat(x,y).ThehorizontalandverticaldistancesfromthecentertotheovalaregivenbyxRadiusandyRadius.Togetanovaloutlinedinadifferentcolor,useDraw.FillOvalwiththeColorparametersettothefillcolorandthencallDraw.OvalwiththeColorparametersettothebordercolor.

Example

Thisprogramdrawsalargefilledovalthatjusttoucheseachedgeofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thecenteroftheovalisat(midx,midy),whichisthemiddleofthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

Draw.FillOval(midx,midy,midx,midy,1)

Execute

Details

Ideally,acircleisdrawnwhenxRadius=yRadius.

Thescreenmustbeina"graphics"mode.SeetheView.Set

procedurefordetails.Ifthescreenisnotina"graphics"mode,amerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillOval,notbycallingFillOval.

Draw.FillPolygon

Syntax Draw.FillPolygon(x,y:array1..*ofint,n:int,Color:int)

Description

TheDraw.FillPolygonprocedureisusedtodrawafilledpolygonwithnpoints.Thepolygonisdescribedbythepoints(x(1),y(1))to(x(2),y(2))to(x(3),y(3))andsoonto(x(n),y(n)).ThepolygonwillbedrawnandfilledwithColor.

Togetanpolygonoutlinedinadifferentcolor,useDraw.FillPolygonwiththeColorparametersettothefillcolorandthencallDraw.PolygonwiththeColorparametersettothebordercolor.

Example

Thisprogramwillcreateafilledoctagonanddisplayitinbrightblueandthenoutlineitincyan.

varx:array1..8ofint:=init(100,100,135,185,

220,220,185,135)

vary:array1..8ofint:=init(100,150,185,185,

150,100,65,65)

Draw.FillPolygon(x,y,8,brightblue)

Draw.Polygon(x,y,8,cyan)

Execute

Details

ThePCallowsamaximumof256points.Aswell,Draw.FillPolygoncanfail(duetolackofmemory).Iffailureoccurs,itwilltrytodrawanoutlineofthepolygon.Ifthatalsofails,itwillnotdrawanything.

Thescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,an

errorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillPolygon,notbycallingFillPolygon.

Draw.FillStar PartofDrawmodule

Syntax Draw.FillStar(x1,y1,x2,y2,Color:int)

Description

TheDraw.FillStarprocedureisusedtodrawafilledfivepointedstaronthescreenboundedbyarectanglewithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)andfilledusingthespecifiedColor.Togetastaroutlinedinadifferentcolor,useDraw.FillStarwiththeColorparametersettothefillcolorandthencallDraw.StarwiththeColorparametersettothebordercolor.Ify1isgreaterthany2,thenthestarisdrawnupsidedown.

Example

Thisprogramwilldrawtwostarsbesideeachother.Thefirstwillbeoutlinedincolor1andfilledincolor2.Thesecondstarwillbeupsidedownandbothfilledandoutlinedincolor3.

Draw.FillStar(0,0,100,100,brightred)

Draw.Star(0,0,100,100,green)

Draw.FillStar(150,100,250,0,brightblue)

Execute

TheDraw.FillStarprocedureisusefulfordrawingtheAmericanflag.

Details Thescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.FillStar,notbycallingFillStar.

Draw.Line PartofDrawmodule

Syntax Draw.Line(x1,y1,x2,y2,Color:int)

Description

TheDraw.Lineprocedureisusedtodrawalineonthescreenfrom(x1,y1)to(x2,y2)usingthespecifiedColor.

Example

ThisprogramdrawsalargeX,reachingtoeachcornerofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreen,(maxx,maxy)istherighttop,etc.

%Firstdrawalinefromtheleftbottomtorighttop

Draw.Line(0,0,maxx,maxy,1)

%Nowdrawalinefromthelefttoptorightbottom

Draw.Line(0,maxy,maxx,0,1)

Execute

Details

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Line,notbycallingLine.

Draw.MapleLeaf PartofDrawmodule

Syntax Draw.MapleLeaf(x1,y1,x2,y2,Color:int)

Description

TheDraw.MapleLeafprocedureisusedtodrawamapleleafonthescreenboundedbyarectangledescribedbythebottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.Ify1isgreaterthany2,thenthemapleleafisdrawnupsidedown.

Example

Thisprogramwilldrawtwomapleleavesbesideeachother.Thefirstwillbeinredandthesecondmapleleafwillbeupsidedownandinyellow.

Draw.MapleLeaf(0,0,100,100,red)

Draw.MapleLeaf(150,100,250,0,yellow)

Execute

Details

TheDraw.MapleLeafprocedureisusefulfordrawingtheCanadianflag.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.MapleLeaf,notbycallingMapleLeaf.

Draw.Oval PartofDrawmodule

Syntax Draw.Oval(x,y,xRadius,yRadius,Color:int)

Description

TheDraw.Ovalprocedureisusedtodrawanovalwhosecenterisat(x,y).ThehorizontalandverticaldistancesfromthecentertotheovalaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsalargeovalthatjusttoucheseachedgeofthescreeninmagenta.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thecenteroftheovalisat(midx,midy),whichisthemiddleofthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

Draw.Oval(midx,midy,midx,midy,magenta)

Execute

Details

Ideally,acircleisdrawnwhenxRadius=yRadius.Infact,theaspectratio(theratioofheighttowidthofpixelsdisplayedonthescreen)oftheIBMPCcompatiblesisnot1.0,sothisdoesnotdrawatruecircle.InCGAgraphicsmodethisratiois5to4.

Thescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,an

errorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Oval,notbycallingOval.

Draw.Polygon PartofDrawmodule

Syntax Draw.Polygon(x,y:array1..*ofint,n:int,Color:int)

Description

TheDraw.Polygonprocedureisusedtodrawapolygonwithnpoints.AlineisdrawninColorfromthepoint(x(1),y(1))to(x(2),y(2))to(x(3),y(3))andsoon.Afterdrawingthelineto(x(n),y(n)),alinewillbedrawnbackto(x(1),y(1)),closingthepolygon.TheDraw.Polygonprocedureisequivalentto:

fori:1..n-1

Draw.Line(x(i),y(i),x(i+1),y(i+1),

endfor

Draw.Line(x(n),y(n),x(1),y(1),Color)

Example

Thisprogramwillcreateanoctagonanddisplayitincolor1.

220,220,185,135)

150,100,65,65)

Draw.Polygon(x,y,8,brightblue)

Execute

Details

TheIBMPClimitsDraw.Polygontoamaximumof256points.

Status

Exportedqualified.

Draw.Polygon,notbycallingPolygon.

Draw.Star PartofDrawmodule

Syntax Draw.Star(x1,y1,x2,y2,Color:int)

Description

TheDraw.Starprocedureisusedtodrawastaronthescreenboundedbyarectangledescribedbythebottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.Ify1isgreaterthany2thenthestarisdrawnupsidedown.

Example

Thisprogramwilldrawtwostarsbesideeachother.Thefirststarwillbeincolor1andthesecondstarwillbeupsidedownandincolor2.

Draw.Star(0,0,100,100,brightred)

Draw.Star(150,100,250,0,brightblue)

Execute

Details

TheDraw.StarprocedureisusefulfordrawingtheAmericanflag.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.Star,notbycallingStar.

Draw.Text PartofDrawmodule

Syntax Draw.Text(txtStr:string,x,y,fontID,Color:int)

Description

Draw.Textisusedtoactuallydrawtextinaspecifiedfont.ThetextStrparametercontainsthestringtobedrawn.Thexandyparamtersarethelocationofthelowerlefthandcornerofthetexttobedisplayed.Theparameteristhenumberofthefontinwhichthetextistobedrawn.Theparameterisusedtospecifythecolorinwhichthetextistoappear.

Notethatthetextthatappearsiscompletelyunrelatedtothetextthatappearsusingput.Draw.Textisagraphicscommandandthusdoesnotuseoraffectthecursorlocation.

ThetextdrawnbytheDraw.Textproceduredoesnoterasethebackground.

Details

IfDraw.TextispassedaninvalidfontID,afatalerroroccurs.IftheDraw.Textcallfailsforother(non-fatal)reasonsthenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgastringwhichcontainsthetextualversionoftheerror.

DetailsDraw.TextisidenticaltoFont.Draw.Itisplacedhereforconsistencywithotherpixelgraphicsdrawingroutines.

Example

Theprogramdrawsaphraseinredsurroundedbyaboxinbrightblue.

varfont:int

font:=Font.New("serif:12")

assertfont1>0

varwidth:int:=Font.Width("Thisisinaseriffont",

varheight,ascent,descent,internalLeading:int

Font.Sizes(font,height,ascent,descent,internalLeading

Draw.Text("Thisisinaseriffont",50,30,font

Draw.Box(50,30+descent,50+width,30+height

Font.Free(font)

Execute

DetailsTousethesamefontasisusedbytheputstatement,usedefFontIDfontnumber.Thisfontdoesnothavetobecreatedorfreedbytheuser,andallowsaprogramtoquicklyplacetextinanylocationonthescreen.

Example

Theprogramdrawstwostringsinthedefaultfont(defFontID).

Draw.Text("DrawingHere",100,120,defFontID,

Draw.Text("andHere",180,90,defFontID,brightgreen

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.TextcallingText.

SeeAlso Fontmoduleformoreinformationaboutselectingthefonttobedisplayed.

Draw.ThickLine PartofDrawmodule

Syntax Draw.ThickLine(x1,y1,x2,y2,lineWidth,Color:int)

Description

TheDraw.ThickLineprocedureisusedtodrawalineonthescreenfrom(to(x2,y2)usingthespecifiedColor.

Example

ThisprogramdrawsalargeX,reachingtoeachcornerofthescreenintwodifferentcolors.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreen,(maxx,maxy)istherighttop,etc.

%Firstdrawalineof5pixelwidthfromtheleftbottomtorighttop

Draw.ThickLine(0,0,maxx,maxy,5,brightred)

%Nowdrawalineof5pixelwidthfromthelefttoptorightbottom

Draw.ThickLine(0,maxy,maxx,0,5,brightgreen)

Execute

DetailsThescreenmustbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingDraw.ThickLinecallingThickLine.

Seealso View.Set,maxx,maxyandthevariousproceduresintheDrawunit.

drawarc graphicsprocedure

Syntaxdrawarc(x,y,xRadius,yRadius:int, initialAngle,finalAngle,Color:int)

Description

Thedrawarcprocedureisusedtodrawanarcwhosecenterisat(x,y).Thisisjustlikedrawoval,exceptthatyoumustalsogivetwoangles,initialAngleandfinalAngle,whichdeterminewheretostartandstopdrawing.Zerodegreesis"threeo'clock",90degreesis"twelveo'clock",etc.ThehorizontalandverticaldistancesfromthecentertothearcaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsasemicircle(actually,anapproximationtoasemicircle)whosecenteris(midx,0)thebottomcenterofthescreen,usingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

constmidx:=maxxdiv2

drawarc(midx,0,maxy,maxy,0,180,1)

Execute

Details

ThemeaningoftheColornumberdependsonthecurrentpalette.Seethepalettestatement.

Thescreenshouldbeina"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotina"graphics"mode,it

willautomaticallybesetto"graphics"mode.

Seealso setscreen,maxx,maxyandthevariousdraw…procedures.

drawbox graphicsprocedure

Syntax drawbox(x1,y1,x2,y2,Color:int)

Description

Thedrawboxprocedureisusedtodrawaboxonthescreenwithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.

Example

Thisprogramdrawsalargebox,reachingtoeachcornerofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreenand(maxx,maxy)istherighttop.

drawbox(0,0,maxx,maxy,1)

Execute

Details

Thescreenshouldbeina"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotina"graphics"mode,itwillautomaticallybesetto"graphics"mode.

drawdot graphicsprocedure

Syntax drawdot(x,y,Color:int)

Description

Thedrawdotprocedureisusedtocolorthedot(pixel)atlocation(x,y)usingthespecifiedColor.

Example

Thisprogramrandomlydrawsdotswithrandomcolors.Themaxx,maxyandmaxcolorfunctionsgivethemaximumx,yandcolorvalues.

varx,y,c:int

randint(x,0,maxx)%Randomx

randint(y,0,maxy)%Randomy

randint(c,0,maxcolor)%Randomcolor

drawdot(x,y,c)

endloop

Execute

Thescreenshouldbeina"graphics"mode.Ifthescreenisnotin

Details a"graphics"mode,itwillautomaticallybesetto"graphics"mode.Seesetscreenfordetails.

Example

Thisprogramdrawsalineofdotsthatbounceoffthe“sides”ofthescreen.Italsodemonstratesthatyoucanuserealcoordinatestostoreposition(x,y),aslongasyouconvertthecoordinatestointvaluesusingroundinthedrawdotcall.

varx,y:real

vardx,dy:real

varclr:int:=1

x:=Rand.Int(1,maxx-1)

y:=Rand.Int(1,maxy-1)

dx:=Rand.Real-0.5

dy:=Rand.Real-0.5

drawdot(round(x),round(y),clr)

clr:=(clr+1)modmaxcolor

x:=x+dx

y:=y+dy

ifx<=0orx>=maxxthen

dx:=-dx

ify<=0ory>=maxythen

dy:=-dy

endloop

Execute

drawfill graphicsprocedure

Syntax drawfill(x,y:int,fillColor,borderColor:int)

Description

Thedrawfillprocedureisusedtocolorinafigurethatisonthescreen.Startingat(x,y),thefigureisfilledwithfillColortoasurroundingborderwhosecolorisborderColor.

Example

Thisprogramdrawsanovalwithxandyradiusof10inthecenterofthescreenusingcolor1.Thentheovalisfilledwithcolor2.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

drawoval(midx,midy,10,10,1)

drawfill(midx,midy,2,1)

Execute

Details

ThemeaningoftheColornumberdependsonthecurrentpalette;seethepalettestatement.

Warning:InTuringforIBMPCcompatibles,drawfillfailstocompletelyfillinsomecomplicatedfiguresthatcontain"islands"withinthemsurroundedbytheborderColor.

drawfillarc graphicsprocedure

Syntaxdrawfillarc(x,y,xRadius,yRadius:int, initialAngle,finalAngle,Color:int)

Description

Thedrawfillarcprocedureisusedtodrawafilledarcwhosecenterisat(x,y).Itthenfillsinthepie-shapedwedgeusingthespecifiedColor.Tooutlineafilledarc,usedrawfillarcwiththeColorparametersettothefillcolorandthendrawarcwiththeColorparametersettothebordercolor.ForinitialAngleandfinalAngle,whichdeterminetheedgesofthewedge,zerodegreesis"threeo'clock"and90degreesis"twelveo'clock",etc.ThehorizontalandverticaldistancesfromthecentertothearcaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsafilledsemicircle(actually,anapproximationtoasemicircle)whosecenteris(midx,0),thebottomcenterofthescreen,usingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.

constmidx:=maxxdiv2

drawfillarc(midx,0,maxy,maxy,0,180,1)

Execute

OnthePC,drawfillarcfillsthepie-shapedwedgebyusinga

Details

"flood"fillandisthussubjecttoalltheconditionsofafloodfill.

drawfillbox graphicsprocedure

Syntax drawfillbox(x1,y1,x2,y2,Color:int)

Description

Thedrawfillboxprocedureisusedtodrawafilledboxonthescreenwithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)filledusingthespecifiedColor.Togetaboxoutlinedinadifferentcolor,usedrawfillboxwiththeColorparametersettothefillcolorandthencalldrawboxwiththeColorparametersettothebordercolor.

Example

Thisprogramwillfillthebottomhalfofthescreenwithcolor1andthenoutlineitincolor2.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreenand(maxx,maxy)istherighttop.

drawfillbox(0,0,maxx,maxydiv2,1)

drawbox(0,0,maxx,maxydiv2,2)

Execute

Details

drawfillmapleleaf graphicsprocedure

Syntax drawfillmapleleaf(x1,y1,x2,y2,Color:int)

Description

Thedrawfillmapleleafprocedureisusedtodrawafilledmapleleafonthescreenboundedbyarectanglewithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)andfilledusingthespecifiedColor.Togetamapleleafoutlinedinadifferentcolor,usedrawfillmapleleafwiththeColorparametersettothefillcolorandthencalldrawmapleleafwiththeColorparametersettothebordercolor.Ify1isgreaterthany2,thenthemapleleafisdrawnupsidedown.

Example

Thisprogramwilldrawtwomapleleavesbesideeachother.Thefirstwillbeoutlinedincolor1andfilledincolor2.Thesecondmapleleafwillbeupsidedownandbothfilledandoutlinedincolor3.

drawfillmapleleaf(0,0,100,100,1)

drawmapleleaf(0,0,100,100,2)

drawfillmapleleaf(150,100,250,0,3)

Execute

Thedrawfillmapleleafprocedureisusefulfordrawingthe

Details

Canadianflag.

drawfilloval graphicsprocedure

Syntax drawfilloval(x,y,xRadius,yRadius,Color:int)

Description

Thedrawfillovalprocedureisusedtodrawafilledovalwhosecenterisat(x,y).ThehorizontalandverticaldistancesfromthecentertotheovalaregivenbyxRadiusandyRadius.Togetanovaloutlinedinadifferentcolor,usedrawfillovalwiththeColorparametersettothefillcolorandthencalldrawovalwiththeColorparametersettothebordercolor.

Example

Thisprogramdrawsalargefilledovalthatjusttoucheseachedgeofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thecenteroftheovalisat(midx,midy),whichisthemiddleofthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

drawfilloval(midx,midy,midx,midy,1)

Execute

Ideally,acircleisdrawnwhenxRadius=yRadius.Infact,theaspectratio(theratioofheighttowidthofpixelsdisplayedonthescreen)oftheIBMPCcompatiblesisnot1.0,sothisdoesnot

Details

drawatruecircle.InCGAgraphicsmodethisratiois5to4.

drawfillpolygon graphicsprocedure

Syntax drawfillpolygon(x,y:array1..*ofint,n:int,Color:int)

Description

Thedrawfillpolygonprocedureisusedtodrawafilledpolygonwithnpoints.Thepolygonisdescribedbythepoints(x(1),y(1))to(x(2),y(2))to(x(3),y(3))andsoonto(x(n),y(n)).ThepolygonwillbedrawnandfilledwithColor.

Togetanpolygonoutlinedinadifferentcolor,usedrawfillpolygonwiththeColorparametersettothefillcolorandthencalldrawpolygonwiththeColorparametersettothebordercolor.

Example

Thisprogramwillcreateafilledoctagonanddisplayitincolor1andthenoutlineitincolor3.

220,220,185,135)

150,100,65,65)

drawfillpolygon(x,y,8,1)

drawpolygon(x,y,8,3)

Execute

Details

ThePCallowsamaximumof256points.Aswell,drawfillpolygoncanfail(duetolackofmemory).Iffailureoccurs,itwilltrytodrawanoutlineofthepolygon.Ifthatalsofails,itwillnotdrawanything.

drawfillstar graphicsprocedure

Syntax drawfillstar(x1,y1,x2,y2,Color:int)

Description

Thedrawfillstarprocedureisusedtodrawafilledfivepointedstaronthescreenboundedbyarectanglewithbottomleftandtoprightcornersof(x1,y1)to(x2,y2)andfilledusingthespecifiedColor.Togetastaroutlinedinadifferentcolor,usedrawfillstarwiththeColorparametersettothefillcolorandthencalldrawstarwiththeColorparametersettothebordercolor.Ify1isgreaterthany2,thenthestarisdrawnupsidedown.

Example

Thisprogramwilldrawtwostarsbesideeachother.Thefirstwillbeoutlinedincolor1andfilledincolor2.Thesecondstarwillbeupsidedownandbothfilledandoutlinedincolor3.

drawfillstar(0,0,100,100,1)

drawstar(0,0,100,100,2)

drawfillstar(150,100,250,0,3)

Execute

ThedrawfillstarprocedureisusefulfordrawingtheAmericanflag.

DetailsThemeaningoftheColornumberdependsonthecurrentpalette.Seethepalettestatement.

drawline graphicsprocedure

Syntax drawline(x1,y1,x2,y2,Color:int)

Description

Thedrawlineprocedureisusedtodrawalineonthescreenfrom(x1,y1)to(x2,y2)usingthespecifiedColor.

Example

ThisprogramdrawsalargeX,reachingtoeachcornerofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thepoint(0,0)istheleftbottomofthescreen,(maxx,maxy)istherighttop,etc.

%Firstdrawalinefromtheleftbottomtorighttop

drawline(0,0,maxx,maxy,1)

%Nowdrawalinefromthelefttoptorightbottom

drawline(0,maxy,maxx,0,1)

Execute

Details

drawmapleleaf graphicsprocedure

Syntax drawmapleleaf(x1,y1,x2,y2,Color:int)

Description

Thedrawmapleleafprocedureisusedtodrawamapleleafonthescreenboundedbyarectangledescribedbythebottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.Ify1isgreaterthany2,thenthemapleleafisdrawnupsidedown.

Example

Thisprogramwilldrawtwomapleleavesbesideeachother.Thefirstwillbeincolor1andthesecondmapleleafwillbeupsidedownandincolor2.

Execute

Details

ThedrawmapleleafprocedureisusefulfordrawingtheCanadianflag.

drawoval graphicsprocedure

Syntax drawoval(x,y,xRadius,yRadius,Color:int)

Description

Thedrawovalprocedureisusedtodrawanovalwhosecenterisat(x,y).ThehorizontalandverticaldistancesfromthecentertotheovalaregivenbyxRadiusandyRadius.

Example

Thisprogramdrawsalargeovalthatjusttoucheseachedgeofthescreenusingcolornumber1.Themaxxandmaxyfunctionsareusedtodeterminethemaximumxandyvaluesonthescreen.Thecenteroftheovalisat(midx,midy),whichisthemiddleofthescreen.

constmidx:=maxxdiv2

constmidy:=maxydiv2

drawoval(midx,midy,midx,midy,1)

Execute

Details

Ideally,acircleisdrawnwhenxRadius=yRadius.Infact,theaspectratio(theratioofheighttowidthofpixelsdisplayedonthescreen)oftheIBMPCcompatiblesisnot1.0,sothisdoesnotdrawatruecircle.InCGAgraphicsmodethisratiois5to4.

ThemeaningoftheColornumberdependsonthecurrentpalette.

Seethepalettestatement.

drawpic graphicsprocedure

Syntax drawpic(x,y:int,buffer:array1..*ofint,picmode:int)

Description

Thedrawpicprocedureisusedtocopyofarectangularpictureontothescreen.Theleftbottomofthepictureisplacedat(x,y).Inthecommoncase,thebufferwasinitializedbycallingtakepic.Thevaluesofpicmodeare:

0:Copyactualpictureonscreen. 1:CopypicturebyXORingitontothescreen.

XORingapictureontothescreentwiceleavesthescreenasitwas(thisisaconvenientwaytomoveimagesforanimation).XORingapictureontoabackgroundeffectivelysuperimposesthepictureontothebackground.

Details

Seetakepicforanexampleoftheuseofdrawpicandforfurtherinformationaboutbuffersfordrawingpictures.

Thescreenmustbeina"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotina"graphics"mode,anerrorwilloccur.

Details

Thedrawpic,takepic,andsizepicsubprogramshavebeenmadeobsoletebythesubprogramsPic.DrawandPic.NewofthePicmodule.Usersarestronglysuggestedtousethoseroutinesinstead.ThePicmodulealsocontainssubprogramstoloadimagesfromfiles.

Seealso

takepicandsizepic.Seealsosetscreen,maxx,maxyandthevariousdraw…procedures.

SeealsopredefinedunitDrawandPic.

drawpolygon graphicsprocedure

Syntax drawpolygon(x,y:array1..*ofint,n:int,Color:int)

Description

Thedrawpolygonprocedureisusedtodrawapolygonwithnpoints.AlineisdrawninColorfromthepoint(x(1),y(1))to(x(2),y(2))to(x(3),y(3))andsoon.Afterdrawingthelineto(x(n),y(n)),alinewillbedrawnbackto(x(1),y(1)),closingthepolygon.Thedrawpolygonprocedureisequivalentto:

fori:1..n-1

drawline(x(i),y(i),x(i+1),y(i+1),

endfor

drawline(x(n),y(n),x(1),y(1),Color)

Example

Thisprogramwillcreateanoctagonanddisplayitincolor1.

220,220,185,135)

150,100,65,65)

drawpolygon(x,y,8,1)

Execute

Details

TheIBMPClimitsdrawpolygontoamaximumof256points.

drawstar graphicsprocedure

Syntax drawstar(x1,y1,x2,y2,Color:int)

Description

Thedrawstarprocedureisusedtodrawastaronthescreenboundedbyarectangledescribedbythebottomleftandtoprightcornersof(x1,y1)to(x2,y2)usingthespecifiedColor.Ify1isgreaterthany2,thenthestarisdrawnupsidedown.

Example

Thisprogramwilldrawtwostarsbesideeachother.Thefirstwillbeincolor1andthesecondstarwillbeupsidedownandincolor2.

drawstar(0,0,100,100,1)

drawstar(150,100,250,0,2)

Execute

Details

ThedrawstarprocedureisusefulfordrawingtheAmericanflag.

Thescreenshouldbeina"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotina"graphics"mode,it

willautomaticallybesetto"graphics"mode.

empty conditionfunction

Syntax empty(variableReference):boolean

Description

Theemptyfunctionisusedinaconcurrentprogram.ItreturnstrueifthevariableReference,whichmustbeaconditionvariable,hasnoprocesseswaitingforit.Processesjointhequeueofaconditionvariablebyexecutingthewaitstatement,andareawakenedbythesignalstatement.

Seealsocondition,wait,signal,forkandmonitor.

SeealsopredefinedunitConcurrency.

enum enumeratedtype

Syntax

AnenumeratedTypeis:

enum(id{,id})

Description

Thevaluesofanenumeratedtypearedistinctandincreasing.Theycanbethoughtofasthevalues0,1,2andsoon,butarithmeticisnotallowedwiththesevalues.

Exampletypecolor:enum(red,green,blue)

varc:color:=color.red

vard:color:=succ(c)%dbecomesgreen

Details

Eachvalueofanenumeratedtypeisthenameofthetypefollowedbyadotfollowedbytheelement'sname,forexample,color.red.Enumeratedvaluescanbecomparedforequalityandforordering.Thesuccandpredfunctionscanbeusedtofindthevaluefollowingorprecedingagivenenumeratedvalue.Theordfunctioncanbeusedtofindtheenumerationpositionofavalue,forexample,ord(color.red)is0.

Enumeratedtypescannotbecombinedwithintegersorwithotherenumeratedtypes.

Details

Itisillegaltodeclarean"anonymous"enum.Theonlylegaldeclarationforanenumisinatypedeclaration.Forexample,thefollowingisnowillegal:

vara:arrayenum(red,green,blue)ofint

Giventhatthereisno(easy)wayofgeneratinganenumvaluewithoutitbeinganamedtype,thisshouldnotimpactanybutthemostbizarrecode.

The"put"and"get"statementsemanticshavebeenexpandedtoallowput'sandget'sofenumvalues.Thevaluesprintedandinputaretheelementnamesthemselves,casesensitive.Forexample,

Details for

typecolors:enum(red,green,blue)

varc:colors:=colors.red

putc%outputs"red"(withoutthequotes)

enumeratedValue enumeratedvalue

Syntax

AnenumeratedValueis:

enumeratedTypeId.enumeratedId

Description

Thevaluesofanenumeratedtypearewrittenasthetypename(enumeratedTypeId)followedbyadotfollowedbyoneoftheenumeratedvaluesofthetype(enumeratedId).

Example

Inthisexample,color.redisanenumeratedValue.

typecolor:enum(red,green,blue)

varc:color:=color.red

vard:color:=succ(c)%dbecomesgreen

Details

Theabovedescriptionhasbeensimplifiedbyignoringthepossibilitythattheenumtypecanbeexportedfromamodule.Ifthisisthecase,eachuseofoneoftheenumeratedvaluesoutsideofmoduleMmustbeprecededbythemodulenameandadot,asinM.color.red.

Seealso theenumtypeandexplicitConstant.

eof end-of-filefunction

Syntax eof(streamNumber:int):boolean

Description

Theeof(endoffile)functionisusedtodetermineifthereisanymoreinput.Itreturnstruewhentherearenomorecharacterstoberead.Theparameteranditsparenthesesareomittedwhenreferringtothestandardinput(usuallythisisthekeyboard);otherwisetheparameterspecifiesthenumberofastream.Thestreamnumberhasbeendetermined(inmostcases)byanopenstatement.

Example

Thisprogramreadsandoutputsallthelinesinthefilecalled"info".

varline:string

varfileNumber:int

open:fileNumber,"info",get

exitwheneof(fileNumber)

get:fileNumber,line:*

putline

endloop

Execute

Details

Seealsothedescriptionofthegetstatement,whichgivesmoreexamplesoftheuseofeof.Seealsotheopenandreadstatements.

Whentheinputisfromthekeyboard,theusercansignalend-of-filebytypingcontrol-ZonaPC(orcontrol-DonUNIX).Ifaprogramtestsforeofonthekeyboard,andtheuserhasnottypedcontrol-Z(orcontrol-D)andtheuserhastypednocharacters

beyondthosethathavebeenread,theprogrammustwaituntilthenextcharacteristyped.Oncethischaracteristyped,theprogramknowswhetheritisattheendoftheinput,andreturnsthecorrespondingtrueorfalsevalueforeof.

Example

AnotherexampleisavailablethatillustratesdetectingEOFfromthekeyboard.

equivalence oftypes

Description

Twotypesareequivalenttoeachotheriftheyareessentiallythesametypes(theexactrulesaregivenbelow).Whenavariableispassedtoavarformalparameter,thetypesofthevariableandtheformalparametermustbeequivalentbecausetheyareeffectivelythesamevariable.Whenanexpressionisassignedtoavariable,theirtypesmustbeequivalent,exceptforspecialcases.Forexample,Turingallowsyoutoassignanintegerexpressiontoarealvariable(seeassignabilityfordetails).

Example

varj:int

typepersonType:

record

age:int

name:string(20)

endrecord

procedurep(vari:int,vara:array1..25of

varr:personType)

…bodyofprocedurep,whichmodifieseachofi,

vars:personType

p(j,b,s)%Procedurecalltop

%iandjhavetheequivalenttypeint

%Arraysaandbhaveequivalenttypes

%Recordsrandshaveequivalenttypes

Twotypesaredefinedtobeequivalentiftheyare:

(a) thesamestandardtype(int,real,booleanorstring),(b) subrangeswithequalfirstandlastvalues,

(c) arrayswithequivalentindextypesandequivalentcomponenttypes,(d) stringswithequalmaximumlengths,(e) setswithequivalentbasetypes,or

Details

(f) pointerstothesamecollection;inaddition,

(g) adeclaredtypeidentifierisalsoequivalenttothetypeitnames(andtothetypenamedbythattype,ifthattypeisanamedtype,etc.)

(h) bothchar,(i) bothchar(n)withthesamelength,

(j) bothproceduretypes,withcorrespondingequivalentparametertypesandcorrespondingvarornon-varoftheparameters,

(k) bothfunctiontypes,withcorrespondingequivalentparametertypesandcorrespondingvarornon-varoftheparametersandequivalentresulttypes,

(l) bothpointertypestothesameclassorequivalenttypeandbotharecheckedorunchecked.

Eachseparateinstanceofarecord,unionorenumeratedtype(writtenoutusingoneofthekeywordsrecord,unionorenum)createsadistincttype,equivalenttonoothertype.Bycontrast,separateinstancesofarrays,strings,subrangesandsetsareconsideredequivalentiftheirpartsareequalandequivalent.

OpaquetypeT,exportedfromamodule,monitororclassMasopaque,isaspecialcaseofequivalence.OutsideofMthistypeiswrittenM.T,andisconsideredtobedistinctfromallothertypes.Bycontrast,iftypeUisexportednon-opaque,theusualrulesofequivalenceapply.TheparameterorresulttypeofanexportedprocedureorfunctionoranexportedconstantisconsideredtohavetypeM.ToutsideofMiftheitemisdeclaredusingthetypeidentifierT.OutsideofM,theopaquetypecanbeassigned,butnotcompared.

Itisnotrequiredthatsubprogramtypeshavethesamenamesandparameternamestobeequivalent.Theyalsodonotrequirethesamefactoringofparametersacrosstheirtypes,asini,j:intinsteadofi:int,j:int.

erealstr real-to-stringfunction

Syntaxerealstr(r:real, width,fractionWidth,exponentWidth:int):string

Description

Theerealstrfunctionisusedtoconvertarealnumbertoastring;forexample,erealstr(2.5e1,10,3,2)="b2.500e+01"wherebrepresentsablank.Thestring(includingexponent)isanapproximationtor,paddedontheleftwithblanksasnecessarytoalengthofwidth.

Thewidthmustbeanon-negativeintvalue.Ifthewidthparameterisnotlargeenoughtorepresentthevalueofr,itisimplicitlyincreasedasneeded.

ThefractionWidthparameteristhenon-negativenumberoffractionaldigitstobedisplayed.Thedisplayedvalueisroundedtothenearestdecimalequivalentwiththisaccuracy.Inthecaseofatie,thevalueisroundedtothelargerofthetwovalues.

TheexponentWidthparametermustbenon-negativeandgivethenumberofexponentdigitstobedisplayed.IfexponentWidthisnotlargeenoughtorepresenttheexponent,morespaceisusedasneeded.Thestringreturnedbyerealstrisoftheform:

{blank}[-]digit.{digit}esigndigit{digit}

wheresignisaplusorminussign.Theleftmostdigitisnon-zero,unlessallthedigitsarezeros.

Theerealstrfunctionapproximatestheinverseofstrreal,althoughround-offerrorskeepthesefrombeingexactinverses.

Seealso frealstr,realstr,strreal,intstrandstrintfunctions.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwitherrorsreturnedfromotherpredefinedsubprograms.

AllroutinesintheErrorunitareexportedqualified(andthusmustbeprefacedwith"Error.").

TheconstantsrepresentingthepossibleerrorsreturnedbythismodulecanbefoundintheErrorNummodule.

EntryPoints

Last Returnsthe(integer)errorcodeproducedbythelastcalltoapredefinedsubprogram.

LastMsg Returnstheerrorstringproducedbythelastcalltoapredefinedsubprogram.

LastStr Returnsthestringversionoftheerrorconstantproducedbythelastcalltoapredefinedsubprogram.

Msg Returnsthestringthatcorrespondstoaspecifiederrorcode.

Str Returnsthestringversionoftheerrorconstantthatcorrespondstoaspecifiederrorcode.

Trip Thiscausesthespecifiederrorcodetobeset.

TripMsg Thiscausesthespecifiederrorcodeanderrormessagetobeset.

Halt Thiscausesexecutiontohaltwiththespecifiederrormessage.

Error.Last PartofErrormodule

Syntax Error.Last:int

Description

Error.Lastisafunctionthatreturnstheerrorcodesetbythelastcalledpredefinedsubprogram.Ifthereisnoerror,thenitreturnseNoError(whichis0).Ifthereisanerror,youcanuseError.LastMsgtoobtainatextualformoftheerrororError.LastStrtoobtainastringversionoftheerrorconstant.

ThefactthatError.LastisnoteNoErrordoesnotnecessarilymeanthatthepreviouspredefinedfunctionfailedorfailedcompletely.Error.Lastalsoreturnsanumberofwarningcodes.Forexample,ifauserspecifiesanumberlargerthanmaxcolorforthecolorparameteroftheDraw.Lineprocedure,thelineisstilldrawn,onlyincolormaxcolor.However,Error.Lastwillreturnacodethatwarnstheuserofthefact.

Example

Thisprogramcreatesthedirectorycalledinformation.Ifthecreationfails,itprintsouttheerrornumberandanerrormessage.

varf:int

open:f,"testdata/information.txt",get

iff<=0then

put"Fileopened"

put"Couldnotopenfile."

put"ErrorNumber:",Error.Last

put"ErrorMessage:",Error.LastMsg

put"ErrorConstant:",Error.LastStr

Execute

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingError.Last,notbycallingLast.

Error.LastMsg PartofErrormodule

Syntax Error.LastMsg:string

Description

Error.LastMsgisafunctionthatreturnstheerrormessagesetbythelastcalledpredefinedsubprogram.Ifthereisnoerror,thenitreturnstheemptystring.Ifthereisanerror,youcanuseError.Lasttoobtaintheerrorcode.

ThefactthatError.LastMsgisnot""doesnotnecessarilymeanthatthepreviouspredefinedfunctionfailedorfailedcompletely.Error.LastMsgalsoreturnsanumberofwarningmessages.Forexample,ifauserspecifiesanumberlargerthanmaxcolorforthecolorparameteroftheDraw.Lineprocedure,thelineisstilldrawn,onlyincolormaxcolor.However,Error.LastMsgwillreturnamessagethatindicatesthatthecolorwasoutofrange

Example

Dir.Create("testdata/information")

put"ErrorMessage:",Error.LastMsg

Execute

Status

Exportedqualified.

Error.LastMsg,notbycallingLastMsg.

Error.LastStr PartofErrormodule

Syntax Error.LastStr:string

Description

Error.LastStrisafunctionthatreturnsthestringversionoftheerrorcodesetbythelastcalledpredefinedsubprogram(i.e.itwouldreturnthestring"eDrawClrNumTooLarge"forusingacolorgreaterthanmaxcolorinaDrawcommand).Ifthereisnoerrorthenitreturnstheemptystring.Ifthereisanerror,youcanuseError.Lasttoobtaintheactualerrorcode.

ThefactthatError.LastStrisnot""doesnotnecessarilymeanthatthepreviouspredefinedfunctionfailedorfailedcompletely.Error.LastStralsoreturnsanumberoferrorcodesforwarningmessages.Forexample,ifauserspecifiesanumberlargerthanmaxcolorforthecolorparameteroftheDraw.Lineprocedure,thelineisstilldrawn,onlyincolormaxcolor.However,Error.LastStrwillreturnastringversionoftheerrorcodethatindicatesthatthecolorwasoutofrange.

YoucantakealookattheerrorconstantsdefinedbylookingattheunitErrorNumwhichcontainsalldefinederrorcodes.

Example

Dir.Create("testdata/information")

put"ErrorConstant:",Error.LastStr

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.LastStr,notbycallingLastStr.

Error.Msg PartofErrormodule

Syntax Error.Msg(errorCode:int):string

Description

Error.Msgisafunctionthatreturnstheerrormessagerelatedtoaspecifiederrorcode.IftheerrorcodeiseNoError,orifthereisnosucherrorcode,itreturnstheemptystring.Ifthereissuchanerror,itreturnsthetextualmessageassociatedwiththaterror.

Example

ThisprogramprintsouttheerrormessageassociatedwitheFsysFileNotFound(“Filenotfound”).

putError.Msg(eFsysFileNotFound)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.Msg,notbycallingMsg.

Error.Str PartofErrormodule

Syntax Error.Str(errorCode:int):string

Description

Error.Strisafunctionthatreturnstheerrormessagerelatedtoaspecifiederrorcode.IftheerrorcodeiseNoErrororifthereisnosucherrorcode,itreturnstheemptystring.Ifthereissuchanerror,itreturnsthetextualmessageassociatedwiththaterror.

ExampleThisprogramprintsoutthestring"eFsysFileNotFound".

putError.Str(eFsysFileNotFound)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.Str,notbycallingStr.

Error.Trip PartofErrormodule

Syntax Error.Trip(errorCode:int)

Description

Error.TripisaprocedurethatsetstheerrornumberthatisreturnedbyError.LastandError.LastMsg.Itdoesnothalttheprogram.

Errorcodesthatdonotcorrespondtorecognizederrorswillcauseanabortwiththeerrormessage"UnknownError#n"wherenistheerrorpassedin.

YoucanfindalistofconstantsforthelegalerrorcodesinthemoduleErrorNum.AnycalltoError.TripshoulduseaconstantfoundintheErrorNummodule.

Example

Thisprogramsetsanerrorcode.Theprogramoutputs201fortheerrornumberand"Filenotfound"forthemessage.

Error.Trip(eFsysFileNotFound)

put"Errorcode=",Error.Last

put"Errormessage=",Error.LastMsg

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.Trip,notbycallingTrip.

ErrorNum

Description

ThisunitcontainsalltheconstantsrepresentingerrorsusedbytheErrormodule.

AllconstantsintheErrorNummoduleareexportedunqualified.(Thismeansyoucanusetheconstantsdirectlywithouthavingtousethequalifier"ErrorNum.".)

Exceptions

Description

ThisunitcontainsalltheconstantscorrespondingtoexceptionnumbersinTuringforuseinbuildingexceptionhandlers.

AllconstantsintheExceptionsmoduleareexportedunqualified.(Thismeansyoucanusetheconstantsdirectlywithouthavingtousethequalifier"Exceptions.".)

exit statement

Syntax

AnexitStatementisoneof:

(a) exitwhentrueFalseExpn (b) exit

Description

Anexitstatementisusedtostoptheexecutionofalooporforstatement.Form(a)isthemostcommon.Here,thetrue/falseexpressionisevaluated.Ifitistrue,theloopisterminatedandexecutionjumpsdownandcontinuesjustbeyondendlooporendfor.Ifitisfalse,theloopkeepsonrepeating.Form(b)alwayscausesthelooptoterminate.Thisformisalmostalwaysusedinsideanotherconditionalstatementsuchasif.

Example

InputnamesuntilfindingJones.

varname:string

getname

exitwhenname="Jones"

endloop

Details

Exitstatementsmustoccuronlyinsidelooporforstatements.Anexittakesyououtoftheclosestsurroundinglooporfor.Theonlyotherwaystoterminatealooporforisbyreturn(inaprocedureorinthemainprogram,inwhichcasetheentireprocedureormainprogramisterminated)orbyresult(inafunction,inwhichcasetheentirefunctionisterminatedandaresultvaluemustbesupplied).

Theform"exitwhentrueFalseExpn"isequivalentto"iftrueFalseExpnthenexitendif".

exp exponentiationfunction

Syntax exp(r:real):real

Description

Theexpfunctionisusedtofindetothepowerr,whereeisthenaturalbaseandristheparametertoexp.Forexample,exp(0)returns1andexp(1)returnsthevalueofe.

Example

Thisprogramprintsouttheexponentialvaluesof1,2,3,…upto100.

fori:1..100

put"Exponentialof",i,"is",exp(i)

endfor

Seealsoln(naturallogarithmfunction).

explicitCharConstant characterliteral

SyntaxAnexplicitCharConstantisasequenceofcharacterssurroundedbysinglequotationmarks,forexample,'Renzo'.

Example

Inthefollowing,theexplicitcharacterconstantsare'H'and'Hi'.

varc:char:='H'

vard:char(2):='Hi'

Details

Anexplicitcharacterconstantmustcontainatleastonecharacter.Ifitcontainsexactlyonecharacter,asin'A',itstypeischar.Ifitcontainstwoormorecharacters(ncharacters),as'Width',itstypeischar(n).Thedifferencebetweenthecharandchar(1)typesisrarelyofsignificance,butdoesmakeadifferenceindeclarationswithoutanexplicittype,forexample:

varc:='H'%Typeischar

vard:='Hi'%Typeischar(2)

vare:="H"%Typeisstring

Thebackslash\isusedinexplicitstringandchar(n)constantstospecifyspecialvalues,forexample,'\T'isthetabcharacter.Similarly,thecarat^isusedtospecifyASCIIcontrolcharacters,forexample,'^H'istheASCIIbackspace.SeeexplicitStringConstantsfordetails.

Explicitcharacterconstantscannotcrosslineboundaries.Torepresentaconstantthatislongerthanaline,breakitintotwoormorestringsonseparatelinesanduse+(catenation)tojointheindividualstrings.Seecatenation.

Anexplicitcharacterconstantmaybelimitedinlengthbytheimplementation.Werecommendthatthislimitationbeatleast32767.

Explicitcharacterconstants,butnotstrings,areallowedtocontainthecharacterinternalvalues0(calledeosforendofstring)and128(calleduninitchar,usedastheuninitializedstringvalue).

explicitConstant literal

Syntax

AnexplicitConstantisoneof:

(a) explicitStringConstant %e.g.:"Helloworld"

(b) explicitIntegerConstant %e.g.:25 (c) explicitRealConstant %e.g.:51.8

(d) explicitTrueFalseConstant%e.g.:true

(e) explicitCharConstant %e.g.:'Hi'

DescriptionAnexplicitConstantgivesitsvaluedirectly.Forexample,thevalueoftheexplicitconstant25istwenty-five.

Example

Inthefollowing,theexplicitconstantsare"Helloworld",3.14159and2.Notethatpiisanamedconstantratherthananexplicitconstant.

put"Helloworld"

vardiameter:real

constpi:=3.14159

diameter:=pi*r**2

varx:=diameter

Details

Insomeprogramminglanguages,explicitconstantsarecalledliteralsorliteralvalues,becausetheyliterally(explicitly)givetheirvalues.

Seealso

explicitStringConstant,explicitIntegerConstant,explicitRealConstant,explicitTrueFalseConstantandexplicitCharConstant.SeealsoenumeratedValue.

explicitIntegerConstant integerliteral

Syntax

AnexplicitIntegerConstantisasequenceofoneormoredecimaldigits(0to9)optionallyprecededbyaplusorminussign.Thisisanalternateformthatspecifiesanumberbase(suchasbase2orbase16).

Example

Inthefollowing,theexplicitintegerconstantsare0,115and5.

varcount:int:=0

constheight:=115

count:=height-5

Details

IncurrentimplementationsofTuring,therangeoftheint(integer)typeisfrom-2147483647to2147483647.Inotherwords,themaximumsizeofintegeris2**31-1.Thisistherangethatfitsintofourbytes,withonepatternleftover(thelargestnegative4-bytenumber)torepresenttheuninitializedvalue.Seemaxint.

Valuescanbewritteninbase2or16oranyotherbaseintherange2to36(36becausethereare10digitsand26letters).Thisformbeginswiththebase,suchas16,then#,andthenthevaluewritteninthatbase,forexample,16#Ahasthevalue10.Thelettersa,b,c…representthedigitvalues10,11,12…CapitallettersA,B,C…canbeusedinsteadoflowercase.Herearesomeexamples.

2#1 =1 (Base2) 2#11 =3 (Base2) 16#a =10 (Base16) 16#FF =255 (Base16) 16#FFFF =32767 (Base16) 8#10 =8 (Base8)

Hereisanexampleofusingthese:

constmaxnat1:=16#FF%Largest1-bytenaturalnumber

constmaxint2:=16#7FFF%Largest2-byteinteger

Youshouldbecarefultoavoidconfusionaboutpatternssuchas16#FFFF.Itistemptingtothinkthatthisisthevalue1,becausethebitpattern(2-bytetwo's

complementinternalrepresentation)for1isthesameasthebitpatternfor16#FFFF=32767.However,thevalue(asopposedtotheinternalrepresentation)of1and32767aredifferent.

Seealso

int,maxint(thelargestintegervalue),nat(positivevaluesonly)andbyteintegers).Seealsointstrandnatstrwhichconvertintegerandnaturalnumbervaluestocorrespondingcharacterstringsinanybase,forexampleintstr(4,0,2)="100".

explicitRealConstant realliteral

SyntaxAnexplicitRealConstantconsistsofanoptionalplusorminussign,asignificantdigitspart,andanexponentpart.

Example

Inthefollowing,theexplicitrealconstantsare0.0and2.93e3.

vartemperature:real:=0.0

constspeed:=2.93e3%Valueis2,930.0

Details

Thesignificantdigitspart(orfractionalpart)ofanexplicitrealconstantconsistsofasequenceofoneormoredigits(0to9)optionallycontainingadecimalpoint(aperiod).Thedecimalpointisallowedtofollowthelastdigitasin16.ortoprecedethefirstdigit,asin.25.

TheexponentpartconsistsofthelettereorEfollowedoptionallybyaplusorminussignfollowedbyoneormoredigits.Forexample,in-9.837e-3theexponentpartise-3.Thevalueof-9.837e-3is-9.837times0.001.

Ifthesignificantfigurespartcontainsadecimalpoint,thentheexponentpartisnotrequired.

explicitStringConstant stringliteral

SyntaxAnexplicitStringConstantisasequenceofcharacterssurroundedbyquotationmarks.

Example

Inthefollowing,theexplicitstringconstantsare"Helloworld",""and"273O'ReillyAve.".

varname:string:="Helloworld"

name:=""%Nullstring,containingzerocharacters

varaddress:string:="273O'ReillyAve."

Details

Withinanexplicitstringconstant(andwithinanexplicitcharacterconstant),thebackslash\isusedtorepresentcertainothercharactersasfollows:

\" quotationmarkcharacter \nor\N endoflinecharacter \tor\T tabcharacter \for\F formfeedcharacter \ror\R returncharacter \bor\B backspacecharacter \eor\E escapecharacter \dor\D deletecharacter \\ backslashcharacter

Forexample,put"One\nTwo"willoutputOneononelineandTwoonthenext.Inanexplicitcharacterconstant(whichissurroundedbysinglequotes,asin'John'),thebackslashisnotrequiredbeforeadoublequote",butitisrequiredbeforeasinglequote',asinthesetwoconstants:

'Johnsaid"Hello"toyou' 'Don\'tcry'.

Youcanusethecaret^tospecifyASCIIcontrolcharacters,forexample:

'^H' ASCIIbackspacecharacter

Thecaretspecifiesthatthetopthreebitsofthecharacteraresettozero.Foranycharacterc,thefollowingistrue:

'^c'=chr(ord('c')&2#11111)

Howeverifcisthequestionmark,asin'^?',thebitsarenotturnedoff.

Explicitstringconstantscannotcrosslineboundaries.Torepresentastringthatislongerthanaline,breakitintotwoormorestringsonseparatelinesandusecatenation(+)tojointheindividualstrings.

Anexplicitstringconstantcancontainatmost255characters(thisisinimplementationconstraint).

Stringvaluesarenotallowedtocontaincharacterswiththecodevaluesof0or128;thesecharactervaluesarecalledeos(endofstring)anduninitchar(uninitializedcharacter).Thesearereservedbytheimplementationtomarktheendofastringvalueandtoseeifastringvariablehasbeeninitialized.

explicitTrueFalseConstant booleanliteral

Syntax

AnexplicitTrueFalseConstantisoneof:

(a) true (b) false

Example

Thefollowingdeterminesifstringscontainsaperiod.Aftertheforstatement,foundwillbetrueifthereisaperiodins.

varfound:boolean:=false

fori:1..length(s)

ifs="."then

found:=true

endfor

Details

true/falsevaluesarecalledbooleanvalues.Abooleanvariable,suchasfoundintheaboveexample,canhaveavalueofeithertrueorfalse.

Seealso booleantype.

expn expression

Syntax

Anexpnisoneof:

(a) explicitConstant %e.g.:25

(b) variableReference %e.g.:width

(c) constantReference %e.g.:pi

(d)expninfixOperatorexpn

%e.g.:3+width

(e) prefixOperatorexpn

%e.g.:-width

(f) (expn) %e.g.:(width-7)

(g) substring %e.g.:s(3..5)

(h) functionCall %e.g.:sqrt(25)

(i) setConstructor %e.g.:modes(4,3)

(j) enumeratedValue %e.g.:color.red

Description

Anexpression(expn)returnsavalue;inthegeneralcase,thismayinvolveacalculation,suchasaddition,asintheexpression:

3+width

put"Helloworld"%"Helloworld"isanexpn

Example vardiameter:real

constpi:=3.14159%3.14159isanexpn

diameter:=pi*r**2%pi*r**2isanexpn

varx:=diameter%diameterisanexpn

Details

Inthesimplestcase,anexpression(expn)issimplyanexplicitconstantsuchas25or"Helloworld".Avariablebyitselfisconsideredtobeanexpressionwhenitsvalueisused.Thisisthecaseabove,wherethevalueofdiameterisusedtoinitializex.Moregenerally,anexpressioncontainsanoperatorsuchas+andcarriesoutanactualcalculation.Anexpressionmayalsobeasubstring,functioncall,setconstructororenumeratedvalue.Fordetails,seethedescriptionsoftheseitems.

TheTuringinfixoperatorsare:+,-,*,/,div,mod,**,<,>,=,<=,>=,not=,not,and,or,=>,in,notin,shr(shiftright),shl(shiftleft),and(exclusiveor).Fordetails,seeinfixOperator.TheTuringprefixoperatorsare+,-andnot,^(pointerfollowing)and#(seecheat).Fordetailsseeprefixoperator.

Seealsoprecedenceofoperators,aswellastheint,real,stringandbooleantypes.

export list

Syntax

AnexportListis:

export[howExport]id{,[howExport]id}

Description

Anexportlistisusedtospecifythoseitemsdeclaredinamodule,monitororclassthatcanbeusedoutsideofit.Itemsthataredeclaredinsideamodule,monitororclassbutnotexportedcannotbeaccessedoutsideofit.

Example

Inthisexample,theproceduresnamespopandpushareexportedfromthestackmodule.Thesetwoproceduresarecalledfromoutsidethemoduleonthelastandthirdfromlastlinesoftheexample.Noticethatthewordstackandadotmustprecedetheuseofthesenames.Sincetopandcontentswerenotexported,theycanbeaccessedonlyfrominsidethemodule.

modulestack

exportpush,pop

vartop:int:=0

procedurepush…endpush

procedurepop…endpop

endstack

stack.push("Harvey")

varname:string

stack.pop(name)%ThissetsnametoHarvey

Procedures,functions,variables,constantsandtypescanbeexported.Modules,monitorsorclassescanotbeexported.Parenthesesareallowedaroundtheitemsinanexportlist,asin:

export(push,pop)

Thefollowingsyntaxspecifiesthateachexportedidentifiercanoptionallybeprecededbythekeywordsvar,unqualified,pervasiveandopaque.Ofthese,onlyopaqueisavailableinTuringproper.

Details

TheformofhowExportis:

{exportMethod}

TheformofexportMethodisoneof:

(a) var (b) unqualified (c) pervasive (d) opaque

Thekeywordvarmeansthattheexportedvariablecanbechangedoutsideoftheexportingmodule,monitororclass.Thiskeywordappliesonlytoexportedvariables.Forexample,ifstringvariablenameisexportedvarfrommoduleM,namecanbechangedfromoutsideofMbyM.name:="Surprise!".

Thekeywordunqualifiedmeansthatreferencestotheexporteditemdonotneedtobeprefixedbythenameoftheexportingitem.Forexample,ifmoduleMexportsprocedurepunqualified,acalltopoutsideofMcanbesimplypinsteadoftheusualM.p.Aclasscannotexportvariablesordynamicconstantsunqualified(becauseeachobjectoftheclasshasitsowncopiesofthese).Theonlythingsaclasscanexportunqualifiedaretypesandcompiletimeconstants.Thekeywordunqualifiedcanbeabbreviatedto~.whichispronouncedas"notdot".

Thekeywordpervasive,whichisonlymeaningfulifunqualifiedisalsopresent,specifiesthattheexporteditemistobevisibleinsubsequentscopes,inotherwordsthatitisnotnecessarytoimportitintointernalmodules,monitorsandclasses.

Thekeywordopaque,whichcanonlyprecedetypenames,specifiesthatoutsidethemodule,monitororclass,thetypeisconsideredtobedistinctfromallothertypes.Thismeans,forexample,thatifthetypeisanarray,itcannotbesubscriptedoutsideofthemodule.Seemoduledeclarationforanexamplethatusesopaquetypes.Inmostcases,classesarepreferabletoopaquetypes.

Exportedsubprogramsareconsideredtobedeferred,meaningthatexpansionsareallowedtooverridethesesubprograms.Seealsodeferredsubprograms.Thesecanbeoverriddenusingthekeywordbodybeforetheresolvingsubprogrambody.

Aclasscannotexportitemsfromitsparentoritparent'sancestors.Allexporteditemmustbedeclaredinthecurrentclass.

Details

Youcanexportallfromamodule,monitororaclass.Thismeansthateverysibmlethatislegaltoexportisexported.Youmayalsoqualifytheall,asinexportopaqueunqualifiedpervasiveallwherethequalifiersareaddedtoeachexportitem(ifitmakessense).

Ifallisspecifiedastheexportitem,nootheritemmaybespecified.Also,andallexportaffectsonlythemodule,monitororclassthatitisgivenin.Anyinheritingorimplementingmodule,monitororclassdoesnotexportallunlesstheyalsospecifyit.

Seealso

unit,module,monitorandclass.Seealsoimportlist,inheritclause,implementclause,implementbyclauseanddeferredsubprogram.

external declaration

Dangerous

Syntax

AnexternalDeclarationisoneof:

(a)external[overrideName]subprogramHeader (b)external[addressSpec]varid[:typeSpec][:=

Description

Anexternaldeclarationisusedtoaccessvariablesorsubprogramsthatarewritteninotherlanguagesorwhichrequirespeciallinkage.Thisfeatureisimplementation-dependentanddangerousandmaycausearbitrarydataorprogramcorruption.FromaninterpretiveenvironmentsuchasTuring,thisprovideslinkagetoitemsthatarepartoftheTuringsystem.ForcompiledversionsofTuring,thelinkagewouldbebymeansofastandard,operatingsystem-specificlinkageeditor.

Details

Inform(a)theoptionaloverrideNamemustbeanexplicitstringconstant,suchas"printf".Ifitisomitted,theexternalnameisthenameinthesubprogramHeaderSeesubprogramHeader.

Thecurrentimplementationdoesnotsupportform(b).Thisformisdocumentedhereincaseafutureversionsupportsit.TheaddressSpecisacompiletimeexpression(itsvaluemustfitintherangeoftheaddressinttype)orisacompiletimestringvalue.IftheaddressSpecisomitted,theidentifieristhenameofanexternalvariable.Thisnamerepresentsanimplementation-dependentmethodoflocatingavariable.AtleastoneoftypeSpecorexpnmustbepresent.

Declaringvariablesatabsoluteaddressesisusefulfordevicemanagementincomputerarchitectureswithmemorymappeddeviceregisters.Externalvariablesdeclaredtobeintornatwillbydefaultbecheckedforinitialization.Toavoidthischeck,declarethemtobeint4ornat4.

Example

PlacevariablettyDataathexadecimallocation9001andassignitthecharacterA.

external16#9001varttyData:char

ttyData:='A'%CharacterAisassignedtohexlocation9001

ExampleAccessanexternalintegervariablenamedERRFLAG.

externalvarERRFLAG:int

ifERRFLAG=0then…

Example

Accessanintegervariablewhichiscalledyinthisprogrambutiscalledexternally.

external"x"vary:int

ExampleDeclaredrawcircletobeaprocedurethatisexternallyknownascircle

external"circle"proceduredrawcircle(x,y,r,

false booleanvalue(nottrue)

Syntax false

DescriptionAboolean(true/false)variablecanbeeithertrueorfalse(seebooleantype).

Example

varfound:boolean:=false

varword:int

fori:1..10

getword

found:=foundorword="gold"

endfor

iffound=truethen

put"Found'gold'inthetenwords"

DetailsThelineiffound=truethencanbesimplifiedtoiffoundthenwithnochangetothemeaningoftheprogram.

fetcharg fetchargumentfunction

Syntax fetcharg(i:int):string

Description

Thefetchargfunctionisusedtoaccessthei-thargumentthathasbeenpassedtoaprogramfromthecommandline.Forexample,iftheprogramisrunfromtheTuringenvironmentusing

:rfile1file2

thenfetcharg(2)willreturn"file2".Ifaprogramcalledprog.xisrununderUNIXusingthiscommand:

prog.xfile1file2

thevalueoffetcharg(2)willsimilarlybe"file2".

Thenargsfunction,whichgivesthenumberofargumentspassedtotheprogram,isusuallyusedtogetherwiththefetchargfunction.Parameteripassedtofetchargmustbeintherange0..nargs.

The0-thargumentisthenameoftherunningprogram.

Example

Thisprogramlistsitsownnameanditsarguments.

put"Thenameofthisprogramis:",fetcharg(0)

fori:1..nargs

put"Argument",i,"is",fetcharg(i)

endfor

Execute

Seealso nargs

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithfilemanipulationonawhole-filebasis(asopposedtomanipulatingthedatainthefileusingopenandclose,etc.).Theseroutinesallowyoutorename,copyanddeletefiles,aswellasgetinformationaboutafileandgetthefreespaceondiskavailableforafile.

AllroutinesintheFilemoduleareexportedqualified(andthusmustbeprefacedwith"File.").

EntryPoints

Exists Returnswhetherafileexists.FullPath Returnsthefullabsolutepathnameofafile.Parent Returnstheparentdirectoryofafileordirectory.

Status Getsinformationaboutafilesuchassize,modificationdate,etc.

Copy Copiesafiletoanotherlocation.Rename Renamesafileordirectory.Delete Deletesafile.

DiskFree Getsthefreespaceonthediskuponwhichafileordirectoryresides.

Details

OnthePC,apathnameofafileoradirectorycanuseeithertheforwardslashorbackwardslashtoseparatedirectorynames.Thedrivemustbefollowedbyacolon.Thusthefollowingarelegalpathnames:

x:\students\west\example.t

c:/turing/test.t

/west/binary.t(usesthedefaultdrive).

OntheMacintosh,apathnameofafileordirectorycanusethestandardMacintoshformatofVolumeName:DirectoryName:DirectoryName:FileNameortheUnixformatof/VolumeName/DirectoryName/DirectoryName/FileName.Notethatthenamescanhavespacesinthem.

HSA:Applications:TuringFiles:example.t

/HSA/Applications/TuringFiles/example.t

OnUNIXsystems,thepathnamemustcorrespondtotheUNIXstandardofusingaforwardslashbetweenpartsofthepath.

/export/home/west/turing/example.t

Ingeneral,youcanachievethegreatestportabilitybyusingtheUNIXstandardforuseinpathnames,asallTuringsystemssupportit.

File.Copy PartofFilemodule

Syntax File.Copy(srcPathName,destPathName:string)

Description

File.CopycopiesafilenamedbythesrcPathNameparametertothefilenamedbythedestPathNameparameter.Thecopycanbebetweendifferentdisksorfilesystems.

Details

Thesourcefilenamemustbeanactualfile.Thisprocedurewillnotcopydirectories.

IftheFile.Copycallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Notethatyoucanuseeitherforwardorbackwardslashestoseparatecomponentsinapath.Ifyouusebackwardslashes,youmustdoubletheminastringliteral.(i.e."d:\\west\\example.t")

Example

Thisprogramcopiesthefile"d:\west\example.dat"to"new_example.t".inthecurrentdirectory.

File.Copy("d:/west/example.dat","new_example.t")

put"Filecopied"

put"Didnotcopythefile."

Execute

AnexampleprogramisavailablethatcopiesafiletothecurrentdirectoryusingFile.Copy,displaysitscontentstotherunwindow,andthendeletesthefileusingFile.Delete.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.Copy,notbycallingCopy.

File.Delete PartofFilemodule

Syntax File.Delete(filePathName:string)

Description

File.DeleteisusedtodeletethefilespecifiedbytheparameterfilePathName.ThisistheequivalentofdoingadelinDOSorrminUNIX.

Details

IftheFile.Deletecallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramdeletesthefilecalledinformation.

File.Delete("information")

put"Filedelete"

put"Didnotdeletethefile."

Execute

Anexampleprogramisavailablethatcreatesafileinthecurrentdirectory,andthendeletesthefileusingFile.Delete.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.Delete,notbycallingFile.

File.DiskFree PartofFilemodule

Syntax File.DiskFree(pathName:string):int

Description

File.DiskFreegetsthenumberofbytesforthediskuponwhichpathNameresides.ThepathNameparametercanspecifyeitherafileoradirectory.Ifitistheemptystring,thenFile.DiskFreereturnsthenumberofbytesoffreediskspaceonthediskuponwhichtheexecutiondirectoryresides.

Details

IftheFile.DiskFreecallfails,thenitreturns-1.AlsoError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Ifthereismorethan2,147,483,647bytesfreeonadisk,theFile.DiskFreefunctionreturns2,147,483,647.

Example

ThisprogramprintsouttheamountofspaceontheA:driveonaPCandintheexecutiondirectory.

varbytesFree:int

bytesFree:=File.DiskFree("A:\\")

ifbytesFree=-1then

put"Can'tgetfreespaceondriveA:."

put"Thereare",bytesFree,"bytesfreeondriveA:"

bytesFree:=File.DiskFree(".")

ifbytesFree=-1then

put"Can'tgetfreespaceondefaultdirectory."

put"Thereare",bytesFree,"bytesfreeonthedefaultdir"

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.DiskFree,notbycallingDiskFree.

File.Exists PartofFilemodule

Syntax File.Exists(pathName:string):boolean

DescriptionFile.ExistsreturnstrueifafilebythenameofpathNameexists.ItwillreturnfalseifpathNameisadirectory.

Details

IftheFile.Existsreturnsfalse,youcanexamineError.LastorError.LastMsgformoreinformation(i.e.whetherthepathfailedorthefilewassimplynotfound).

Example

Thisprogramloopsuntiltheusertypesinapathnamethateitherdoesn'talreadyexistorisallowedtobeoverwritten.

varpathName:string

varchoice:string

put"Enterfilenametowriteresultsto"..

getpathName

ifFile.Exists(pathName)then

put"Overwrite",pathName,"?"..

getchoice

exitwhenchoice="y"

endloop

Execute

Anexampleprogramisavailablethatcreatesafileinthecurrentdirectory,testsforitsexistenceusingFile.ExistsanddeletesthefileusingFile.Delete.

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingFile.Exists,notbycallingExists.

File.FullPath PartofFilemodule

Syntax File.FullPath(pathName):string):string

Description

File.FullPathreturnsastringrepresentingthefullabsolutepathnameinTuringformat(forwardslashes)ofthepaththatispassedtothefunction.Thepathnamepassedindoesnothavetodescribeanexistingfileordirectory.

DetailsThefullpathnamewillbeinTuringformatandincludethedrivename(forexample"d:/turing/examples/games/SpaceGame.t")

Example

Thisprogramobtainsapathfromtheuserandthenoutputsafullpathnamebasedonthepath.

varpathName:string

getpathName

put"Fullpath=",File.FullPath(pathName)

Execute

Details

Anotherexampleisavailablethatcheckswhetherafileandallofthedirectoriesinthepathtothefileexist.ThisprogramillustratestheuseofFile.FullPath,File.Parent,File.Exists,andDir.Exists.

Exportedqualified.

StatusThismeansthatyoucanonlycallthefunctionbycallingFile.FullPath,notbycallingFullPath.

File.Parent PartofFilemodule

Syntax File.Parent(pathName:string):string

Description

File.ParentreturnsastringrepresentingtheparentdirectoryinTuringformat(forwardslashes)ofthepathpassedasaparameter.Thepathnamepassedindoesnothavetodescribeanexistingfileordirectory.Attemptingtoobtaintheparentdirectoryofarootdirectory(forexample"c:/")willreturnthesamerootdirectoryandwillsetthevaluereturnedbyError.Lasttoanon-zerovalue.

Example

Thisprogramobtainsapathfromtheuserandthenlistsalltheparentdirectoriesuntilitreachestherootdirectory.

varpathName:string

put"Enterapath:"..

getpathName

pathName:=File.Parent(pathName)

exitwhenError.Lastnot=eNoError

putpathName

endloop

Execute

Details

Anotherexampleisavailablethatcheckswhetherafileandallofthedirectoriesinthepathtothefileexist.ThisprogramillustratestheuseofFile.FullPath,File.Parent,File.Exists,andDir.Exists.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.Parent,notbycallingParent.

File.Rename PartofFilemodule

Syntax File.Rename(srcPathName,destName:string)

Description

File.CopyrenamesafileordirectorynamedbythesrcPathNameparametertothedestNameparameter.ThedestNameparametermustbeanameonly.InotherwordsFile.Renamecan'tmoveafilebetweendifferentdirectories.

Details

IftheFile.Renamecallfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Thisprogramrenamesthefile"/usr/west/example"to"testcase"

File.Rename("/usr/west/example","testcase")

put"Filerenamed"

put"Didnotrenamethefile."

Execute

Anexampleprogramisavailablethatcreatesafileinthecurrentdirectory,renamesittoadifferentnameusingFile.Rename,checkstheexistenceofbothfilesusingFile.ExistsandthendeletesthefileusingFile.Delete.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.Rename,notbycallingRename.

File.Status PartofFilemodule

Syntax File.Status(pathName:string,varsize,attribute,fileTime:int)

Description

File.Statusisusedtogetassortedinformationaboutafileordirectory.WhenthefunctioniscalledwithaspecifiedpathName,itreturnstheinformationaboutthefileintheotherparameters.

Thesizeparameteristhesizeofthefileinbytes.

TheattributeparameterhasitsindividualbitssetasexactlyastheattributeparameterinDir.GetLongsubprogramdoes.SeeDir.GetLongforthelistofattributeconstants.

ThefileTimeisthetimeoflastmodificationofthefile.Itisreturnedasthenumberofsecondssince00:00:00GMT1/1/1970.Toconvertthistoastring,useTime.SecDate.

Details

IftheFile.Statuscallfails,size,attributeandfileTimeareallsetto1.Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

ThisprogramprintsinformationabouttheNotePad.exeapplicationinWindowsfoundat"c:\windows\notepad.exe".(Noteonsomesystems,thiswillbe"c:\winnt\notepade.exe"

constpathName:string:="c:/windows/notepad.exe"

File.Status(pathName,size,attribute,fileTime

put"Name:",File.FullPath(pathName)

put"Created:",Time.SecDate(fileTime)

put"Size:",size,"bytes"

put"Attributes:"..

if(attributeandootAttrDir)not=0then

put"Directory"..

put""..

if(attributeandootAttrRead)not=0then

put"Readable"..

put""..

if(attributeandootAttrWrite)not=0then

put"Writable"..

put""..

if(attributeandootAttrExecute)not=0then

put"Executable",skip

putskip

put"Unabletogetfileinformation"

put"Error:",Error.LastMsg,skip

Execute

AnotherexampleprogramisavailablethatusesFile.Statustodeterminethestatusofseveralfilesanddirectories.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFile.Status,notbycallingStatus.

flexible arrayinitialization

Syntax flexiblearrayindexType{,indexType}oftypeSpec

Description

Theflexiblekeywordallowsanarraytoberesizedusingnewatalaterpointintime.Theindicesmayhavecompile-timeorrun-timeupperbounds(thelowerboundmustbecompile-time).Theupperboundscanbechangedbyusing:

Additionally,theupperbound(bothinthedeclarationandthenewstatement)canbemadeonelessthanthelowerbound.Thiseffectivelymakesanarraythatcontains0elements.Itcanlaterbeincreasedinsizewithanothernew.

Currently,onlyvariablescanbedeclaredinthisform.Thereisnoflexiblearrayparametertype,althoughaflexiblearraycanbepassedtoanarrayparameterwith“*”astheupperbound.

Example Seearrayforanexampleofflexible.

Execute

Seealso arrayandnew.

floor real-to-integerfunction

Syntax floor(r:real):int

Description Returnsthelargestintegerthatislessthanorequaltor.

Details

Thefloorfunctionisusedtoconvertarealnumbertoaninteger.Theresultisthelargestintegerthatislessthanorequaltor.Inotherwords,thefloorfunctionroundsdowntothenearestinteger.Forexample,floor(3)is3,floor(2.75)is2andfloor(-8.43)is-9.

Seealso ceilandroundfunctions.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithfonts.Usingtheseroutines,youcandisplaytextinaselectedfontname,sizeandstyleonthescreen.Notethatoutputinaparticularfontistreatedasgraphicsoutput.

AllroutinesintheFontmoduleareexportedqualified(andthusmustbeprefacedwith"Font.").

Details

Thereisadefaultfont.YoucandrawinandobtaininformationaboutthedefaultfontbypassingfontDefaultIDtoFont.Draw,Font.WidthandFont.Sizes.Thedefaultfontisthesamefontasisusedbyputintheoutputwindow.

EntryPoints

New Selectsaparticularfontname,sizeandstyleforanewfont.

Free FreesupthefontcreatedbyusingNew.Draw Drawstextinagivenfont.

Width Getsthewidthinpixelsofaparticularpieceoftextinaspecifiedfont.

Sizes Getstheheightandvariousleadingsofaspecifiedfont.

Name Returnsthenameofthespecifiedfont.StartName Preparestolistallavailablefonts,GetName Getsthenextfontname.GetStyle Getsalltheavailablestylesforaspecifiedfont.

StartSize Preparestolistallavailablesizesforaspecifiedfontandstyle.

GetSize Getsthenextfontsize.

Font.Draw PartofFontmodule

Syntax Font.Draw(txtStr:string,x,y,fontID,Color:int)

Description

Font.Drawisusedtoactuallydrawtextinaspecifiedfont.ThetextStrcontainsthestringtobedrawn.Thexandyparametersarethelocationofthelowerlefthandcornerofthetexttobedisplayed.ThefontIDparameteristhenumberofthefontinwhichthetextistobedrawn.TheColorparameterisusedtospecifythecolorinwhichthetextistoappear.

Notethatthetextthatappearsiscompletelyunrelatedtothetextthatappearsusingput.Font.Drawisagraphicscommandandthusdoesnotuseoraffectthecursorlocation.

ThetextdrawnbytheFont.Drawproceduredoesnoterasethebackground.

Details

IfFont.DrawispassedaninvalidfontID,afatalerroroccurs.Ifthefailsforother(non-fatal)reasons,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramprintsoutseveralphrasesinavarietyoffonts.

varfont1,font2,font3,font4:int

font1:=Font.New("serif:12")

assertfont1>0

font2:=Font.New("sansserif:18:bold")

assertfont2>0

font3:=Font.New("mono:9")

assertfont3>0

font4:=Font.New("Palatino:24:bold,italic")

assertfont4>0

Font.Draw("Thisisinaseriffont",50,30,font1,red

Font.Draw("Thisisinasansseriffont",50,80,

Font.Draw("Thisisinamonofont",50,130,font3,colorfg

Font.Draw("ThisisinPalatino(ifavailable)",50,180,

Font.Free(font1)

Font.Free(font2)

Font.Free(font3)

Font.Free(font4)

Execute

DetailsTousethesamefontasisusedbytheputstatement,usedefFontIDnumber.Thisfontdoesnothavetobecreatedorfreedbytheuser,andallowsaprogramtoquicklyplacetextinanylocationonthescreen.

Example

Theprogramdrawstwostringsinthedefaultfont(defFontID).

Font.Draw("DrawingHere",100,120,defFontID,

Font.Draw("andHere",180,90,defFontID,brightgreen

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.DrawDraw.

Font.Free PartofFontmodule

Syntax Font.Free(fontID:int)

Description

Font.Freeisusedtoreleaseafontthatisnolongerneeded.Thereisalimittothenumberoffontsthatmaybedefinedatanyonetime.ByhavingaFont.FreeeveryFont.New,thenumberofsimultaneouslydefinedfontsiskepttoaminimum.

Details

IfFont.FreeispassedaninvalidfontID,afatalerroroccurs.Ifthefailsforother(non-fatal)reasons,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

assertfont1>0

assertfont2>0

assertfont3>0

font4:=Font.New("Palatino:24:Bold,Italic")

assertfont4>0

Font.Free(font1)

Font.Free(font2)

Font.Free(font3)

Font.Free(font4)

Execute

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingFont.FreeFree.

Font.GetName PartofFontmodule

Syntax Font.GetName:string

Description

Font.GetNameisusedtogetthenextfontavailableonthesystem.ByusingFont.StartNameandthencallingFont.GetNamerepeatedly,youcangetthenamesofallthefontsavailabletotheprogram.

Font.StartNamemustbecalledbeforeanycallstoFont.GetName.Afterthat,Font.GetNamereturnsthelistofthefontnames,onepercall.Whentherearenomoresizes,Font.GetNamereturnstheemptystring.

Oncethenameofafontisknown,it'spossibletolisttheavailablestyles(usingFont.GetStyle)andtheavailablesizes(usingFont.StartSizeandFont.GetSize)forthatfont.

Example

Theprogramlistsallthefontsavailableonthesystem.

varfontName:string

Font.StartName

fontName:=Font.GetName

exitwhenfontName=""

putfontName

endloop

Execute

Anotherexampleisavailablethatdisplaysfullinformationaboutthefontsincludingname,styles,andpointsizes.

Example

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.GetName,notbycallingGetName.

Font.GetSize PartofFontmodule

Syntax Font.GetSize:int

Description

Font.GetSizeisusedtogetthenextsizeinthelistofavailablefontsizesforaparticularfontnameandstyle.

Font.StartSizemustbecalledbeforeanycallstoFont.GetSize.Afterthat,Font.GetSizereturnsthelistofsizes,onepercall.Whentherearenomoresizes,Font.GetSizereturns0.

Somefontsare“scalable”.Thismeansthatthecomputercanscalethefontstofitanygivensize.(UnderMicrosoftWindowsandtheAppleMacintosh,TrueTypeandPostScriptfontsarescalablewiththeappropriateutilities.)Inthiscase,Font.GetSizereturns-1.

ExampleSeeFont.StartSizeforaprogramthatlistsallthefonts,stylesandsizesavailableonthesystem.

Example

Anexampleisavailablethatdisplaysfullinformationaboutthefontsincludingname,styles,andpointsizes.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.GetSize,notbycallingGetSize.

Font.GetStyle PartofFontmodule

SyntaxFont.GetStyle(fontName:string,varbold,italic,underline:boolean):string

Description

Font.GetStyleisusedtogetthestylesavailableonthesystemforaspecifiedfont.bold,italicandunderlinearesettotrueifbold,italicorunderlineversionsofthefontareavailable.Oncethestylesavailableforafontareknown,it'spossibletogetthesizesavailableforeachstylebyusingFont.StartSizeandFont.GetSize.

Example

Theprogramlistsallthefontsandtheirstylesavailableonthesystem.

varfontName:string

varbold,italic,underline:boolean

Font.StartName

exitwhenfontName=""

Font.GetStyle(fontName,bold,italic,underline

putfontName:30..

ifboldthen

put"bold"..

ifitalicthen

put"italic"..

ifunderlinethen

put"underline"..

endloop

Execute

Example

Anexampleisavailablethatdisplaysfullinformationaboutthefontsincludingname,styles,andpointsizes.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.GetStyle,notbycallingGetStyle.

Font.Name PartofFontmodule

Syntax Font.Name(fontID:int)fontName:string

Description

Font.Nameisusedtogetthenameofafontthatisbeingused.Thestringthatisreturnedcanbeusedtodeterminewhichfontisactuallybeingusedforthedefaultfonts“serif”,“sansserif”and“mono”.

Example

Theprogramprintsoutthefontsusedfor“serif”,“sansserif”and“mono”.

varserifFont,sansSerifFont,monoFont:int

serifFont:=Font.New("serif:12")

assertserifFont>0

sansSerifFont:=Font.New("sansserif:12")

assertsansSerifFont>0

monoFont:=Font.New("mono:12")

assertmonoFont>0

put"serif=",Font.Name(serifFont)

put"sansserif=",Font.Name(sansSerifFont)

put"mono=",Font.Name(monoFont)

Font.Free(serifFont)

Font.Free(sansSerifFont)

Font.Free(monoFont)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.Name,notbycallingName.

Font.New PartofFontmodule

Syntax Font.New(fontSelectStr:string):int

Description

Font.Newisusedtoobtainafontfordrawing.ThefontSelectStrparameterspecifiesthename,sizeandstyleofthefont.Font.NewreturnsafontidentifierusedbytheFont.Drawproceduretodrawtextintheselectedfont.

TheformatforthefontSelectStrparameteris"Family:Size:Style".Eachelementisseparatedbyacolon.The":Style"isoptional.Ifleftout,thetextappearsinthestandardfaceforthefont.

Familyisthenameofthefont,suchas"Times","Helvetica",etc.Thenamemustmatchanexistingfontonthesystem.Becauseonedoesnotnecessarilyknowwhichfontswillbeavailableandnamesforthesamefontchangebetweendifferentsystems(i.eTimes,Times-Roman,etc.),Turingdefinesthreefamilynamesbemappedascloselyaspossibletofontsthatexistonthesystem.

"serif"isusedforaserifedbodyfont.ThiswillusuallybemappedtoTimes-Roman.

"sansserif"isusedforanon-serifeddisplayfont.ThiswillusuallybemappedtoArial.

"mono"isusedforamonospacedfont.ThiswillusuallybemappedtoCourier.

Sizeisthepointsizeinwhichthetextshouldappear.Ifthenumberislargerorsmallerthancanbecreatedonagivensystem,thesystemwillreturnthefontofthelargestorsmallestsizeavailableandsetError.Last.

UnderTuring,thesizeparametermayalsohavetheformheightxwidthheightandwidtharethepixelheightandwidthdesired.Whatisreturnedisthescaledinordertofitintothewidthandheightrequested.Thefontnamemustbeascaleablefontforthistosucceed.

examplefontID:=Font.New("Ariel:18x12:Italic")

Styleisthefontstyleinwhichthetextshouldappear.Itcanbeoneof"bold","italic"or"underline".Youcanalsohave"bold,italic"andanyothercombination.

Details

IftheFont.Newcallfails,thenitreturns0.AlsoError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnacontainsthetextualversionoftheerror.

ItisquitepossibleforError.Lasttobeset,evenifthecallsucceeds.reportsuccessevenifunabletosuccessfullymatchtherequestedfontwiththeavailableresources.AfontwillbesetthatmatchesascloselyaspossiblerequestedfontandLast.Errorwillbesettoindicatethatsomesubstitutionswererequired.

Example

font4:=Font.New("Palatino:24:Bold,Italic")

assertfont1>0andfont2>0andfont3>0and

Font.Free(font1)

Font.Free(font2)

Font.Free(font3)

Font.Free(font4)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.NewNew.

Font.Sizes PartofFontmodule

SyntaxFont.Sizes(fontID:int,varheight,ascent,descent, internalLeading:int)

Description

Font.Sizesisusedtogetthemetricsofaparticularfont.Thevariouspartsofthemetricareillustratedbelow.Notethatyoucancalculatetheexternalleadingbysubtractingtheascentanddescentfromtheheight.

Details

IfFont.SizesispassedaninvalidfontID,afatalerroroccurs.Ifthefailsforother(non-fatal)reasons,themetricsforthedefaultfontwillbereturned.Aswell,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramgetsinformationabout24ptBoldItalicPalatino.

varfontID,height,ascent,descent,internalLeading,

varexternalLeading:int

fontID:=Font.New("Palatino:24:bold,italic")

Font.Sizes(fontID,height,ascent,descent,internalLeading

externalLeading:=heightascentdescent

put"Theheightofthefontis",height,"pixels"

put"Theascentofthefontis",ascent,"pixels"

put"Thedescentofthefontis",descent,"pixels"

put"Theinternalleadingofthefontis",internalLeading

put"Theexternalleadingofthefontis",externalLeading

Font.Free(fontID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.SizesSizes.

Font.StartName PartofFontmodule

Syntax Font.StartName

Description

Font.StartNameisusedtostartthelistingofallthefontsavailableonthesystem.ThisprocedureiscalledbeforemakingcallstoFont.GetNametogetthenameofthefontsavailable.Oncethenameofafontisknown,it'spossibletolisttheavailablestyles(usingFont.GetStyle)andtheavailablesizes(usingFont.StartSizeandFont.GetSize).

Example

Theprogramlistsallthefontsavailableonthesystem.

varfontName:string

Font.StartName

exitwhenfontName=""

putfontName

endloop

Execute

Example

Anotherexampleisavailablethatdisplaysfullinformationaboutthefontsincludingname,styles,andpointsizes.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.StartName,notbycallingStartName.

Font.StartSize PartofFontmodule

Syntax Font.StartSize(fontName,fontStyle:string)

Description

Font.StartSizeisusedtostartalistingofallthesizesforaparticularfontnameandstyle.

ThefontNameparametershouldbeanactualfontname(asopposedtothedefaultnamesof“serif”,etc).YoucangetalistofthefontnamesbyusingtheFont.StartNameFont.GetNamesubprograms.ThefontStyleparametershouldbeinthesameformataswouldappearintheFont.Newprocedure.

Example

Theprogramlistsallthefonts,stylesandsizesavailableonthesystem.

varfontName:string

varbold,italic,underline:boolean

varsize:int

varstyles:arrayboolean,boolean,booleanofstring

init("","underline","italic","italic,underline","bold",

"bold,underline","bold,italic","bold,italic,underline")

Font.StartName

exitwhenfontName=""

Font.GetStyle(fontName,bold,italic,underline

forb:false..bold

fori:false..italic

foru:false..underline

putfontName:30,styles(b,i,

Font.StartSize(fontName,styles

size:=Font.GetSize

exitwhensize=0

ifsize=-1thenput"scalable"..

elseputsize,""..

endloop

endfor

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.StartSizeStartSize.

Font.Width PartofFontmodule

Syntax Font.Width(txtStr:string,fontID:int):int

Description

Font.Widthisusedtoobtainthewidthinpixelsthataspecifiedstringwilltaketodrawinaspecifiedfont.ThetextStrparameteristhestring.ThefontIDparameteristhefontinwhichthestringwouldbedrawn.

Details

IfFont.WidthispassedaninvalidfontID,afatalerroroccurs.IftheFont.Widthcallfailsforother(non-fatal)reasons,thewidthforstringinthedefaultfontwillbereturned.Aswell,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramgetsinformationabout24ptBoldPalatino.

consttestString:="TestString"

varwidth,fontID:int

fontID:=Font.New("Palatino:24:Bold")

width:=Font.Width(testString,fontID)

put"Thewidthof\""+testString+"\"is",width

Font.Draw(testString,100,100,fontID,black)

Draw.Line(100,50,100,150,brightred)

Draw.Line(100+width,50,100+width,150,brightred

Font.Free(fontID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingFont.WidthbycallingWidth.

for statement

Syntax

AforStatementis:

for[decreasing][id]:first..last[byincrement] statementsAndDeclarations endfor

Description

Thestatementsanddeclarationsinaforstatementarerepeatedlyexecuted.Inthefirstiteration,theidentifierisassignedthevalueoffirst.Witheachadditionaliteration,theidentifierincreasesby1(orbyincrement,ifthebyclauseispresent).Theloopstopsexecutingwhenadding1(orincrement)totheidentifierwouldcausetheidentifiertoexceedlast.firstandlastmustbeintegervalues(orelseenumeratedorcharvalues).Ifyouspecifydecreasing,thentheidentifierdecreasesby1(orbyincrement)eachtimethrough.

Incrementmustbeapositiveintegervalue.Whenthebyclauseispresent,theforloopterminatesassoonastheidentifierwouldbecomegreaterthanlast,unlessdecreasingispresent.Ifdecreasingispresent,theloopterminateswhentheidentifierwouldbecomelessthanlast.

Details

Theidentifierischeckedbeforeitisaddedto(orsubtractedfrom).Thismeansthattheloop

fori:1..maxint

willnotcauseanoverflow.

Example

Output1,2,3to10.

fori:1..10

endfor

Output1,3,5,7and9.

Example fori:1..10by2

endfor

Example

Output10,9,8,downto1.

fordecreasingj:10..1

endfor

Example

Output10,6,and2.

fordecreasingj:10..1by4

endfor

Example

Output1.

forj:1..10by20

endfor

Example

Outputnothing.

forj:5..2

endfor

Details

Theforstatementdeclaresthecountingidentifier(aseparatedeclarationshouldnotbegivenforiorj).Thescopeofthisidentifierisrestrictedtotheforstatement.

Iffirstisavaluebeyondlast,therewillbenorepetitions(andnoerrormessage).Thecountingidentifierisalwaysincreased(ordecreased)by1orincrementifthebyclauseispresent.Executinganexitstatementinsideaforstatementcausesajumptojustbeyondendfor.Youarenotallowedtochangethecountingvariable(forexample,youarenotallowedtowritei:=10).

Thecountingidentifiercanbeomitted.Inthiscase,thestatementisjustasbefore,exceptthattheprogramcannotusethevalueof

theidentifier.

Ifdecreasingisnotpresent,first..lastcanbereplacedbythenameofasubrangetype,forexamplebydozen,declaredby:

typedozen:1..12

Procedures,functionsandmodulescannotbedeclaredinsideaforstatement.Justprecedingthestatementsanddeclarations,youareallowedtowritean"invariantclause"oftheform:

invarianttrueFalseExpn

Thisclauseisequivalentto:asserttrueFalseExpn.

fork statement

Dirtyparts

Syntax

AforkStatementis:

forkprocessId[([expn{,expn}])] [:reference[,expn[,reference]]]

Description

Aforkactivates(startstheconcurrentexecutionof)aprocessdeclaration.Iftheprocesshasparameters,aparenthesizedlistofexpressions(expns)mustfollowtheprocess'name(processId).

Example

Thisprograminitiates(forks)twoconcurrentprocesses,oneofwhichrepeatedlyoutputsHiandtheotherHo.TheresultingoutputisanunpredictablesequenceofHi'sandHo's,asgreetingsexecutestwiceconcurrently,oneinstancewithitswordsettoHiandtheotherwithitswordsettoHo.

processgreetings(word:string)

putword

endloop

endgreetings

forkgreetings("Hi")

forkgreetings("Ho")

Seeproceduredeclarationfordetailsaboutparameters.Thefirstoptionalreferenceintheforkstatementmustbeabooleanvariablereference.Theforksetsthistotrueiftheprocessisactuallyactivated.Ifthisfailstooccur(probablybecausestackspacecouldnotbeallocated),thisreferenceissettofalse.Iftheforkfailsbutthisreferenceisomitted,anexceptionoccurs.Seeexceptionhandlers.

Theoptionalexpnspecifiesthenumberofbytesfortheprocess'stack;thisoverridestheoptionallygivenstacksizeintheprocessdeclaration.Thesecondoptionalreferencemustbeavariablereferencewiththetypeaddressint.Seeaddressint.Thisvariableissettoidentifythe

Details processactivation.Thisreferencehastheimplementation-dependentmeaningoflocatingtheprocess'internaldescriptor.

Inthisexplanationoftheforkstatement,wehaveuptothispointignoredthepossibilityofprocessesexportedfrommodules.Iftheprocessisbeingforkedfromoutsideofamodulefromwhichithasbeenexported,thesyntaxoftheforkstatementis:

forkmoduleId.procedureId[(expn{,expn})]…

Inotherwords,themodule'snameandadotmustprecedetheprocess'name.

forward subprogramdeclaration

Syntax

AforwardDeclarationis:

forwardsubprogramHeader [importimportItem{,importItem}]

Description

Aprocedureorfunctionisdeclaredtobeforwardwhenyouwanttodefineitsheaderbutnotitsbody.Thisisthecasewhenoneprocedureorfunctioncallsanother,whichinturncallsthefirst;thissituationiscalledmutualrecursion.Theuseofforwardisnecessaryinthiscase,becauseeveryitemmustbedeclaredbeforeitcanbeused.

Example

Thisexampleprogramevaluatesaninputexpressioneoftheformt}wheretisoftheformp{*p}andpisoftheform(e)oranexplicitrealexpression.Forexample,thevalueof1.5+3.0*(0.5+1.5)haltis7.5.

vartoken:string

forwardprocedureexpn(vareValue:real)

forwardprocedureterm(vartValue:real)

forwardprocedureprimary(varpValue:real)

bodyprocedureexpn

varnextValue:real

term(eValue)%Evaluatet

loop%Evaluate{+t}

exitwhentokennot="+"

gettoken

term(nextValue)

eValue:=eValue+nextValue

endloop

endexpn

bodyprocedureterm

varnextValue:real

primary(tValue)%Evaluatep

loop%Evaluate{*p}

exitwhentokennot="*"

gettoken

primary(nextValue)

tValue:=tValue*nextValue

endloop

endterm

bodyprocedureprimary

iftoken="("then

gettoken

expn(pValue)%Evaluate(e)

asserttoken=")"

else%Evaluate"explicitreal

pValue:=strreal(token)

gettoken

endprimary

gettoken%Startbyreadingfirsttoken

varanswer:real

expn(answer)%Scanandevaluateinputexpression

put"Answeris",answer

Execute

Details

Followingaforwardprocedureorfunctiondeclaration,thebodyoftheproceduremustbegivenatthesamelevel(inthesamesequenceofstatementsanddeclarationsastheforwarddeclaration).Thisistheonlyuseofthekeywordbody.Seealsobody.

Anyprocedureorfunctionthatisdeclaredusingforwardrequiresanimportlist.Inthislist,importedproceduresorfunctionsthathavenotyetappearedmustbelistedasforward.Forexample,theimportlistforexpnisimportforwardterm…Beforeaprocedureorfunctioncanbecalled,beforeitsbodyappears,andbeforeitcanbepassedasaparameter,itsheaderaswellasheadersofproceduresorfunctionsimporteddirectlyorindirectlybyitmusthaveappeared.

Thekeywordforwardisalsousedincollectionandtypedeclarations.

Seealso collectionandtypedeclarations.

frealstr real-to-stringfunction

Syntax frealstr(r:real,width,fractionWidth:int):string

Description

Thefrealstrfunctionisusedtoconvertarealnumbertoastring.Forexample,frealstr(2.5e1,5,1)="b25.0"wherebrepresentsablank.Thestringisanapproximationtor,paddedontheleftwithblanksasnecessarytoalengthofwidth.

ThenumberofdigitsofthefractiontobedisplayedisgivenbyfractionWidth.

Thewidthmustbenon-negative.Ifthewidthparameterisnotlargeenoughtorepresentthevalueofr,itisimplicitlyincreasedasneeded.

ThefractionWidthmustbenon-negative.Thedisplayedvalueisroundedtothenearestdecimalequivalentwiththisaccuracy.Inthecaseofatie,thevalueisroundedtothenextlargervalue.Theresultstringisoftheform:

{blank}[-]{digit}.{digit}

Iftheleftmostdigitiszero,thenitistheonlydigittotheleftofthedecimalpoint.

Thefrealstrfunctionapproximatestheinverseofstrreal,althoughround-offerrorskeepthesefrombeingexactinverses.

Seealso theerealstr,realstr,strreal,intstrandstrintfunctions.

free statement

Syntax

AfreeStatementis:

free[collectionOrClassId,]pointerVariableReference

DescriptionAfreestatementdestroys(deallocates)anelementthathasbeenallocatedbyanewstatement.

Example

Usingacollection,declarealistofrecordsandallocateoneoftheserecords.Thendeallocatetherecord.

varlist:collectionof

record

contents:string(10)

next:pointertolist

%Shortform:next:^list

endrecord

varfirst:pointertolist%Shortform:varnext:^list

newlist,first

%Allocateanelementoflist;placeitslocationinfirst

%Shortform:newfirst

freelist,first%Deallocatetheelementoflistlocatedbyfirst

%Shortform:freefirst

Details

Thefreestatementsetsthepointervariabletothenilvalue.Seetheforexamplesofallocatingelementsofclassesandvaluesoftypes.Itthepointerlocatesatype,thecollectionOrClassIdinthefreestatementmustbeomitted.

Animportedclasscanhaveoneofitsobjectsdestroyed(bythefreeonlyiftheclassisimportedvar.

ThecollectionOrClassIdisoptionalinthefreestatement.

Seealsoclassandcollectiondeclarations,thepointertype,thenewstatementvalue.

function declaration

Syntax

AfunctionDeclarationis:

functionid[([paramDeclaration{,paramDeclaration}])]

:typeSpec statementsAndDeclarations endid

Description

Afunctiondeclarationcreates(butdoesnotrun)anewfunction.Thenameofthefunction(id)isgivenintwoplaces,justafterfunctionandjustafterend.

Example

functiondoubleIt(x:real):real

result2.0*x

enddoubleIt

putdoubleIt(5.3)%Thisoutputs10.6

Thesetofparametersdeclaredwiththefunctionarecalledformalparameters.Forexample,inthedoubleItfunction,xisaformalparameter.Afunctioniscalled(invoked)byafunctioncallwhichconsistsofthefunction'snamefollowedbytheparenthesizedlistofactualparameters(ifany).Forexample,doubleIt(5.3)isacallhaving5.3asanactualparameter.Iftherearenoparametersandnoparentheses,thecalldoesnothaveparentheses.Thekeywordfunctioncanbeabbreviatedtofcn.SeealsofunctionCallandprocedureDeclaration.

Eachactualnon-varparametermustbeassignabletothetypeofitscorrespondingformalparameter.Seealsoassignability.

Afunctionmustfinishbyexecutingaresultstatement,whichproducesthefunction'svalue.Intheaboveexample,theresultstatementcomputesandreturnsthevalue2.0*x.

Details

Inprinciple,afunction(1)shouldnotchangeanyvariablesoutsideofitself(globalvariables)or(2)shouldnothavevarparameters.Inotherwords,itshouldhavenosideeffects.Theoriginalimplementationprevented(1)and(2)andtherebypreventedfunctionsideeffects.CurrentimplementationsofTuringdonotenforcethisrestriction.

Theupperboundsofarraysandstringsthatareparametersmaybedeclaredtobeanasterisk(*),meaningtheboundisthatoftheactualparameter.SeeparamDeclarationfordetailsaboutparameters.

Proceduresandfunctionscannotbedeclaredinsideotherproceduresandfunctions.

ThesyntaxofafunctionDeclarationpresentedabovehasbeensimplifiedbyleavingouttheoptionalresultidentifier,importlist,precondition,initclause,postconditionandexceptionhandler.Thefullsyntaxis

function[pervasive]id

[([paramDeclaration{,paramDeclaration}])]

[resultId]:typeSpec

[pretrueFalseExpn]

[initid:=expn{,id:=expn}]

[posttrueFalseExpn]

[exceptionHandler]

statementsAndDeclarations

TheresultIdisthenameoftheresultofthefunctionandcanbeusedonlyinthepostcondition.

Afunctionmustbedeclaredbeforebeingcalled;toallowformutuallyrecursiveproceduresandfunctions,thereareforwarddeclarationswithlaterdeclarationoftheprocedureorfunctionbody.Seeforwardandbodydeclarationsforexplanations.

Youdeclareparameterlessfunctionsusinganemptyparameterlist.Whenthisisdone,acalltothefunctionmustincludeanemptyparameterlist.

Seealso

importlist,precondition,initclause,postconditionandexceptionHandlerforexplanationsoftheseadditionalfeatures.

Seealsopervasive.

functionCall

Syntax

AfunctionCallis:

functionId[([expn{,expn}])]

Description

Afunctioncallisanexpressionthatcalls(invokesoractivates)afunction.Ifthefunctionhasparameters,aparenthesizedlistofexpressions(expns)mustfollowthefunction'sname(functionId).

Example

Thisfunctiontakesastringcontainingablankandreturnsthefirstwordinthestring(allthecharactersuptothefirstblank).

functionfirstWord(str:string):string

fori:1..length(str)

ifstr(i)=""then

resultstr(1..i-1)

endfor

endfirstWord

put"Thefirstwordis:",firstWord("HenryHudson")

%TheoutputisHenry.

Details

Theparameterdeclaredintheheaderofafunction,isaformalparameter,forexample,straboveisaformalparameter.Eachexpressioninthecallisanactualparameter,forexample,sampleaboveisanactualparameter.

Eachactualparameterpassedtoitsnon-varformalparametermustbeassignabletothatparameter(seeassignabilityfordetails).SeealsofunctionDeclarationandprocedureDeclaration.

InthisexplanationoffunctionCall,wehaveuptothispointignoredthepossibilityoffunctionsexportedfrommodules.Ifthefunctionisbeingcalledfromoutsideofamodulefromwhichithasbeenexported,thesyntaxofthefunctionCallis:

moduleId.functionId[(expn{,expn})]

Inotherwords,themoduleormonitornameandadotmustprecede

thefunction'sname.Ifthefunctionisbeingcalledfromoutsideofaclassfromwhichithasbeenexported,thesyntaxofthefunctionCallisoneof:

(a)classId(p).functionId[([expn{,expn

(b)p->functionId[([expn{,expn}])]

Inthesepmustbeapointervaluethatlocatesanobjectintheclass.Form(b)isashortformforform(a).

Seealso class.

get filestatement

Syntax

AgetStatementis:

get[:streamNumber,]getItem{,getItem}

Description

ThegetstatementinputseachofthegetItems.Ordinarily,theoutputcomesfromthekeyboard.However,ifthestreamNumberispresent,theinputcomesfromthefilespecifiedbythestreamnumber(seetheopenstatementfordetails).Also,inputcanberedirectedsoitistakenfromafileratherthanthekeyboard.Checkthedocumentationontheenvironmentforinstructionsondoingso.

ThesyntaxofagetItemisoneof:

(a)variableReference

(b)skip

(c)variableReference:*

(d)variableReference:widthExpn

Theseitemsareusedtosupportthreekindsofinput:

(1)tokenandcharacterorientedinput:supportedbyforms(a)and(b),

(2)lineorientedinput:supportedbyform(c),and

(3)characterorientedinput:supportedbyform(d).

Examplesofthesewillbegiven,followedbydetailedexplanations.

Example

Token-orientedinput.

varname,title:string

varweight:real

getname%IfinputisAlice,itisinput

gettitle%Ifinputis"Alady",Aladyisinput

varweight%Ifinputis9.62,itisinputintoweight

Example

Line-orientedinput.

varquery:string

getquery:*%Entirelineisinputintoquery

Example

Character-orientedinput.

varcode:string

getcode:2%Next2charactersareinputintocode.

Details

Atokenisasequenceofcharacterssurroundedbywhitespace,wherewhitespaceisdefinedasthecharacters:blank,tab,formfeed,newline,andcarriagereturnaswellasend-of-file.Thesequenceofcharactersmakingupthetokenareeitherallnon-whitespaceorelsethetokenmustbeaquotedstring(anexplicitstringconstant).WhenthevariableReferenceinform(a)isastring,integer,real,intn,natn,orrealn.Turingskipswhitespace,readsatokenintothevariableReference,andthenskipswhitespace(stoppingatthebeginningofthenextline).

IfthevariableReferenceisastring,thetokenisassignedtothevariable(ifthetokenisquoted,thequotationmarksarefirstremoved).Seetheexamplesinvolvingnameandtitleabove.IfthevariableReferenceisanintegerorareal,thetokenisconvertedtobenumericbeforebeingassignedtothevariable.Seetheexampleinvolvingweightabove.

Whentheinputiscomingfromthekeyboard,noinputisdoneuntilReturnistyped.Thelinethatisinputmaycontainmorethanonetoken.Anytokensthatarenotinputbyonegetstatementwillremaintobeinputbythenextgetstatement.

Turinghasbeenmodifiedsothattoken-orientedinputnowalsoskipswhitespacefollowingthetoken,butdoesnotskipbeyondthebeginningofthenextline.Thischangeimpliesthatform(b)isusuallynotneeded,asskipwasusedtoskipwhitespaceafterthetoken.

Form(a)supportscharandchar(n).Ifthetypeischar,exactlyonecharacterisread,withnoskippingofwhitespacebeforeorafter.Thischaractermaybe,forexample,ablankoracarriagereturn.Ifthetypeischar(n),exactlyncharactersareread,withnoskippingofwhitespace.

Inputtingcharandchar(n)typesusingform(a).Thestatementgetc:1

Example

isnotlegal,becauselengthspecificationisnotallowedwithcharactervariables.

varc:char

vard:char(3)

getc%Readonecharacter.

getd%Readthreecharacters

Details

Form(a)supportsenumeratedtypes.Ifthetypeisanenumeratedtype,thenthetokenreadinmustbeoneoftheelementsoftheenumeratedtype.

Example

Inputtinganenumeratedtypeusingform(a).Thestatementgetc:1notlegal,becauselengthspecificationisnotallowedwithenumeratedvariables.

typecolors:enum(red,blue,green)

varc:colors

getc%Readoneofred,greenorblue

DetailsForm(a)supportsboolean.Ifthetypeisanbooleantype,thenthetokenreadinmustbeoneof"true"or"false"

Example

Inputtingabooleantypeusingform(a).Thestatementgetc:1isnotlegal,becauselengthspecificationisnotallowedwithbooleanvariable.

vartf:boolean

gettf%Readoneoftrueorfalse

Details

Inform(b)ofgetItem,skipcauseswhitespaceintheinputtobeskippeduntilnon-whitespace(atoken)ortheend-of-fileisreached.Thisisusedwhentheprogramneedstodetermineiftherearemoretokenstobeinput.Todetermineiftherearemoretokenstoberead,theprogramshouldfirstskipoveranypossiblewhitespace(suchasafinalnewlinecharacter)andthentesttoseeifeof(end-of-file)istrue.Thisisillustratedinthisexample:

Usingtoken-orientedinput,inputandthenoutputalltokens.Thisexamplegiveswhatusedtobethestandardwayofreadingtokensuptoendoffile.Withthenewmeaningofform(a)forreadingtokens,the

Example

getskiplinecanbeomitted.Thisomissionispossiblebecausethelinegetwordnowautomaticallyskipswhitespacefollowingtheinputvalue,uptothebeginningofthenextline.

varword:string

getskip%Skipoveranywhitespace

exitwheneof%Aretheremorecharacters?

getword%Inputnexttoken

putword%Outputthetoken

endloop

Intheaboveandthenextexample,iftheinputhasbeenredirectedsothatitisfromafile,eofbecomestrueexactlywhentherearenomorecharacterstoberead.Iftheinputiscomingfromthekeyboard,youcansignaleofbytypingcontrol-Z(onaPC)orcontrol-D(onUNIX).

Details

Inform(c)ofgetItem,thevariableReferenceisfollowedby:*whichimpliesline-orientedinput.Thisformcausestheentireline(ortheremainderofthecurrentline)toberead.Inthiscasethevariablemustbeastring(notanintegerorreal).Thenewlinecharacterattheendofthelineisdiscarded.Itisanerrortotrytoreadanotherlinewhenyouarealreadyattheendofthefile.Thefollowingexampleshowshowtouseline-orientedinputtoreadalllinesintheinput.

Example

Usingline-orientedinput,inputandthenoutputalllines.

varline:string

getline:*%Readentireline

putline

endloop

Details

Inform(d)ofgetItem,thevariableReferenceisfollowedby

:widthExpn

whichspecifiescharacter-orientedinput.Thisformcausesthespecifiednumber(widthExpn)ofcharacterstobeinput(oralloftheremainingcharactersifnotenoughareleft).Ifnocharactersremain,thenullstringisreadandnowarningisgiven.Inthisform,thenewlinecharacterisactuallyinputintothevariableReference(thisdiffersfrom

line-orientedinputwhichdiscardsnewlinecharacters).Thefollowingexampleshowshowtousecharacter-orientedinputtoreadeachcharacteroftheinput.Form(d)canbeusedwithstringandchar(nvariables,butnotwithchar,intoranyothertype.

Example

Usingcharacter-orientedinput,inputandthenoutputallcharacters.

varch:string(1)

getch:1%Readonecharacter

putch..%Outputthecharacter,which

%maybeanewlinecharacter

endloop

Example

Usingcharacter-orientedinput,inputtwocharacters.

vard:char(3):='abc'

getd:2%Readtwocharacter(replace'ab')

Seealso readstatement,whichprovidesbinaryfileinput.

getch getcharacterprocedure

Syntax getch(varch:string(1))

Description

Thegetchprocedureisusedtoinputasinglecharacterwithoutwaitingfortheendofaline.Theparameterchissettothenextcharacterinthekeyboardbuffer(theoldestnot-yet-readcharacter).

Example

ThisprogramcontainsaprocedurecalledgetKeywhichcausestheprogramtowaituntilakeyispressed.

proceduregetKey

varch:string(1)

getch(ch)

endgetKey

fori:1..1000

puti:4,"Pausetillakeyispressed"

getKey

endfor

Details

Thescreenshouldbeina"screen"or"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotinoneofthesemodes,itwillautomaticallybesetto"screen"mode.

OnIBMPC'ssomekeys,suchastheleftarrowkey,insertkey,deletekey,andfunctionkeysdonotproduceordinarycharactervalues.Thesekeystrokesarereturnedbygetchastheir"scancode"with128addedtothem,unlessthescancodealreadyhasavalueof128orgreater.Thisprovidesauniquevalueforeverykeyonthekeyboard.SeeAppendixDforthesecodes.

Seealso

hasch(hascharacter)whichisusedtoseeifacharacterhasbeentypedbutnotyetread.

SeealsopredefinedunitInput.

getchar getcharacterfunction

Syntax getchar:char

Description

Thegetcharfunctionisusedtoinputasinglecharacterwithoutwaitingfortheendofaline.Thenextcharacterinthekeyboardbuffer(theoldestnot-yet-readcharacter)isreturned.

Example

proceduregetKey

varch:char

ch:=getchar

endgetKey

fori:1..1000

getKey

endfor

Details

OnIBMPC'ssomekeys,suchastheleftarrowkey,insertkey,deletekey,andfunctionkeysdonotproduceordinarycharactervalues.Thesekeystrokesarereturnedbygetcharastheir"scancode"with128addedtoit,unlessthescancodealreadyhasavalueof128orgreater.Thisprovidesauniquevalueforeverykeyonthekeyboard.SeeAppendixDforthesecodes.

Seealso

hasch(hascharacter)whichisusedtoseeifacharacterhasbeentypedbutnotyetread.

getenv getenvironmentfunction

Syntax getenv(symbol:string):string

Description

Thegetenvfunctionisusedtoaccesstheenvironmentstringwhosenameissymbol.Thesestringsaredeterminedbytheshell(commandprocessor)ortheprogramthatcausedyourprogramtorun.Seealsothenargsandfetchargfunctions.

Example

OnaPC,thisretrievestheenvironmentvariableUSERLEVELandprintsextrainstructionsifUSERLEVELhadbeensettoNOVICE.USERLEVELcanbesettoNOVICEwiththecommandSETUSERLEVEL=NOVICEintheautoexec.batfileorinanybatchfile.

constuserLevel:string

userLevel:=getenv("USERLEVEL")

ifuserLevel="NOVICE"then

…%putasetofinstructions

Seealso SeealsopredefinedunitSys.

getpid getprocessidfunction

Syntax getpid:int

Description

ThegetpidfunctionisusedtodeterminetheI.D.(number)thatidentifiesthecurrentoperatingsystemtask(process).Bewarethatthereareprocesses,activatedbytheforkstatement,thatareindependentoftheoperatingsystemstasks.

UnderUNIX,thenumberisused,forexample,forcreatingauniquenameofafile.

Seealsonargs,fetchargandgetenv.

SeealsopredefinedunitSys.

getpriority function

Syntax getpriority:nat

Description

Thegetpriorityfunctionreturnsthepriorityofanexecutingprocessinaconcurrentprogram.Asmallervaluemeansafasterspeed.

Seealsosetpriority,forkandmonitor.

Description

ThisunitcontainsthepredefinedsubprogramsforcreatingandusingaGUI(GraphicalUserInterface).ElementsoftheGUIincludebuttons,checkboxes,textboxes,scrollbars,menus,etc.

ForageneralintroductiontothetheGUImodule,seeIntroductiontoGraphicalUserInterfaces.

GUI.AddLine PartofGUImodule

Syntax GUI.AddLine(widgetID:int,text:string)

Description

GUI.AddLineaddstextandanewlinetothecurrentlineofthetextboxspecifiedbywidgetID.Itisessentiallyequivalenttoputtextinthetextbox.GUI.AddLinescrollsthetextbox(ifnecessary)sothattheaddedtextisnowvisible.ThewidgetIDparametermustbethewidgetidofatextbox.Thetextparameteristhetexttobeaddedtothetextbox.

Example

Thefollowingcreatesatextboxandputsthenumbersfrom1to25init.

importGUI

varboxID:int:=GUI.CreateTextBox(50,50,200,200)

fori:1..25

GUI.AddLine(boxID,intstr(i))

endfor

exitwhenGUI.ProcessEvent

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.AddLine,notbycallingAddLine.

Seealso GUI.CreateTextBox.

GUI.AddText PartofGUImodule

Syntax GUI.AddText(widgetID:int,text:string)

Description

GUI.AddTextaddstexttothecurrentlineofthetextboxspecifiedbywidgetID.Itdoesnotaddanewlineafterthetext.Itisessentiallyequivalenttoputtext...inthetextbox.GUI.AddLinescrollsthetextbox(ifnecessary)sothattheaddedtextisnowvisible.ThewidgetIDparametermustbethewidgetidofatextbox.Thetextparameteristhetexttobeaddedtothetextbox.

Details

Toforceatextboxtoscrolltotheendofthetextwithoutaddinganyextratext,callGUI.AddTextwith""(thenullstring)forthetextparameter.

Example

Thefollowingcreatesatextboxandputsthenumbersfrom1to26followedbytheappropriateletterofthealphabetinit.

importGUI

varboxID:int:=GUI.CreateTextBox(50,50,200,200)

fori:1..26

GUI.AddText(boxID,intstr(i))

GUI.AddText(boxID,"")

GUI.AddLine(boxID,chr(64+i))

endfor

endloop

Execute

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingGUI.AddText,notbycallingAddText.

GUI.Alert[2,3,Full] PartofGUImodule

Syntax

Oneoffourprocedures:

GUI.Alert(title,msg:string) GUI.Alert2(title,msg1,msg2:string) GUI.Alert3(title,msg1,msg2,msg3:string) GUI.AlertFull(title:string, msg:array1..*ofstring,button:string)

Description

Displaysadialogboxwiththestringspecifiedbymsginit.ThereisasinglebuttonlabelledOKwhichdismissesthedialogandresumesexecution.ThetitleparameterspecifiesthewindowtitleunderMicrosoftWindows.OntheAppleMacintosh,thereisnotitle,sodonotassumetheuserwillseethetitle.Thedialogboxiscenteredonthescreen.

TheGUI.Alert2andGUI.Alert3proceduresallowtheusertospecifyatwoorthreelinemessagerespectively.TheGUI.AlertFullprocedureallowstheusertospecifyanynumberoflinesoftextinthestringarrayspecifiedbymsgaswellasthetextinthedismissalbutton.Anyemptystringsattheendofthearrayarenotdisplayed.

Note:ThisfunctionisnotavailableinthecurrentversionoftheGUIProcedureLibrary(shippingwithTuring4.0andMacOOT1.5).ItisdocumentedhereforusewithfutureshippingversionofTuring.ItislikelytobeimplementedintheversionofTuringreleasedinSeptember2002.Checkthereleasenotesthatarefoundintheon-linehelptofindoutifthisfunctionisnowavailable.

Thefollowingprogramaskstheuserforthenameofafileputsupanalertdialogboxifitfails.

importGUIin"%oot/lib/GUI"

Example

varfileName:string

varstreamNumber:int

fileName:=GUI.SaveFile("SaveAs")

open:streamNumber,fileName,put

exitwhenstreamNumber>0

GUI.Alert("OpenFailure","\""+fileName+

"\"couldnotbeopened")

endloop

Example

Thefollowingprogramaskstheuserforthenameofafileputsupamorecompletealertdialogboxifitfails.

varfileName:string

varstreamNumber:int

fileName:=GUI.SaveFile("SaveAs")

exitwhenstreamNumber>0

GUI.Alert2("OpenFailure",

"\""+fileName+"\"couldnotbeopened.",

"Reason:"+Error.LastMsg)

endloop

Example

Thefollowingprogramfragmentdisplaysanalertwithfourlinesoftextandabuttonthatsays"Abort".

varmessage:array1..10ofstring

fori:1..10

message(i):=""

endfor

message(1):="Theprogrammustnowquit"

message(2):="becasueofanunrecoverableerror."

message(3):="AReadErroroccurredwhilereading"

message(4):="file\""+fileName+"\"."

message(5):=Error.LastMsg

GUI.AlertFull("Error",message,"Abort")

Status

Exportedqualified.

GUI.Alert,notbycallingAlert.

GUI.Choose[Full] PartofGUImodule

Syntax

Oneoftwoprocedures:

GUI.Choose(title,msg1,msg2,msg3:string, btn1,btn2,btn3:string):int GUI.ChooseFull(title:string, msg:array1..*ofstring, btn1,btn2,btn3:string, defaultBtn:int):int

Description

Displaysadialogboxwithtextandfromonetothreebuttons.Theuserselectsabuttontodismissthedialog.Thenumberofthebuttonpressedisreturnedbythefunction.Thedialogboxiscenteredonthescreen.

Thetitleparameterspecifiesthetitleinthewindowbarofthedialogbox.TheAppleMacintoshdoesnothaveatitlebar,sodonotassumethattheuserwillseethestringinthetitleparameter.Themessageisspecifiedbystringsinandmsg3forGUI.ChooseandthestringarraymessageforGUI.ChooseFulleachcase,emptystringsattheendofthelistofstringsareignored.Theandbtn3parametersspecifythetexttoappearinthebuttons.Ifthetextisanemptystring(""),thebuttonisnotdisplayed.

Thefunctionreturnsthebuttonnumberfromonetothreethatwaschosen.

ThedefaultBtnparameterinGUI.ChooseFullspecifieswhich,ifany,buttonshouldbethedefaultbutton.ThedefaultbuttonisselectediftheuserpressesEnter.Ifthedefaultbuttonis0,thennobuttonishighlightedasthedefaultbutton.

Note:ThisfunctionisnotavailableinthecurrentversionoftheGUIProcedureLibrary(shippingwithTuring4.0andMacOOT1.5).ItisdocumentedhereforusewithfutureshippingversionofTuring.ItislikelytobeimplementedintheversionofTuring.Checkthereleasenotesthatarefoundintheon-linehelptofindoutifthisfunctionisnowavailable.

ThefollowingprogramasksiftheuserwantscoffeeorteaandsetwantsCoffee

Example

appropriately.

varwantsCoffee:boolean

varchoice:int:=GUI.Choose("BeverageChoice",

"Doyouwantcoffeeortea?","","","Coffee","Tea","")

ifchoice=1then

wantsCoffee:=true

wantsCoffee:=false

Example

Thefollowingprogramaskstheuserwhethertheywanttosavetheirwork,don'tsavetheirworkorCancel.

%Returnsfalseifcancellingoperation

procedureCheckUnsavedWork:boolean

varmessage:array1..3ofstring

message(1):="Changesto"+fileName+"havenotbeen"

message(2):="saved.Unsavedworkwillbelost.Doyou"

message(3):="wanttosavebeforequitting."

varchoice:int:=GUI.ChooseFull("SaveBeforeQuit",

message,"Save","Don'tSave","Cancel",1)

ifchoice=1then

SaveWork

elsifchoice=3then

returnfalse

returntrue

endCheckUnsavedWork

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.ChoosecallingChoose.

GUI.ClearText PartofGUImodule

Syntax GUI.ClearText(widgetID:int)

DescriptionClearsallthetextinatextboxspecifiedbywidgetID.ThewidgetIDmustbethewidgetidofatextbox.

Example

Theprogramlists25numbersinatextbox.Everytimethebuttonispressed,itclearsthetextboxandprintsthenext25numbers.

importGUI

varboxID,buttonID,start:int

start:=1

procedurePrintTwentyFive

GUI.ClearText(boxID)

fori:start..start+24

GUI.AddLine(boxID,intstr(i))

endfor

start+=25

endPrintTwentyFive

boxID:=GUI.CreateTextBox(50,50,200,200)

buttonID:=GUI.CreateButton(50,5,0,"Next25",

PrintTwentyFive

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.ClearTextbycallingClearText.

GUI.CloseWindow PartofGUImodule

Syntax GUI.CloseWindow(window:int)

Description

Closesawindowwithwidgetsinit.ThisprocedureautomaticallydisposesofanywidgetsinthewindowandmakescertainthattheGUILibraryrecognizesthatthewindownolongerexists.ThisprocedurewillcallWindow.Close,sothereisnoneedfortheusertodoso.

Example

Theprogramopensupawindowwithtwobuttons.Ifthebuttonlabelled"CloseandOpen"ispressed,thewindowisclosedandanewwindowwithtwobuttonsisopenedinarandomlocationonthescreen.

importGUI

constscreenWidth:int:=Config.Display(cdScreenWidth

constscreenHeight:int:=Config.Display(cdScreenHeight

consttitleBarHeight:int:=32

constwindowEdgeSize:int:=13

constwindowWidth:int:=150

constwindowHeight:int:=100

varwindowID,windowNumber,closeButton,quitButton

procedureCloseAndOpen

ifwindowIDnot=0then

GUI.CloseWindow(windowID)

windowNumber+=1

varxPos:int:=Rand.Int(0,screenWidth-

windowEdgeSize)

varyPos:int:=Rand.Int(0,screenHeight-

titleBarHeight)

windowID:=Window.Open("title:Window#"+

intstr(windowNumber)+",graphics:"+

intstr(windowWidth)+";"+intstr(windowHeight

",position:"+intstr(xPos)+";"+intstr

closeButton:=GUI.CreateButton(10,60,130,

"CloseAndOpen",CloseAndOpen)

quitButton:=GUI.CreateButton(10,10,130,"Quit",

endCloseAndOpen

CloseAndOpen

endloop

GUI.CloseWindow(windowID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CloseWindow,notbycallingCloseWindow.

SeealsoGUI.ShowWindowandGUI.HideWindow,forshowingandhidingwindowswithwidgetsinthem.

GUI.CreateButton[Full] PartofGUImodule

Syntax

GUI.CreateButton(x,y,width:int,text:string,actionProc:procedurex()):int

GUI.CreateButtonFull(x,y,width:int,text:string,actionProc:procedurex(),height:int,shortcut:char,defaultint

Description

Createsabuttonandreturnsthebutton'swidgetID.

Thebuttonwidgetisusedtoimplementatextualbutton.Whenyoubutton,thebutton'sactionprocedureiscalled.Ifabuttonisgivenashortcut,thenenteringthekeystrokewillcausetheactionproceduretobecalled.Itwillnotvisiblycausethebuttontodepress.

TwoButtons

Thexandyparametersspecifythelower-leftcornerofthebutton.Theparameterspecifiesthewidthofthebutton.Ifwidthislessthanthesizenecessarytodisplaythebutton,thebuttonisautomaticallyenlargedtofitthetext.Thetextparameterspecifiesthetexttoappearinthebutton.Theparameteristhenameofaprocedurethatiscalledwhenthebuttonispressed.

ForGUI.CreateButtonFull,theheightparameterspecifiestheheightofthebutton.Ifheightislessthanthesizenecessarytodisplaythebutton,thebuttonisautomaticallyenlargedtofitthetext.Theshortcutparameteristhekeystroketobeusedasthebutton'sshortcut.Thedefaultparameterisabooleanindicating

whetherthebuttonshouldbethedefaultbutton.Ifthereisalreadyadefaultbutton,anddefaultissettotrue,thenthisbuttonbecomesthenewdefaultbutton.

Example

Thefollowingprogramcreatestwobuttons,onewhichdrawsarandomthescreenandonewhichquitstheprogram.

importGUI

procedureDrawRandomCircle

varr:int:=Rand.Int(20,50)

varx:int:=Rand.Int(r,maxx-r)

vary:int:=Rand.Int(r,maxy-r)

varc:int:=Rand.Int(0,maxcolor)

Draw.FillOval(x,y,r,r,c)

%Incasewedrewoverthebuttons,redrawthem.

GUI.Refresh

endDrawRandomCircle

View.Set("graphics:300;200,nobuttonbar")

vardraw:int:=GUI.CreateButtonFull(50,10,0,"DrawCircle",

DrawRandomCircle,0,'^D',true)

varquitBtn:int:=GUI.CreateButton(200,10,0,"Quit",

endloop

Execute

Details

WhenGUI.CreateButtonorGUI.CreateButtonFulliscalled,thenewlycreatedbuttonwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Ifabutton'swidthorheightissettozero(ornotspecifiedatall),thenthebuttonisshapedtofitthetext.

Abuttoncanbethedefaultbuttonforawindow.Thedefaultbuttonwithathickerborderaroundit.IftheuserpressesENTERinawindowwithadefaultbutton,thedefaultbutton'sactionprocedureiscalled.

Whenabuttonisnotenabled,thetextinthebuttonisgrayedoutandthebuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithabuttonastheparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.DisposeGUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.SetLabel,GUI.SetDefault

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateButtonnotbycallingCreateButton.

SeealsoGUI.SetLabelforchangingthebutton'stext,GUI.SetDefaultforsettingdefaultbuttoninawindowandGUI.SetColorforsettingthebutton'scolor.

GUI.CreateCanvas[Full] PartofGUImodule

Syntax

GUI.CreateCanvas(x,y,width,height:int):int

GUI.CreateCanvasFull(x,y,width,height:int,border:int,mouseDown:procedurex(mx,my:int),mouseDrag:procedurex(mx,my:int),mouseUp:procedurex(mx,my:int)):int

Description

Createsacanvasandreturnsthecanvas'widgetID.

Acanvasisadrawingsurfaceforusebytheprogram.Itdiffersfromjustusingthewindowsurfacetodrawoninthat(0,0)representsthelower-leftcornerofthecanvasandalldrawingisclippedtothecanvas.(Thismeansthatifyouaccidentlyattempttodrawoutsideofthecanvas,itwillnotactuallydrawbeyondtheborderofthecanvas.)

CanvaseshaveproceduresthatemulatealltheproceduresintheDrawmoduleaswellasaproceduretoemulateFont.Draw,Pic.Draw,Pic.New,Pic.ScreenLoadandPic.ScreenSave.

Youcangetmousefeedbackfromacanvas.UsingtheCreateCanvasFullmethod,youcanspecifythreeroutinesthatarecalledwhenthemousebuttonisdepressedwhilepointinginacanvas.Oneroutinewillbecalledwhentheuserpressesthemousebuttondowninacanvas.Anotherroutinewillbecalledwhiletheuserdragsthemousewiththemousebuttondown.Thisroutineisrepeatedlycalledwheneverthemousechangespositionwhilethemousebuttonisdown.Thelastroutineiscalledwhenthemousebuttonisreleased.Allthreeroutinestakeanandyparameter,whichisthelocationofthemousewithrespecttothecanvas(i.e.(0,0)isthelower-leftcornerofthecanvas).

OutputofCanvases.dem

Thexandyparametersspecifythelower-leftcornerofthecanvas.Thewidthandheightparametersspecifythewidthandheightofthecanvas.

ForGUI.CreateCanvasFull,theborderparameterspecifiesthetypeofborderthatsurroundsthecanvasandisoneof0,GUI.LINE,GUI.INDENTorGUI.EXDENT.Aborderof0isthedefaultandisthesameasGUI.LINE.GUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthecanvasappearindentedorrecessed.GUI.EXDENTmakesthecanvasappeartostandoutfromthewindow.

ThemouseDownparameterisaprocedurecalledwhentheuserpressesthemousebuttoninthecanvas.ThemouseDragparameterisaprocedurecalledwhentheuserdragsthemousewhilethemousebuttonisstillpressed.ThemouseUpparameterisaprocedurecalledwhentheuserreleasesthemousebutton.Theparameterstoallthreearethexandylocationofthemousewherethebuttonwaspressed(dragged/released).Thecoordinatesaregivenwithrespecttothecanvas(i.e.(0,0)isthelower-leftcornerofthecanvas).

Example

Thefollowingprogramdraws10randomstarsinthecanvas.

importGUI

varcanvas:int:=GUI.CreateCanvas(10,10,maxx

fori:1..10

varx:int:=Rand.Int(0,maxx-20)

vary:int:=Rand.Int(0,maxy-20)

varc:int:=Rand.Int(0,maxcolor)

GUI.DrawFillOval(canvas,x,y,20,20,c)

endfor

Execute

Details

WhenGUI.CreateCanvasorGUI.CreateCanvasFulliscalled,thenewlycreatedcanvaswillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Theborderofthecanvasisjustoutsidethedrawingsurface,soGUI.GetWidthandGUI.GetHeightwillreturnslightlargervaluesthanwidthandheight.

Whenthecanvasisdisabled,clickingthemouseinthecanvasdoesnotcallanyofthemouseDown,mouseDrag,ormouseUpprocedures.Theappearanceofthecanvasdoesnotchange.

Details

ThefollowingGUIsubprogramscanbecalledwithabuttonasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.DisposeGUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.Draw…,GUI.FontDraw,GUI.Pic…,GUI.SetXOR

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateCanvas,notbycallingCreateCanvas.

SeealsoGUI.Draw…,GUI.FontDraw,GUI.Pic…,andGUI.SetXORfordrawingonacanvas.

GUI.CreateCheckBox[Full] PartofGUImodule

Syntax

GUI.CreateCheckBox(x,y:int,text:string,actionProc:procedurex(filled:boolean)):int

GUI.CreateCheckBoxFull(x,y:int,text:string,actionProc:procedurex(filled:boolean),alignment:int,shortcutint

Description

Createsacheckbox(withaccompanyingtext)andreturnsthecheckbox'swidgetID.

Thecheckboxwidgetisusedtoimplementacheckboxthatcanbesetorunset.Whenyouclickonacheckbox,thestatusofthecheckboxflipsfromsettounsetandbackagainandthecheckbox'sactionprocedureiscalledwiththenewstatusasaparameter.Ifacheckboxisgivenashortcut,thenenteringthekeystrokewillcausethecheckboxtochangestatusandtheactionprocedurebecalled.Thenewstatuswillbedisplayedimmediately.

TwoCheckBoxes

Thexandyparametersspecifythelower-leftcornerofthecheckbox(unlessalignmentissettoGUI.RIGHT,inwhichcasetheyspecifythelower-rightcornerofthecheckbox).Thetextparameterspecifiesthetext(orlabel)besidethecheckbox.TheactionProcparameteristhenameofaprocedurethatiscalledwhenthestatusofthecheckboxchanges.TheactionProcproceduremusthaveonebooleanparameterwhichisthenewstatusofthecheckbox.InGUI.CreateCheckBox,thecheckbox'stextisalwaystotherightoftheactualcheckbox.InGUI.CreateCheckBoxFull,thetextcanbesettotherightorleftofthecheckboxwiththealignmentparameter.

ForGUI.CreateCheckBoxFull,thealignmentparameterspecifiesthepositionofthecheckboxinrelationtothetextaswellasthemeaningofthe

parameters.Thealignmentparameterisoneof0,GUI.LEFT,orGUI.RIGHTalignmentof0isthedefaultandisthesameasGUI.LEFT.GUI.LEFTactualboxinthecheckboxappearstotheleftofthecheckbox'slabeland(specifiesthelower-leftcorner.AnalignmentofGUI.RIGHTmeansthattheactualboxappearstotherightofthecheckbox'slabeland(x,y)specifiesthelower-rightcornerofthecheckbox.Theshortcutparameteristhekeystroketobeusedasthebutton'sshortcut.Thedefaultparameterisabooleanindicatingwhetherthebuttonshouldbethedefaultbutton.Ifthereisalreadyadefaultbutton,anddefaultissettotrue,thenthisbuttonbecomesthenewdefaultbutton.

Acheckbox'ssizeisnotspecifiedduringcreation.Itisdeterminedbasedonthesizeofthetext.Insteadtheuserspecifiesthelower-leftcornerofthecheckbox(orthelower-rightifthecheckboxisrightjustified).

Example

Thefollowingprogramcreatestwobuttons,onewhichdrawsarandomcircleonthescreenandonewhichquitstheprogram

importGUI

procedureDoNothing(status:boolean)

endDoNothing

varcb1:int:=GUI.CreateCheckBox(10,10,"CheckBox1",

DoNothing)

varcb2:int:=GUI.CreateCheckBoxFull(200,10,"CheckBox2",

DoNothing,GUI.RIGHT,'2')

GUI.SetCheckBox(cb2,true)

varquitBtn:int:=GUI.CreateButton(230,10,0,"Quit",

endloop

varcb1Status:boolean:=GUI.GetCheckBox(cb1)

varcb2Status:boolean:=GUI.GetCheckBox(cb2)

ifcb1Statusthen

put"Checkbox1:filled"

put"Checkbox1:empty"

ifcb2Statusthen

put"Checkbox2:filled"

put"Checkbox2:empty"

Execute

Details

WhenGUI.CreateButtonorGUI.CreateButtonFulliscalled,thenewlycreatedcheckboxwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenacheckboxisnotenabled,thelabelbesidethecheckboxisgrayedoutandthecheckboxnolongerrespondstoanymouseclicksorkeystrokesuntilthecheckboxisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithacheckboxastheparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.DisposeGUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.SetLabel,GUI.GetCheckBox,GUI.SetCheckBox

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateCheckBoxnotbycallingCreateCheckBox.

SeealsoGUI.SetLabelforchangingthechecbox'stextandGUI.GetCheckBoxGUI.SetCheckBoxforreadingandsettingthecheckbox'sstate.

GUI.CreateFrame PartofGUImodule

Syntax GUI.CreateFrame(x1,y1,x2,y2,kind:int):int

Description

Createsaframeandreturnstheframe'swidgetID.

AframeisaboxdrawnaroundotherGUIwidgetstomakethewindowlookbetterandhelporganizetheGUIelements.

ThreeTypesofFramesWithaLabelinEachFrame

FramesaretheonlyGUIwidgetsthatcanhaveotherwidgetsplacedwithinthem.Framesarepassivewidgets,meaningthattheydonotrespondtobuttonclicksorkeystrokes.

Thex1andy1parametersspecifythelower-leftcorneroftheframeandthex2andy2parametersspecifytheupper-rightcorneroftheframe.Thekindparameterspecifiesthetypeofframe.Thisisoneof0,GUI.LINEGUI.INDENT,orGUI.EXDENT.Akindof0isthedefaultandisthesameasGUI.LINE.

GUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthecontentsframeappearindentedorrecessed.GUI.EXDENTmakesthecontentsoftheframeappeartostandoutfromthewindow.

Thefollowingprogramdrawsthreeframesinthewindowanddrawsalabelineachone.

importGUI

GUI.SetBackgroundColor(gray)

varlineFrame,indentFrame,exdentFrame:int

ExamplevarlineLabel,indentLabel,exdentLabel:int

lineFrame:=GUI.CreateFrame(10,10,80,70,0)

indentFrame:=GUI.CreateFrame(90,10,160,70,

exdentFrame:=GUI.CreateFrame(170,10,240,70,

%Labelthelines.

lineLabel:=GUI.CreateLabelFull(10,10,"Line",70,60,

GUI.CENTER+GUI.MIDDLE,0)

indentLabel:=GUI.CreateLabelFull(90,10,"Indent",70,60,

exdentLabel:=GUI.CreateLabelFull(170,10,"Exdent",70,60,

Execute

Details

WhenGUI.CreateFrameiscalled,thenewlycreatedframewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Aframewidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithaframeasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSizeGUI.SetPositionAndSize

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateFrame,notbycallingCreateFrame.

GUI.CreateHorizontalScrollBar[Full] PartofGUImodule

Syntax

GUI.CreateHorizontalScrollBar(x,y,size:int,min,max,start:int,actionProc:procedurex(value:int

GUI.CreateHorizontalScrollBarFull(x,y,size:int,min,max,start:int,actionProc:procedurex(value:int),arrowInc,pageInc,thumbSize:int):int

Description

Createsahorizontal(left-right)scrollbarandreturnsthescrollbar'swidgetID.

Ascrollbarisawidgetthatallowsuserstoseeapieceofadocumentthatcannotbedisplayedonthescreeninitsentirety.Thepicturebelowshowsahorizontalscrollbar.Tocontrolascrollbar,thereareafewchoices:theusercanclickonthethumb(theboxinthescrollbar)andslideitleftorright,ortheusercanclickinthescrollbaritselftotheleftorrightofthethumb(inwhichcasethethumbismovedupordownone"page"),ortheusercanclickontheleftorrightarrowsattheendsofthescrollbar(inwhichcasethethumbismovedleftorrightone"arrowincrement").

AHorizontalScrollBar

Theprogrammerdefinesapageoranarrowincrement.Whenthevalueofthescrollbarchanges,theactionprocedureofthescrollbariscalledwiththenewvalueasaparameter.Theactionprocedureshouldthenredrawthecontentsusingthenewvalueofthescrollbar.

TherangeofvaluesthatthescrollbarwillgiveisdeterminedbythemaxparametersintheCreatecall.Theleftsideofthescrollbarrepresentstheminimumvalue,whiletherightrepresentsthemaximumvalue.Thereisalsothe"thumbsize".Thisrepresentstherangeofvaluesthatcanbeseenatonceonthescreen.

Bydefault,thearrowincrement(theamountthevalueischangedwhenthescrollingarrowsarepressed)issettoone.Thepageincrement(theamountthevalueischangedwhentheuserclicksinthebartotherightorleftofthethumb)issettoonequarterthedifferencebetweentheminimumandthemaximum.The"thumbsize"issettozero(seethedescriptionofscrollbarsforanexplanationofthethumbsize).

Thexandyparametersspecifythelower-leftcornerofthescrollbar.Theparameterspecifiesthelengthofthescrollbar(includingthearrows)inpixels.Theminandmaxparametersaretheminimumandmaximumvaluesreturnedbythescrollbar.Thestartparameteristheinitialvalueofthescrollbarandshouldbebetweenminandmaxinclusive.TheactionProcparameternameofaprocedurethatiscalledwhenthevalueofthescrollbarischanged.Theparametertotheactionprocedureisthecurrentvalueofthescrollbar.

Example

Thefollowingprogramcreatesahorizontalscrollbar.Wheneverthescrollbar'svalueischanged,amessageisdisplayedinthewindow.

importGUI

varscrollBar:int

procedureScrollBarMoved(value:int)

Text.Locate(2,3)

put"HorizontalScrollBar:",value:4

endScrollBarMoved

scrollBar:=GUI.CreateHorizontalScrollBar(10,10,250,

50,150,50,ScrollBarMoved)

endloop

Execute

ForGUI.CreateHorizontalScrollBarFull,thearrowIncparameterspecifies

Description

thearrowincrement(theamountthescrollbar'svalueischangedwhenthescrollarrowsarepressed).ThepageIncspecifiesthepageincrement(theamountthescrollbar'svalueischangedwhentheuserclicksinthepageleft/rightsectionofthescrollbar).ThethumbSizeparameterspecifiesthe"thumbsize".(Seethescrollbarexplanationformoredetailonascrollbar's"thumbsize").

Forexample,ifyouhaveawindowthatcandisplay20linesoftextatonceandthereare100linesoftext,youwouldsetminto1,maxto100and20.Thevaluereturnedbythescrollbarwouldthenbethelinenumberofthefirstlineonthescreentobedisplayed.Whenthescrollbarwasatitsmaximumvalue,itwouldreturn81,sincebydoingso,lines81-100wouldbedisplayed.

Example

Hereisanexampleprogramthatscrollsalargepictureoverasmallerwindow.

%The"ScrollPic"program.

importGUI

varh,v:int%Thescrollbars.

varcanvas:int%Thecanvas.

varpic:int%Thepicture.

constwidth:int:=220%Thewidthofthecanvas.

procedureScrollPic(ignore:int)

%Getthecurrentvalueofthescrollbars.

varx:int:=GUI.GetSliderValue(h)

vary:int:=GUI.GetSliderValue(v)

GUI.PicDraw(canvas,pic,-x,-y,picCopy)

endScrollPic

pic:=Pic.FileNew("Forest.jpg")

ifpic<=0then

put"Errorloadingpicture:",Error.LastMsg

return

View.Set("graphics:265;265")

canvas:=GUI.CreateCanvas(15,15+GUI.GetScrollBarWidth

width,width)

%Notetheframeofthecanvasis:

%(14,14+ScrollbarWidth)-(235,235+ScrollbarWidth)

h:=GUI.CreateHorizontalScrollBarFull(14,14,

221,0,Pic.Width(pic),0,ScrollPic,3,100,

v:=GUI.CreateVerticalScrollBarFull(235,

14+GUI.GetScrollBarWidth,221,0,Pic.Height

Pic.Height(pic),ScrollPic,3,100,width)

ScrollPic(0)%Drawthepictureinitially

endloop

Execute

Details

Insomeinstances,youwillwantthetheminimumandmaximumvaluesofthescrollbartobereversed(right/topisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesofthescrollbar.

Scrollbarsalwayshaveafixedheight(forhorizontalscrollbars)orwidth(forverticalscrollbars).Togetascrollbar'swidth,usetheGUI.GetScrollBarWidthfunction.

WhenGUI.CreateHorizontalScrollBarorGUI.CreateHorizontalScrollBarFulliscalled,thenewlycreatedscrollbarwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenascrollbarisnotenabled,thegrayinthebarissettowhiteandthethumbisnotdisplayed.Thescrollbarnolongerrespondstoanymouseclicksuntilthescrollbarisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithascrollbarastheparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.DisposeGUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.GetSliderValue,GUI.SetSliderValue,GUI.SetSliderMinMaxGUI.SetSliderSize,GUI.SetSliderReverse,GUI.SetScrollAmount

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateHorizontalScrollBar,notbycallingCreateHorizontalScrollBar

Seealso

GUI.GetSliderValueandGUI.SetSliderValueforreadingandsettingthevalueofascrollbar,GUI.SetSliderMinMaxforchangingtheminimumandmaximumvaluesofascrollbar,andGUI.SetScrollAmountforchangingthescrollingincrementsandthumbsizeofascrollbar.SeealsoGUI.SetSliderSizeforsettingthelengthofascrollbarandGUI.SetSliderReverseforreversingthesenseofascrollbar.

GUI.CreateHorizontalSlider PartofGUImodule

Syntax

GUI.CreateHorizontalSlider(x,y,length:int,min,max,start:int,actionProc:procedurex(value:int)):int

Description

Createsahorizontal(left-right)sliderandreturnstheslider'swidgetID.

Asliderisawidgetthatallowstheusertosetacontinuoussetofvalues.Ithasareal-lifeequivalentinthingssuchasastereovolumecontrol.

AHorizontalSlider

Tocontrolaslider,theuserclicksonthesliderboxanddragsitbackandforth.Everytimethevaluechanges,aprocedureiscalledwiththenewvalueasaparameter.

TherangeofvaluesthatthesliderwillgiveisdeterminedbytheminandmaxparametersintheCreatecall.Theleftsideofthesliderrepresentstheminimumvalue,whiletherightrepresentsthemaximumvalue.

Thexandyparametersspecifythelower-leftcorneroftheslidertrack.Thismeansthattheslideractuallyextendsaboveandbelowthispoint(andslightlytotheleftofittotakeintoaccounttheroundedendofthetrack).Thelengthparameterspecifiesthelengthofthetrackinpixels.(YoucanuseGUI.GetX,GetY,GetWidth,andGetHeighttogettheexactdimensionsoftheslider.)Theminandmaxparametersaretheminimumandmaximumvaluesreturnedbytheslider.Thestartparameteristheinitialvalueofthesliderandshouldbebetweenminandmaxinclusive.TheactionProcparameteristhenameofaprocedure

thatiscalledwhenthevalueofthesliderischanged.Theparametertotheactionprocedureisthecurrentvalueoftheslider.

Example

Thefollowingprogramcreatesahorizontalslider.Whenevertheslider'svalueischanged,amessageisdisplayedinthewindow.

importGUI

varslider:int

procedureSliderMoved(value:int)

Text.Locate(2,3)

put"HorizontalSlider:",value:4

endSliderMoved

slider:=GUI.CreateHorizontalSlider(10,10,250,

50,150,50,SliderMoved)

endloop

Execute

Details

Insomeinstances,youwillwantthetheminimumandmaximumvaluesoftheslidertobereversed(rightisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesoftheslider.

Slidersalwayshaveafixedheight(forhorizontalsliders)orwidth(forverticalsliders).

WhenGUI.CreateHorizontalSliderorGUI.CreateHorizontalSliderFulliscalled,thenewlycreatedsliderwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplay

parametersettofalse.

Whenasliderisnotenabled,theappearancedoesnotchange.However,theslidernolongerrespondstoanymouseclicksuntilitisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithasliderasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.Dispose,GUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.GetSliderValue,GUI.SetSliderValue,GUI.SetSliderMinMax,GUI.SetSliderSize,GUI.SetSliderReverse

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateHorizontalSlider,notbycallingCreateHorizontalSlider.

Seealso

GUI.GetSliderValueandGUI.SetSliderValueforreadingandsettingthevalueofaslider,GUI.SetSliderMinMaxforchangingtheminimumandmaximumvaluesofaslider.SeealsoGUI.SetSliderSizeforsettingthelengthofasliderandGUI.SetSliderReverseforreversingthesenseofaslider.

GUI.CreateLabel[Full] PartofGUImodule

Syntax

GUI.CreateLabel(x,y:int,text:string):int

GUI.CreateLabelFull(x,y:int,text:string,width,height,alignment,fontID:int):int

Description

Createsalabelandreturnsthelabel'swidgetID.

Thelabelwidgetisusedtodisplaytext.Itcanbeusedtodisplaytextinavarietyoffontsandsizes.Labelwidgetscanalsobealignedinavarietyofways.

ThreeLabels

Thexandyparametersspecifythelower-leftcorneroftheareainwhichthetextwillbedrawn.ForGUI.CreateLabel,thisisthelower-leftcornerofthetext.Thetextparameterspecifiesthetextofthelabel.

ForGUI.CreateLabelFull,thewidthandheightparametersspecifytheareainwhichthelabelistoappear.Thisisusedforalignmentpurposes.Seetheprogrambelowforanexampleofaligningthetexttodifferentcornersofthewindow.Thealignmentparameterspecifiesthealignmentofthetextinthetextarea.Thisvalueisthesumofhorizontalalignmentandtheverticalalignment.Thehorizontalalignmentisoneof0,GUI.LEFT,GUI.CENTER,orGUI.RIGHT.Ahorizontalalignmentof0isthedefaultandisthesameasthealignmentofGUI.LEFTverticalalignmentisoneof0,GUI.TOP,GUI.MIDDLE,orGUI.BOTTOMhorizontalalignmentof0isthedefaultandisthesameasthealignmentofGUI.BOTTOM.Thesealignmentsalignthetextinvariouswaysinthetextarea.ThefontIDparameterspecifiesthefontIDofthefonttobeusedinthetextfield.ThefontIDisreceivedfromaFont.Newcall.DonotcallFont.FreeIDuntilthelabelhasbeendisposedofbycallingGUI.Dispose.

ByusingthefondIDparameter,labelscanbehaveanysizeortypeface.

Labelsarepassivewidgets,meaningthattheydonotrespondtobuttonclicksorkeystrokes.

Example

Thefollowingprogramcreatesthreelabels,onewiththedefaultalignment,theothertwoalignedtoappearinthecenterandupper-rightcornerofthewindow.

importGUI

varlowerLeft:int:=GUI.CreateLabel(0,0,"Lower-Left")

varcenter:int:=GUI.CreateLabelFull(0,0,"Center",

GUI.MIDDLE+GUI.CENTER,0)

varupperRight:int:=GUI.CreateLabelFull(0,0,"Upper-Right",

maxx,maxy,GUI.RIGHT+GUI.TOP,0)

Execute

Details

WhenGUI.CreateLabelorGUI.CreateLabelFulliscalled,thenewlycreatedlabelwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedcalledwiththedisplayparametersettofalse.

Aframewidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithalabelasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSizeGUI.SetPositionAndSize,GUI.GetSliderValue,GUI.SetSliderValueGUI.SetSliderMinMax,GUI.SetLabel

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateLabelbycallingCreateLabel.

Seealso GUI.SetLabelforchangingthelabel'stext.

GUI.CreateLabelledFrame PartofGUImodule

SyntaxGUI.CreateLabelledFrame(x1,y1,x2,y2,kind:int,text:string):int

Description

Createsalabelledframeandreturnstheframe'swidgetID.

AlabelledframeisaboxwithatextlabeldrawnaroundotherGUIwidgetstomakethewindowlookbetterandhelporganizetheGUIelements.

ThreeTypesofLabelledFrames

FramesandlabelledframesaretheonlyGUIwidgetsthatcanhaveotherwidgetsplacedwithinthem.Labelledframesarepassivewidgets,meaningthattheydonotrespondtobuttonclicksorkeystrokes.

Thex1andy1parametersspecifythelower-leftcorneroftheframeandthex2andy2parametersspecifytheupper-rightcorneroftheframe.(Thetextwillextendabovetheframe.)Thekindparameterspecifiesthetypeofframe.Thisisoneof0,GUI.LINE,GUI.INDENTorGUI.EXDENT.AkindthedefaultandisthesameasGUI.LINE.

GUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthecontentsframeappearindentedorrecessed.GUI.EXDENTthecontentsoftheframeappeartostandoutfromthewindow.

Example

Thefollowingprogramdrawsthreeframesinthewindow.

importGUI

varlineFrame,indentFrame,exdentFrame:int

lineFrame:=GUI.CreateLabelledFrame(10,10,80,70,0,"Line")

indentFrame:=GUI.CreateLabelledFrame(90,10,160,70,

GUI.INDENT,"Indent")

exdentFrame:=GUI.CreateLabelledFrame(170,10,240,70,

GUI.EXDENT,"Exdent")

Execute

Details

WhenGUI.CreateLabelledFrameiscalled,thenewlycreatedlabelledframewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedbeencalledwiththedisplayparametersettofalse.

Alabelledframewidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithalabelledframeasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSizeGUI.SetPositionAndSize,GUI.SetLabel

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateLabelledFrame,notbycallingCreateLabelledFrame

Seealso GUI.SetLabelforchangingtheframe'stext.

GUI.CreateLine PartofGUImodule

Syntax GUI.CreateLine(x1,y1,x2,y2,kind:int):int

Description

Createsalineandreturnstheline'swidgetID.

Linesaregenerallyusedtoseparatepartsofawindow.AlineisusedtomakethewindowlookbetterandhelporganizetheGUIelements.

ThreeTypesofLines

Linesarepassivewidgets,meaningthattheydonotrespondtobuttonclicksorkeystrokes.

Thex1andy1parametersspecifyoneend-pointofthelineandthespecifytheotherendpoint.Thelinemusteitherbehorizontalorvertical(i.e.x1mustequalx2ory1mustequaly2).Thekindparameterspecifiesthetypeofline.Thisisoneof0,GUI.LINE,GUI.INDENTorGUI.EXDENT.Akindof0isthedefaultandisthesameasGUI.LINE.

GUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthelineappearindentedorrecessed.GUI.EXDENTmakesthelineappeartostandoutfromthewindow.

Example

Thefollowingprogramdrawsthreelineswiththreelabelsinthewindow.

importGUI

varline,indentLine,exdentLine:int

varlineLabel,indentLabel,exdentLabel:int

line:=GUI.CreateLine(30,20,30,90,0)

indentLine:=GUI.CreateLine(90,20,90,90,GUI.INDENT

exdentLine:=GUI.CreateLine(150,20,150,90,

lineLabel:=GUI.CreateLabelFull(30,15,"Line",0,0,

GUI.CENTER+GUI.TOP,0)

indentLabel:=GUI.CreateLabelFull(90,15,"Indent",0,0,

exdentLabel:=GUI.CreateLabelFull(150,15,"Exdent",0,0,

Execute

Details

WhenGUI.CreateLineiscalled,thenewlycreatedlinewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplay

Alinewidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithalineasthewidgetID

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateLineCreateLine.

GUI.CreateMenu PartofGUImodule

Syntax GUI.CreateMenu(name:string):int

Description

Createsamenuandreturnsthemenu'swidgetID.Themenuwillbeaddedaftertheothermenusinthemenubar.Iftherearenopreviousmenus,thenamenubarisautomaticallycreatedandthemenuadded.

Thenameparameterspecifiesthetextthatappearsinthemenubar.

AMenuWithanItemSelected

Menusareusedinmostmoderninterfaces.Inordertocreateafullsetofmenus,youmustcreatethemenuandthencreatethemenuitemsinthatmenu.Themenusareautomaticallyaddedtothemenubaroftheselectedmenu.

Asofthev1.0releaseoftheGUILibrary,itisanerrortocreateamenuitemwithouthavingcreatedamenufirst.Infuturereleasesitwillbepossibletocreatemenusandattachandremovethemfrommenubarswhendesired.

Thefollowingprogramcreatesaseriesofmenuswithmenuitemsinthem.Itthendisablesthesecondmenu.

varfirst,second:int%Themenus.

varitem:array1..12ofint%Themenuitems.

varname:array1..12ofstring(20):=

init("Quit","---","A","B","---","C","D",

"DisableBMenuItem","EnableBMenuItem","---",

Example

"DisableSecondMenu","EnableSecondMenu")

procedureMenuSelected

fori:1..12

ifitem(i)=GUI.GetEventWidgetIDthen

Text.Locate(maxrow,1)

putname(i)+"selected"..

endfor

endMenuSelected

procedureDisableB

GUI.Disable(item(4))

endDisableB

procedureEnableB

GUI.Enable(item(4))

endEnableB

procedureDisableFirst

GUI.Disable(first)

endDisableFirst

procedureEnableFirst

GUI.Enable(first)

endEnableFirst

%Createthemenus

first:=GUI.CreateMenu("First")

item(1):=GUI.CreateMenuItem(name(1),GUI.Quit

forcnt:2..7

item(cnt):=GUI.CreateMenuItem(name(cnt),

MenuSelected)

endfor

second:=GUI.CreateMenu("Second")

item(8):=GUI.CreateMenuItem(name(8),DisableB

item(9):=GUI.CreateMenuItem(name(9),EnableB

item(10):=GUI.CreateMenuItem(name(10),MenuSelected

item(11):=GUI.CreateMenuItem(name(11),DisableFirst

item(12):=GUI.CreateMenuItem(name(12),EnableFirst

endloop

Execute

DetailsWhenamenuisnotenabled,thetextinthemenubarisgrayedoutandclickingonthemenudoesnotcausethemenutoappear.

Details

ThefollowingGUIsubprogramscanbecalledwithamenuasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.Enable,GUI.Disable

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateMenu,notbycallingCreateMenu.

Seealso

GUI.CreateMenuItemforaddingitemstoamenu.SeealsoGUI.ShowMenuBarandGUI.HideMenuBarforshowingandhidingthemenubar.

GUI.CreateMenuItem[Full] PartofGUImodule

Syntax

GUI.CreateMenuItem(name:string,actionProc:procedurex()):int

GUI.CreateMenuItemFull(name:string,actionProc:procedurex(),shortCut:char,addNow:boolean):int

Description

Createsamenuitemandreturnsthemenuitem'swidgetID.

Menuitemsaretheindividualentriesofamenu.Tocreatemenusforawindow,youmustcreateamenu,thencreatethemenuitemsforthatmenu,thencreatethenextmenu,etc.Allmenuitemsareautomaticallyaddedtothelastmenuandafterthelastmenuitemofthecurrentlyselected(notactive!)window.

Themenuitemwillbeaddedtothelastmenuaftertheothermenuitemsinthemenu.Iftherearenomenusdefined,anerrorresults.

Thenameparameterspecifiesthetextthatistoappear.Anameofthreedashes("---")createsaseparatoracrossthemenu.TheactionProcparameterspecifiesthenameofaproceduretobecalledwhenusertheselectsthemenuitemfromthemenu.

ForGUI.CreateMenuItemFull,theshortCutparameterspecifiesthekeystroketobeusedasthemenuitem'sshortcut.Ifnoshortcutisdesired,then'\0'canbeused.TheaddNowparameterhasnoeffectinthecurrentversionoftheGUILibrary.Infutureversions,itwillallowyoutocreatemenuitemsthatcanthenbeaddedtoamenulaterintheprogram.

Examples SeetheexampleforGUI.CreateMenu.

Execute

Details

Whenamenuitemisnotenabled,thetextofthemenuitemisgrayedoutandclickingonthemenuitemdoesnotcausethemenutoappear.

Details

ThefollowingGUIsubprogramscanbecalledwithamenuasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.Enable,GUI.Disable

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateMenuItem,notbycallingCreateMenuItem.

GUI.CreatePicture PartofGUImodule

SyntaxGUI.CreatePicture(x,y,picture:int,mergePic:boolean):int

Description

Createsapictureandreturnsthepicture'swidgetID.

Thepicturewidgetisusedtodisplayapicture.Itcanbeusedtodisplayapictureeithermergedintothebackgroundornot.

Thexandyparametersspecifythelower-leftcornerofthepicture.TheparameterspecifiesthepictureIDofthepicture.ThepictureIDisreceivedfromaPic.NeworPic.FileNewcall.DonotcallPic.FreeforthispictureIDuntilthebuttonhasbeendisposedofbycallingGUI.Dispose.ThemergePicparameterisabooleanthatspecifieswhetheranythingthatwasthebackgroundcolourinthepicture(usuallycolour0)shouldbesettothebackgroundcolourofthewindow.

Apicturewidgetisapassivewidgetandcannotbeenabledordisabled.

TwoPictures

Example

Thefollowingprogramdrawstwopictures,mergedandnotmerged.

importGUI

%We'llneedtocreateapictureforourPicturewidget.Normally

%anexternalfile(andPic.FileNew)wouldbeused.

Draw.FillOval(50,50,50,50,blue)

Draw.FillBox(17,17,83,83,brightred)

Draw.FillStar(17,17,83,83,brightgreen)

Draw.FillMapleLeaf(37,37,63,63,brightpurple

varpic:int:=Pic.New(0,0,100,100)

varpicture1,picture2:int

varlabel1,label2:int

label1:=GUI.CreateLabel(15,5,"Picture(nomerge)")

picture1:=GUI.CreatePicture(10,25,pic,false

label2:=GUI.CreateLabel(135,5,"Picture(merge)")

picture2:=GUI.CreatePicture(120,25,pic,true

Execute

Details

WhenGUI.CreatePictureiscalled,thenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththeparametersettofalse.

Apicturewidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithapictureasthe

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreatePicturecallingCreatePicture.

GUI.CreatePictureButton[Full] PartofGUImodule

Syntax

GUI.CreatePictureButton(x,y,picture:int,actionProc:procedurex()):int

GUI.CreatePictureButtonFull(x,y,picture:int,actionProc:procedurex(),width,height:int,shortcut:char,mergePic:boolean):int

Description

Createsapicturebuttonandreturnsthebutton'swidgetID.

Picturebuttonsbehavelikebuttons(seeGUI.CreateButton)exceptthatinsteadoftextonthebutton,apicturespecifiedbytheuserisdisplayedonthebutton.Thepicturebuttonwidgetrespondstomouseclicksandkeystrokesinthesamemannerasaregularbuttonwidget.

ThepicturemustbecreatedbytheprogrambeforehandusingPic.NewPic.FileNew.TheresultingpicturecanthenbeusedasaparametertoGUI.CreatePictureButton.Ingeneral,picturesshouldbeamaximumofabout50pixelshighandwide,althoughthereisnobuilt-inlimitintheGUIlibrary.

Thexandyparametersspecifythelower-leftcornerofthepicturebutton.ThepictureparameterspecifiesthepictureIDofthepicturetobedisplayedonthebutton.(Notethat,ingeneral,thispictureshouldbefairlysmall.)ThepictureIDisreceivedfromaPic.NeworPic.FileNewcall.DonotcallPic.FreepictureIDuntilthebuttonhasbeendisposedofbycallingGUI.DisposeactionProcparameterspecifiesthenameofaprocedurethatiscalledwhenthepicturebuttonispressed.

ForGUI.CreatePictureButtonFull,thewidthandheightparametersspecifythewidthandheightofthebutton.Iftheyaresetto0,thenthepictureradiobuttonisautomaticallysizedtofitthepicture.Ifyouneedtoknowtheprecisesizeofthebutton,usetheGUI.GetWidthandGUI.GetHeightfunctions.Ifwidthheightarelargerthanthepicture,thepictureiscenteredinthebutton.TheshortCutparameteristhekeystroketobeusedasthebutton'sshortcut.ThemergePicparameterspecifieswhetheranythingthatwasthebackgroundcolourinthepicture(usuallycolour0)shouldbesettothebackgroundcolourofthebutton(whichisusuallygray).ThisdefaultstotrueforCreatePictureButton

TwoPictureButtons

Example

Thefollowingprogramdisplaysfivepicturebuttonswhichoutputamessagewhenpressed.

importGUI

constsize:int:=25%Thebuttonssize.

constborder:int:=3

varstarButton,mapleButton,starPic,mapleLeafPic

procedureStarPressed

Text.Locate(1,1)

put"StarPressed"

endStarPressed

procedureMaplePressed

Text.Locate(1,1)

put"MaplePressed"

endMaplePressed

%Createthepictures.

%Thestar.

Draw.Star(border,border,border+size,border

Draw.Star(border+1,border+1,border+size

border+size-1,black)

Draw.FillStar(border+2,border+2,border+

border+size-2,brightred)

starPic:=Pic.New(0,0,2*border+size,2*

%Themapleleaf.

Draw.FillBox(border,border,border+size,border+size,white)

Draw.MapleLeaf(border,border,border+size,border

Draw.MapleLeaf(border+1,border+1,border+

Draw.FillMapleLeaf(border+2,border+2,border

mapleLeafPic:=Pic.New(0,0,2*border+size

%Createthepicturebuttons.

Draw.Cls

starButton:=GUI.CreatePictureButton(10,10,starPic

mapleButton:=GUI.CreatePictureButton(55,10,

MaplePressed)

endloop

Execute

Details

WhenGUI.CreatePictureButtonorGUI.CreatePictureButtonFullthenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenapicturebuttonisnotenabled,thepicturebuttonisgrayedoutandthepicturebuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithapicturebuttonasthewidgetIDparameter:

StatusExportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreatePictureButton,notbycallingCreatePictureButton.

GUI.CreatePictureRadioButton[Full] PartofGUImodule

Syntax

GUI.CreatePictureRadioButton(x,y,picture:int,joinID:int,actionProc:procedurex()):int

GUI.CreatePictureRadioButtonFull(x,y:int,picture,joinID:int,actionProc:procedurex(),width,height:shortcut:char,mergePic:boolean):int

Description

Createsapictureradiobuttonandreturnsthebutton'swidgetID.

Pictureradiobuttonsbehavelikepicturebuttons(seeGUI.CreatePictureButton)exceptthattheyhavethe"radio"property.Thatis,oneofthebuttonsintheradiogroupisalwaysselected,andifanotherbuttoninthegroupisselected,thepreviouslyselectedbuttonisunselected.

Acommonexampleisthebuttonsonapaintprogramthatindicatethecurrentshapebeingpainted.Themapleleafbuttoniscurrentlyselected.Ifthestarbuttonisselectedbytheuser,themapleleafbuttonbecomesunselected.Forpicturebuttons,theselectedbuttonappearsdepressed.

FourPictureRadioButtonswiththeMapleLeafSeledcted

Aradiogroupiscreatedbyfirstcreatingasingleradiobutton.Toaddanotherbuttontothegroup,asecondradiobuttoniscreatedspecifyingthefirstradiobuttoninthejoinIDparameter.Subsequentradiobuttonsareadded,eachspecifyingapreviousmemberofthegroupinthejoinIDparameter.

ThepicturemustbecreatedbytheprogrambeforehandusingPic.NewPic.FileNew.TheresultingpicturecanthenbeusedasaparametertoGUI.CreatePictureButton.Ingeneral,picturesshouldbeamaximumofabout50pixelshighandwide,althoughthereisnobuilt-inlimitintheGUIlibrary.

Thexandyparametersspecifythelower-leftcornerofthepictureradiobutton.Iftheseareboth1andjoinIDisnotzero,thenthebuttonwillbeplaceddirectlybelowthepreviouspictureradiobuttoninthegroup.ThepictureparameterspecifiesthepictureIDofthepicturetobedisplayedonthebutton.(Notethat,ingeneral,thispictureshouldbefairlysmall.)ThepictureIDisreceivedfromaPic.NeworPic.FileNewcall.DonotcallPic.FreeforthispictureIDuntilthebuttonhasbeendisposedofbycallingGUI.Dispose.ThejoinIDparameterspecifiesamemberoftheradiogroupthatthiswidgetshouldjoin.Asepecifiesthisradiobuttonisnotamemberofanygroup.TheactionProcparameterspecifiesthenameofaprocedurethatiscalledwhenthepicturebuttonispressed.

ForGUI.CreatePictureRadioButtonFull,thewidthandheightparametersspecifythewidthandheightofthebutton.Iftheyaresetto0,thenthepictureradiobuttonisautomaticallysizedtofitthepicture.Ifyouneedtoknowtheprecisesizeofthebutton,usetheGUI.GetWidthandGUI.GetHeightfunctions.Ifwidthandheightarelargerthanthepicture,thepictureiscenteredinthebutton.TheshortCutparameteristhekeystroketobeusedasthebutton'sshortcut.ThemergePicparameterspecifieswhetheranythingthatwasthebackgroundcolourinthepicture(usuallycolour0)shouldbesettothebackgroundcolourofthebutton(whichisusuallygray).ThisdefaultstotrueforCreatePictureRadioButton.

Thefollowingprogramcreatesanddisplaysforpictureradiobuttons.

importGUI

constsize:int:=25%Thebuttonssize.

constborder:int:=3

varstarButton,mapleButton,circleButton,squareButton

varstarPic,mapleLeafPic,circlePic,squarePic:

procedureStarPressed

Text.Locate(1,1)

put"StarPressed"

Example

endStarPressed

procedureMaplePressed

Text.Locate(1,1)

put"MaplePressed"

endMaplePressed

procedureCirclePressed

Text.Locate(1,1)

put"CirclePressed"

endCirclePressed

procedureSquarePressed

Text.Locate(1,1)

put"SquarePressed"

endSquarePressed

%Createthepictures.

%Thestar.

Draw.Star(border,border,border+size,border

Draw.Star(border+1,border+1,border+size

Draw.FillStar(border+2,border+2,border+

starPic:=Pic.New(0,0,2*border+size,2*

%Themapleleaf.

Draw.FillBox(border,border,border+size,border

Draw.MapleLeaf(border,border,border+size,border

Draw.MapleLeaf(border+1,border+1,border+

Draw.FillMapleLeaf(border+2,border+2,border

mapleLeafPic:=Pic.New(0,0,2*border+size

%Thecircle.

constradius:int:=sizediv2

Draw.Oval(border+radius,border+radius,radius

black)

Draw.FillOval(border+radius,border+radius,

radius-2,brightred)

circlePic:=Pic.New(0,0,2*border+size,2*

%Thesquare.

Draw.Box(border,border,border+size,border+

Draw.Box(border+1,border+1,border+size-1,

Draw.FillBox(border+2,border+2,border+size

squarePic:=Pic.New(0,0,2*border+size,2*

%Createthepicturebuttons.

Draw.Cls

starButton:=GUI.CreatePictureRadioButton(10,maxy80,

starPic,0,StarPressed)

mapleButton:=GUI.CreatePictureRadioButton(-1,-1,

mapleLeafPic,starButton,MaplePressed)

circleButton:=GUI.CreatePictureRadioButton(-1,-1,

circlePic,mapleButton,CirclePressed)

squareButton:=GUI.CreatePictureRadioButton(-1,-1,

squarePic,circleButton,SquarePressed)

endloop

Execute

Details

WhenGUI.CreatePictureRadioButtonorGUI.CreatePictureRadioButtonFulliscalled,thenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenapictureradiobuttonisnotenabled,thepictureradiobuttonisgrayedoutandthepicturebuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithapictureradiobuttonasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.DisposeGUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.SelectRadio

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreatePictureRadioButton,notbycallingCreatePictureRadioButton

Seealso

GUI.SelectRadioforselectingapictureradiobuttoninaprogram.SeealsoGUI.CreatePictureButtonandGUI.CreateRadioButtonforinformationonpicturebuttonsandradiobuttons.

GUI.CreateRadioButton[Full] PartofGUImodule

Syntax

GUI.CreateRadioButton(x,y:int,text:string,joinID:int,actionProc:procedurex()):int

GUI.CreateRadioButtonFull(x,y:int,text:string,joinID:int,actionProc:procedurex(),alignment:int,shortCut:char):int

Description

Createsaradiobuttonandreturnstheradiobutton'swidgetID.

Asliderisawidgetthatallowstheusertoselectoneofasetofvalues.Ithasareal-lifeequivalentintheoldcarstereoswhereasinglestationisselectedatatime.Thatis,oneofthebuttonsintheradiogroupisalwaysselected,andifanotherbuttoninthegroupisselected,thepreviouslyselectedbuttonisunselected.

SixRadioButtonsinTwoGroups

Aradiogroupiscreatedbyfirstcreatingasingleradiobutton.Toaddanotherbuttontothegroup,asecondradiobuttoniscreatedspecifyingthefirstradiobuttoninthejoinIDparameter.Subsequentradiobuttonsareadded,eachspecifyingapreviousmemberofthegroupinthejoinIDparameter.

Thexandyparametersspecifythelower-leftcorneroftheradiobutton(unlessalignmentissettoGUI.RIGHT,inwhichcasetheyspecifythelower-rightcorneroftheradiobutton).Iftheseareboth1andjoinIDisnotzero,thenthebuttonwillbeplaceddirectlybelowthepreviousradiobuttoninthegroup.Thetextparameterspecifiesthetext(orlabel)besidetheradiobutton.ThejoinIDparameterspecifiesamemberoftheradiogroupthatthiswidgetshouldjoin.AjoinIDof0sepecifiesthisradiobuttonisnota

memberofanygroup.TheactionProcparameteristhenameofaprocedurethatiscalledwhentheradiobuttonisselected.InGUI.CreateRadioButton,theradiobutton'stextisalwaystotherightoftheactualradiobutton.InGUI.CreateRadioButtonFull,thetextcanbesettotherightorleftoftheradiobuttonwiththealignmentparameter.

ForGUI.CreateRadioButtonFull,thealignmentparameterspecifiesthepositionoftheradiobuttoninrelationtothetextaswellasthemeaningofthexandyparameters.Thealignmentparameterisoneof0,GUI.LEFT,orGUI.RIGHT.Analignmentof0isthedefaultandisthesameasGUI.LEFT.GUI.LEFTmeanstheactualboxinthecheckboxappearstotheleftofthecheckbox'slabeland(x,y)specifythelower-leftcorner.AnalignmentofGUI.RIGHTmeansthattheactualboxappearstotherightoftheradiobutton'slabeland(x,y)specifythelower-rightcorneroftheradiobutton.Theshortcutparameteristhekeystroketobeusedasthebutton'sshortcut.

Aradiobutton'ssizeisnotspecifiedduringcreation.Itisdeterminedbasedonthesizeofthetext.Insteadtheuserspecifiesthelower-leftcorneroftheradiobutton(orthelower-rightiftheradiobuttonisrightjustified).

Thefollowingprogramcreatessixradiobuttonsintwogroups.

importGUI

varradio:array1..6ofint%TheradiobuttonIDs.

procedureRadioPressed

Text.Locate(1,1)

put"RadioButton"..

fori:1..6

ifradio(i)=GUI.GetEventWidgetIDthen

puti..

endfor

put"Selected"

endRadioPressed

radio(1):=GUI.CreateRadioButton(15,maxy35,

Example "RadioButton1",0,RadioPressed)

radio(2):=GUI.CreateRadioButton(1,1,"RadioButton2",

radio(1),RadioPressed)

radio(4):=GUI.CreateRadioButtonFull(maxx15,

"RadioButtonA(Shortcut:'a')",0,RadioPressed

GUI.RIGHT,'a')

radio(5):=GUI.CreateRadioButtonFull(1,1,

"RadioButtonB(Shortcut:'b')",radio(4),

GUI.RIGHT,'b')

radio(6):=GUI.CreateRadioButtonFull(1,1,

"RadioButtonC(Shortcut:'c')",radio(5),

GUI.RIGHT,'c')

endloop

Execute

Details

Whenagroupofradiobuttonsisselected,thefirstradiobuttoncreatedinthegroupwillbetheselectedone.YoucanchangethisbyusingtheGUI.SelectRadioproceduretoselectadifferentone.

WhenGUI.CreateRadioButtonorGUI.CreateRadioButtonFulliscalled,thenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenaradiobuttonisnotenabled,theradiobuttonisgrayedoutandtheradiobuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

ThefollowingGUIsubprogramscanbecalledwitharadiobuttonasthewidgetIDparameter:

Details

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.Dispose,GUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.SetLabel,GUI.SelectRadio

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateRadioButton,notbycallingCreateRadioButton.

SeealsoGUI.SelectRadioforselectingaradiobuttoninaprogram.SeealsoGUI.SetLabelforchangingtheradiobutton'stext.

GUI.CreateTextBox[Full] PartofGUImodule

Syntax

GUI.CreateTextBox(x,y,width,height:int):int

GUI.CreateTextBoxFull(x,y,width,height:int,border,fontID:int):int

Description

Createsatextboxandreturnsthetextbox'swidgetID.

Atextboxisaboxusedfordisplayingtext.Ithasscrollbarsthatactivatewhentextappearsoutsidetheborderofthetextbox.Theusercannotdirectlyselect,editormodifythetextinthetextbox.

Thexandyparametersspecifythelower-leftcorneroftheareainwhichthetextwillbedrawn.ThewidthandheightparametersspecifythewidthandheightofthetextdrawingareaThetextboxborderisjustoutsidethetextdrawingarea.Becauseofthis,GUI.GetXandGUI.GetYwillreturnavalueslightlysmallerthanxandyandGUI.GetWidthandGUI.GetHeightreturnvaluesslightlylargerthanwidthandheight.

ForGUI.CreateTextBox,theborderaroundthetextboxisalwaysaline.ForGUI.CreateTextBoxFull,thetypeofborderisspecifiedbytheborderparameter.Theborderparameterisoneof0,GUI.LINE,GUI.INDENTGUI.EXDENT.Aborderof0isthedefaultandisthesameasGUI.LINEGUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthetextboxappearindentedorrecessed.GUI.EXDENTmakesthetextboxappeartostandoutfromthewindow.ThefontIDparameterspecifiesthefontIDofthefonttobeusedinthetextbox.ThefontIDisreceivedfromaFont.Newcall.DonotcallFont.FreeforthisfontIDuntilthelabelhasbeendisposedofbycallingGUI.Dispose.

ByusingthefondIDparameter,textboxescanhaveanysizeortypeface.

Atextboxdisplayingthecontentsofafile.

Example

Thefollowingprogramdisplaysthecontentsofafileinatextbox.

importGUI

constfileNameToBeViewed:string:="TextBxs.DEM"

vartextBox:int%TheTextFieldID.

vartitle:int%Thelabelforthetitle.

varf:int%Thestreamnumberofthefile.

varline:string%Linestobereadfromthefile.

%Openthefile.

open:f,fileNameToBeViewed,get

iff=0then

put"Unabletoopen"+fileNameToBeViewed+":",

return

%Setbackgroundcolortograyforindentedtextbox.

%Createthetitlelabelandtextbox.

title:=GUI.CreateLabelFull(20,280,fileNameToBeViewed

GUI.CENTER,0)

textBox:=GUI.CreateTextBoxFull(10,10,280,265,

GUI.INDENT,0)

%Readthefileandplaceitinthetextbox.

exitwheneof(f)

get:f,line:*

GUI.AddLine(textBox,line)

endloop

close:f%Closethefile.

endloop

Execute

Details

WhenGUI.CreateTextBoxorGUI.CreateTextBoxFulliscalled,thenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Atextboxwidgetisapassivewidgetandcannotbeenabledordisabled.

Details

ThefollowingGUIsubprogramscanbecalledwithatextboxastheparameter:

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSizeGUI.SetPositionAndSize,GUI.AddLine,GUI.AddText,GUI.ClearText,GUI.SetTopLine,GUI.SetScrollOnAdd

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateTextBoxnotbycallingCreateTextBox.

GUI.AddLine,GUI.AddTextforaddingtexttothetextbox.Seealso

Seealso GUI.SetTopLinetosetthetoplineoftextinthetextbox.SeealsoGUI.SetScrollOnAddtosetstopthetextboxfromscrollingwhentexttothetextbox.SeealsoGUI.ClearTextforclearingthetextbox.

GUI.CreateTextBoxChoice PartofGUImodule

SyntaxGUI.CreateTextBoxChoice(x,y,width,height:int,border,fontID:int,actionProc:procedurex(line:int

Description

Createsatextboxthatcanbeusedforselectingindividualitemsandreturnsthetextbox'swidgetID.

Atextboxisaboxusedfordisplayingtext.ByusingGUI.AddLinetheprogramcanthenwaitfortheusertodoubleclickonlinesinthetextbox.highlightswhentheuserclicksthelineonce,andcallstheactionprocedurewhentheuserclicksthehighlightedlineasecondtime.Likeatextbox,thetextboxchoicehasscrollbarsthatactivatewhentextappearsoutsidetheborderofthetextbox.Theusercannotdirectlyeditormodifythetextinthetextboxchoice.

Thexandyparametersspecifythelower-leftcorneroftheareainwhichthetextwillbedrawn.ThewidthandheightparametersspecifythewidthandheightofthetextdrawingareaThetextboxborderisjustoutsidethetextdrawingarea.Becauseofthis,GUI.GetXandGUI.GetYwillreturnavalueslightlysmallerthanGUI.GetWidthandGUI.GetHeightwillreturnvaluesslightlylargerthanheight.

ForGUI.CreateTextBox,theborderaroundthetextboxisalwaysaline.ForGUI.CreateTextBoxFull,thetypeofborderisspecifiedbytheborderborderparameterisoneof0,GUI.LINE,GUI.INDENT,orGUI.EXDENTisthedefaultandisthesameasGUI.LINE.GUI.INDENTandGUI.EXDENTdisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthetextboxappearindentedorrecessed.GUI.EXDENTmakesthetextboxappeartostandoutfromthewindow.ThefontIDparameterspecifiesthefontIDofthefonttobeusedinthetextbox.TheisreceivedfromaFont.Newcall.DonotcallFont.FreeforthisfontIDuntilthelabelhasbeendisposedofbycallingGUI.Dispose.

ByusingthefontIDparameter,textboxescanhaveanysizeortypeface.

Atextboxchoiceafterauserdoubleclickedaline.

Example

Thefollowingprogramdisplaysthecontentsofafileinatextbox.

importGUI

procedureChoseLine(line:int)

location(1,1)

put"Theuserchose",line

endChoseLine

varx:int:=GUI.CreateTextBoxChoice(20,20,200,100,0,0,

GUI.AddLine(x,"ChooseA")

GUI.AddLine(x,"ChooseB")

GUI.AddLine(x,"ChooseC")

GUI.AddLine(x,"ChooseD")

GUI.AddLine(x,"ChooseE")

GUI.AddLine(x,"ChooseF")

GUI.AddLine(x,"ChooseG")

GUI.AddLine(x,"ChooseH")

GUI.AddLine(x,"ChooseI")

GUI.AddLine(x,"ChooseJ")

endloop

Execute

Details

WhenGUI.CreateTextBoxorGUI.CreateTextBoxFulliscalled,thenewlycreatedtextboxchoicewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedbeencalledwiththedisplayparametersettofalse.

Details

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSizeGUI.AddLine,GUI.AddText,GUI.ClearText,GUI.SetTopLineGUI.SetScrollOnAdd

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateTextBoxChoicenotbycallingCreateTextBoxChoice.

Seealso

GUI.AddLineforaddingtexttothetextbox.SeealsoGUI.SetTopLinelineoftextinthetextbox.SeealsoGUI.SetScrollOnAddtosetstopthetextboxfromscrollingwhentextisaddedtothetextbox.SeealsoGUI.ClearTexttextbox.

GUI.CreateTextField[Full] PartofGUImodule

Syntax

GUI.CreateTextField(x,y,width:int,text:string,actionProc:procedurex(text:string)):int

GUI.CreateTextFieldFull(x,y,width:int,text:string,actionProc:procedurex(text:string),border,fontID,inputKind:int):int

Description

Createsatextfieldandreturnsthetextfield'swidgetID.

Atextfieldisusedtocreatealineoftextthatcanbeeditedbytheuser.Theusercanusethemousetoselectpartofthetextandcanentertextintothetextfield.

Ifoneormoretextfieldsareenabledinawindow,thenoneofthetextfieldswillbeactive.Thismeansthatwhenanykeystrokesareenteredintothewindow,theactivetextfieldwillreceivethekeystrokes.TheactivetextfieldcanbechangedusingtheGUI.SetActiveprocedure.

Thexandyparametersspecifythelower-leftcorneroftheareainwhichthetextwillbedrawn.Thetextfieldborderisjustoutsidethetextdrawingarea.Thewidthparameterspecifiesthewidthofthetextdrawingarea.Theheightofthetextfieldisdeterminedbytheheightofthefontusedbythetextfield.Theborderofthetextfieldisjustoutsidethetextdrawingarea,soGUI.GetWidthwillreturnvaluesslightlylargerthanwidth.TheactionProcparameterspecifiesthenameoftheproceduretobecalledwhentheuserpressesENTER(RETURNonaMacintosh)whenthetextfieldisactive.Theparameteristhecurrenttextinthetextfield.

ForGUI.CreateTextField,theborderaroundthetextfieldisalwaysaline.ForGUI.CreateTextFieldFull,thetypeofborderisspecifiedbytheparameter.Theborderparameterisoneof0,GUI.LINE,GUI.INDENTGUI.EXDENT.Aborderof0isthedefaultandisthesameasGUI.LINEGUI.INDENTandGUI.EXDENTonlydisplayproperlyifthebackgroundcolourhasbeensettograyusingGUI.SetBackgroundColor.GUI.INDENTmakesthetextfieldappearindentedorrecessed.GUI.EXDENTmakesthetextfieldappeartostandoutfromthewindow.ThefontIDparameterspecifiesthe

fontIDofthefonttobeusedinthetextfield.ThefontIDisreceivedfromaFont.Newcall.DonotcallFont.FreeforthisfontIDuntilthelabelhasbeendisposedofbycallingGUI.Dispose.TheinputKindparameterspecifiesthetypeofinputacceptedbythetextfield.Thisisoneof0,GUI.ANY,orGUI.REAL.Aninputtypeof0isthedefaultandisthesameasGUI.ANYGUI.ANYallowsanytypeofinputinthetextfield.GUI.INTEGERpositiveintegerinputinthetextfield.GUI.REALallowsanyrealnumberinputinthetextfield.Notethatusing

GUI.INTEGERorGUI.REALdoesnotguaranteethatthetextfieldstringcanbeconvertedtoanintegerorareal.Thetextcouldbeanullstring,andforGUI.REALcouldbepartofanumbersuchasthestring""or"1.25E"bothofwhichareillegalnumbers.(Tochecktheconversion,usethestrintokstrrealokfunctionsbeforecallingstrintorstrreal.)

TwoTextFields

Example

ThefollowingprogramcreatesatextfieldandechoesitonthescreenwhentheuserpressesENTER.

importGUI

varnameTextField,addressTextField:int%TheTextFieldIDs.

procedureNameEntered(text:string)

GUI.SetSelection(addressTextField,0,0)

GUI.SetActive(addressTextField)

endNameEntered

procedureAddressEntered(text:string)

GUI.SetSelection(nameTextField,0,0)

GUI.SetActive(nameTextField)

endAddressEntered

varquitButton:=GUI.CreateButton(52,5,100,"Quit",

nameTextField:=GUI.CreateTextFieldFull(50,70,100,"",

NameEntered,GUI.INDENT,0,0)

addressTextField:=GUI.CreateTextFieldFull(50,40,100,"",

AddressEntered,GUI.INDENT,0,0)

varnameLabel:=GUI.CreateLabelFull(45,70,"Name",0,0,

GUI.RIGHT,0)

varaddressLabel:=GUI.CreateLabelFull(45,40,"Address",0,0,

GUI.RIGHT,0)

endloop

GUI.Dispose(quitButton)

colorback(gray)

Text.Locate(maxrow-1,1)

put"Name=",GUI.GetText(nameTextField)

put"Address=",GUI.GetText(addressTextField)..

Execute

Details

Onlyonetextfieldisactiveatatime.Theactivetextfieldhasablinkingcursor(oritsselectionhighlighted).Ifakeystrokeoccurswhenawindowhasanactivetextfieldinit,thekeystrokewillbedirectedtotheactivetextfield.YoucanchangewhichtextfieldisactivewiththeGUI.SetActiveprocedureorbysimplyclickingonanothertextfieldwiththemouse.

Whenmultipletextfieldsarecreatedinawindow,thefirsttextfieldcreatedisactivewhentheprogrambegins.

Thecurrentversionofthetextfielddoesnotsupportcutandpasteorkeyboardcommandstoextendtheselection.

Becausestringsareamaximumof255characters,thisisthemaximumnumberofcharactersinatextfield.

TheTABcharactercyclesbetweendifferenttextfieldsinawindow.Itcyclesthroughthetextfieldsintheorderinwhichtheywerecreated.BACKTAB

(shift+TAB)cyclesthroughthefieldsinreverseorder.

Details

WhenGUI.CreateTextFieldorGUI.CreateTextFieldFulliscalled,thenewlycreatedpicturewillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenatextfieldisnotenabled,thetextfieldcannotbemadeactiveandthetextinthefieldcannotbeedited.

Details

GUI.Show,GUI.Hide,GUI.Dispose,GUI.GetX,GUI.GetYGUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSizeGUI.SetPositionAndSize,GUI.GetText,GUI.SetText,GUI.SetSelection,GUI.SetActive,GUI.SetEchoChar

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateTextField,notbycallingCreateTextField.

Seealso

GUI.GetTextandGUI.SetTextforreadingandsettingthetextinthetextfield.SeealsoGUI.SetEchoCharforsettingthecharacterechoedwhentheuserentersacharacterinatextfield(oftenusedforenteringpasswords).alsoGUI.SetSelectionforsettingtheselectedareaofthetext.SeealsoGUI.SetActiveformakingthetextfieldactive.

GUI.CreateVerticalScrollBar[Full] PartofGUImodule

Syntax

GUI.CreateVerticalScrollBar(x,y,size:int,min,max,start:int,actionProc:procedurex(value:int)):int

GUI.CreateVerticalScrollBarFull(x,y,size:int,min,max,start:int,actionProc:procedurex(value:int),arrowInc,pageInc,thumbSize:int):int

Createsavertical(up-down)scrollbarandreturnsthescrollbar'swidgetID.

Ascrollbarisawidgetthatallowsuserstoseeapieceofadocumentthatcannotbedisplayedonthescreeninitsentirety.Thepicturebelowshowsaverticalscrollbar.Tocontrolascrollbar,thereareafewchoices:theusercanclickonthethumb(theboxinthescrollbar)andslideitupanddown,ortheusercanclickinthescrollbaritselfaboveorbelowthethumb(inwhichcasethethumbismovedupordownone"page"),ortheusercanclickontheupordownarrowsattheendsofthescrollbar(inwhichcasethethumbismovedupordownone"arrowincrement"or"line").

AVerticalScrollBar

DescriptionTheprogrammerdefinesapageoranarrowincrement.Whenthevalueofthescrollbarchanges,theactionprocedureofthescrollbariscalledwiththenewvalueasaparameter.Theactionprocedureshouldthenredrawthecontentsusingthenewvalueofthescrollbar.

TherangeofvaluesthatthescrollbarwillgiveisdeterminedbytheminandmaxparametersintheCreatecall.Theleftsideofthescrollbarrepresentstheminimumvalue,whiletherightrepresentsthemaximumvalue.Thereisalsothe"thumbsize".Thisrepresentstherangeofvaluesthatcanbeseenatonceonthescreen.

Bydefault,thearrowincrement(theamountthevalueischangedwhenthescrollingarrowsarepressed)issettoone.Thepageincrement(theamountthevalueischangedwhentheuserclicksinthebartotherightorleftofthethumb)issettoonequarterthedifferencebetweentheminimumandthemaximum.The"thumbsize"issettozero(seethedescriptionofscrollbarsforanexplanationofthethumbsize).

Thexandyparametersspecifythelower-leftcornerofthescrollbar.Thesizeparameterspecifiesthelengthofthescrollbar(includingthearrows)inpixels.Theminandmaxparametersaretheminimumandmaximumvaliesreturnedbythescrollbar.Thestartparameteristheinitialvalueofthescrollbarandshouldbebetweenminandmaxinclusive.TheactionProcparameteristhenameofaprocedurethatiscalledwhenthevalueofthescrollbarischanged.Theparametertotheactionprocedureisthecurrentvalueofthescrollbar.

Thefollowingprogramcreatesaverticalscrollbar.Wheneverthescrollbar'svalueischanged,amessageisdisplayedinthewindow.

importGUI

varscrollBar:int

ExampleprocedureScrollBarMoved(value:int)

Text.Locate(9,7)

put"Scroll"

Text.Locate(10,8)

put"Bar"

Text.Locate(11,8)

putvalue:3

endScrollBarMoved

scrollBar:=GUI.CreateVerticalScrollBar(10,10,180,

50,150,50,ScrollBarMoved)

endloop

Execute

Description

ForGUI.CreateVerticalScrollBarFull,thearrowIncparameterspecifiesthearrowincrement(theamountthescrollbar'svalueischangedwhenthescrollarrowsarepressed).ThepageIncspecifiesthepageincrement(theamountthescrollbar'svalueischangedwhentheuserclicksinthepageleft/rightsectionofthescrollbar).ThethumbSizeparameterspecifiesthe"thumbsize".Seethescrollbarexplanationformoredetailonascrollbar's"thumbsize".

Forexample,ifyouhaveawindowthatcandisplay20linesoftextatonceandthereare100linesoftext,youwouldsetminto1,maxto100andthumbSizeto20.Thevaluereturnedbythescrollbarwouldthenbethelinenumberofthefirstlineonthescreentobedisplayed.Whenthescrollbarwasatitsmaximumvalue,itwouldreturn81,sincebydoingso,lines81-100wouldbedisplayed.

ExampleForanexampleprogramthatscrollsalargepictureoverasmallerwindow,seeGUI.CreateHorizontalScrollBar.

Details

Insomeinstances,youwillwantthetheminimumandmaximumvaluesofthescrollbartobereversed(right/topisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesofthescrollbar.

Scrollbarsalwayshaveafixedheight(forhorizontalscrollbars)orwidth(forverticalscrollbars).Togetthescrollbar'swidth,usetheGUI.GetScrollBarWidthfunction.

WhenGUI.CreateVerticalScrollBarorGUI.CreateVerticalScrollBarFulliscalled,thenewlycreatedscrollbarwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenascrollbarisnotenabled,thegrayinthebarissettowhiteandthethumbisnotdisplayed.Thescrollbarnolongerrespondstoanymouseclicksuntilthescrollbarisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithascrollbarasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.Dispose,GUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.GetSliderValue,GUI.SetSliderValue,GUI.SetSliderMinMax,GUI.SetSliderSize,GUI.SetSliderReverse,GUI.SetScrollAmount

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateVerticalScrollBar,notbycallingCreateVerticalScrollBar.

GUI.GetSliderValueandGUI.SetSliderValueforreadingandsettingthevalueofascrollbar,GUI.SetSliderMinMaxfor

Seealsochangingtheminimumandmaximumvaluesofascrollbar,andGUI.SetScrollAmountforchangingthescrollingincrementsandthumbsizeofascrollbar.SeealsoGUI.SetSliderSizeforsettingthelengthofascrollbarandGUI.SetSliderReverseforreversingthesenseofascrollbar.

GUI.CreateVerticalSlider PartofGUImodule

Syntax

GUI.CreateVerticalSlider(x,y,length:int,min,max,start:int,actionProc:procedurex(value:int)):int

Description

Createsavertical(up-down)sliderandreturnstheslider'swidgetID.

Asliderisawidgetthatallowstheusertosetacontinuoussetofvalues.Ithasareal-lifeequivalentinthingssuchasastereovolumecontrol.

AVerticalSlider

Tocontrolaslider,theuserclicksonthesliderboxanddragsitbackandforth.Everytimethevaluechanges,aprocedureiscalledwiththenewvalueasaparameter.

TherangeofvaluesthatthesliderwillgiveisdeterminedbytheminandmaxparametersintheCreatecall.Theleftsideofthesliderrepresentstheminimumvalue,whiletherightrepresentsthemaximumvalue.

Thexandyparametersspecifythelower-leftcorneroftheslidertrack.Thismeansthattheslideractuallyextendsaboveandbelowthispoint(andslightlytotheleftofittotakeintoaccounttheroundedendofthetrack).Thelengthparameterspecifiesthe

lengthofthetrackinpixels.(YoucanuseGUI.GetX,GetY,GetWidth,andGetHeighttogettheexactdimensionsoftheslider.)Theminandmaxparametersaretheminimumandmaximumvaliesreturnedbytheslider.Thestartparameteristheinitialvalueofthesliderandshouldbebetweenminandmaxinclusive.TheactionProcparameteristhenameofaprocedurethatiscalledwhenthevalueofthesliderischanged.Theparametertotheactionprocedureisthecurrentvalueoftheslider.

Example

Thefollowingprogramcreatesaverticalslider.Whenevertheslider'svalueischanged,amessageisdisplayedinthewindow.

importGUI

varslider:int

procedureSliderMoved(value:int)

Text.Locate(9,7)

put"Slider"

Text.Locate(10,9)

putvalue:3

endSliderMoved

slider:=GUI.CreateVerticalSlider(20,10,180,

50,150,50,SliderMoved)

endloop

Execute

Insomeinstances,youwillwantthetheminimumandmaximumvaluesoftheslidertobereversed(rightisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesoftheslider.

Details

Slidersalwayshaveafixedheight(forhorizontalsliders)orwidth(forverticalsliders).

WhenGUI.CreateVerticalSliderorGUI.CreateVerticalSliderFulliscalled,thenewlycreatedsliderwillbedisplayedimmediatelyunlessGUI.DisplayWhenCreatedhasbeencalledwiththedisplayparametersettofalse.

Whenasliderisnotenabled,theappearancedoesnotchange.However,theslidernolongerrespondstoanymouseclicksuntilitisenabledagain.

Details

ThefollowingGUIsubprogramscanbecalledwithasliderasthewidgetIDparameter:

GUI.Show,GUI.Hide,GUI.Enable,GUI.Disable,GUI.Dispose,GUI.GetX,GUI.GetY,GUI.GetWidth,GUI.GetHeight,GUI.SetPosition,GUI.SetSize,GUI.SetPositionAndSize,GUI.GetSliderValue,GUI.SetSliderValue,GUI.SetSliderMinMax,GUI.SetSliderSize,GUI.SetSliderReverse

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.CreateVerticalSlider,notbycallingCreateVerticalSlider.

Seealso

GUI.GetSliderValueandGUI.SetSliderValueforreadingandsettingthevalueofaslider,GUI.SetSliderMinMaxforchangingtheminimumandmaximumvaluesofaslider.SeealsoGUI.SetSliderSizeforsettingthelengthofasliderandGUI.SetSliderReverseforreversingthesenseofaslider.

GUI.Disable PartofGUImodule

Syntax GUI.Disable(widgetID:int)

Description

DisablesawidgetspecifiedbywidgetID.

UsedinconjunctionwithGUI.Enabletoenableanddisablewidgets.

Disabledwidgetsgenerallyare"grayedout"tovisuallydepicttheirdisabledstatus.

Disabledwidgetsdonotrespondtokeystrokesormouseclicks.

Example

Thethreecolorradiobuttonsareenabledonlywhenthecolorcheckboxisselected.

varcolorCheckBox,redRadio,greenRadio,blueRadio

procedureDoNothing

endDoNothing

procedureColorCheckBoxProc(filled:boolean)

iffilledthen

GUI.Enable(redRadio)

GUI.Enable(greenRadio)

GUI.Enable(blueRadio)

GUI.Disable(redRadio)

GUI.Disable(greenRadio)

GUI.Disable(blueRadio)

endColorCheckBoxProc

colorCheckBox:=GUI.CreateCheckBox(10,80,

"UseColor",ColorCheckBoxProc)

redRadio:=GUI.CreateRadioButton(33,60,"Red",0,

greenRadio:=GUI.CreateRadioButton(1,1,"Green",

redRadio,DoNothing)

blueRadio:=GUI.CreateRadioButton(1,1,"Blue",

greenRadio,DoNothing)

ColorCheckBoxProc(false)

endloop

Details

Thefollowingtypesofwidgetscanbeenabledordisabled:

Buttons,CheckBoxes,RadioButtons,PictureButtons,

PictureRadioButtons,HorizontalScrollBars,HorizontalSliders,Canvases,TextFields,VerticalScrollBars,VerticalSliders

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheprocedurebycallingGUI.DisablenotbycallingDisable.

Seealso GUI.Enable.

GUI.Dispose PartofGUImodule

Syntax GUI.Dispose(widgetID:int)

Description

EliminatesthewidgetspecifiedbywidgetID.

Ifthewidgetisvisible,itisimmediatelymadeinvisiblebeforebeingdeleted.Itshouldbecalledinordertofreeupanymemorythatthewidgetmighthaveallocated.Notethatyoucannotusethewidgetafterithasbeendisposedof.Ifyouwishtotemporarilygetridofawidget,considerusingtheHidemethodandthentheShowmethodwhenyouwanttouseitagain.

Example

ThefollowingprogramwaitsfortheQuitbuttontobepressed.Whenitis,theQuitbuttonisdeletedandamessageisdisplayedinthecenterofthescreen.

varbutton,message:int

button:=GUI.CreateButton(20,40,0,"Quit",GUI.Quit

endloop

GUI.Dispose(button)

message:=GUI.CreateLabelFull(0,0,"Done",maxx

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheprocedurebycallingGUI.Dispose,notbycallingDispose.

GUI.Draw... PartofGUImodule

Syntax

GUI.DrawArc(widgetID,x,y,xRadius,yRadius:int,initialAngle,finalAngle,Color:int)

GUI.DrawBox(widgetID,x1,y1,x2,y2,Color:int)

GUI.DrawCls(widgetID:int)

GUI.DrawDot(widgetID,x,y,Color:int)

GUI.DrawFill(widgetID,x,y:int,fillColor,borderColor:int)

GUI.DrawFillArc(widgetID,x,y:int,xRadius,yRadius:int,initialAngle,finalAngle,Color:int)

GUI.DrawFillBox(widgetID,x1,y1,x2,y2:int,Color:int)

GUI.DrawFillMapleLeaf(widgetID,x1,y1:int,x2,y2,Color:int)

GUI.DrawFillOval(widgetID,x,y:int,xRadius,yRadius:int,Color:int)

GUI.DrawFillPolygon(widgetID:int,x,y:array1..*ofint,n:int,Color:int)

GUI.DrawFillStar(widgetID,x1,y1,x2,y2:int,Color:int)

GUI.DrawLine(widgetID,x1,y1,x2,y2,Color:int)

GUI.DrawMapleLeaf(widgetID,x1,y1,x2,y2:int,Color:int)

GUI.DrawOval(widgetID,x,y:int,

xRadius,yRadius,Color:int)

GUI.DrawPolygon(widgetID:int,x,y:array1..*ofint,n:int,Color:int)

GUI.DrawStar(widgetID,x1,y1,x2,y2,Color:int)

GUI.DrawText(widgetID:int,textStr:string,x,y:int,fontID,Color:int)

Description

PerformsaDraw…commandtothecanvasspecifiedbywidgetID.

Alloftheseroutinesareessentiallythesameasthesimilarly-namedproceduresintheDrawmodule.Allcoordinatesarebasedonthecanvasandalldrawingisclippedtothecanvasdrawingsurface.Ifthecanvasisin"xormode",allthedrawingwillbedonewith"xor"set.(SeeView.Setformoreinformationabout"xor".)

ThewidgetIDmustspecifyacanvaswidget.

Example SeeGUI.CreateCanvasforanexampleofGUI.DrawFillOval.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.Draw…,notbycallingDraw….

Seealso GUI.CreateCanvas.

GUI.Enable PartofGUImodule

Syntax GUI.Enable(widgetID:int)

Description

EnablesadisabledwidgetspecifiedbywidgetID.

UsedinconjunctionwithGUI.Disabletoenableanddisablewidgets.

Disabledwidgetsgenerallyare"grayedout"tovisuallydepicttheirdisabledstatus.

Disabledwidgetsdonotrespondtokeystrokesormouseclicks.

ExampleSeeGUI.DisableforanexampleofGUI.Enable.

Details

Thefollowingtypesofwidgetscanbeenabledordisabled:

Buttons,CheckBoxes,RadioButtons,PictureButtons,

PictureRadioButtons,HorizontalScrollBars,HorizontalSliders,Canvases,TextFields,VerticalScrollBars,VerticalSliders

ThismeansthatyoucanonlycalltheprocedurebycallingGUI.Enable,notbycallingEnable.

SeealsoGUI.Disable.

GUI.FontDraw PartofGUImodule

SyntaxGUI.FontDraw(widgetID:int,textStr:string,x,y,fontID,Color:int)

Description

PerformsaFont.DrawcommandtothecanvasspecifiedbywidgetID.

ThisroutineisessentiallythesameastheFont.DrawprocedureintheFontmodule.Allcoordinatesarebasedonthecanvasandalldrawingisclippedtothecanvasdrawingsurface.Ifthecanvasisin"xormode",allthedrawingwillbedonewith"xor"set.(SeeView.Setformoreinformationabout"xor".)

ThewidgetIDmustspecifyacanvaswidget.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheprocedurebycallingGUI.FontDraw,notbycallingFontDraw.

GUI.GetCheckBox PartofGUImodule

Syntax GUI.GetCheckBox(widgetID:int):boolean

Description

ReturnsthestatusofthecheckboxspecifiedbywidgetID.Ifthecheckboxisset(hasanXinit),GetCheckBoxreturnstrue,otherwiseitreturnsfalse.

ExampleSeeGUI.CreateCheckBoxforanexampleofGUI.GetCheckBox.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetCheckBox,notbycallingGetCheckBox.

Seealso GUI.CreateCheckBox.

GUI.GetEventTime PartofGUImodule

Syntax GUI.GetEventTime:int

Description

Returnsthetimeinmillisecondswhentheevent(mousebuttonorkeystroke)tookplace.ThisvalueisthesamevalueasTime.Elapsedreturnsifcalledwhentheeventwasprocessed.Thisfunctionshouldonlybecalledinanactionproceduredefaultmouse,keystroke,ornulleventhandler,asitwillreturn1whenthereisnoeventbeingprocessed.

Thiseventcanbeusedasatimerforvariousfunctionssuchasdeterminingwhetherasingleclickoradoubleclickofthemousebuttontookplaceorfortimingkeyboardinput.

Example

Thefollowingprogramtimestheintervalbetweentwobuttonpresses.

varstartTime,startButton,finishButton:int

procedureStart

startTime:=GUI.GetEventTime

endStart

procedureFinish

Text.Locate(1,1)

put"Thetimebetweenbuttonpressedis",

GUI.GetEventTimestartTime,"msecs"

GUI.Quit

endFinish

startButton:=GUI.CreateButton(10,10,110,"ClickFirst",

finishButton:=GUI.CreateButton(180,10,110,"ClickSecond",

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetEventTimebycallingGetEventTime.

Seealso GUI.ProcessEvent.

GUI.GetEventWidgetID PartofGUImodule

Syntax GUI.GetEventWidgetID:int

Description

ReturnsthewidgetIDofthewidgetthatwasactivatedbythemousebuttonpressorthekeystroke.Thisfunctionshouldonlybecalledinanactionprocedure,asitwillreturn1whenthereisnoeventthatactivatedawidgetbeingprocessed.

Thisfunctionisusedwhenaseveralbuttonsusethesameactionproceduretodeterminewhichbuttonwaspressed.

Example

Thefollowingprogramprintsamessagestatingwhichbuttonwasselected.

varbuttonNames:array1..5ofstring:=init

"Blue","Yellow","Purple")

varbuttons:array1..5ofint

procedureButtonPush

fori:1..5

ifGUI.GetEventWidgetID=buttons(i)then

Text.Locate(1,1)

putbuttonNames(i),"selected"

endfor

endButtonPush

fori:1..5

buttons(i):=GUI.CreateButton(10,21040*

buttonNames(i),ButtonPush)

endfor

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetEventWidgetID,notbycallingGetEventWidgetID.

GUI.GetEventWindow PartofGUImodule

Syntax GUI.GetEventWindow:int

Description

ReturnsthewindowIDofthewindowinwhichtheevent(mousebuttonorkeystroke)tookplace.Thisfunctionshouldonlybecalledinanactionprocedureorinadefaultmouseorkeystrokeeventhandler,asitwillreturn1whenthereisnoeventbeingprocessed.

Thisfunctioniscommonlyusedwhenseveralwindowssharethesamelayout.Thesamebuttonsineachwindowpointtothesameactionproceduresdeterminewhichbuttonwasactuallypressed,thefunctioniscalledtogetthewindow.

Example

Thefollowingprogramcreatesfourwindowsinarow,eachwithabuttonthat,whenpressed,causesastartobedrawninthatwindow.

procedureDrawStar

varwindowID:int:=GUI.GetEventWindow

Window.Select(windowID)

Draw.FillStar(25,40,175,190,Rand.Int(10,15))

endDrawStar

fori:0..3

varwindow:int:=Window.Open("graphics:200;200")

%Placewindowabovetaskbar,acrossfrompreviousone.

Window.SetPosition(window,220*i,27)

varbutton:int:=GUI.CreateButton(5,5,190,"DrawStar",

DrawStar)

endfor

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetEventWindow,notbycallingGetEventWindow.

GUI.GetHeight PartofGUImodule

Syntax GUI.GetHeight(widgetID:int):int

Description

Returnstheactualheightofawidget.NotethatthismaybedifferentfromtheheightspecifiedintheCreatecall(especiallysincemanywidgetsdonotspecifyaheight.TheGUImoduledeterminestheactualheight).

ThisfunctionisusedinconjunctionwithGUI.GetX,GUI.GetYandGUI.GetWidthtodeterminetheboundsofawidget.Theentirewidgetshouldalwaysfitinthebox(GUI.GetX,GUI.GetY)-(GUI.GetX+GUI.GetWidth1,GUI.GetY+GUI.GetHeight1)

Thepositionandsizeofawidgetisknownonlyafterithasbeendrawntothescreen.Attemptingtogetthelocationordimesionsofthewidgetmaycauseanuninitializedvariableerror.

Example

ThefollowingproceduredrawsaredboxaroundthewidgetspecifiedbywidgetID.

procedureBoxWidget(widgetID:int)

varx,y,width,height:int

x:=GUI.GetX(widgetID)

y:=GUI.GetY(widgetID)

width:=GUI.GetWidth(widgetID)

height:=GUI.GetHeight(widgetID)

Draw.Box(x1,x1,x+width,y+height,

Draw.Box(x2,x2,x+width+1,y+height

endBoxWidget

vartitle:int:=GUI.CreateLabel(20,20,"FrameThis!")

BoxWidget(title)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetHeight,notbycallingGetHeight.

Seealso GUI.GetX,GUI.GetY,andGUI.GetWidth.

GUI.GetMenuBarHeight PartofGUImodule

Syntax GUI.GetMenuBarHeight:int

Description

Returnstheheightofthemenubar.Usefulwhendrawingorplacingwidgetstomakecertainthattheydon'toverlapthemenubar.

Example

Thefollowingprogramdrawsaredboxinthewindowjustbelowethemenubar.

varmenu:int:=GUI.CreateMenu("File")

varitem:int:=GUI.CreateMenuItem("Quit",GUI.Quit

Draw.FillBox(0,0,maxx,maxyGUI.GetMenuBarHeight

brightred)

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetMenuBarHeight,notbycallingGetMenuBarHeight.

Seealso GUI.CreateMenu.

GUI.GetScrollBarWidth PartofGUImodule

Syntax GUI.GetScrollBarWidth:int

DescriptionReturnsthewidthofascrollbar.Usefulwhenplacingascrollbarwidgetbeneathorbesideanotherwidgetorobject.

Example

SeetheScrollPicprograminGUI.CreateHorizontalScrollBarFullforanexampleofGUI.GetScrollBarWidth.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetScrollBarWidth,notbycallingGetScrollBarWidth.

SeealsoGUI.CreateHorizontalScrollBarandGUI.CreateVerticalScrollBar.

GUI.GetSliderValue PartofGUImodule

Syntax GUI.GetSliderValue(widgetID:int):int

Description

ReturnsthecurrentvalueofasliderorscrollbarspecifiedbywidgetID.ThewidgetIDmustspecifyeitherscrollbaroraslider(horizontalorvertical).

Example

SeetheScrollPicprograminGUI.CreateHorizontalScrollBarFullforanexampleofGUI.GetSliderValue.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetSliderValue,notbycallingGetSliderValue.

Seealso

GUI.SetSliderValueforsettingasliderorscrollbar'svalue.SeealsoGUI.CreateHorizontalScrollBar,GUI.CreateVerticalScrollBar,GUI.CreateHorizontalSlider,andGUI.CreateVerticalSlider.

GUI.GetText PartofGUImodule

Syntax GUI.GetText(widgetID:int):string

DescriptionReturnsthecurrenttextofatextfieldspecifiedbywidgetID.ThewidgetIDmustspecifyatextfieldwidget.

Example SeeGUI.CreateTextFieldforanexampleofGUI.GetText.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetText,notbycallingGetText.

SeealsoGUI.SetTextforsettingthetextinatextfield.SeealsoGUI.CreateTextField.

GUI.GetVersion PartofGUImodule

Syntax GUI.GetVersion:int

Description

ReturnsthecurrentversionoftheGUIProcedureLibrary.BecausetheGUIProcedureLibraryisexpectedtogrow,newversionswillprobablybemadeavailableatourwebsitehttp://www.holtsoft.com/turing.Ifyouwishtousefeaturesthatdonotappearinearlierversionsofthelibrary,youcanhaveyourprogramcheckthatthecurrentavailableversionmeetstheprogramsneeds.GUI.GetVersionreturnsanintegerfrom100-999andisreadas1.00to9.99.

Example

ThefollowingprogramfragmentimmediatelyexitsifOOTdoesnotsupportversion1.1oftheGUIProcedureLibrary

ifGUI.GetVersion<110then

put"Youmustupdatetoatleastversion1.1ofthe"

put"GUIProcedureLibrarytousethisprogram."

return

DetailsInversion1.00(shippedwithMacOOT1.5),GUI.GetVersiondidnotexist.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetVersion,notbycallingGetVersion.

GUI.GetWidth PartofGUImodule

Syntax GUI.GetWidth(widgetID:int):int

Description

Returnstheactualwidthofawidget.NotethatthismaybedifferentfromthewidthspecifiedintheCreatecall(especiallysincesomewidgetsdonotspecifyawidth.TheGUImoduledeterminestheactualwidth).

ThisfunctionisusedinconjunctionwithGUI.GetX,GUI.GetYandGUI.GetHeighttodeterminetheboundsofawidget.Theentirewidgetshouldalwaysfitinthebox(GUI.GetX,GUI.GetY)-(GUI.GetX+GUI.GetWidth1,GUI.GetY+GUI.GetHeight1)

Example

endBoxWidget

BoxWidget(title)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetWidth,notbycallingGetWidth.

Seealso GUI.GetX,GUI.GetY,andGUI.GetHeight.

GUI.Get{X,Y} PartofGUImodule

SyntaxGUI.GetX(widgetID:int):int

GUI.GetY(widgetID:int):int

Description

Returnsthexcoordinateoftheleftedgeofawidget.Notethatthismaybedifferentfromthexcoordinatespecifiedinthewidget'sCreatecall.Forexample,ifaradiobuttoniscreatedwithrightjustification,thexcoordinateintheCreatemethodspecifiestherightedgewhileGUI.GetXwillreturnthexcoordinateoftheleftedge.

ThisfunctionisusedinconjunctionwithGUI.GetWidthandGUI.GetHeighttodeterminetheboundsofawidget.Theentirewidgetshouldalwaysfitinthebox(GUI.GetX,GUI.GetY)-(GUI.GetX+GUI.GetWidth-1,GUI.GetY+GUI.GetHeight-1)

Example

endBoxWidget

BoxWidget(title)

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingGUI.GetX,notbycallingGetX.

Seealso GUI.GetHeightandGUI.GetWidth.

GUI.Hide PartofGUImodule

Syntax GUI.Hide(widgetID:int)

Description

HidesawidgetspecifiedbywidgetID.UsedinconjunctionwithShowtohideandshowwidgets.Hiddenwidgetscannotgetevents(i.e.respondtokeystrokesormouseclicks).Ifanactivetextfield(seetextfield)ishidden,thenanykeystrokesinthewindowwillbeignored.

Inmostcaseswhereawidgetistoappear,thendisappear,thenappearagain,itisadvisedtocreatethewidgetonceandhideituntilitistoappear,whereuponGUI.Showiscalled.Whentheuserisfinishedwiththewidget,thewidgetishiddenusingGUI.Hide.Thissavestheoverheadofcreatinganddisposingofthesamewidgetseveraltimes.

Example SeeGUI.SetDisplayWhenCreatedforanexampleofGUI.Hide.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.Hide,notbycallingHide.

Seealso GUI.Show.

GUI.HideMenuBar PartofGUImodule

Syntax GUI.HideMenuBar

Description

Hidesthemenubarintheselectedwindow.Nomenuitemscanbeselectedwhenthemenubarishidden.(Menuitemshortcutsareignoredwhilethemenubarishidden.)

ExampleSeeGUI.SetMouseEventHandlerforanexampleofGUI.HideMenuBar.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.HideMenuBar,notbycallingHideMenuBar.

Seealso GUI.ShowMenuBar.SeealsoGUI.CreateMenu.

GUI.HideWindow PartofGUImodule

Syntax GUI.HideWindow(window:int)

Description

Hidesawindowwithwidgetsinit.ThisproceduremakescertainthattheGUILibraryrecognizesthatthewindownolongervisible.ThisprocedurewillcallWindow.Hide,sothereisnoneedfortheusertodoso.

Example

importGUI

varwindowA,windowB:int

varbuttonA,buttonB,buttonQuit:int

varbackToMainA,backToMainB:int

procedureShowWindowA

GUI.HideWindow(defWinID)

GUI.ShowWindow(windowA)

endShowWindowA

procedureShowWindowB

GUI.ShowWindow(windowB)

endShowWindowB

procedureShowMain

GUI.HideWindow(Window.GetActive)

GUI.ShowWindow(defWinID)

endShowMain

%Placethebuttonsinthemainwindow

buttonA:=GUI.CreateButton(10,10,0,"ShowWindowA",

buttonB:=GUI.CreateButton(150,10,0,"ShowWindowB",

buttonQuit:=GUI.CreateButton(100,60,0,"Quit",

windowA:=Window.Open("title:WindowA,graphics:150;100,position:bottom;left")

backToMainA:=GUI.CreateButton(20,20,0,"BacktoMain",

Window.Hide(windowA)

windowB:=Window.Open("title:WindowB,graphics:150;100,position:bottom;right")

backToMainB:=GUI.CreateButton(20,20,0,"BacktoMain",

Window.Hide(windowB)

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.HideWindowbycallingHideWindow.

SeealsoGUI.ShowWindowforshowingawindowwithwidgetsinit.SeealsoGUI.CloseWindowforclosingawindowwithwidgetsinit.

GUI.OpenFile PartofGUImodule

Syntax GUI.OpenFile(title:string):string

Description

Displaysan"OpenFile"dialogboxtoobtainthenameofanalreadyexistingfile.Thecaption(awindowtitleunderMSWindows,astringinaMacintoshdialogbox)isspecifiedbythetitleparameter.Thefunctionusesadialogboxspecifictotheoperatingsystemtheprogramisbeingrunon.

Iftheuserdidnotchooseafile(i.e.hittheCancelbuttoninthedialog),thefunctionreturns""(theemptystring).

Example

Thefollowingprogramaskstheuserforthenameofafileandthenechoesthecontentsofit.

varfileName,line:string

varstreamNumber:int

fileName:=GUI.OpenFile("ChooseaTextFile")

open:streamNumber,fileName,get

exitwheneof(streamNumber)

get:streamNumber,line:*

putline

endloop

close:streamNumber

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingGUI.OpenFile,notbycallingOpenFile.

GUI.OpenFileFull PartofGUImodule

SyntaxGUI.OpenFileFull(title,filter:string,startDir:string):string

Description

Displaysan"OpenFile"dialogboxtoobtainthenameofanalreadyexistingfile.Thecaption(awindowtitleunderMSWindows,astringinaMacintoshdialogbox)isspecifiedbythetitleparameter.Thelistoffilesshownisspecifiedbythefilterparameter.Theinitialdirectorytobedisplayedisspecifiedbytheparameter.Thefunctionusesadialogboxspecifictotheoperatingsystemtheprogramisbeingrunon.

Thefilterparameterisafilenamesuffixthatshouldbedisplayed.Multiplesuffixescanbespecifiedbyseparatingthemwithcommas.Iftheuserspecifiestheemptystringforfilter,thenallthefilesinthedirectoryaredisplayed.IfthestartDirparameterisempty,orifitspecifiesanon-existentdirectory,thenthecurrentdirectoryisdisplayedinthe"OpenFile"dialogbox.

Example

Thefollowingprogramaskstheusertoselectafileendingin".txt".TheinitialdirectoryistherootdirectoryoftheCdrive.

varfileName:string

fileName:=GUI.OpenFileFull("ChooseaTextFile","txt","C:\\")

DetailsIfasuffixisplacedinsinglequotes,itwillbeignoredonallbuttheAppleMacintosh,whereitwillspecifyaMacintoshfiletype.

Theexamplemakesthedialogboxdisplayallfilesendingin".txt"or".text"on

ExampleallsystemsbuttheMacintosh.OntheAppleMacintosh,onlyfilesoffiletype'TEXT'willbedisplayed.

fileName:=GUI.OpenFileFull("Open","txt,text,'TEXT'","")

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.OpenFileFullbycallingOpenFileFull.

GUI.Pic... PartofGUImodule

Syntax

GUI.PicDraw(widgetID:int,picID,x,y,mode:int)

GUI.PicNew(widgetID:int,x1,y1,x2,y2:int):int

GUI.PicScreenLoad(widgetID:int,fileName:string,x,y,mode:int)

GUI.PicScreenSave(widgetID:int,x1,y1,x2,y2:int,fileName:string)

Description

PerformsaPic…commandtothecanvasspecifiedbywidgetID.

Alloftheseroutinesareessentiallythesameasthesimilarly-namedproceduresinthePicmodule.Allcoordinatesarebasedonthecanvasandalldrawingisclippedtothecanvasdrawingsurface.

Example

SeetheScrollPicprograminGUI.CreateHorizontalScrollBarFullforanexampleofGUI.PicDraw.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.Pic…,notbycallingPic….

GUI.ProcessEvent PartofGUImodule

Syntax GUI.ProcessEvent:boolean

Description

Thisfunctionprocessesasingleevent(amousebuttonpressorakeystroke).Iftheeventactivatesawidget,thentheactionprocedureofthewidgetiscalled.

ThefunctionreturnsfalseuntilGUI.Quitiscalled.Itthenreturnstrue

Inorderforthewidgetstofunctiononceplaced,theGUI.ProcessEventmustbecalledcontinually.WithoutacalltoGUI.ProcessEvent,thewidgetswillappear,butwillnotreacttomouseclicksorkeystrokes.

AlmostallprogramsinvolvingtheGUIProcedureLibraryhavethefollowingcodefragmentintheprogram.Thiscodefragmentisoftencalledtheeventloop

endloop

ThelooprunscontinuouslyuntilGUI.Quitiscalled,whereuponGUI.ProcessEventwillreturntrueandtheloopwillexit.Therestoftheprogramisreachedthroughtheactionproceduresthatarecalledwhentheuserinteractswithvariouswidgets.

Details

Itisusuallydesirabletoallowtheusersomewayofquittingtheprogramwithouthavingtoabortit.ThiscanbedonemostsimplybyaddingaQuitbuttonandplacingitinanappropriatelocation.

Example

Hereisprogramthatdoesnothingbutwaitfortheusertopressthequitbutton.

varquitButton:int:=GUI.CreateButton(10,10,0,"Quit",

endloop

Tofindoutwhichwidgetwasactivatedandcalledtheactionprocedureifseveralwidgetshavethesameactionprocedure),youcancallGUI.GetEventWidgetID.Togettheexacttimethattheeventoccurred,youcan

Details

callGUI.GetEventTime.Togetthewindowinwhichtheeventtookplace,youcancallGUI.GetEventWindow.

Ifamouseclickoccured,butdidnotactivateanywidget,thenthedefaultmouseeventhandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtorespondtomouseeventsthatdonotaffectawidget,callGUI.SetMouseEventHandlertospecifyyourowndefaultmouseeventhandler.

Ifakeystrokeoccurred,butdidnotactivateanywidget(i.e.itwasn'tashortcutforawidgetandtherearenotextfieldsinthewindow)thenthedefaultkeystrokehandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtorespondtokeystrokeeventsthatdonotaffectawidget,callGUI.SetKeyEventHandlertospecifyyourowndefaultkeyeventhandler.

Ifnoeventoccurred,thenthenulleventhandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtoperformsomeactionrepetetivelywhenitisnotdoinganythingelse,thencallGUI.SetNullEventHandleryourownnulleventhandler.Thenulleventhandlerisoftenusedforsuchthingsasupdatingaclockandmakingcertainthatmusicisplayinginthebackground.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.PProcessEventnotbycallingProcessEvent.

Seealso

GUI.GetEventWidgetID,GUI.GetEventTime,andGUI.GetEventWindowobtaininginformationaboutaneventinanactionprocedure.SeealsoGUI.SetMouseEventHandler,GUI.SetKeyEventHandlerandGUI.SetNullEventHandlerforhandlingmouse,keyboardandnulleventsintheeventloop.SeealsoGUI.Quitforinformationonexittingtheevent

GUI.Quit PartofGUImodule

Syntax GUI.Quit

Description

ThisprocedurecausesGUI.ProcessEventtoreturntrue.Iftheprogramisstructuredproperlywitha

endloop

attheendoftheprogram,thentheprogramwillexittheloopaftercurrentactionprocedure.ThisprocedureisusuallycalledfromtheprocedureofaQuitbuttonorExitmenuitem.

Example

Hereisprogramthatdoesnothingbutwaitfortheusertopressthequitbuttonortypetheletter'Q','q','X',or'x'.

importGUI

procedureKeyHandler(ch:char)

ifch='Q'orch='q'orch='X'orch='x'

GUI.Quit

endKeyHandler

varquitButton:int:=GUI.CreateButton(10,10,0,"Quit",

GUI.SetKeyEventHandler(KeyHandler)

endloop

put"Done!"

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.QuitcallingQuit.

SeealsoGUI.ProcessEvent.SeealsoGUI.ResetQuitforresettingthe"quit"flag,sothatasecondeventloopcanbeusedinthesameprogram.

GUI.Refresh PartofGUImodule

Syntax GUI.Refresh

Description

Thisroutineredrawsallthewidgetsinthecurrently-selectedwindow.Thisisusedwhensomeformofdrawingmayhaveoverwrittenthewidgetsinawindow.

Itisoftenusedwhenthereissomepossibilitythatthewidgetsmayhavebeendrawnover.Forexample,aprogramthatplacesbuttonsontopofabackgroundimageshouldcallGUI.Refreshwhentheimageischanged.

DetailsGUI.RefreshisusedbytheGUILibrarytoredrawallthewidgetswhenthebackgroundcolourofawindowhaschanged.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.Refresh,notbycallingRefresh.

GUI.ResetQuit PartofGUImodule

Syntax GUI.ResetQuit

Description

TheGUI.ResetQuitprocedureresetsthe"quitting"flagthatissetbytheTheGUI.ResetQuitcanbeusedwheneveryouwanttohaveaprogramthatexitsmainprocessingloop,doessomework,andthenreenterstheprocessingloop.

WithoutGUI.ResetQuit,theprogramwillexitthesecondloopimmediatelybecauseGUI.ProcessEventwillreturntrue.

Thisprogramallowstheusertoselectthecolorthatstarsaretobedrawnin.pressesthebutton,theprogramexitsthefirsteventloopanddrawsthestars.anotherbuttonandenteringasecondeventloop,itcallsGUI.ResetQuit

importGUI

varradio:array1..4ofint

varbutton:int

varstarColor:int:=red

%Actionproceduresfortheradiobuttons

procedureRed

starColor:=brightred

endRed

procedureGreen

starColor:=brightgreen

endGreen

procedureBlue

starColor:=brightblue

endBlue

procedureCyan

starColor:=brightcyan

endCyan

%Createtheradiobuttons

radio(1):=GUI.CreateRadioButton(15,maxy-35,"Red",0,

radio(2):=GUI.CreateRadioButton(-1,-1,"Green",

radio(3):=GUI.CreateRadioButton(-1,-1,"Blue",

radio(4):=GUI.CreateRadioButton(-1,-1,"Cyan",

%Createthepushbutton

Example button:=GUI.CreateButton(100,maxy-70,0,"DrawStars",

%Processeventsuntilthe"DrawStars"buttonispressed

endloop

%Disposeofalltheradiobuttonsandthepushbutton

fori:1..4

GUI.Dispose(radio(i))

endfor

GUI.Dispose(button)

%Drawabunchofstars-Nomorehandlingofeventsorwidgets

fori:1..100

varx:int:=Rand.Int(0,maxx-20)

vary:int:=Rand.Int(0,maxy-20)

Draw.FillStar(x,y,x+20,y+20,starColor)

endfor

%Createanewbutton

button:=GUI.CreateButton(300,10,0,"Quit",

%Resetthequitflag.Withoutthisstatement,theloopfollowingwould

%exitimmediatelybecausethequitflagwassetinthepreviousloop

GUI.ResetQuit

%Processeventsuntilthe"Quit"buttonispressed

endloop

%Closethewindow

GUI.CloseWindow(defWinID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.ResetQuitResetQuit.

GUI.SaveFile PartofGUImodule

Syntax GUI.SaveFile(title:string):string

Description

Displaysan"SaveFile"dialogboxtoobtainthenameofafile.Thecaption(awindowtitleunderMSWindows,astringinaMacintoshdialogbox)isspecifiedbythetitleparameter.Thefunctionusesadialogboxspecifictotheoperatingsystemtheprogramisbeingrunon.

Note:ThisfunctionisnotavailableinthecurrentversionoftheGUIProcedureLibrary(shippingwithTuring4.0andMacOOT1.5).ItisdocumentedhereforusewithfutureshippingversionofTuring.Checkthereleasenotesthatarefoundintheon-linehelptofindoutifthisfunctionisnowavailable.

Example

Thefollowingprogramaskstheuserforthenameofafileandthenwritesthenumbers1to10init.

varfileName:string

varstreamNumber:int

fileName:=GUI.SaveFile("ChooseaTextFile")

fori:1..10

put:streamNumber,i

endloop

close:streamNumber

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SaveFile,notbycallingSaveFile.

GUI.SaveFileFull PartofGUImodule

SyntaxGUI.SaveFileFull(title,filter:string,startDir:string):string

Description

Displaysan"SaveFile"dialogboxtoobtainthenameofanalreadyexistingfile.Thecaption(awindowtitleunderMSWindows,astringinaMacintoshdialogbox)isspecifiedbythetitleparameter.Thelistoffilesshownisspecifiedbythefilterparameter.TheinitialdirectorytobedisplayedisspecifiedbythestartDirparameter.Thefunctionusesadialogboxspecifictotheoperatingsystemtheprogramisbeingrunon.

Thefilterparameterisafilenamesuffixthatshouldbedisplayed.Multiplesuffixescanbespecifiedbyseparatingthemwithcommas.Iftheuserspecifiestheemptystringforfilter,thenallthefilesinthedirectoryaredisplayed.IfthestartDirparameterisempty,orifitspecifiesanon-existentdirectory,thenthecurrentdirectoryisdisplayedinthe"OpenFile"dialogbox.

Note:ThisfunctionisnotavailableinthecurrentversionoftheGUIProcedureLibrary(shippingwithTuring4.0andMacOOT1.5).ItisdocumentedhereforusewithfutureshippingversionofTuring.Checkthereleasenotesthatarefoundintheon-linehelptofindoutifthisfunctionisnowavailable.

Example

Thefollowingprogramsegmentaskstheuserforthenameofafileendingin".txt".TheinitialdirectoryistherootdirectoryoftheCdrive.

varfileName:string:=GUI.SaveFileFull("ChooseaTextFile",

"txt","C:\\")

DetailsIfasuffixisplacedinsinglequotes,itwillbeignoredonallbuttheAppleMacintosh,whereitwillspecifyaMacintoshfiletype.

Example

Thefollowingprogramsegmentaskstheuserforthenameofafile.Itdisplaysfilesoftype'TEXT'.Theinitialdirectoryisthe"TuringPrograms"directoryonthe"MacintoshHD"volume.

varfileName:string:=GUI.SaveFileFull("ChooseaTextFile",

"'TEXT'","MacintoshHD:TuringPrograms")

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SaveFileFull,notbycallingSaveFileFull.

GUI.SelectRadio PartofGUImodule

Syntax GUI.SelectRadio(widgetID:int)

DescriptionSelectsaradiobuttonspecifiedbywidgetID.Thepreviously-selectedradiobuttonis"de-selected".Theactionprocedureoftheradiobuttoniscalled.

Example

Thefollowingprogramcreatessizradiobuttons.Selectingoneofthebuttonscausethebottomtworadiobuttonstobecomeselected.

varradio:array1..6ofint%TheradiobuttonIDs.

procedureRadioPressed

Text.Locate(1,1)

fori:1..6

ifradio(i)=GUI.GetEventWidgetIDthen

put"RadioButton",i,"Selected"

endfor

endRadioPressed

procedureSelect

GUI.SelectRadio(radio(3))

GUI.SelectRadio(radio(6))

endSelect

radio(1):=GUI.CreateRadioButton(15,maxy35,

"RadioButton1",0,RadioPressed)

radio(4):=GUI.CreateRadioButtonFull(maxx15,

"RadioButton4",0,RadioPressed,GUI.RIGHT

radio(5):=GUI.CreateRadioButtonFull(1,1,"RadioButton5",

radio(4),RadioPressed,GUI.RIGHT,GUI.NONE

radio(6):=GUI.CreateRadioButtonFull(1,1,"RadioButton6",

radio(5),RadioPressed,GUI.RIGHT,GUI.NONE

varselectButton:int:=GUI.CreateButton(15,10,100,

"SelectBottomButtons",Select)

varquitButton:int:=GUI.CreateButton(maxx15100,10,100,

"Quit",GUI.Quit)loop

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.SelectRadio,notbycallingSelectRadio.

Seealso GUI.CreateRadioButtonandGUI.CreatePictureRadioButton.

GUI.SetActive PartofGUImodule

Syntax GUI.SetActive(widgetID:int)

Description

MakesatextfieldspecifiedbywidgetIDactive.Ifthetextfieldisnotinanactivewindow,thenthetextfieldwillbecomeactivewhenthewindowdoes.Ifanothertextfieldwasactiveinthewindow,itisdeactivated.

Example SeeGUI.CreateTextFieldforanexampleofGUI.SetActive.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.SetActive,notbycallingSetActive.

Seealso GUI.CreateTextField.

GUI.SetBackgroundColor PartofGUImodule

Syntax GUI.SetBackgroundColor(Color:int)

Description

Changesthebackgroundcolourofthecurrently-selectedwindowtothecolorspecifiedbyColor.Thisdoesnotchangethevalueofcolor0inthewindow.Insteaditfillstheentirewindowwiththenewbackgroundcolorandthenredrawsallthewidgets.

Forindentedandextendeditems,thebackgroundcolorisassumedtobesettogray.

ThealternatespellingisGUI.SetBackgroundColour

ExampleSeeGUI.CreateFrameforanexampleofGUI.SetBackgroundColour.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.SetBackgroundColor,notbycallingSetBackgroundColor.

GUI.SetCheckBox PartofGUImodule

Syntax GUI.SetCheckBox(widgetID:int,status:boolean)

Description

SetsthestatusofacheckboxspecifiedbywidgetID.Ifstatusistrue,thecheckboxisfilled(markedwithan'X').Ifstatusisfalse,thecheckboxissetempty.GUI.SetCheckBoxcallsthecheckbox'sactionprocedurewiththenewstatusandredrawsthewidgetwiththenewstatus.

ExampleSeeGUI.CreateCheckBoxforanexampleofGUI.SetCheckBox.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.SetCheckBox,notbycallingSetCheckBox.

Seealso GUI.CreateCheckBox.

GUI.SetColor PartofGUImodule

Syntax GUI.SetColor(widgetID:int,clrNumber:int)

Description

TheGUI.SetColorprocedureisusedbuttonstochangethecolorofabutton.ThecolorisspecifiedbytheclrNumberparameter.TheedgesofthebuttonareadarkerversionofthecolorspecifiedbyclrNumbergeneralyoushouldusebrightercolorsforbuttons.

Example

Thisprogramdisplaysthreebuttonswithdifferentcolors.

importGUI

procedureDoNothing

endDoNothing

varb1:=GUI.CreateButton(100,100,0,"PushMe",

GUI.SetColor(b1,brightred)

GUI.SetColor(b2,brightgreen)

GUI.SetColor(b3,brightblue)

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetColornotbycallingSetColor.

GUI.SetDefault PartofGUImodule

Syntax GUI.SetDefault(widgetID:int,default:boolean)

Description

Setsthe"defaultstatus"ofabuttonspecifiedbywidgetID.Ifabuttonisthedefaultbutton,thenitisdrawnwithaheavyoutlineanditisactivatedwhentheuserpressesENTER.

Onlyonebuttoncanbethedefaultbuttonperwindow.Ifabuttonissettobethedefaultbutton,thenthepreviousdefaultbuttonhasits"defaultstatus"removed.

Status

Exportedqualified.

ThismeansthatyoucanonlycalltheproceduresbycallingGUI.SetDefault,notbycallingSetDefault.

Seealso GUI.CreateButton.

GUI.SetDisplayWhenCreated PartofGUImodule

Syntax GUI.SetDisplayWhenCreated(display:boolean)

Description

Bydefault,wheneverawidgetiscreatedwithaGUI.Create…procedure,thewidgetinstantlyappears.Sometimes,thisisnotthedesiredbehaviour.Forexample,ifseveralwidgetsaretooccupythesamelocationwithonlyonebeingdisplayedatatime,thenitisdesirablenottohavethewidgetappearwhenfirstcreated.

Ifawidgetisnotdisplayedwhencreated,thenGUI.Showmustbecalledtomakethewidgetvisible.

Ifthedisplayparameteristrue,thenwidgetsaredisplayedimmediatelyuponcreation.Ifthedisplayparameterissettofalse,thenthewidgetisnotmadevisibleoncreationandGUI.Showmustbecalledtodisplaythewidget.

Example

Thefollowingprogramtogglesthevisiblilityoftheframewhenthebuttonispushed.Theframestartsoutinvisible.

varvisible:boolean:=false

varbutton,frame:int

procedureToggle

ifvisiblethen

GUI.Hide(frame)

GUI.Show(frame)

visible:=notvisible

endToggle

button:=GUI.CreateButton(25,40,0,"ToggleFrame",

GUI.SetDisplayWhenCreated(false)

frame:=GUI.CreateFrame(10,10,140,90,0)

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetDisplayWhenCreated,notbycallingSetDisplayWhenCreated

GUI.SetEchoChar PartofGUImodule

Syntax GUI.SetEchoChar(widgetID:int,echoChar:char)

Description

TheGUI.SetEchoCharprocedureisusedwithtextfields,especiallywhenusingatextfieldtoinputapassword.WhentheGUI.SetEchoChariscalledwithatextfield,anycharacterenteredintothetextfieldwillappearasthecharacterspecifiedbyinputChar

Thisallowsyoutousethetextfieldtoenterapassword.ThecharactersthattheusertypeswillbeechoedwiththecharacterspecifiedbyinputChar(oftenanasterisk).

Example

Thisprogramdisplaysatextfield.Astheuserenterscharacters,eachcharacterisrepresentedasa'*'.Whentheuserentersreturn,theprogramexitsafterdisplayingtheactualtextenteredintothetextfield.

importGUI

procedureEchoString(s:string)

put"Youentered\"",s,"\""

GUI.Quit

endEchoString

vartf:=GUI.CreateTextField(10,100,100,"",

GUI.SetEchoChar(tf,'*')

endloop

Execute

Details

NotethattheechoCharargumenttoGUI.SetEchoCharmustbeacharacter,notastring.Thismeansthecharactershouldbeenclosedinsinglequotemarks('),notdoublequotes(").

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetEchoChar,notbycallingSetEchoChar.

GUI.SetKeyEventHandler PartofGUImodule

SyntaxGUI.SetKeyEventHandler(keyEventHandler:procedurex(ch:char))

Description

Setsthenewdefaultkeystrokeeventhandler.ThekeyEventHandlerthenameofaprocedurethatiscalledeverytimeGUI.ProcessEventthereisakeystrokewhichisnothandledbyanywidget.ThechparameterinthekeyEventHandleristhekeystroketypedbytheuser.

Thisprocedureisoftenusedtoallowformorethanoneshortcutcharacterforagivenbutton.

Example

Thefollowingprogramdrawsastarorquitsdepeningonthebutton.TheDrawStarbuttoncanbeactivatedbyclickingonitortyping'D','d','S','s'orCtrl+S.TheQuitbuttoncanbeactivatebytyping'Q','q'orCtrl+Q.TheDrawStarbuttonisalsothedefaultbutton.ItisactivatedwhenevertheuserpressesENTER.

importGUI

procedureDrawStar

Draw.FillStar(25,40,175,190,Rand.Int(10,15))

endDrawStar

ifch='q'orch='^Q'then

Draw.Cls

GUI.Quit

elsifch='d'orch='^d'orch='S'orch

DrawStar

endKeyHandler

varbutton:int:=GUI.CreateButtonFull(5,5,100,"DrawStar",

DrawStar,0,'D',true)

varquitButton:int:=GUI.CreateButtonFull(115,5,100,"Quit",

GUI.Quit,0,'Q',false)

endloop

Exportedqualified.

StatusThismeansthatyoucanonlycallthefunctionbycallingGUI.SetKeyEventHandler,notbycallingSetKeyEventHandler.

GUI.SetLabel PartofGUImodule

Syntax GUI.SetLabel(widgetID:int,text:string)

Description

ChangesthetextofawidgetspecifiedbywidgetIDtotext.Thisprocedurecanacceptabutton,checkbox,radiobutton,label,oralabelledframewidgetasthewidgetIDparameter.

Inmostcases,ifthetextwillnotfitinthewidget'scurrentsize,thewidgetwillberesizedtofitthetext.Ifthewidgetwasmadelargertofitthetextandthenthetextischanged,thewidgetwillberesizedasappropriatefortheoriginalwidthspecifiedandthenewtext.

Example

Thefollowingprogramchangesthetextinthebuttonwheneverakeystrokeoccurs.Whenthetextischangedbackto"Quit",thebuttonassumesawidthof100again.

varshort:boolean:=true

varbutton:int

ifshortthen

GUI.SetLabel(button,"PressThisButtontoQuit")

GUI.SetLabel(button,"Quit")

short:=notshort

endKeyHandler

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetLabel,notbycallingSetLabel.

Seealso

GUI.CreateButton,GUI.CreateCheckBox,GUI.CreateRadioButton,GUI.CreateLabel,andGUI.CreateLabelledFrame.

GUI.SetMouseEventHandler PartofGUImodule

SyntaxGUI.SetMouseEventHandler(mouseEventHandler:procedurex(mx,my:int))

Description

Setsthenewdefaultmouseeventhandler.ThemouseEventHandlerparameteristhenameofaprocedurethatiscalledeverytimeGUI.ProcessEventiscalledandthereisamousebuttondownwhichisnothandledbyanywidget.ThemxandmyparametersinthemouseEventHandlerarethelocationofmousewhenthebuttonwaspressed.

Thisprocedureisusedbyprogramstoallowformouseinputinaprogramthatuseswidgets.

Thisisaprogramthatallowstheusertoplacestarsonthescreen.Themenubarallowstheusertoquittheprogramatanytime.Theusercanalsotoggletheappearanceofthemenubarbypressinganykey.

importGUI

varstarX,starY,starColor:array1..100ofint

varnumStars:int:=0

varmenuVisible:boolean:=true

procedureDrawStar(i:int)

ifmenuVisiblethen

View.ClipSet(0,0,maxx,

maxyGUI.GetMenuBarHeight)

Draw.FillStar(starX(i)20,starY(i)20,

starY(i)+20,starColor(i))View.ClipOff

endDrawStar

procedureRedraw

fori:1..numStars

DrawStar(i)

endfor

put"Pressanykeytotogglemenubar"..

endRedraw

Example ifmenuVisiblethen

GUI.HideMenuBarelse

GUI.ShowMenuBar

menuVisible:=notmenuVisible

Redraw

endKeyHandler

procedureMouseHandler(x,y:int)

ifnumStars=100then

put"Maximumnumberofstarsexceeded!"..

return

numStars+=1

starX(numStars):=x

starY(numStars):=y

starColor(numStars):=Rand.Int(9,15)

DrawStar(numStars)

endMouseHandler

varmenu:int:=GUI.CreateMenu("File")

varmenuItem:int:=GUI.CreateMenuItemFull("Quit",

GUI.Quit,'^Q',false)

GUI.SetMouseEventHandler(MouseHandler)

Redraw

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetMouseEventHandler,notbycallingSetMouseEventHandler.

GUI.SetNullEventHandler PartofGUImodule

SyntaxGUI.SetNullEventHandler(nullHandler:procedurex())

Description

Setsthenewnulleventhandler.ThenullHandlerparameteristhenameofaprocedurethatiscalledeverytimeGUI.ProcessEventiscalledandtherearenomousebuttonpressesorkeystrokestobeprocessed.

Thisisusedbyprogramsthatneedtocallsubprogramsoften,butdonotwishtointerrupttheactionofuserwidgets.

Example

ThefollowingprogramhasaQuitbutton.Whennowidgetsarebeingprocessed,aclockinthecornerisupdated.

importGUI

varoldTime:string:=""

varbutton:int

procedureNullHandler

varnewTime:string:=Time.Date

newTime:=newTime(11..*)

ifnewTimenot=oldTimethen

Text.Locate(maxrow,maxcol9)

putnewTime..

oldTime:=newTime

endNullHandler

GUI.SetNullEventHandler(NullHandler)

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetNullEventHandler,notbycallingSetNullEventHandler

GUI.SetPosition PartofGUImodule

Syntax GUI.SetPosition(widgetID,x,y:int)

Description

MovesawidgetspecifiedbywidgetIDtothelocation(x,y).Ifthewidgetisvisible,itismovedimmediatelytothenewlocation.Ifthewidgetishidden,itwillappearatthenewlocationwhentheShowprocedureiscalled.NotethatthexandyspecifiedherearethesameasintheCreatemethod.Forexample,ifyouhadspecifiedacheckboxtoberightjustifiedintheCreateCheckBoxFullfunction,then(x,y)inacalltoSetPositionwouldspecifythelower-rightcornerasopposedtothelower-leftcorner.

Example

Thefollowingprogrammovesthebuttoneverytimethebuttonispressed.

varbutton:int

procedureMoveButton

varnewX,newY:int

newX:=Rand.Int(0,maxxGUI.GetWidth(button

newY:=Rand.Int(0,maxyGUI.GetHeight(button

GUI.SetPosition(button,newX,newY)

endMoveButton

button:=GUI.CreateButton(100,100,0,"MoveButton",

MoveButton)

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetPosition,notbycallingSetPosition.

GUI.SetPositionAndSize PartofGUImodule

SyntaxGUI.SetPositionAndSize(widgetID,x,y:int,width,height:int)

Description

ChangesthepositionandsizeofthewidgetspecifiedbywidgetIDsimultaneously.Thex,y,widthandheightparametershavethesamemeaningasintheGUI.Createfunctionforthatwidget.Anywidgetexceptamenuoramenuitemcanberesized,althoughforsomewidgets,thewidthorheightparametermaybeignored.

GUI.SetPositionAndSizeworksthesamewayastheGUI.SetPositionandGUI.SetSizeprocedures.

Example

Thefollowingprogrammovesandresizesthebuttoneverytimethebuttonispressed.

varbutton,minWidth,minHeight:int

procedureMoveButton

varnewX,newY,newWidth,newHeight:int

newWidth:=max(minWidth,Rand.Int(0,200))

newHeight:=max(minHeight,Rand.Int(0,100))

newX:=Rand.Int(0,maxxnewWidth)

newY:=Rand.Int(0,maxynewHeight)

GUI.SetPositionAndSize(button,newX,newY,

newWidth,newHeight)

endMoveButton

button:=GUI.CreateButton(100,100,0,"MoveButton",

MoveButton)

minHeight:=GUI.GetHeight(button)

minWidth:=GUI.GetWidth(button)

endloop

Status

Exportedqualified.

GUI.SetPositionAndSize,notbycallingSetPositionAndSize.

GUI.SetScrollAmount PartofGUImodule

SyntaxGUI.SetScrollAmount(widgetID:int,arrowInc,pageInc,thumbSize:int)

Description

Setsascrollbar'sarrowincrement,pageincrementandthumbsize.Redrawsthescrollbartotakeintoaccountthenewthumbsize.ThewidgetIDspecifiesthescrollbartobechanged.ThearrowIncparameteristhenewarrowincrement(theamountthescrollbar'svalueischangedwhenthescrollarrowsarepressed).Avalueof1meanstousethepreviously-definedarrowincrementvalue.ThepageIncparameterspecifiesthenewpageincrement(theamountthescrollbar'svalueischangedwhentheuserclicksinthepageup/downsectionofthescrollbar).Avalueof1meanstousethepreviously-definedpageincrementvalue.Thespecifieshenewthumbsize.Seethescrollbarexplanationformoredetailonascrollbar'sthumbsize.Avalueof1meanstousethepreviously-definedthumbsize.

Thefollowingprogramdisplaysanimageinacanvasinawindow.Iftheimageislargerthanthecanvas,scrollbarstothebottomandleftareusedtoallowtheusertoseetheentireimage.Atextfieldallowsuserstoloadadditionalimageswheneverthe"LoadFile"buttonispressed.

%The"ScrollPic2"program.

%Themaximumwidth/heightofthecanvas.

constmaxSize:int:=220

constleftBorder:int:=15%Leftmargin.

constbottomBorder:int:=25%Bottommargin.

varh,v:int%Thescrollbars.

varcanvas:int%Thecanvas.

varpic:int%Thepicture.

varfileNameField:int%Thefilenametextfield.

varerrorLabel:int%Theerrormessagelabel.

varloadButton:int%The"LoadPicture"button.

procedureScrollPic(ignore:int)

%Getthecurrentvalueofthescrollbars.

varx:int:=GUI.GetSliderValue(h)

vary:int:=GUI.GetSliderValue(v)

GUI.PicDraw(canvas,pic,x,y,picCopy)

endScrollPic

procedureLoadFile(fileName:string)

varpicWidth,picHeight,canvasWidth,canvasHeight

varnewPic:int:=Pic.FileNew(fileName)

ifnewPic<=0then

GUI.SetLabel(errorLabel,

Example

"Errorloadingpicture:"+Error.LastMsg

GUI.SetSelection(fileNameField,1,1)

return

GUI.SetLabel(errorLabel,"")

pic:=newPic

picWidth:=Pic.GetWidth(pic)

picHeight:=Pic.GetHeight(pic)

canvasWidth:=min(picWidth,maxSize)

canvasHeight:=min(picHeight,maxSize)

%Hidethecanvasandthethreeitems,readjustthem

%andthenshowthem.

GUI.Hide(canvas)

GUI.Hide(h)

GUI.Hide(v)

GUI.SetSize(canvas,canvasWidth,canvasHeight

GUI.SetSliderSize(h,canvasWidth+1)

GUI.SetPosition(v,15+canvasWidth,

bottomBorder+GUI.GetScrollBarWidth-1)

GUI.SetSliderSize(v,canvasHeight+1)

GUI.SetSliderMinMax(h,0,picWidth1)

GUI.SetSliderMinMax(v,0,picHeight1)

GUI.SetScrollAmount(h,3,100,canvasWidth)

GUI.SetScrollAmount(v,3,100,canvasHeight

GUI.SetSliderValue(h,0)

GUI.SetSliderValue(v,picHeight)

GUI.Show(canvas)

GUI.Show(h)

GUI.Show(v)

ScrollPic(0)

endLoadFile

procedureLoadFileButton

varfileName:string:=GUI.GetText(fileNameField

LoadFile(fileName)

endLoadFileButton

%Weplacethecanvasfirstandeverythingelseisplaced

%relativetothecanvas.

canvas:=GUI.CreateCanvas(leftBorder,

bottomBorder+GUI.GetScrollBarWidth,maxSize

GUI.GetY(canvas)GUI.GetScrollBarWidth,

GUI.GetWidth(canvas),0,100,0,ScrollPic,3,100,

v:=GUI.CreateVerticalScrollBarFull(

GUI.GetX(canvas)+GUI.GetWidth(canvas),

GUI.GetY(canvas),GUI.GetHeight(canvas),0,100,

100,ScrollPic,3,100,maxSize)

fileNameField:=GUI.CreateTextField(GUI.GetX(

GUI.GetY(canvas)+GUI.GetHeight(canvas)+10,150,"",

LoadFile)

loadButton:=GUI.CreateButton(GUI.GetX(fileNameField

GUI.GetWidth(fileNameField)+20,

GUI.GetY(fileNameField),0,"LoadFile",LoadFileButton

errorLabel:=GUI.CreateLabel(GUI.GetX(canvas),5,"")

%Settheinitialpictureandreturnifitisnotfound.

GUI.SetText(fileNameField,"Forest.bmp")

LoadFileButton

ifpic=0then

return

endloop

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetScrollAmount

Seealso GUI.CreateHorizontalScrollBarandGUI.CreateVerticalScrollBar

GUI.SetScrollOnAdd PartofGUImodule

Syntax GUI.SetScrollOnAdd(widgetID:int,scrollOnAdd:boolean

Description

TheGUI.SetScrollOnAddprocedureallowsyoutospecifywhetheratextboxscrollstothebottomofthetextwhennewtextisadded(thedefaultbehaviour).BycallingthisprocedurewithscrollOnAddsettofalse,thetextboxwillnotscrollunlesstheusermanipulatesthetextbox'sscrollbars.

Example

Thisprogramdisplaysthecontentsofafileinatextbox.Afterthefileisdisplayed,thetoplineinthetextboxwillbethefirstlineinthefile.

importGUI

constfileNameToBeViewed:string:="TextBxs.DEM"

vartitle:int%Thelabelforthetitle.

varf:int%Thestreamnumberofthefile.

varline:string%Linestobereadfromthefile.

%Openthefile.

open:f,fileNameToBeViewed,get

iff=0then

put"Unabletoopen"+fileNameToBeViewed+":",

return

%Setbackgroundcolortograyforindentedtextbox.

%Createthetitlelabelandtextbox.

title:=GUI.CreateLabelFull(20,280,fileNameToBeViewed

GUI.CENTER,0)

GUI.INDENT,0)

GUI.SetScrollOnAdd(textBox,false)

exitwheneof(f)

get:f,line:*

GUI.AddLine(textBox,line)

endloop

close:f%Closethefile.

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetScrollOnAdd,notbycallingSetScrollOnAdd.

GUI.SetSelection PartofGUImodule

Syntax GUI.SetSelection(widgetID,fromSel,toSel:int)

Description

SetstheselectedtextinthetextfieldspecifiedbywidgetID.ThevalueofthefromSelandtoSelparametersindicatethecharacterswheretheselectionwillbeginandend.Forexample,ifthetextwas"Hellothere",settingfromSelto2andtoSelto5wouldselect"ell".SettingfromSelandtoSelautomaticallyselectstheentiretext.

ThefromSelparameterspecifiesthestartoftheselection.Thisrangesfrom1(beforethefirstcharacter)tothenumberofcharactersinthetext+1(afterthelastcharacter).Avalueof1forbothfromSelandtoSelselectstheentiretext.

ThetoSelparameterspecifiestheendoftheselection.Thisrangesfrom1(beforethefirstcharacter)tothenumberofcharactersinthetext+1(afterthelastcharacter).Avalueof1forbothfromSelandtoSelselectstheentiretext.

Example

Thefollowingprogramallowstheusertotypeintoatextfield.WhentheuserpressesENTER,itsearchesforanynon-lowercasetextandifitfindsany,selectsittomakeiteasyfortheusertocorrectit.Ifalltheinputislower-casetext,theprogramterminates.

vartextField,lbl:int

procedureCheckInput(s:string)

fori:1..length(s)

if(s(i)<'a'or'z'<s(i))ands(i

GUI.SetSelection(textField,i,i+1)

return

endfor

GUI.Quit

endCheckInput

textField:=GUI.CreateTextField(100,100,200,"",

lbl:=GUI.CreateLabelFull(100+GUI.GetWidth(

100+GUI.GetHeight(textField),

"OnlyAllowsLowerCaseLetters",0,0,

GUI.CENTER+GUI.BOTTOM,0)

endloop

GUI.SetLabel(lbl,"ProgramFinished!")

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetSelectionnotbycallingSetSelection.

GUI.SetSize PartofGUImodule

Syntax GUI.SetSize(widgetID,width,height:int)

Description

ChangesthesizeofthewidgetspecifiedbywidgetID.Ifthewidgetisvisible,itssizeischangedimmediately,otherwisethewidgetwillappearinitsnewsizewhenthewidgetisnextmadevisible.Notethatthewidthandheightparametersarenonecessarilytheactualwidthandheightofthewidget.Forexample,theTextFieldwidgetignorestheheightparameter,calculatingthewidget'sactualheightfromtheheightofthetextintheTextField.

Example

Thefollowingprogramresizesthebuttoneverytimethebuttonispressed.

varbutton:int

procedureResizeButton

varnewWidth,newHeight:int

newWidth:=Rand.Int(0,200)

newHeight:=Rand.Int(0,200)

GUI.SetSize(button,newWidth,newHeight)

endResizeButton

button:=GUI.CreateButton(100,100,0,"ResizeButton",

ResizeButton)

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetSize,notbycallingSetSize.

GUI.SetSliderMinMax PartofGUImodule

Syntax GUI.SetSliderMinMax(widgetID,min,max:int)

Description

SetstheminimumandmaximumvaluesofthesliderorscrollbarspecifiedbywidgetID.Theminparameterspecifiesthenewminimumvalueofthesliderorscrollbar.Themaxparameterspecifiesthenewmaximumvalueofthesliderorscrollbar.Themaxparametermustbegreaterthantheminparameter.

GUI.SetSliderMinMaxredrawsthethumbtotakeintoaccountthenewminimumandmaximum.Ifthecurrentvalueofthesliderisoutsidethenewminimum/maximum,thenthevalueisadjustedappropriately.

ExampleSeeGUI.SetScrollAmountforanexampleofGUI.SetSliderMinMax.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetSliderMinMax,notbycallingSetSliderMinMax.

Seealso

GUI.CreateHorizontalScrollBar,GUI.CreateVerticalScrollBar,GUI.CreateHorizontalSlider,andGUI.CreateVerticalSlider.

GUI.SetSliderReverse PartofGUImodule

Syntax GUI.SetSliderReverse(widgetID:int)

Description

SetsasliderorscrollbarspecifiedbywidgetIDinto(oroutof,ifalreadyinto)"reversemode".Normally,asliderorscrollbarisatitsminimumvaluewhenthethumbisonthelefthandside(bottomforaverticalslider).Thisreversesit,sotheminimumvalueiswhenthethumbisattherighthandside(topforverticalsliders)ofthetrack.Callingthisroutineasecondtimereversesitbacktonormal.Thisprocedureredrawstheslidertomovethethumbtoitsnewlocation.

Example

Thefollowingprogramcreatestwosliders,oneofwhichisreversed.

varsBar,sBarLabel,reverseSBar,reverseSBarLabel

procedureSBarMoved(value:int)

GUI.SetLabel(sBarLabel,intstr(value))

endSBarMoved

procedureReverseSBarMoved(value:int)

GUI.SetLabel(reverseSBarLabel,intstr(value

endReverseSBarMoved

sBar:=GUI.CreateHorizontalScrollBar(10,10,250,

50,150,50,SBarMoved)

sBarLabel:=GUI.CreateLabel(

GUI.GetX(sBar)+GUI.GetWidth(sBar)+10,10,"50")

reverseSBar:=GUI.CreateHorizontalScrollBar(10,40,250,

50,150,50,ReverseSBarMoved)

GUI.SetSliderReverse(reverseSBar)

reverseSBarLabel:=GUI.CreateLabel(GUI.GetX(

GUI.GetWidth(reverseSBar)+10,40,"50")

endloop

Status

Exportedqualified.

GUI.SetSliderReverse,notbycallingSetSliderReverse.

SeealsoGUI.CreateHorizontalScrollBar,GUI.CreateVerticalScrollBar,GUI.CreateHorizontalSlider,andGUI.CreateVerticalSlider.

GUI.SetSliderSize PartofGUImodule

Syntax GUI.SetSliderSize(widgetID,length:int)

Description

ChangesthelengthofasliderorscrollbarspecifiedbywidgetIDtothevaluespecifiedbythelengthparameter.Redrawsthesliderorscrollbarandchangesthepositionofthethumbtotakeintoaccountthenewsizeofthesliderorscrollbar.

ExampleSeeGUI.SetScrollAmountforanexampleofGUI.SetSliderSize.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetSliderSize,notbycallingSetSliderSize.

Seealso

GUI.CreateHorizontalScrollBar,GUI.CreateVerticalScrollBar,GUI.CreateHorizontalSlider,andGUI.CreateVerticalSlider.

GUI.SetSliderValue PartofGUImodule

Syntax GUI.SetSliderValue(widgetID,value:int)

Description

SetsthevalueofasliderorscrollbarspecifiedbywidgetIDtovalue.Itmovesthethumbonthesliderorscrollbartotheappropriatelocationandcallstheslider'sactionprocedurewiththenewvalue.

ExampleSeeGUI.SetScrollAmountforanexampleofGUI.SetSliderValue.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetSliderValue,notbycallingSetSliderValue.

Seealso

GUI.GetSliderValueforreadingasliderorscrollbar'svalue.SeealsoGUI.CreateHorizontalScrollBar,GUI.CreateVerticalScrollBar,GUI.CreateHorizontalSlider,andGUI.CreateVerticalSlider.

GUI.SetText PartofGUImodule

Syntax GUI.SetText(widgetID:int,text:string)

DescriptionSetsthetextofatextfieldspecifiedbywidgetIDtotext.Theselectionissetto1,1(i.e.thecursorisatthebeginningofthetext).

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetTextbycallingSetText.

Example

ThefollowingprogramconvertsalllowercaseinputinthetextfieldtouppercasewhentheuserpressesENTER.

importGUI

vartextField,lbl:int

procedureCheckInput(s:string)

varnewString:string:=""

fori:1..length(s)

if'a'<=s(i)ands(i)<='z'then

newString+=chr(ord(s(i))32)

newString+=s(i)

endfor

GUI.SetText(textField,newString)

GUI.SetSelection(textField,1,1)

endCheckInput

textField:=GUI.CreateTextField(100,100,200,"",

lbl:=GUI.CreateLabelFull(100+GUI.GetWidth(

100+GUI.GetHeight(textField),"ConvertstoUpperCase",

0,0,GUI.CENTER+GUI.BOTTOM,0)

endloop

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetTextbycallingSetText.

GUI.SetTopLine PartofGUImodule

Syntax GUI.SetTopLine(widgetID:int,lineNum:int)

Description

TheGUI.SetTopLineprocedurescrollsthetextinatextboxsoastoplacethelinenumberspecifiedbylineNumatthetopofthetextbox(ifpossible).Thisisoftenusedtoscrollthetextbacktothebeginningofthetextboxbyassigningavalueof1tolineNum.

Example

Thisprogramdisplays100linesoftextinatextbox,thensetsthetextboxtodisplayline50atthetopofthebox.

importGUI

GUI.INDENT,0)

fori:1..100

GUI.AddLine(textBox,intstr(i))

endfor

GUI.SetTopLine(textBox,50)

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetTopLine,notbycallingSetTopLine.

GUI.SetXOR PartofGUImodule

Syntax GUI.SetXOR(widgetID:int,xor:boolean)

Description

Setsthe"xormode"ofthecanvasspecifiedbywidgetID.Ifthexorparmeterissettotrue,thecanvasissettoxormode.Wheninxormode,alltheDraw...proceduresofacanvasaretreatedasiftheView.Set("xor")statementhadbeenexecutedbeforetheDrawprocedure.

Example

SeeGUI.SetDisplayWhenCreatedforanexampleofGUI.Show.

varcanvas1,label1,canvas2,label2:int

canvas1:=GUI.CreateCanvas(10,20,maxxdiv220,

label1:=GUI.CreateLabelFull(10,2,"XOR",maxx

GUI.CENTER,0)

canvas2:=GUI.CreateCanvas(maxxdiv2+10,20,

maxxdiv220,maxy30)

label2:=GUI.CreateLabelFull(maxxdiv2+10,2,"Normal",

maxxdiv220,0,GUI.CENTER,0)

GUI.SetXOR(canvas1,true)

fori:1..20

varx:int:=Rand.Int(0,maxxdiv220)

vary:int:=Rand.Int(0,maxy20)

varc:int:=Rand.Int(1,15)

GUI.DrawFillStar(canvas1,x20,y20,x+20,

endfor

GUI.SetXOR(canvas2,false)

fori:1..20

varx:int:=Rand.Int(0,maxxdiv220)

vary:int:=Rand.Int(0,maxy20)

varc:int:=Rand.Int(1,15)

GUI.DrawFillStar(canvas2,x20,y20,x+20,

endfor

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.SetXOR,notbycallingSetXOR.

GUI.Show PartofGUImodule

Syntax GUI.Show(widgetID:int)

Description

ShowsawidgetspecifiedbywidgetID.UsedinconjunctionwithGUI.Hidetoshowandhidewidgets.Hiddenwidgetscannotgetevents(i.e.respondtokeystrokesormouseclicks).Ifanactivetextfield(seetextfield)ishidden,thenanykeystrokesinthewindowwillbeignored.

Inmostcaseswhereawidgetistoappear,thendisappear,thenappearagain,itisadvisedtocreatethewidgetonceandhideituntilitistoappear,whereuponGUI.Showiscalled.Whentheuserisfinishedwiththewidget,thewidgetishiddenusingGUI.Hide.Thissavestheoverheadofcreatinganddisposingofthesamewidgetseveraltimes.

ExampleSeeGUI.SetDisplayWhenCreatedforanexampleofGUI.Show.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.Show,notbycallingShow.

Seealso GUI.Hide.

GUI.ShowMenuBar PartofGUImodule

Syntax GUI.ShowMenuBar

Description Showsthemenubarintheselectedwindow.

ExampleSeeGUI.SetMouseEventHandlerforanexampleofGUI.HideMenuBar.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.ShowMenuBar,notbycallingShowMenuBar.

Seealso GUI.HideMenuBar.SeealsoGUI.CreateMenu.

GUI.ShowWindow PartofGUImodule

Syntax GUI.ShowWindow(window:int)

Description

Hidesawindowwithwidgetsinit.ThisproceduremakescertainthattheGUILibraryrecognizesthatthewindownolongervisible.ThisprocedurewillcallWindow.Hide,sothereisnoneedfortheusertodoso.

Example

importGUI

varwindowA,windowB:int

varbuttonA,buttonB,buttonQuit:int

varbackToMainA,backToMainB:int

procedureShowWindowA

GUI.ShowWindow(windowA)

endShowWindowA

procedureShowWindowB

GUI.ShowWindow(windowB)

endShowWindowB

procedureShowMain

GUI.HideWindow(Window.GetActive)

GUI.ShowWindow(defWinID)

endShowMain

%Placethebuttonsinthemainwindow

buttonA:=GUI.CreateButton(10,10,0,"ShowWindowA",

buttonB:=GUI.CreateButton(150,10,0,"ShowWindowB",

buttonQuit:=GUI.CreateButton(100,60,0,"Quit",

windowA:=Window.Open("title:WindowA,graphics:150;100,position:bottom;left")

backToMainA:=GUI.CreateButton(20,20,0,"BacktoMain",

Window.Hide(windowA)

windowB:=Window.Open("title:WindowB,graphics:150;100,position:bottom;right")

backToMainB:=GUI.CreateButton(20,20,0,"BacktoMain",

Window.Hide(windowB)

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingGUI.ShowWindowbycallingShowWindow.

SeealsoGUI.HideWindowforhidingawindowwithwidgetsinit.SeealsoGUI.CloseWindowforclosingawindowwithwidgetsinit.

handler exceptionhandler

Syntax

AexceptionHandleris:

handler(id) statementsAndDeclarations endhandler

Description

Anexceptionhandlerisanoptionalblockofstatementsanddeclarationsinasubprogram(orprocess).Itisactivatedwhentheprogram(orprocess)fails.Thisoccurs,forexamplewhendividingbyzero.

Example

Thisprogramparsestheinputstreamusingastack.Ifthestackoverflows(itstopexceedsitsmaximum),aquitstatementinthepushprocedureabortstheparsingandgivescontroltotheexceptionhandlerintheparseprocedure.TheparseprocedurecallsparseExpnwhichcallspush.Ifpushoverflowsthestack,itexecutesaquitandcontrolispassedtotheexceptionhandlerintheparseprocedure.Theinterruptedprocedures(parseExpnandpush)areterminatedandtheirlocalvariablesaredeleted.

conststackOverflow:=500

constmaxTop:=100

vartop:0..maxTop:=0

varstack:array1..maxTopofint

procedurepush(i:int)

iftop=maxTopthen

quit:stackOverflow

top:=top+1

stack(top):=i

endpush

procedureparse

handler(exceptionNumber)

put"Failurenumber",exceptionNumber

caseexceptionNumberof

labelstackOverflow:

put"Stackhasoverflowed!!"

…otherexceptionshandledhere…

label:%Unexpectedfailures

quit>%Passexceptionfurther

endcase

endhandler

parseExpn%Eventuallypushiscalled

endparse

SeethequitstatementforanexplanationofitsquitReason(stackOverflowinthefirstquitstatementabove)anditsguiltyParty(>inthesecondquitstatement,meaningtheexceptionisduetocausesoutsideofthishandler).

Anexceptionhandlercanappearonlyinthebodyofasubprogram(orprocess),justprecedingthedeclarationsandstatements.Theformofaprocedureis:

procedure[pervasive]id

[import[[var]id{,[var]id}]]

[pretrueFalseExpn]

[posttrueFalseExpn]

[exceptionHandler]

Exactlythesamedeclarationsandstatementscanappearinahandlerascanappearinthesubprogrambodyfollowingthehandler.Intheabsenceofexceptions,handlershavenoobservableeffect.Aparticularhandlerisactivated(itbecomesreadytohandleanexception)whenitisencounteredduringexecution.Itremainsactiveuntilthesubprogram(orprocess)containingithascompleted,orthehandlerisgivencontrol.Activationofahandlerwhenaprevioushandlerisalreadyactivewillcauseexceptionstobepassedtothenewly-activatedhandler.Inotherwords,handlershaveadynamicscopethatbeginswhentheexceptionhandlerisencounteredandendswhenthesubprogram(orprocess)containingthehandlerhasterminatedorthehandlerisgivencontrol.

Details

Whenahandlerisgivencontrol,itbecomes,ineffect,areplacementforthedeclarationsandstatementsfollowingit.Ifthehandlerisinafunction,itmustterminatewitharesultstatementorwithaquit.Ifthehandlerisinaprocedure(orprocess),thehandlermustterminatewithareturn,aquit,orbyencounteringtheendofthehandler(whichisequivalenttoareturn).

Whenahandlerterminateswitharesultorreturnstatement(orbyreachingtheendofaprocedure'shandler),thesubprogram'spostcondition(ifany)mustbetrue.Aquitstatementdoesnotneedtoestablishthepostcondition.

Programmingwithexceptionhandlerseasilyleadstoincomprehensiblesoftware,duetothedifficultyofkeepingtrackoftheflowofcontrol.Oneofthemostinsidioussituationsiswhenanexceptionoccursinamodule,classormonitorandispropagatedoutsideoftheunit.Thiscanleavethecontaineddatainaninconsistentstate;inthecaseofamonitor,itisleftlockedforever.Toavoidthispossibility,youcanuseahandlerineachexportedsubprogram.Ifanexceptioninaprocessisnothandled,theentireprogramisaborted.Ifanimplementationallocatesdynamicarraysontheheap,anexceptionmaypreventthedeallocationofsuchanarray.

Withoutexceptionhandling,aprogramexecutesaccordingtothelanguagedefinitionorelseisaborted.Ifanexceptionhandlerisactive,insteadofaborting,controlisgiventothehandler.ThequitNumberforasystem-detectedfailureisimplementation-dependent.Thereisafile"%exceptions"whichliststhesenumbers.Theuserprogramcansimulateasystemexceptionbydoingaquitwiththecorrespondingnumber.

Iftheuserturnsoffcheckingexplicitly,thesystemmaynotdetectfailures.Insomecasesthefailuremayyieldincorrectdataorarbitrarybehavior.

Someexceptionsareunpredictableorimplementation-dependent.Forexample,inx:=24divi+24/i,ifiiszero,theexception

couldbeeitheranintegerorarealdivisionbyzero,becausetheorderorevaluationisimplementation-dependent.

hasch hascharacterfunction

Syntax hasch:boolean

DescriptionThehaschprocedureisusedtodetermineifthereisacharacterthathasbeentypedbutnotyetbeenread.

Example

Thisprogramsimulatestherollingofapairofdiceuntiltheuserpressedthekeyboard.

put"Pressanykeytostopthedicerolling"

vardie1,die2:int

varch:string(1)

exitwhenhasch

randint(die1,1,6)

randint(die2,1,6)

locate(1,1)

put"Yourolled",die1+die2

endloop

getch(ch)%Discardthecharacter

Execute

Details

Thescreenshouldbeina"graphics"mode.Seethesetscreenprocedurefordetails.Ifthescreenisnotin"graphics"mode,itwillautomaticallybesetto"graphics"mode.

Ifthereisthepossibilitythattherearealreadykeystrokesinthekeyboardbuffer,theInput.Flushcommandcanbeusedtoflushthekeyboardbuffer(removeallkeystrokesfromthebuffer)beforeenteringthelooptocheckforinput.

getchandgetchar.

SeealsoSeealsotheInput.Flushcommandforflushingthekeyboardbuffer.

id (identifier)nameofaniteminaprogram

Description

Variables,constants,types,procedures,etc.inTuringprogramsaregivennamessuchasincomeTax,x,andheight.Thesenamesarecalledidentifiers(ids).

Anidentifiermuststartwithaletter(largeorsmall)oranunderscore(_)andcancontainupto50characters,eachofwhichmustbealetter,adigit(0to9)oranunderscore(_).Largeandsmalllettersareconsidereddistinct,sothatAandaaredifferentnames.ThisdiffersfromPascalwherelargeandsmalllettersinnamesareequivalent.

Everycharacterinanameissignificantindistinguishingonenamefromanother.

Byconvention,wordsthatmakeupanidentifierarecapitalized(exceptthefirstone),asinincomeTaxandjustInTime.

AniteminaTuringprogramcannotbegiventhesamenameasakeywordsuchasgetorasareservedwordsuchasindex.SeeAppendixAforalistofkeywordsandreservedwords.Aswell,therearesomeidentifiersthatareusedbytheTuringerrorrecoveryproceduresandarethusunavailableforuseasidentifiers.Specifically,theyare:endif,elseif,endloopandendfor.

#if usedforconditionalcompilation

Syntax

Aconditionalcompilation#ifhastheform:

#ifexpnthen …anysourcetext… {#elsifexpnthen …anysourcetext…} [#else …anysourcetext…] #endif

Description

An#ifconstructsupportscompiletimeselectionofsectionsofsourcetexttomakeupaprogram(orunitofaprogram),inotherwordsconditionalcompilation.Anyarbitrarysourcetext(characters)canbeselected.

Eachoftheselectingexpressions(expns)havetheformofabooleanexpression,withtheuseoftheoperatorsand,orandnot(butnot=>)andparentheses.Theshortforms&and~aresupported.Theoperandsoftheexpressionsmustbepreprocessorflags,whicharesetbyasystem-dependentmechanismnotdescribedhere.Aflagisconsideredtobetrueifitisexplicitlyset.Ifitisnotexplicitlyset,itisconsideredfalse.

Unlikeotherpartsofthelanguage,the#if,#elsif,#elseand#endifconstructsarenotfreeformat.Specifically,theymustbeplacedbythemselvesonasingleline.

Example

Apairofdeclarationsischosenifbothstatsanddebugareset,otherwisetheputstatementisselected.Theselectedpartbecomespartoftheprogramandtheotherpartsareignored.

#ifstatsanddebugthen

varcount:array1..5ofreal

varmessage:string

put"Debuggingmessage"

#endif

if statement

Syntax

AnifStatementis:

iftrueFalseExpnthen statementsAndDeclarations {elsiftrueFalseExpnthen statementsAndDeclarations} [else statementsAndDeclarations] endif

Description

Anifstatementisusedtochooseamongasetofstatements(anddeclarations).Oneset(atmost)ischosenandexecutedandthenexecutioncontinuesjustbeyondendif.

Theexpressions(thetrueFalseExpressions)followingthekeywordifandeachelsifarecheckedoneaftertheotheruntiloneofthemisfoundtobetrue,inwhichcasethestatements(anddeclarations)followingthecorrespondingthenareexecuted.Ifnoneoftheseexpressionsevaluatestotrue,thestatementsfollowingelseareexecuted.Ifnoelseispresentandnoneoftheexpressionsaretrue,nostatementsareexecutedandexecutioncontinuesfollowingtheendif.

Example

Outputamessagebasedonvalueofmark.

ifmark>=50then

put"Youpass"

put"Youfail"

OutputA,B,C,DorFdependingonmark.

ifmark>=80then

put"A"

elsifmark>=70then

Exampleput"B"

elsifmark>=60then

put"C"

elsifmark>=50then

put"D"

put"F"

Example

Ifxisnegative,changeitssign.

ifx<0then

Example

Ifxislessthanzeroorgreaterthanmaxx,putamessage.

ifx<0orx>maxxthen

put"Outofbounds!"

Example

Ifthebooleanflagistrueandnameis“stop”,putamessageandreturn.

ifflagandname="stop"then

put"Exitingroutine"

return

DetailsSeveralstatementsanddeclarationscanappearafteraparticularthen.

Seealso casestatementsforanotherwaytoselectamongstatements.

implementby clause

Syntax

AnimplementByClauseis:

implementbyimplementByItem

Description

Animplement-byclauseisusedtospecifythatamodule,monitororclassCistobeautomaticallyimplementedbytheimplementByItem.CiscalledtheinterfaceandtheimplementByItem,whichmustcontainanimplementclause,iscalledtheimplementation.Seeimplementclausefordetailsandanexample.

Theimplement-byclausecanonlybeusedinaunit.Seeunitforthedefinitionofaunit.

AnimplementByItemisoneof:

(a) id (b) idinfileName

Thesecondformisusedwhentheimplement-byclauseisforaseparateunitandtheimporteditemisinafilewhosenameisdifferentfromtheitem'sname,asin:

implementbyledgerBodyin"ledgbod.t"

ThefileNamemustbeanexplicitcharacterstring,e.g.,"ledgbod.t".Seealsounit.Parenthesesareallowedaroundtheitemsinanimplement-byclauses,asin:

implementby(ledgerBodyin"ledgbod.t")

implement clause

Syntax

AnimplementClauseis:

implementimplementItem

Description

Animplementclauseisusedtospecifythatthemodule,monitororclasscontainingtheclauseistobetheimplementationofanothermodule,monitororclass.Thisimplementationisaspecialkindofexpansion.Themodule,monitororclasscontainingtheclausegainsaccessto(inherits)allthedeclarationsinsidethetargetitem.Seeinheritclauseforrulesaboutexpansions,whicharealsorulesforimplementations.

Theimplementclausecanonlybeusedinaunit.Seeunitforthedefinitionofaunit.

Example

Hereisastackmodulewhichdefersallofitsexportedsubprograms.Thismoduleisaninterfacebutnotanimplementation.FollowingstackisthestackBodymodulethatimplementsthestackmodule,givingthebodiesforstack'ssubprograms.Anycalltostack'spushorpopprocedures,suchasstack.push("Ed"),willactuallycalltheproceduresgiveninstackBody.

modulestack%Interface

implementbystackBody

%stackBodyhasimplementation

exportpush,pop

deferredprocedurepush(s:string)

deferredprocedurepop(vars:string)

endstack

Nextcomestheexpansionwhichgivesthebodiesforthedeferredprocedurespushandpop.ThestackBodybodyalsoaddsdeclarationsforthetopandcontentsvariables.

modulestackBody%Implementation

implementstack%stackhasinterface

vartop:int:=0

bodyprocedurepush%(s:string)

top:=top+1

contents(top):=s

endpush

bodyprocedurepop%(vars:string)

s:=contents(top)

top:=top-1

endpop

endstackBody

Details

Module,monitororclassDcanbeinC'simplement-byclauseif,andonlyif,CisinD'simplementclause.Inotherwords,aninterfacemustapplytoexactlyoneimplementationandviceversa.Amodulecanimplementonlyamodule,amonitoronlyamonitor,andaclassonlyaclass.Classes(butnotmodulesandmonitors)cancontaininheritclauses.Aclasscannotcontainbothaninheritandanimplementclause.

AnimplementItemisoneof:

(b)idinfileName

Thesecondformisusedwhentheimplementclauseisforaseparateunitandtheimporteditemisinafilewhosenameisdifferentfromtheitem'sname,asin:

implementledgerin"ledg.t"

ThefileNamemustbeanexplicitcharacterstring,e.g.,"ledg.t".Seealsounit.Parenthesesareallowedaroundtheitemsinimplementclauses,asin:

implement(ledgerin"ledg.t")

Thereisnorestrictiononthedeclarationsthataninterfacemaycontain.Inparticular,aninterface(anymodule,monitororclasscontaininganimplement-byclause),cancontainsubprogrambodiesandvariabledeclarations,exactlyasisthecaseinexpansions.ThisisdifferentfromlanguagessuchasC++inwhichtherearestrictruleslimitingwhatyoucanputinaninterface.

EventhoughDcontainsanimplementclause,Dcanalsocontainanimplement-byclause,whichimpliesfurtherimplementationbyfurtherautomaticexpansion.

SupposeclassDisinclassC'simplement-byclauseandthatpisapointertoclassC:

varp:^C

EventhoughCisimplementedbyD,premainsapointertoclassC.EachcreationofanobjectofclassCactuallycreatesanobjectoftypeD,forexample:

newp%CreatesobjectofclassD

ClassD,whichimplementsC,couldalsohaveanimplement-byclause,whichcausesitsimplementationtobeautomaticallycreatedandsoon.IfanotherclassEinheritsC,thisexpansiondoesnotincludeD.

IfthenewstatementcontainsanexplicitclassnameEthatisadescendantofC(butnotactuallyC),asin

newE,p

theobjectoftheexplicitclassiscreated.IfEhasanimplement-byclause,theexpansioniscreated.

Seealsounit,module,monitorandclass.Seealsoimplementbyclause,inheritclause,exportlist,andimportlist.Seealsodeferredsubprograms.

import list

Syntax

AnimportListis:

import[howImport]importItem {,[howImport]importItem}

Description

Animportlistisusedtospecifythoseitemsthataprocedure,function,module,monitor,oraclassusesfromoutsideofitself.Notethatafunctionorprocedureisnotallowedtohaveanimportlistandthusautomaticallyimportswhicheverfunctionsorproceduresareusedbythefunctionorprocedure.Thecompilerdeterminesthelistautomaticallybylookingtoseewhatitemsareactuallyused.

Example

Inthisexample,thetypeTisimportedintothestackmoduleandusedasthetypethatcanbepushedontoorpoppedoffthestack.Sincenootheritemsareimported,theonlyidentifiersfromoutsideofstackthatcanbeusedinitmustbepredefined,suchassqrt,ordeclaredtobepervasive.

typeT:string

modulestack

importT

exportpush,pop

vartop:int:=0

varcontents:array1..100ofT

procedurepush…endpush

procedurepop…endpop

endstack

TheimportItemisoneof:

(a)id (b)idinfileName

ThesecondformisusedinOOTwhenthelististheimportlistforaseparateunit(orthemainprogram),andtheimporteditem

Details

isinafilewhosenameisdifferentfromtheitem'sname,forexample:

importledgerin"newledg.t"

ThefileNamemustbeanexplicitcharacterstring.Seealsounit.

Parenthesesareallowedaroundtheitemsinanimportlists,asin:

import(ledgerin"newledg.t")

Therearevariouswaystoimportitems,asdeterminedbyhowImport.TheformofhowImportisoneof:

(a)var (b)const (c)forward

CommonlythehowImportisomitted,whichmeansthedefaultaccessfortheitemisthesameaccessastheitemhas.Inotherwords,aread-writeitemthatisimportedwithoutahowImportisimportedread-write.Aread-onlysymbolthatisimportedwithoutahowImportisimportedread-only.

IftheimportItemisforward,theimportlistispartofaforwardprocedureorfunctiondeclarationandtheimporteditemisitselfnecessarilyaprocedureorfunction.Seeforwarddeclarationsfordetailsandanexample.

Iftheimportlistofamodule,monitororclassisomitted,theimplementationassumesthatthelistisimport(),meaningthatnoitemsareimported.Forexample,amodulemustexplicitlyimportanyglobalidentifiersthatarenotpredefinedorpervasive.

Circular(recursive)importsarenotallowed.Forexample,ifunitAimportsBthenBcannotimportA.However,circularusageofseparatelycompiledunitsispossiblebyseparatingtheunitsintointerfacesandbodiesandhavingthebodiesimporttheinterfaces.Forexample,ifCistheparentclassofD,DcanimportC,butnotviceversa.

Inanexpansion(orimplementation),theimportlistoftheexpansionaugmentstheimportlistoftheparent.

Anoverridingsubprogram(inanexpansion)ignorestheimportlistofthetargetsubprogramandusesitsownimportlist.

Turinginitializesmodulesandmonitorsinorderofimportation.Initializationbeginswiththemainprogram,whichfirstinitializesitsimportsintheordergiveninitsimportlist,andtheninitializesitself.

Seealsounit,module,monitorandclass.Seealsoexportlist,inheritclause,implementclauseandimplementbyclause.

in memberofaset

Syntax in

Description Theinoperatordeterminesifanelementisinaset.

ExampletyperankSet:setof0..10

varrankings:rankSet:=rankSet(0)%Theset

if5inrankingsthen…%Is5intherankingsset?

Description

Thenotinoperatorisexactlytheoppositeofin.Forexample,7notinrankingsmeansthesameasnot(7inrankings).

Theelementisrequiredtobeintheset'sindextype.Intheaboveexamplethisissatisfiedbecauseelement5isintheindextype0..10.

Thekeywordinisalsousedinlistssuchasimportlists.Seeimportlist.

Seealso thesettype,infixoperators,andprecedenceofoperators.

include sourcefiles

Syntax

AnincludeConstructis:

includefileName

Description

AnincludeisusedtocopypartsoffilessothattheybecomepartoftheTuringprogram.Thiscopyingistemporary,thatis,nofilesarechanged.Thefilenamemustbeanexplicitstringconstantsuchas"stdstuff".

Example

OnIBMPCcompatiblecomputers,therearearrowkeysthatproducecharactervaluessuchas200and208.Letussupposethatafilecalledarrowscontainsdefinitionsofthesevalues:

constupArrow:=200

constdownArrow:=208

constrightArrow:=205

constleftArrow:=203

Thesedefinitionscanbeincludedinanyprograminthefollowingmanner:

include"arrows"

varch:string(1)

getch(ch)%Readonecharacter

caseord(ch)of

labelupArrow:

…handleuparrow…

labeldownArrow:

…handledownarrow…

labelrightArrow:

…handlerightarrow…

labelleftArrow:

…handleleftarrow…

label:

…handleanyotherkey…

endcase

Anincludefilecanitselfcontainincludeconstructs.Thiscancontinuetoanylevel,althoughacircularpatternofincludes

Detailswouldbeamistake,asitwouldleadtoaninfinitelylongprogram.

Itiscommontosaveprocedures,functionsandmodulesinseparatefiles.Thefilesarecollectedtogetherusinginclude.

Details

Ifthefilenameintheincludestatementstartswitha"%",thenTuringsearchesthesystemdirectoryforthefile.Seetheeditorreferencefortheenvironmenttoseehowtosetthesystemdirectory.Thismethodcanbeusedtoallowthesystemadministratortoeasilysupplyasetofroutinesinafiletoalargenumberofusersbyplacingitinoneeasy-to-findlocation.

Example

Ifthesystemdirectoryissetto"C:\TURING",thentheline

include"%sorting.t"

willincludethefile"C:\TURING\SORTING.T"intheprogram.

Details

UnderOOT,thereareseveralsystemdirectoriesavailable.The"%oot"directoryisthedirectorywherealltheOOTsystemfilesarelocated.The"%home"directoryistheuser'shomedirectory.

Example

Iftheootdirectoryissetto"/usr/local/lib/oot"thentheline

include"%oot/teacher/sorting.t"

willincludethefile"/usr/local/lib/oot/teacher/sorting.t"intheprogram.

index findpatterninstringfunction

Syntax index(s,patt:string):int

DescriptionTheindexfunctionisusedtofindthepositionofpattwithinstrings.Forexample,index("chair","air")is3.

Example

Thisprogramoutputs2,because"ill"isasubstringof"willing",startingatthesecondcharacterof"willing".

varword:string:="willing"

putindex(word,"ill")

Details

Ifthepattern(patt)doesnotappearinthestring(s),indexreturns0(zero).Forexample,hereisanifstatementthatcheckstoseeifstringscontainsablank:

ifindex(s,"")not=0then…

Theindexissometimesusedtoefficientlydetermineifacharacterisoneofagivensetofcharacters.Forexample,hereisanifstatementthatcheckstoseeifch,whichisdeclaredusingvarch:string(1),isadigit:

ifindex("0123456789",ch)not=0then…

Ifastringcontainsmorethatoneoccurrenceofthepattern,theleftmostlocationisreturned.Forexample,index("pingpong","ng")returns3.

Ifpattisthenullstring,theresultis1.

indexType

Syntax

AnindexTypeisoneof:

(a) subrangeType (b) enumeratedType

(c) namedType %Whichisasubrangeorenumeratedtype

(d) char (e) boolean

Description

Anindextypedefinesarangeofvaluesthatcanbeusedasanarraysubscript,asacaseselector,asaselector(tag)forauniontype,orasthebasetypeofasettype.

Example varz:array1..9ofreal%0..9isanindextype

typesmallSet:setof0..2%0..2isanindextype

indirection operator(@)

Dangerous

Syntax targetType@(expn)

Description

Theindirectionoperator@isusedtoaccessvaluesthatlieatabsolutemachineaddressesinthecomputer'smemory.Thisisdangerousandimplementation-dependentandcancausearbitrarycorruptionofdataandprograms.

Example

Copythebytevalueatmemorylocation246intobandthensetthatmemorybytetozero.

varb:nat1%Onebytenaturalnumber

b:=nat1@(246)

nat1@(246):=0

Details

TheformoftargetTypemustbeoneof:

(a)[id.]typeId

(b)int,int1,int2orint4

(c)nat,nat1,nat2ornat4

(d)boolean

(e)char[(numberOfCharacters)]

(f)string[(maximumLength)]

(g)addressint

Inform(a)thebeginningidentifieridmustbethenameofamodule,monitororclassthatexportsthetypeId.EachofnumberOfCharactersandmaximumLengthmustbecompiletimeintegerexpressions.Thesearethesametargettypesasintypecheats.

Theindirectionoperator@takesanintegerasanaddress.Thisvaluemustfitintherangeofaddressint.Seeaddressint.Seealsopointertypesandthe^operator(whichaccessesobjectslocatedbypointers).

Seealsocheat.SeealsoexplicitIntegerConstant(whichexplainshowtowritehexadecimalconstants,whichareoftenusedforaddresses).

infix operator

Syntax

AninfixOperatorisoneof:

(a) + %Integerandrealaddition;setunion;

%stringcatenation

(b) - %Integerandrealsubtraction;setdifference

(c) * %Integerandrealmultiplication;setintersection

(d) / %Realdivision

(e) div %Truncatingintegerdivision

(f) mod %Modulo (g) rem %Remainder

(h) ** %Integerandrealexponentiation

(i) < %Lessthan (j) > %Greaterthan (k) = %Equal

(l) <= %Lessthanorequal;subset

(m) >= %Greaterthanorequal;superset

(n) not= %Notequal

(o) and %And(booleanconjunction)

(p) or %Or(booleandisjunction)

(q) => %Booleanimplication (r) in %Memberofset (s) notin %Notmemberofset (t) shr %Shiftright (u) shl %Shiftleft (v) xor %ExclusiveOR

Aninfixoperatorisplacedbetweentwovaluesoroperandstoproduceathirdvalue.Forexample,theresultof5+7is12.Insomecasesthemeaningoftheoperatorisdeterminedbyitsoperands.Forexample,in"pine"+"apple",the+operatormeansstringcatenationwhilein5+7itmeansintegeraddition.Therearealsoprefixoperators(-,+andnot),whichareplacedinfrontofasinglevalue.Seeprefixoperator.

Inexpressionswithseveraloperators,suchas3+4*5,theprecedencerulesdeterminetheorderinwhichtheoperationisdone(seeprecedenceforalistingoftheserules).Inthisexample,themultiplicationisdonebeforetheaddition,sotheexpressionisequivalentto3+(4*5).

Thenumerical(integerorreal)operatorsare+,-,*,/,div,mod,and**.Alloftheseexceptdivproducearealresultwhenatleastoneoftheiroperandsisreal.Ifbothoperandsareintegers,theresultisanintegerexceptinthecaseofrealdivision(/)whichalwaysproducesarealresultregardlessoftheoperands.

Thedivoperatorislikerealdivision(/),exceptthatitalwaysproducesanintegerresult,truncatinganyfractiontoproducethenearestintegerinthedirectionofzero.

Themodoperatoristhemoduloandtheremoperatoristheremainder.Thesignoftheresultofmodoperatoristhesameasthesignofthesecondoperand.TheremoperatoroperateslikethemodoperatorinTuring(andinmostotherlanguages).It

Descriptionproducestheremainder,whichisthedifferencebetweenrealdivision(/)andintegerdivision(div).Whenbothoperandsarepositive,thisisthemodulo.Forexample,14mod10is4.Ifoneoftheoperandsisnegative,anegativeanswermayresult,forexample,7mod2is1.Seealsotheintandrealtypes.

Thecomparisonoperators(<,>,=,<=,>=,not=)canbeappliedtonumbersaswellastoenumeratedtypes.Theycanalsobeappliedtostringstodeterminetheorderingbetweenstrings(seestringtypefordetails).Arrays,records,unionsandcollectionscannotbecompared.Booleanvalues(trueandfalse)canbecomparedonlyforequality(=andnot=);thesameappliestopointervalues.Setvaluescanbecomparedusing<=and>=,whicharethesubsetandsupersetoperators.Thenot=operatorcanbewrittenas~=.

Stringsaremanipulatedusingcatenation(+)aswellassubstringexpressions(seesubstring)andtheindexfunction(seeindex).Seealsothestringtype.

Theoperatorstocombinetrue/falsevaluesareand,or,and=>(implication),aswellasequality(=andnot=).Seealsothebooleantype.

Thesetoperatorsareunion(+),intersection(*),setdifference(-),subset(<=),superset(>=),andmembership(inandnotin).Seealsothesettype.

Theshr(shiftright),shl(shiftleft)andxor(exclusiveOR)operatorsacceptandproducenaturalnumbers.Seeshr,shl,andxor.

inherit inheritanceclause

Syntax

AninheritClauseis:

inheritinheritItem

Description

Aninheritclausespecifiesthattheclasscontainingtheclauseistobeanexpansionofanotherclass.Thisexpansioniscalledinheritance.Theclasscontainingtheclausegainsaccessto(inherits)allthedeclarationsinsidethetargetitem.Expansionsareusedtoaddnewdeclarationsandexportsandtosupportpolymorphism(overridingsubprograms).

Example

Hereisanexampleofastackclass.Followingit,weshowanotherclass,calledstackWithDepth,thatinheritsstackbyaddingafunctioncalleddepth.

classstack

exportpush,pop

vartop:int:=0

top:=top+1

contents(top):=s

endpush

s:=contents(top)

top:=top-1

endpop

endstack

Nextcomesanexpansion,whichinheritstheinternaldeclarationsofthestackclassandaddsthedepthfunction.

classstackWithDepth

inheritstack

exportdepth

functiondepth:int

resulttop

endpush

endstackWithDepth

Details

ObjectsoftheinheritedclassstackWithDeptharelikeobjectsoftheparentclassstack,exceptthereisanadditionalexportedfunctionnameddepth

AninheritItemisoneof:

(a)id (b)idinfileName

Thesecondformisusedwhentheinheritclauseisforaseparateunittheimporteditemisinafilewhosenameisdifferentfromtheitem'sname,forexample:

inheritledgerin"newledg.t"

ThefileNamemustbeanexplicitcharacterstring,e.g.,"newledg.t".Parenthesesareallowedaroundtheiteminaninheritclause,asin:

inherit(ledgerin"newledg.t")

Thereisaspecialformofinheritclause,calledanimplementclauseisusedtoseparateaninterfacefromanimplementation.Modulesandmonitors,aswellasclasses,usetheseclauses.Seeimplementclauseandimplementbyclause.

IfclassDinheritsclassC,wesaythatCistheparentandDisthechildClassBissaidtobeanancestorofclassD(andDisthedescendantifBandDarethesameclass,orifBistheparentofD,orifBistheparentoftheparentofD,etc.Wewritethisasfollows:

B<=D%BisanancestorofD

IfBisanancestorofDbutnotthesameasD,wesayBisastrictancestorofD.Wewritethisas:

B<D%BisastrictancestorofD

WealsousethenotationsD>=B,D>BandD=Bwiththeobviousmeanings.Allofthesenotationscanbeusedinaprogram.Theirmainuseisinconjunctionwithobjectclass,whichdeterminestheclassofanobjectlocatedbyapointer.Forexample,ifpisdeclaredtobeapointertoawecanwritethefollowingtoseeifpcurrentlylocatesanobjectwiththe

depthoperation:

%Doestheobjectlocatedbyphavethedepthoperation

ifstackWithDepth<=objectclass(p)then

ApointerthatlocatesanobjectcreatedasclassEcanbeassignedtoapointertoclassB,onlyifBisanancestorofE.Forexample,apointertoanobjectthatisastackWithDepthcanbeassignedtoapointertostacknotviceversa.Thepointernilcanbeassignedtoanypointervariable,butthevaluenil(C)canonlybeassignedtoapointertoanancestorofC.

Anobject(locatedbyapointer)canbeassignedtoanotherobjectonlyiftheywerecreatedasobjectsofthesameclass.However,assignmentofobjectsthataremonitorsorthatcontaindynamicarraysorcollectionsisnotallowed.

Circular(recursive)inheritsarenotallowed.Forexample,ifunitBAthenAcannotinheritB.Onlyoneitemisallowedinaninheritclause;inotherwords,Turingsupportssingleinheritancebutnotmultipleinheritance.

Seeimplementclauseforaspecialkindofexpansionthatseparatesamodule,monitororclass'interfacefromitsimplementation.Seeclassanexampleofpolymorphism,inwhichaninheritingclassoverridessubprogramsofitsparentclass.

Theinitializationofamodule,amonitororanobjectisimmediatelyprecededbytheinitializationoftheitemthatitinheritsorimplements(ifany).Correspondingly,iftheitemhasanimplementbyclause,theimplementationisinitializedimmediatelyaftertheinitializationofthecurrentitem.

WithinaclassC,withancestorB,youcanforceacalltoexportedsubprogrampusingtheformC.p(orB.p).ThiscallsthesubprogramdeclaredinC(orinBinthecaseofB.p),regardlessoftheactualclassoftheobjectandanyoverridingofp.ThisissimilartothenotationCtheC++language.ThisnotationcanonlybeusedinsideclassC.

Seealso

unit,module,monitorandclass.Seealsoexportlist,importlist,implementclause,implementbyclauseanddeferredsubprogram.See

alsoobjectclass.

init arrayinitialization

Syntax init

Description

Theinit(initialization)keywordisusedfortwodifferentpurposesinTuring.Themostcommonisforinitializingarrays,recordsandunions.Thelesscommonisforrecordingparametervaluesinsubprogramsforlateruseinpostconditions.

Example

varmensNames:array1..3ofstring:=

init("Tom","Dick","Harry")

putmensNames(2)%ThisoutputsDick

varnames:array1..2,1..3ofstring:=

init("Tom","Dick","Harry",

"Alice","Barbara","Cathy")

putnames(2,1)%ThisoutputsAlice

Details

Theorderofinitializingvaluesformulti-dimensionalarraysisbasedonvaryingtherightsubscripts(indexes)mostrapidly.Thisiscalledrowmajororder.Initializationofrecordsandunionsisanalogoustoinitializingarrays.Valuesarelistedintheorderinwhichtheyappearinthetype.Seearray,record,anduniontypes.

Example

Thisprocedureissupposedtosetintegervariableitoanintegerapproximationofitssquareroot.Theinitclauserecordstheinitialvalueofiasjsoitcanbeusedinthepostconditiontomakesurethattheapproximationissufficientlyaccurate.Thenamejcanbeusedonlyinthepostconditionandnowhereelseintheprocedure.

procedureintSqrt(vari:int)

prei>=0

initj:=i

postabs(i-sqrt(j))<=1

…statementstoapproximatesquareroot…

endintSqrt

Seealso preandpostassertionsandprocedureandprocessdeclarations.

Description

Thisunitcontainsthepredefinedproceduresthatdealwithhandlinginputonacharacter-by-characterbasis.

AllroutinesintheInputmoduleareexportedunqualified.(Thismeansyoucancalltheentrypointsdirectly.)

EntryPoints

getch Getsthenextcharacterinthekeyboardbuffer(procedurewithastring(1)argument).

hasch Returnstrueiftherearecharacterswaitinginthekeyboardbuffer.

getchar Getsthenextcharacterinthekeyboardbuffer(functionreturningachar).

Pause Waitsforakeytobepressed.KeyDown Detectwhichkeysarecurrentlypressed.Flush Emptythekeyboardbuffer.

Input.getch PartofInputmodule

Syntax getch(varch:string(1))

Description

Thegetchprocedureisusedtoinputasinglecharacterwithoutwaitingfortheendofaline.Theparameterchissettothenextcharacterinthekeyboardbuffer(theoldestnot-yet-readcharacter).

Example

proceduregetKey

varch:string(1)

getch(ch)

endgetKey

fori:1..1000

getKey

endfor

Details

Thescreenshouldbeina"screen"or"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotinoneofthesemodes,itwillautomaticallybesetto"screen"mode.

Somekeys,suchastheleftarrowkey,insertkey,deletekey,andfunctionkeysdonotproduceordinarycharactervalues.Thesekeystrokesarereturnedbygetchasspecialvalues.SeeAppendixDforthesevalues.

Status

ThismeansthatyoucancallthefunctionbycallinggetchorbycallingInput.getch.

Seealsohasch(hascharacter)procedurewhichisusedtoseeifacharacterhasbeentypedbutnotyetread.

Input.getchar PartofInputmodule

Syntax getchar:char

Description

Thegetcharfunctionisusedtoinputasinglecharacterwithoutwaitingfortheendofaline.Thenextcharacterinthekeyboardbuffer(theoldestnot-yet-readcharacter)isreturned.

Example

proceduregetKey

varch:char

ch:=getchar

endgetKey

fori:1..1000

getKey

endfor

Details

Somekeys,suchastheleftarrowkey,insertkey,deletekey,andfunctionkeysdonotproduceordinarycharactervalues.Thesekeystrokesarereturnedbygetchasspecialvalues.SeeAppendixDforthesevalues.

Status

ThismeansthatyoucancallthefunctionbycallinggetcharorbycallingInput.getchar.

Seealsohasch(hascharacter)procedurewhichisusedtoseeifacharacterhasbeentypedbutnotyetread.

Input.hasch PartofInputmodule

Syntax hasch:boolean

DescriptionThehaschprocedureisusedtodetermineifthereisacharacterthathasbeentypedbutnotyetbeenread.

Example

Theflushproceduregetsridofanycharactersthathavebeentypedbutnotyetread.

procedureflush

varch:string(1)

exitwhennothasch

getch(ch)%Discardthischaracter

endloop

endflush

Details

Status

ThismeansthatyoucancallthefunctionbycallinghaschorbycallingInput.hasch.

Seealso getchandgetchar.

Input.Flush PartofInputmodule

Syntax Input.Flush

Description

TheInput.Flushprocedureemptiesthekeyboardbuffer.Itisoftenusedtoavoidaccidentallyreadingmultiplekeystrokesbecausetheuserpressedakeyfortoolong,causingautorepeat.

Example

Thisprogramechoesinputfromthekeyboardatarateof10characterspersecond.Ifyouholddownakey,theechoingwillstopassoonasyoustoppressingthekey.WithouttheInput.Flush,theprogramcontinuestoechomanymorekeystrokesthathaveaccumulatedinthekeyboardbuffer.

ifhaschthen

putgetchar..

Input.Flush

delay(100)

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingInput.Flush,notbycallingFlush.

Input.KeyDown PartofInputmodule

Syntax Input.KeyDown(varchars:arraycharofboolean)

Description

TheInput.Keydownprocedureallowsaprogramtoreadwhichkeysarecurrentlybeingpressed.Thisprocedureisdifferentfromgetchinthatitallowsaprogramtodetectwhenauserpressesandreleasesabutton.Assuch,itisnottobeusedinconjunctionwithgetch.

Theprocedurecanbeusedingameswhereanactiontakesplacewhileakeyisdepressed.

Example

DetermineiftheTkeyispressed.Notethatwecheckforthelowercaseletter.

varchars:arraycharofboolean

Input.KeyDown(chars)

ifchars('t')then

put"TheTkeyispressed"

Details

Thearrayreturnedisalistofallthecharacters.Akeyiscurrentlypressedifthearrayelementwiththecorrespondingcharacteristrue.Forexample,theakeyispressedischars('a')istrue.Notethateachkeyisindividuallyrepresented,soiftheuserhaspressedShift+atogeta'A',thenInput.KeyDownwouldregisterShiftand'a'aspressed,butnot'A'.

AfulllistofallthepossiblecharactersthatcanbesetwithInput.KeyDowncanbefoundintheKeyCodesappendix.

Details

Thearrayreturnedisalistofallthecharacters.Akeyiscurrentlypressedifthearrayelementwiththecorrespondingcharacteristrue.Forexample,theakeyispressedischars('a')istrue.Notethateachkeyisindividuallyrepresented,soiftheuserhaspressedShift+atogeta'A',thenInput.KeyDownwouldregisterShiftand'a'aspressed,butnot'A'.

Details

Thenumberofkeysthatcanbepressedsimultaneouslyishardwaredependent.Mostkeyboardscandetectaminimumoftwokeys+Shift+Control+Alt.Thismeansthatifyouaredesigningatwoplayergametobeplayedatasinglekeyboardandyouwishtomakecertainthatplayerscannot“hogthekeyboard”byholdingdownkeys,youshouldnotusemorethan6differentkeysandthreeofthemshouldbetheShift,ControlandAltkeys.

Example

Theprogramreadsthekeyboardanddisplaysamessagewhilethearrowkeysarepressed.Itcandetectuptoallfourarrowkeyspressedatonce.

varchars:arraycharofboolean

Input.KeyDown(chars)

locate(1,1)

ifchars(KEY_UP_ARROW)then

put"UpArrowPressed"..

put""..

ifchars(KEY_RIGHT_ARROW)then

put"RightArrowPressed"..

put""..

ifchars(KEY_LEFT_ARROW)then

put"LeftArrowPressed"..

put""..

ifchars(KEY_DOWN_ARROW)then

put"DownArrowPressed"..

put""..

endloop

Execute

Example

Anotherexampleisavailablethatchecksforallpossiblekeys.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingInput.KeyDown,notbycallingKeyDown.

Input.Pause PartofInputmodule

Syntax Input.Pause

Description

TheInput.Pauseproceduresimplywaitsforakeytobepressedandthenreturns.Itechoesthekeypressedifechomodeisset.(SeeView.Setforsettingechomode)

Thissubprogramhelpsavoidhavingtodeclareavariabledeclarationandthenmakeacalltogetchorgetchar.

Example

Thisprogrampausesaftereverynamereadfromthefile.

varf:int

varline:string

open:f,"data.txt",get

exitwheneof(f)

get:f,line:*

putname

Input.Pause

endloop

close:f

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingInput.Pause,notbycallingPause.

int integertype

Syntax int

Description

Theint(integer)typehasthevalues…2,1,0,1,2…Integerscanbecombinedbyvariousoperatorssuchasaddition(+)andmultiplication(*).Integerscanalsobecombinedwithrealnumbers,inwhichcasetheresultisgenerallyarealnumber.Anintegercanalwaysbeassignedtoarealvariable,withimplicitconversionto

Examplevarcounter,i:int

varj:int:=9

vartax:=0%Thetypeisimplicitlyint

Details

SeealsoexplicitIntegerConstant.Therealtypeisusedinsteadofinthavefractionalpartsasin16.837.Seetherealtypefordetails.

Theoperatorsonintegersare+,-,*(multiply),div(truncatingintegerdivision),(integerremainder),**(exponentiation),aswellascomparisons(+,<=).Theoperatorsand,orandxorcanbeappliedtonon-negativeintegervalues.Thebit-wisebooleanresultisproducedasaninteger(actually,asanaturalnumber).Theshr(shiftright)andshl(shiftleft)operatorsarealsointroduced.

Realnumberscanbeconvertedtointegersusingceil(ceiling),floordescriptionsofthesefunctions).Integerscanbeconvertedtorealnumbersusingintreal,butinpracticethisisrarelyused,becauseanintegervalueusedinplaceofarealvaluewillbeautomaticallyconvertedtoreal.

IntegerscanbeconvertedtostringsandbackusingintstrandstrintconvertedtocorrespondingASCII(orEBCDIC)charactersusingchrthedescriptionsofthesefunctions.

Pseudo-randomsequencesofintegerscanbegeneratedusingrandint

IncurrentimplementationsofTuring,therangeofintegersisfrom-2147483647to2147483647.Inotherwords,themaximumsizeofintegeris2**31-1.SeeThisrangeexistsbecauseintegersarestoredin4bytes.Theremainingnegativevalue,-2147483648recordsuninitialization.Thetypesint1,int2andintegersthatfitinto1,2or4bytes.Theintntypes(int1,int2andint4

checkedforinitializationandallowalltheirbitpatternsasnumbers.

Thenaturalnumbertypenatallowsonlythenon-negativevalues:0,1,2,3,…Naturalnumbervaluescanbeusedwheneverintegervaluesareexpectedandviceversa,giventhatthevaluedoesnotexceedtherangeoftheexpectedtype.

Seealso natandintn.

intn n-byteintegertype

Syntax (a) int1 %1-byteinteger (b) int2 %2-byteinteger (c) int4 %4-byteinteger

Description

Theintn(n-byteinteger)typesaremachine-dependenttypesthatoccupyaspecifiednumberofbytes.Bycontrast,theinttypeisinprincipleamachine-independentandmathematicaltype(itoverflows,however,whenthevalueistoolargeorsmall,thatis,whenthevaluedoesnotfitinto4bytes).

Examplevarcounter1:int1%Rangeis-128..127

varcounter2:int2%Rangeis-32768..32767

varcounter4:int4%Rangeis-2147483648..2147483647

Details

IncurrentimplementationsofTuring,therangeoftheintis-2147483647to2147483647,whichmeansthattheint4typeallowsonemorevalue,-2147483648.Thisextravalueisusedininttorepresentthestateofbeinginitialized.Theintntypesallowuseofallpossiblevaluesthatfitintonbytesandtherebycannotcheckforinitialization.

TheintntypesareliketheClanguagetypesshortint,int,andlongint,exceptthatthenumberofbytesoccupiedbytheCtypesdependsontheparticularCcompiler.

Seealsothenatntypeswhicharenbytenatural(non-negative)values.Seealsointandnat.

intreal integer-to-realfunction

Syntax intreal(i:int):real

Description

Theintrealfunctionisusedtoconvertanintegertoarealnumber.Thisfunctionisrarelyused,becauseinTuring,anintegervaluecanbeusedwhereeverarealvalueisrequired.Whentheintegervalueisusedwherearealvalueisrequired,theintrealfunctionisimplicitlycalledtodotheconversionfrominttoreal.

Seealso floor,ceilandroundfunctions.

intstr integer-to-stringfunction

Syntax intstr(i:int[,width:int[,base:int]]):string

Description

Theintstrfunctionisusedtoconvertanintegertoastring.Thestringisequivalenttoi,paddedontheleftwithblanksasnecessarytoalengthofwidth,writteninthegivennumberbase.Forexample,intstr(14,4,10)="bb14"wherebrepresentsablank.Thewidthandbaseparametersarebothoptional.Iftheyareomitted,thestringismadejustlongenoughtoholdthevalue,andthenumberbaseis10.Forexample,intstr(14,4)="bb14"andintstr(23)="23".

Thewidthparametermustbenon-negative.Ifwidthisnotlargeenoughtorepresentthevalueofi,thelengthisautomaticallyincreasedasneeded.

Thestringreturnedbyintstrisoftheform:

{blank}[-]digit{digits}

where{blank}meanszeroormoreblanks,[-]meansanoptionalminussign,anddigit{digit}meansoneormoredigits.Theleftmostdigitiseithernon-zeroorelseasinglezerodigit.Inotherwords,leadingzerosaresuppressed.

ThelettersA,B,C…areusedtorepresentthedigitvalues10,11,12,…Thebasemustbeintherange2to36(36becausetherearetendigitsand26letters).Forexample,intstr(255,0,16)="FF".

Theintstrfunctionistheinverseofstrint,soforanyintegeri,

strint(intstr(i))=i.

Seealso

chr,ordandstrintfunctions.Seealsothenatstrandstrnatfunctions.SeealsoexplicitIntegerConstantsforthewaytowritenonbase10valuesinaprogram.

invariant assertion

Syntax

AninvariantAssertionis:

Description

Aninvariantassertionisaspecialformofanassertstatementthatisusedonlyinloopandforstatementsandinmodules,monitors,andclasses.Itisusedtomakesurethataspecificrequirementismet.ThisrequirementisgivenbythetrueFalseExpn.ThetrueFalseExpnisevaluated.Ifitistrue,alliswellandexecutioncontinues.Ifitisfalse,executionisterminatedwithanappropriatemessage.Seeassert,loopandforstatementsandthemoduledeclarationsformoredetails.

Example

Thisprogramusesaninvariantinaforloop.TheinvariantusesthefunctionnameInListtospecifythatakeyhasnotyetbeenfoundinanarrayofnames.

varname:array1..100ofstring

varkey:string

…inputnameandkey…

functionnameInList(n:int):boolean

fori:1..n

ifkey=name(i)then

resulttrue

endfor

resultfalse

endnameInList

forj:1..100

invariantnotnameInList(j-1)

ifkey=name(j)then

put"Foundnameat",j

endloop

Joystick

Description

ThisunitcontainsthepredefinedsubprogramthatdealwithreadingthejoystickinaTuringprogram.Theroutinesallowyoutogetthecurrentjoystickpositionandwhethereitheroneofthetwobuttonsarepressed.

AllroutinesintheJoystickmoduleareexportedqualified(andthusmustbeprefacedwith"Joystick.").AlltheconstantsareexportedunqualifiedandthusdonotneedtheJoystickprefix.

EntryPoints

joystick1,joystick2 joysticknamecontants(exportedunqualified)

GetInfo Readsthecurrentvalueofajoystickandstatusofthejoystickbuttons.

Joystick.GetInfo PartofJoystickmodule

SyntaxJoystick.GetInfo(joystick:int,varxPos,yPos:int,btn1Pressed,btn2Pressed:boolean)

Description

Readsthepositionandbuttonstatusofthejoystickspecifiedbytheparameter.ThexandyparameterarereturnedinthexPosandyPosIfbutton1orbutton2onthejoystickarecurrentlypressed,btn1Pressedbtn2Pressedwillbesettotrue.Thejoystickparametercanbeeitherorjoystick2.

ThexandypositionsvaryfromjoyMintojoyMax.Tousethemwithrespecttoascreen,thecoordinatesreturnedfromJoystick.GetInfomustbetranslatedintoscreencoordinates.Thefollowingformulacanbeused:

screenX=round(maxx*(xPosjoyMin)/(joyMax

screenY=round(maxy*(yPosjoyMin)/(joyMax

Details

TheJoystickmodulecontainsundocumentedsubprogramsforthosewhoneedtoaccessmorethantwobuttonsoraxesonajoystick.ContactHoltSoftwareifyouneedmoreinformation.

Example

Thefollowingprogramoutputsthecurrentlocationofjoystick#1anddrawsacursoronthescreentopointoutwhereitisshowing.

varjx,jy,x,y,ox,oy:int:=1

varb1,b2,oB1,oB2:boolean:=false

Joystick.GetInfo(joystick1,jx,jy,b1,b2)

%Convertjoystickcoordinatesintoscreencoordinates.

x=round(maxx*(jxjoyMin)/(joyMaxjoyMin

y=round(maxy*(jyjoyMin)/(joyMaxjoyMin

ifxnot=oxorynot=oyorb1not=oB1or

Text.Locate(1,1)

put"x=",x,"y=",y,"b1=",b1

View.Set("xor")

Draw.Line(ox10,oy,ox+10,oy,brightred

Draw.Line(ox,oy10,ox,oy+10,brightred

Draw.Line(x10,y,x+10,y,brightred

Draw.Line(x,y10,x,y+10,brightred

oB1:=b1

oB2:=b2

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingJoystick.GetInfobycallingGetInfo.

Keyboard

Description

ThisunitcontainsalltheconstantsrepresentingboththecharactersandtheirordinalvaluesforallpossiblekeystrokesthatcanbereadbyTuring.

Constantsbeginningwith“KEY_”arecharvalues.ThesearethevaluesreturnedbygetchandusedasanindexintotheInput.KeyDownarray.TheconstantsthattheconstantsKEY_KEYPAD_5,KEY_SHIFT,KEY_CTRLandKEY_ALTcanonlybeusedinconjunctionwithInput.KeyDown.Thegetchandgetcharsubprogramsdonotreturnthesevalues.AllotherconstantswithwithSHIFT,CTRLandALTaspartofthenamecannotbecheckedforintheInput.KeyDownarray.

Constantsbeginningwith“ORD_”areintvaluesandrepresenttheordinalvalues(valuesreturnedbytheordfunction)forallthepossiblekeystrokes.

Hereisalistofmostoftheconstants

KEY_F1..KEY_F12

KEY_CTRL_A..KEY_CTRL_Z

KEY_SHIFT_F1.. KEY_ALT_A..KEY_ALT_Z

KEY_HOME

KEY_SHIFT_F12KEY_CTRL_F1..KEY_CTRL_F12

KEY_ALT_1..KEY_ALT_0

KEY_ALT_F1..KEY_ALT_F12

KEY_UP_ARROW KEY_CTRL_UP_ARROWKEY_PGUP KEY_CTRL_PGUPKEY_LEFT_ARROW KEY_CTRL_LEFT_ARROWKEY_RIGHT_ARROW KEY_CTRL_RIGHT_ARROWKEY_END KEY_CTRL_ENDKEY_DOWN_ARROW KEY_CTRL_DOWN_ARROWKEY_PGDN KEY_CTRL_PGDNKEY_INSERT KEY_CTRL_INSERTKEY_DELETE KEY_CTRL_DELETEKEY_BACKSPACE KEY_KEYPAD_5*KEY_TAB KEY_SHIFT*KEY_ENTER KEY_CTRL*KEY_ESC KEY_ALT*KEY_CTRL_OPEN_BRACKET KEY_CTRL_BACKSLASHKEY_CTRL_CLOSE_BRACKET KEY_CTRL_CARETKEY_CTRL_UNDERSCORE KEY_CTRL_BACKSPACEKEY_ALT_MINUS KEY_ALT_EQUALSKEY_BACK_TAB KEY_SHIFT_TAB

Aboveconstantswith“ORD_”insteadof“KEY_”

ORD_A..ORD_Z ORD_0..ORD_9ORD_LOWER_A..ORD_LOWER_Z ORD_SPACE ORD_EXCALAMATION_MARKORD_QUOTATION_MARK ORD_HAS_MARKORD_DOLLAR_SIGN ORD_PERCENT_SIGN

ORD_AMPERSAND ORD_SINGLE_QUOTEORD_OPEN_PARENTHESIS ORD_CLOSE_PARENTHESISORD_ASTERISK ORD_PLUSORD_COMMA ORD_MINUSORD_PERIOD ORD_DOTORD_SLASH ORD_COLONORD_SEMICOLON ORD_LESS_THANORD_EQUALS ORD_GREATER_THANORD_QUESTION_MARK ORD_AT_SIGNORD_OPEN_BRACKET ORD_BACKSLASHORD_CLOSE_BRACKET ORD_CARETORD_UNDERSCORE ORD_APOSTROPHEORD_OPEN_BRACE ORD_BARORD_CLOSE_BRACE ORD_TILDE

Charactersmarkedwithanasterisk(*)arekeysthatcanonlybedetectedusingInput.KeyDown.

AllconstantsintheKeyboardmoduleareexportedunqualified.(Thismeansyoucanusetheconstantsdirectlywithouthavingtousethequalifier"Keyboard.".)

Seealsogetch,getchar,andInput.KeyDown.

length ofastringfunction

Syntax length(s:string):int

DescriptionThelengthfunctionreturnsthenumberofcharactersinthestring.Thestringmustbeinitialized.Forexample,length("table")is5.

Example

Thisprograminputsthreewordsandoutputstheirlengths.

varword:string

fori:1..3

getword

putlength(word)

endfor

Ifthewordsare"cat","robin"and"crow",theprogramwilloutput3,5and4.

Details

Thelengthfunctiongivesthecurrentlengthofthestring.Tofindthemaximumlengthofastring,useupper.Forexample,giventhedeclarationvars:string(10),upper(s)returns10.

Seealso upper.

Limits

Description

Thisunitcontainsconstantsandfunctionsusedindeterminingthemathematicalaccuracyofthelanguage.

AllroutinesintheLimitsmoduleareexportedqualified(andthusmustbeprefacedwith"Limits.")exceptmaxint,maxnat,minintandminnat,whichareexportedunqualified(thismeansyoucancallthoseentrypointsdirectly).

EntryPoints

DefaultFW Defaultfractionwidthusedinprintingusingthe"put"statement.

DefaultEW Defaultexponentwidthusedinprintingusingthe"put"statement.

minint TheminimumintegerinTuring(exportedunqualified).

maxint ThemaximumintegerinTuring(exportedunqualified).

minnat TheminimumnaturalnumberinTuring(exportedunqualified).

maxnat ThemaximumnaturalnumberinTuring(exportedunqualified).

RealnumbersarerepresentedinTuringas:f*(radix**e)or0wherefornon-zerof:(1/radix)<=abs(f)andabs(f)<1.0minexp<=eande<=maxexp.

Radix The"radix"(usually2).NumDigits Thenumberofradixdigitsinf.MinExp "minexp"(thesmallestexponentallowed).MaxExp "maxexp"(thelargestexponentallowed).GetExp Functionthatreturnsthevalueof"e".SetExp Procedurethatsetsthevalueof"e".

Rreb Therelativeround-offerrorbound.

ln naturallogarithmfunction

Syntax ln(r:real):real

DescriptionThelnfunctionisusedtofindthenaturallogarithm(basee)ofanumber.Forexample,ln(1)is0.

Example

Thisprogramprintsoutthelogarithmsof1,2,3,…upto100.

fori:1..100

put"Logarithmof",i,"is",ln(i)

endfor

DetailsSeealsotheexp(exponential)function.Youcannottakethelogarithmofzerooranegativenumber.

Note logn(i)=ln(i)/ln(n)

Seealsoexp(theexponentiationfunction).

locate procedure

Syntax locate(row,column:int)

Description

Thelocateprocedureisusedtomovethecursorsothatthenextoutputfromputwillbeatthegivenrowandcolumn.Row1isthetopofthescreenandcolumn1istheleftsideofthescreen.

Example

Thisprogramoutputsstarsofrandomcolorstorandomlocationsonthescreen.Thevariablecolrispurposelyspelleddifferentlyfromthewordcolortoavoidtheprocedureofthatname(usedtosetthecolorofoutput).Therownumberispurposelychosensothatitisonelessthanmaxrow.Thisavoidsthescrollingofthescreenwhichoccurswhenacharacterisplacedinthelastcolumnofthelastrow.

setscreen("screen")

varrow,column,colr:int

randint(row,1,maxrow-1)

randint(column,1,maxcol)

randint(colr,0,maxcolor)

color(colr)

locate(row,column)

put"*"..%Usedot-dottoavoidclearingendofline

endloop

Details

Thelocateprocedureisusedtolocatethenextoutputbasedonrowandcolumnpositions.Seealsothelocatexyprocedurewhichisusedtolocatetheoutputbasedxandypositions,wherex=0,y=0istheleftbottomofthescreen.

Seealsosetscreenanddrawdot.

locatexy graphicsprocedure

Syntax locatexy(x,y:int)

Description

Thelocatexyprocedureisusedtomovethecursorsothatthenextoutputfromputwillbeatapproximately(x,y).Theexactlocationmaybesomewhattotheleftofxandbelowytoforcealignmenttoacharacterboundary.

Example

Thisprogramoutputs"Hello"startingatapproximately(100,50)onthescreen.

locatexy(100,50)

put"Hello"

Details

Thelocatexyprocedureisusedtolocatethenextoutputbasedonxandypositions,wherethepositionx=0,y=0istheleftbottomofthescreen.Seealsothelocateprocedurewhichisusedtolocatetheoutput-basedrowandcolumnpositions,whererow1isthetoprowandcolumn1istheleftcolumn.

Seealsosetscreenanddrawdot.

loop statement

Syntax

AloopStatementis:

loop statementsAndDeclarations endloop

Description

Aloopstatementcausesthestatements(anddeclarations)inittoberepeatedlyexecuted.Thiscontinuesuntilterminatedbyoneofitsenclosedexitstatements(orbyanenclosedreturnorresultstatement).

Example

Outputonseparatelines:Happy,Happy,Happy,etc.

put"Happy"

endloop

Example

ReadwordsuptothewordStop.

varword:string

getword

exitwhenword="Stop"

endloop

Details

Aloopstatementcancontainmorethanoneexit,ornoneatall(inwhichcaseitisaninfiniteloop).Whentheexitwhenisatthebeginningoftheloop,theloopworkslikePascal'sdowhile;whenattheend,theloopworkslikePascal'srepeatuntil.

Justprecedingthestatementsanddeclarations,youareallowedtowritean"invariantclause"oftheform:

Thisclauseisequivalentto:asserttrueFalseExpn.

lower bound

Syntax lower(reference[,dimension]):int

Description

Thelowerattributeisusedtofindthelowerboundofanarray,string,char(n)ornon-opaquesubrangetype.Sincethelowerboundisnecessarilyknownatcompiletime,lowerisrarelyused.

Seealso upperwhichfindstheupperbound.

Description

Thisunitcontainsallthemathematicalroutines.Therearethreeroutinesthatarepartofthelanguage,butareconceptuallypartoftheMathunit.

AllroutinesintheMathunitexceptMath.DistanceandMath.DistancePointLineareexportedunqualified.(Thismeansyoucancalltheentrypointsdirectly.)Math.DistanceandMath.DistancePointLineareexportedqualified.AllconstantsintheMathunitareexportedqualified.(BothMath.PIandMath.Emustbeprefacedwith"Math.".)

DescriptionsofallthesubprogramsintheMathmodulecanbefoundinthischapter.

ConstantsMath.PI Theconstantp(3.14...).Math.E Thenaturalbasee(2.718...).

EntryPoints

abs* Theabsolutevaluefunction.arccos Thearccosfunction(radians).arccosd Thearccosfunction(degrees).arcsin Thearcsinfunction(radians).arcsind Thearcsinfunction(degrees).arctan Thearctanfunction(radians).arctand Thearctanfunction(degrees).cos Thecosinefunction(radians).cosd Thecosinefunction(degrees).exp Theexponentiationfunction.ln Thenaturallogarithmfunction.max* Themaximumvaluefunction.min* Theminimumvaluefunction.sign Thesignfunction.sin Thesinefunction(radians).sind Thesinefunction(degrees).

tan Thetangentfunction(radians).tand Thetangentfunction(degrees).sqrt Thesquarerootfunction.Distance Thedistancebetweentwopoints.

DistancePointLine Thedistancebetweenapointandalinesegment.

*Partofthelanguage,conceptuallypartoftheMathunit.

Math.Distance PartofMathmodule

Syntax Math.Distance(x1,y1,x2,y2:real):real

Description Math.Distanceisusedtocalculatethedistancebetweentwopoints.(x1,y1)isthelocationofthefirstpoint,and(x2,y2)isthelocationofthesecondpoint.

Details TheparameterstoMath.Distancearereal,butyoucanpassintegervariablesandconstants.

Example Thisprogamdrawstwocircleswithradius75onthescreenandoutputswhethertheytouch.

varx1,y1,x2,y2:int

constRADIUS:int:=75

x1:=Rand.Int(RADIUS,maxx-RADIUS)

y1:=Rand.Int(RADIUS,maxy-RADIUS)

x2:=Rand.Int(RADIUS,maxx-RADIUS)

y2:=Rand.Int(RADIUS,maxy-RADIUS)

Draw.FillOval(x1,y1,RADIUS,RADIUS,brightred

Draw.FillOval(x2,y2,RADIUS,RADIUS,brightgreen

ifMath.Distance(x1,y1,x2,y2)<RADIUS*2then

put"Thetwocirclestouch"

put"Thetwocirclesdonottouch"

Execute

Status Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMath.Distance,notbycallingDistance.

Math.DistancePointLine PartofMathmodule

Syntax Math.DistancePointLine(xp,yp,x1,y1,x2,y2:real):real

Description Math.DistancePointLineisusedtocalculatethedistancebetweenapointandalinesegment.Itisoftenusedingamestodetermineifacollisionhasoccurred.(xp,yp)isthelocationbetweenthepoint.(x1,y1)and(x2aretheendpointsofthelinesegment.

Details TheparameterstoMath.DistancePointLinearereal,butyoucanpassintegervariablesandconstants.Theparametersareinthesameorderasthesubprogramname(thatispoint,thenline).

Example Thisprogamdrawsalinesegmentandacirclewithradius75onthescreenandoutputswhethertheytouch.

varxp,yp,x1,y1,x2,y2:int

constRADIUS:int:=75

xp:=Rand.Int(RADIUS,maxx-RADIUS)

yp:=Rand.Int(RADIUS,maxy-RADIUS)

x1:=Rand.Int(0,maxx)

y1:=Rand.Int(0,maxy)

x2:=Rand.Int(0,maxx)

y2:=Rand.Int(0,maxy)

Draw.FillOval(xp,yp,RADIUS,RADIUS,brightred

Draw.Line(x1,y1,x2,y2,brightgreen)

ifMath.DistancePointLine(xp,yp,x1,y1,x2,y2

put"Thecircletouchestheline"

put"Thecircledoesnottouchtheline"

Execute

Status Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMath.DistancePointLine,notbycallingDistancePointLine.

max maximumfunction

Syntax max(expn,expn)

Description

Themaxfunctionisusedtofindthemaximumoftwonumbers(thetwoexpn's).Forexample,max(5,7)is7.Ifbothnumbersareint,theresultisint.Ifbothnumbersarenat(naturalnumbers),theresultisnat.Butifoneorbothofthenumbersarereal,theresultisreal.Seealsotheminfunction.

Example

varx:real:=74.61

vary:real:=85.72

putmax(x,y)%Outputs85.72

Example

Thisprograminputs10numbersandoutputstheirmaximum.

varm,t:real

getm%Inputfirstnumber

fori:2..10%Handleremaining9numbers

m:=max(m,t)

endfor

put"Themaximumis",m

Seealso SeealsopredefinedunitMath.

maxcol maximumcolumnfunction

Syntax maxcol:int

DescriptionThemaxcolfunctionisusedtodeterminethenumberofcolumnsonthescreen.

ExampleThisprogramoutputsthemaximumcolumnnumber.

put"Numberofcolumnsonthescreenis",maxrow

Details

ForIBMPCcompatiblesaswellasmostUNIXdumbterminals,in"text"or"screen"mode,maxcol=80.ForthedefaultIBMPCcompatible"graphics"mode(CGA),maxcol=40.

Seealso locateprocedureforanexampleoftheuseofmaxcol.

maxcolor graphicsfunction

Syntax maxcolor:int

Description

Themaxcolorfunctionisusedtodeterminethemaximumcolornumberforthecurrentmodeofthescreen.Thealternatespellingismaxcolour.

Example

Thisprogramoutputsthemaximumcolornumber.

put"Themaximumcolornumberis",maxcolor

Details

Thescreenshouldbeina"screen"or"graphics"mode.Ifitisnot,itwillautomaticallybesetto"screen"mode.Seesetscreenfordetails.

ForIBMPCcompatiblesin"screen"mode,maxcolor=15.ForthedefaultIBMPCcompatible"graphics"mode(CGA),maxcolor=3.

Seealso

drawdotandpaletteforexamplesoftheuseofmaxcolor.Seethecolorprocedurewhichisusedforsettingthecurrentlyactivecolor.

maxint maximumintegerfunction

Syntax maxint:int

DescriptionThemaxintfunctionisusedtodeterminethelargestinteger(int)thatcanbeusedinaprogram.

ExampleThisprogramoutputsthemaximuminteger.

put"Thelargestintegerthatcanbeusedis",

Details

IncurrentTuringandOOTimplementations,intvaluesarestoredin4bytes,i.e.,32bits.Thisdeterminesthemaximumintvalue,whichis2**311,equaling2147483647.

Thereisananomalyincomputerarithmeticinthattheabsolutevalueofthelargestnegativeintegerisonelargerthanmaxint.Turingreservesthisextravaluetorepresenttheuninitializedinteger.Thisvaluecanbecomputedbutanyattempttoassignittoanintvariableisdetectedasanoverflow.Youcanusethisextravaluebyusingtheint4typeinsteadofint,butthistypehasnoinitializationchecking.

Seealsomaxnatandminint.

SeealsoOOTpredefinedunitMath.

maxnat maximumnaturalnumberfunction

Syntax maxnat:nat

DescriptionThemaxnatfunctionisusedtodeterminethelargestnaturalnumberthatcanbeusedinaprogram.

ExampleThisprogramoutputsthemaximumnaturalnumber.

put"Thelargestnaturalnumberthatcanbeusedis",

Details

Incurrentimplementations,naturalnumbersarestoredin4bytes,i.e.,32bits.Thisdeterminesthemaximumnaturalnumber,whichis2**32-2,equaling4294967294.

Infourbytesitispossibletorepresentonemorevalue,namely,2**32-1=4294967295.ThisextravalueisusedinTuringtorepresenttheuninitializednaturalnumber.Althoughitcanbecomputed,anyattempttoassignittoavariableisdetectedasanoverflow.Youcanusethisextravaluebyusingthetypeinsteadofnat,butthistypehasnoinitializationchecking.

Seealsomaxintandminnat.

SeealsopredefinedunitLimits.

maxrow maximumrowfunction

Syntax maxrow:int

DescriptionThemaxrowfunctionisusedtodeterminethenumberofrowsonthescreen.

ExampleThisprogramoutputsthemaximumrownumber.

put"Numberofrowsonthescreenis",maxrow

DetailsForIBMPCcompatibles,maxrow=25.FormanyUNIXdumbterminals,maxrow=24.

Seealso locateprocedureforanexampleoftheuseofmaxrow.

maxx graphicsfunction

Syntax maxx:int

DescriptionThemaxxfunctionisusedtodeterminethemaximumvalueofxforthecurrentgraphicsmode.

Example

Thisprogramoutputsthemaximumxvalue.

put"Themaximumxvalueis",maxx

Details

Thescreenshouldbeina"graphics"mode.Ifitisnot,itwillautomaticallybesetto"graphics"mode.Seesetscreenfordetails.

ForthedefaultIBMPCcompatiblegraphicsmode(CGA),maxx=319.

Seealsodrawdotforanexampleoftheuseofmaxxandforadiagramillustratingxandypositions.

maxy graphicsfunction

Syntax maxy:int

DescriptionThemaxyfunctionisusedtodeterminethemaximumvalueofyforthecurrentgraphicsmode.

Example

Thisprogramoutputsthemaximumyvalue.

put"Themaximumyvalueis",maxy

Details

Thescreenshouldbeina"graphics"mode;.Ifitisnot,itwillautomaticallybesetto"graphics"mode.Seesetscreenfordetails.

ForthedefaultIBMPCcompatiblegraphicsmode(CGA),maxy=199.

Seealsodrawdotforanexampleoftheuseofmaxyandforadiagramillustratingxandypositions.

min minimumfunction

Syntax min(expn,expn)

Description

Theminfunctionisusedtofindtheminimumoftwonumbers(thetwoexpn's).Forexample,min(5,7)is5.Ifbothnumbersareint,theresultisint.Ifbothnumbersarenat(naturalnumbers),theresultisnat.Butifoneorbothofthenumbersarereal,theresultisreal.Seealsothemaxfunction.

Example

varx:real:=74.61

vary:real:=85.72

putmin(x,y)%Outputs74.61

Example

Thisprograminputs10numbersandoutputstheirminimum.

varm,t:real

getm%Inputfirstnumber

fori:2..10%Handleremaining9numbers

m:=min(m,t)

endfor

put"Theminimumis",m

minint minimumintegerfunction

Syntax minint:int

DescriptionTheminintfunctionisusedtodeterminethesmallestinteger(int)thatcanbeusedinaprogram.

ExampleThisprogramoutputsthemaximuminteger.

put"Thesmallestintegerthatcanbeusedis",

Details

Incurrentimplementations,intvaluesarestoredin4bytes,i.e.,32bits.Thisdeterminestheminimumintvalue,whichis-2**31-1,equaling-2147483647.

Thereisananomalyincomputerarithmeticinthattheabsolutevalueofthelargestnegativeintegerisonelargerthanmaxint.Turingreservesthisextravaluetorepresenttheuninitializedinteger.Thisvaluecanbecomputedbutanyattempttoassignittoanintvariableisdetectedasanoverflow.Youcanusethisextravaluebyusingtheint4typeinsteadofbutthistypehasnoinitializationchecking.

Seealsominnatandmaxint.

minnat minimumnaturalnumberfunction

Syntax minnat:nat

DescriptionTheminnatfunctionisusedtodeterminethesmallestnaturalnumberthatcanbeusedinaprogram.

ExampleThisprogramoutputsthesmallestnaturalnumber.

put"Thesmallestnaturalnumberthatcanbeusedis",

Details

IncurrentTuringandOOTimplementations,naturalnumbersarestoredin4bytes,i.e.,32bits.However,theminimumnaturalnumberinallimplementationsis0.minnatisprovidedforpurposesofsymmetrywithminint,maxint

Infourbytesitispossibletorepresentonemorevalue,namely,2**32-1=4294967295.ThisextravalueisusedinTuringtorepresenttheuninitializednaturalnumber.Althoughitcanbecomputed,anyattempttoassignittoadetectedasanoverflow.Youcanusethisextravaluebyusingthenat4ofnat,butthistypehasnoinitializationchecking.

Seealsominintandmaxnat.

mod modulooperator

Syntax mod

Description

Themod(modulo)operatorproducesthemoduloofonenumberwithanother.Inotherwords,theresultisalwaysanumberbetween0andthesecondoperand.Ifbothoperandsarepositive,theresultisidenticaltotheremainderoperator.Forexample,7mod2produces1and12mod5produces3.

Example

Inthisexample,hoursisthecurrenttime.Itismovedbackandforthbyarandomamount,butthefinalresultmustalwaysbebetween1and12(themodoperationproducesanumberbetween0and11andthen0becomes12).

varhours:int:=12

varhoursPassed:int

put"Thetimeisnow",hours,"o'clock"

randint(hoursPassed,-12,12)

exitwhenhoursPassed=0

ifhoursPassed<0then

puthoursPassed,"hoursbefore"..

puthoursPassed,"hourslater"..

puthours,"o'clock"..

hours:=(hours+hoursPassed)mod12

ifhours=0then

hours=12

put"itwas",hours,"o'clock"

endloop

Details

Ifthesecondoperandispositive,thentheresultisalwaysnon-negative.Likewise,ifthesecondoperandisnegative,thentheresultisalwaysnon-positive.Ifbothoperandsarenegative,theresultisthesameastheremainderoperator.

Seealsoinfixoperators,precedenceofoperatorsandtheremanddivoperators.

module declaration

Syntax

AmoduleDeclarationis:

moduleid [implementimplementItem] [implementbyimplementByItem] [import[var]importItem {,[var]importItem}] [export[howExport]id{,[howExport]id}] statementsAndDeclarations endid

Description

Amoduledeclarationcreatesapackageofvariables,constants,types,subprograms,etc.Thenameofthemodule(id)isgivenintwoplaces,justaftermoduleandjustafterend.Itemsdeclaredinsidethemodulecanbeaccessedoutsideofthemoduleonlyiftheyareexported.Itemsfromoutsidethemodulethataretobeusedinthemoduleneedtobeimported(unlesstheyarepredefinedorpervasive).

Example

Thismoduleimplementsastackofstrings.

modulestack%ImplementsaLIFOlistofstrings

exportpush,pop

vartop:int:=0

top:=top+1

contents(top):=s

endpush

s:=contents(top)

top:=top-1

endpop

endstack

stack.push("Harvey")

varname:string

stack.pop(name)%ThissetsnametoHarvey

Outsideofthestackmodule,theprocedurespushandpopcanbecalledusingthenotationstack.pushandstack.pop.Thisaccessisallowedbecausepopareexportedfromthemodule.Otheritemsdeclaredinthemodule(contents)cannotbeaccessedfromoutsidebecausetheyarenotexported.

Details

Insomeotherprogramminglanguages,amoduleiscalledapackageobject.

Amoduledeclarationisexecuted(itisinitialized)byexecutingitsdeclarationsandstatements.Forexample,thestackmoduleisinitializedbysettingthevariableto0.Thisinitializationexecutesallthestatementsanddeclarationsinthemodulethatarenotcontainedinproceduresorfunctions.Theinitializationiscompletedbeforeanyprocedureorfunctionofthemodulecanbecalledfromoutsidethemodule.Anexportedsubprogrammustnotbecalleduntilinitializationofthemoduleiscomplete.

Acalltoanexportedprocedureorfunctionfromoutsidethemoduleexecutesthebodyofthatprocedureorfunction(themoduleisnotinitializedwitheachsuchcall).Seealsomonitorandclassdeclarations.

Theimportlistgivesthenamesofitemsdeclaredoutsidethemodulethatcanbeaccessedinsidethemodule.Sincestackhasnoimportlist,itisnotallowedtoaccessanynamesdeclaredoutsideofit.Seealsoimportlists.Separately-compiledunitsthatareimportedareinitializedbeforetheimportingunit.

Theexportlistisusedtoimplementinformationhiding,whichisolatesimplementationdetailsinsidethemodule.Theexportlistgivesthenamesofitemsdeclaredinsidethemodulethatcanbeusedoutsidethemodule.Forexample,pushandpopareexportedfromstack.Eachsuchuseofanexporteditemmustbeprecededbythemodulenameandadot,forexample,(Seeunqualifiedforadviceonhowtoavoidusingtheprefix"stack.thatarenotexported,suchastopandcontents,cannotbeaccessedoutsidethemodule.

Procedures,functions,variables,constantsandtypescanbeexported;modules,monitorsorclassescannotbeexported.

Aclassisessentiallyatemplateforcreatingindividualmodules(objects).Seeclassfordetails.Amonitorisessentiallyamoduleinwhichonlyoneprocesscanbeactiveatatime.Seemonitorandprocessfordetails.

Theopaquekeywordisused(only)inexportliststoprecedeexportedtypenamesthathavedeclarationsinthemodule.Outsideofthemodule,thetypewillbedistinctfromallotherstypes.Thismeans,forexample,thatiftheopaquetypeisarecord,itsfieldscannotbeaccessedoutsideofthemodule.Opaquetypesareusedtoguaranteethatcertainitemsareinspectedandmanipulatedinonlyoneplace,namely,insidethemodule.Thesetypesaresometimescalledabstractdatatypes.Seealsoexportlists,whichalsodescribesunqualifiedandpervasiveexports.

Implementandimplement-bylistsareusedtoseparateamodule'sinterfacefromitsbody.Thisallowsonlyapartofamodule(itsinterface)tobevisibletoitsusers(itsimporters),whilehidingitsimplementation.Seeimplementimplementbylists.

Example

Useanopaquetypetoimplementcomplexarithmetic.

modulecomplex

exportopaquevalue,constant,add,

…otheroperations…

typevalue:

record

realPt,imagPt:real

endrecord

functionconstant(realPt,imagPt:real):

varanswer:value

answer.realPt:=realPt

answer.imagPt:=imagPt

resultanswer

endconstant

functionadd(L,R:value):value

varanswer:value

answer.realPt:=L.realPt+R.realPt

answer.imagPt:=L.imagPt+R.imagPt

resultanswer

endadd

…otheroperationsforcomplexarithmeticgohere…

endcomplex

varc,d:complex.value:=complex.constant(1,5)

%canddbecomethecomplexnumber(1,5)

vare:complex.value:=complex.add(c,d)

%ebecomesthecomplexnumber(2,10)

Details

Moduledeclarationscanbenestedinsideothermodulesbutcannotbenestedinsideproceduresorfunctions.Amodulemustnotcontainabindasoneofits(outermost)declarations.Areturnstatementcannotbeusedasoneofthe(outermost)statementsinamodule.

ThesyntaxofamoduleDeclarationpresentedabovehasbeensimplifiedbyleavingoutpre,invariantandpostclauses;thefullsyntaxis:

moduleid

[implementimplementItem]

[implementbyimplementByItem]

[import[var]importItem{,[var]importItem

[export[howExport]id{,[howExport]id

[pretrueFalseExpn]

[invarianttrueFalseExpn]

[posttrueFalseExpn]

Thetrue/falseexpressioninthepreandpostclausesmustbetruewheninitializationreacheseachofthem.Afterthat,thesehavenoeffect.Thetrue/falseexpressionintheinvariantmustbetrueanytimethemoduleisexited(whenfinishinginitializationorwhenreturningfromanexternalcalltoanexportedsubprogram)orcalled(viaanexportedsubprogram).Theseclauses(pre,postandinvariant)arenotinheritedbyexpansions.Forexample,ifmoduleBinheritsA,thesubprogramsofBareboundbyB'sclausesandnotbyA's.

Seealsounit,monitorandclass.Seealsoexportlist,importlist,implementimplementbylist,inheritlistanddeferredsubprogram.

monitor declaration

Syntax

AmonitorDeclarationis:

monitorid [implementimplementItem] [implementbyimplementByItem] [import[var]importItem {,[var]importItem}] [export[howExport]id{,[howExport]id}] statementsAndDeclarations endid

Description

Amonitorisaspecialpurposemodule(seemodule)thatisusedwithconcurrentprocesses(seeprocess).Atmost,oneconcurrentprocess(seeprocess)canbeactiveinamonitoratatime.Thismeansthataprocesswillbeblockedifitcallsamonitorthatisalreadyactive.Theprocesswillnotbeallowedtoproceeduntilthemonitorisinactive.Themonitorprovidesmutuallyexclusiveaccesstothemonitor'sinternaldata.

Thismonitorcontrolsaccesstothecountvariablesoitcanbeupdatedbytwoprocesses(theobserverandthereporter)withoutbeingcorruptedbythisconcurrentaccess.Generally,itisnotsafetohaveoneprocessupdateavariablethatotherprocessesaresimultaneouslyaccessing.Theobserverprocessrepeatedlyincrementsthecounterwhenitobservesanevent.Thereporterprocessrepeatedlywritesoutthenumberofeventsthathaveoccurredsincethelastreport,resettingthecountertozero.

monitorcontroller

exportobserve,report

varcounter:int:=0

procedureobserve

counter:=counter+1

Example

endobserve

procedurereport(varn:int)

n:=counter

counter:=0

endreport

endcontroller

processobserver

…observeoneevent…

controller.observe

endloop

endobserver

processreporter

varn:int

controller.report(n)

…reportnevents…

endloop

endreporter

forkobserver%Activatetheobserver

forkreporter%Activatethereporter

Details

Amonitorisessentiallyamoduleinwhichonlyoneprocesscanbeactiveatatime.Seemoduledeclarationsfordetailsaboutinitialization.Initializationisthesameformodulesandmonitors.

Amonitorcancontainwaitstatements(thatputprocessestosleep)andsignalstatements(thatwakethemupagain).Thesestatementsoperateonconditionvariables,whichareessentiallyqueuesofsleepingprocesses.

Aclassisessentiallyatemplateforcreatingindividualmodules(objects).Seeclassfordetails.Iftheclassdeclarationisprecededbythekeywordmonitor,thecreatedmodulesareactuallymonitors.Monitorclassescanonlyinherit(inheritfrom)othermonitorclasses.

Thebodyofamonitorhasthesameformasthatofamodule,exceptthatmodules,monitorsandprocessescannotbedeclaredinsidemonitors,andcertainstatements(waitandsignal)areallowedinmonitors.

Details

ThesyntaxofamonitorDeclarationpresentedabovehasbeensimplifiedbyleavingoutpre,invariantandpostclauses.Seemoduleforanexplanationoftheseextrafeatures.ThereisalsoanoptionalcompilerTimeIntegerExpressioninthefirstline,whichisexplainedbelow.Thefullsyntaxis:

monitorid[:compileTimeIntegerExpn]

[implementimplementItem]

[implementbyimplementByItem]

[import[var]importItem{,[var]importItem

[export[howExport]id{,[howExport]id

[pretrueFalseExpn]

[invarianttrueFalseExpn]

[posttrueFalseExpn]

IftheoptionalcompileTimeIntegerExpressionispresent,thisisadevicemonitor.Itsexclusiveaccessisenforcedbyanimplementation-dependenttrick,suchasexecutingitatahardwareprioritylevelgivenbytheexpression.Adevicemonitorisrestrictedfromcallingmonitors(directlyorindirectly).Thisrestrictionisimposedtoeliminatethepossibilityofblockingaprocesswithanon-zerohardwarepriority(asthiswouldinadvertentlyallowmultipleentryintoadevicemonitor).Itistheprogrammer'sresponsibilitytomeetthisrestriction;thecompilerwillnotingeneralenforcetherestriction.Thecurrent(1999)implementationignoresthiscompileTimeIntegerExpression.

Anunexportedparameterlessprocedureinamonitorcanbespecifiedtobeaninterrupthandlingprocedurebyspecifyingadeviceinitsheader,usingtheform:

procedureid[:deviceSpecification]

ThedeviceSpecificationisacompiletimenaturalnumberthatdesignates,totheimplementation,theclassofinterruptsthateffectivelycallthisprocedure.Interrupthandlingprocedurescannotbecalledexplicitlywithintheprogram.

Details Therearetworestrictionsthattheprogrammermustfollowwhenusinginterrupthandlingprocedures;theserestrictionswillnotnecessarilybeenforcedbythesoftware.Thefirstisthataninterrupthandlingproceduremustnotexecuteawait,eitherdirectlyorindirectly,bycallinganotherprocedure.Thesecondisthattheinterrupthandlingproceduremustnotdirectlyorindirectlycauseanexception,unlesstheexceptionwillbecaughtbyanexceptionhandlerthatisactivateddirectlyorindirectlybytheinterrupthandlingprocedure.

Details

Declarationsofmonitorswithinmonitorsaredisallowed.Thiswouldberedundantanyway,asonlyoneprocesscanbeinsidetheoutermonitor,sotheinnermonitorisguaranteedtobesuccessful.

Declarationsofclasseswithinmonitorsarealsodisallowed.

Anysubprogramdeclaredwithinasubprogramisnowallowedtobeassignedtoasubprogramvariable,norpassedasaparametricsubprogram.

Seealsounit,moduleandclass.Seealsoexportlist,importlist,implementlist,implementbylistanddeferredsubprogram.

Description

ThisunitcontainsthepredefinedsubprogramsthatdealwithusingthemouseinaTuringprogram.Theroutinesallowyoutogetthecurrentmousecursorposition,checkifabuttonhasbeenpressedandgettheinformationifithas.Therearealsoroutinestohideandshowthemouseonsystemswhereitmakessense.(OnGUIbasedsystemsliketheMacintosh,themousecan'tbehiddenasitmaybeneededbyotherapplicationsrunningatthesametime.)

AllroutinesintheMousemoduleareexportedqualified(andthusmustbeprefacedwith"Mouse.").

EntryPoints

Where Getsthecurrentlocationofthemousecursorandstatusofthemousebuttons.

ButtonMoved Checkstoseeifamousebuttonhasbeenpressed.

ButtonWait Getsinformationaboutamousebuttonbeingpressedsuchaswhereitwaspressed,whichbuttonwaspressed,etc.

ButtonChoose Selectsthemodeforthemouse(eithersinglebuttonmodeormulti-buttonmode).

Mouse.ButtonChoose PartofMousemodule

Syntax Mouse.ButtonChoose(choice:string)

Description

TheMouse.ButtonChooseprocedureisusedtochangethemodeofthemouse.InTuring,themousecaneitherbein"single-buttonmode"orin"multi-buttonmode".In"single-buttonmode"themouseistreatedasaonebuttonmouse.Abuttonisconsideredpressedwhenanybuttonispressedandreleasedonlywhenallbuttonshavebeenreleased.

InTuring,themousestartsin"single-buttonmode".

Theparameterchoicecanbeoneof"singlebutton","onebutton"(whichswitchthemouseinto"single-buttonmode")or"multibutton"(whichswitchesthemouseinto"multi-buttonmode").

Example

Mouse.ButtonChoose("multibutton")

varx,y,button,left,middle,right:int

Mouse.Where(x,y,button)

left:=buttonmod10%left=0or1

middle:=(button-left)mod100%middle=0or10

right:=button-middle-left%right=0or100

ifleft=1then

put"leftbuttondown"

ifmiddle=10then

put"middlebuttondown"

ifright=100then

put"rightbuttondown"

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMouse.ButtonChoose,notbycallingButtonChoose.

Seealso

Mouse.ButtonMovedandMouse.ButtonWaittogetmouseeventssavedinaqueue.SeealsoMouse.Wheretogetthecurrentstatusofmousebutton(s).

Mouse.ButtonMoved PartofMousemodule

Syntax Mouse.ButtonMoved(motion:string):boolean

Description

TheMouse.ButtonMovedfunctionindicateswhetherthereisamouseeventoftheappropriatetypeonthemousequeue.Eventsareeither"up","down","updown"or"downup"events(althoughthe"downup"and"updown"arethesameevent).

Theparametermotionmustbeoneof"up","down","updown"or"downup".Ifaneventofthetyperequestedisinthequeue,Mouse.ButtonMovedreturnstrue.Iftheeventisnotinthequeue,thenMouse.ButtonMovedreturnsfalse.

Example

Thisprogramdrawsrandomcirclesonthescreenuntiltheuserclicksthemousebutton,whereuponisstartsdrawingrandomboxes.Clickingthemousebuttonswitchesbetweenthetwo.

varcircles:boolean:=true

varx,y,radius,clr:int

ifMouse.ButtonMoved("down")then

varbuttonnumber,buttonupdown:int

Mouse.ButtonWait("down",x,y,buttonnumber

buttonupdown)

circles:=notcircles

x:=Rand.Int(0,maxx)

y:=Rand.Int(0,maxy)

radius:=Rand.Int(0,100)

clr:=Rand.Int(0,maxcolor)

ifcirclesthen

Draw.FillOval(x,y,radius,radius,clr

Draw.FillBox(x,y,x+radius,y+radius

endloop

Example

varch:string(1)

ifhaschthen

getch(ch)

Text.Locate(1,1)

Mouse.ButtonWait("down",x,y,btnnum,

Text.Locate(1,1)

endloop

Details

Mouse.ButtonMovedcanbethoughtofasthemouseequivalentofhaschinthattheybothcheckforsomethinginaqueueandbothreturnimmediately.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMouse.ButtonMoved,notbycallingButtonMoved.

Seealso

Mouse.ButtonMovedtogetmouseeventssavedinthequeue.SeealsoMouse.ButtonChoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

Mouse.ButtonWait PartofMousemodule

SyntaxMouse.ButtonWait(motion:string, varx,y,buttonNumber,buttonUpDown:int)

Description

TheMouse.ButtonWaitproceduregetsinformationaboutamouseeventandremovesitfromthequeue.

Theparametermotionmustbeoneof"up","down","updown"or"downup".Ifaneventofthetyperequestedisinthequeue,Mouse.ButtonWaitreturnsinstantly.Ifthereisn'tsuchanevent,Mouse.ButtonWaitwaitsuntilthereisoneandthenreturns(muchlikegetchhandleskeystrokes).

Theparametersxandyaresettothepositionofthemousecursorwhenthebuttonwaspressed.Theparameterbuttonnumberissetto1whenin"single-buttonmode".In"multi-buttonmode",itissetto1iftheleftbuttonwaspressed,2ifthemiddlebuttonwaspressed,and3iftherightbuttonwaspressed.Theparameterbuttonupdownissetto1,ifabuttonwaspressedand0ifabuttonwasreleased.

Thisprogramdrawslines.Itstartsalinewheretheuserpressesdownandcontinuestoupdatethelinewhilethemousebuttonishelddown.Whenthebuttonisreleased,thelineispermanentlydrawandtheusercandrawanotherline.

varx,y,btnNumber,btnUpDown,buttons:int

varnx,ny:int

Mouse.ButtonWait("down",x,y,btnNumber,btnUpDown

Example nx:=x

Draw.Line(x,y,nx,ny,0)%Erasepreviousline

exitwhenMouse.ButtonMoved("up")

Mouse.Where(nx,ny,buttons)

Draw.Line(x,y,nx,ny,1)%Drawlinetoposition

endloop

Mouse.ButtonWait("up",nx,ny,btnNumber,btnUpDown

Draw.Line(x,y,nx,ny,2)%Drawlinetofinalposition

endloop

Example

varch:string(1)

varx,y,btnNum,btnUpDown:int

ifhaschthen

getch(ch)

Text.Locate(1,1)

Mouse.ButtonWait("down",x,y,btnNum,

Text.Locate(1,1)

endloop

Details

Mouse.ButtonWaitcanbethoughtofasthemouseequivalentofgetchinthattheybothreadsomethinginaqueueandbothwaituntiltheygetthethingthey'relookingfor.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMouse.ButtonWait,notbycallingButtonWait.

Seealso

Mouse.ButtonWaittoseeifanappropriateeventisinthequeue.SeealsoMouse.ButtonChoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

Mouse.Where PartofMousemodule

Syntax Mouse.Where(varx,y,button:int)

Description

TheMouse.Whereprocedureisusedtogetcurrentinformationaboutthestatusofthemouse.Theparametersxandyaresettothecurrentlocationofthemousecursor.Iftheprogramisrunningonasystemusingwindows,thecursormaybeoutsidethewindow.Thismeansthatxandymaybesettovaluesoutsideoftheboundsof0tomaxxand0tomaxy.

Theparameterbuttonissetdependingonthecurrentmode.In"single-buttonmode"(wherethemouseistreatedlikeaone-buttonmouse),buttonissetto0ifallthemousebuttonsareup,and1ifanyofthemousebuttonsaredown.In"multi-buttonmode",buttonisassignedthesumof1iftheleftbuttonisdown,10ifthemiddlebuttonisdown,and100iftherightbuttonisdown.Thusifbuttonhasthevalueof101,thenitmeansthattheleftandrightmousebuttonsweredepressed.

Example

varx,y,button:int

Mouse.Where(x,y,button)

Text.Locate(1,1)

ifbutton=0then

putx:4,"",y:4,"buttonup"

putx:4,"",y:4,"buttondown"

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMouse.Where,notbycallingWhere.

Mouse.ButtonMovedandMouse.ButtonWaittogetmouse

Seealso eventssavedinaqueue.SeealsoMouse.ButtonChoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

mousewhere

Syntax mousewhere(varx,y,button:int)

Description

Themousewhereprocedureisusedtogetcurrentinformationaboutthestatusofthemouse.Theparametersxandyaresettothecurrentlocationofthemousecursor.Iftheprogramisrunningonasystemusingwindows,thecursormaybeoutsidethewindow.Thismeansthatxandymaybesettovaluesoutsideoftheboundsof0tomaxxand0tomaxy.

Theparameterbuttonissetdependingonthecurrentmode.In"single-buttonmode"(wherethemouseistreatedlikeaone-buttonmouse),buttonissetto0ifallthemousebuttonsareup,and1ifanyofthemousebuttonsaredown.In"multi-buttonmode",buttonisassignedthesumof1iftheleftbuttonisdown,10ifthemiddlebuttonisdown,and100iftherightbuttonisdown.Thusifbuttonhasthevalueof101,thenitmeansthattheleftandrightmousebuttonsweredepressed.

Example

varx,y,button:int

mousewhere(x,y,button)

locate(1,1)

ifbutton=0then

putx:4,"",y:4,"buttonup"

putx:4,"",y:4,"buttondown"

endloop

Seealso

buttonmovedandbuttonwaittogetmouseeventssavedinaqueue.Seealsobuttonchoosetoswitchbetween"single-buttonmode"and"multi-buttonmode".

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithsoundandmusic.Someoftheseroutineshavenotbeenimplementedatthetimeofthewritingofthismanualandwillbeimplementedinfuturereleases.

AllroutinesintheMusicmoduleareexportedqualified(andthusmustbeprefacedwith"Music.").

EntryPoints

Play Playsaseriesofnotes.

PlayFile Playsmusicfromafile,returningwhenthefileisfinishedplaying.Filemustbeinanallowableformat.

PlayFileReturn Playsmusicfromafile,returningassoonasthemusicstarts.Filemustbeinanallowableformat.

PlayFileLoop Playsmusicfromafile,loopingoverandover.Returnsassoonasthemusicstarts.Filemustbeinanallowableformat.

PlayFileStop Immediatelyterminatesanyplayingmusicfiles.

Sound Playsaspecifiedfrequencyforaspecifiedduration.

SoundOff Immediatelyterminatesanysoundplaying.

Music.Play PartofMusicmodule

Syntax Music.Play(music:string)

Description

TheMusic.Playprocedureisusedtosoundmusicalnotesonthecomputer.

Soundsareproducedsynchronouslyonaperprocessbasis.ThismeansthatwhenaprocessexecutesaMusic.SoundorMusic.Playcommand,itstopsuntilthecommandisfinished.However,otherprocesseswillcontinuetoexecuting.

ExampleThisprogramsoundsthefirstthreenotesoftheCscale.

Music.Play("cde")

Example

ThisprogramplaysfrommiddleCtooneoctaveabovemiddleCanddownagainin8thnotes.

Music.Play("8cdefgab>c")

Music.Play("<bagfedc")

Execute

Details

Thesyntaxoftheplaystringmaybeenhancedinthefuture.

TheMusic.Playproceduretakesstringscontainingcharactersthatspecifynotes,rests,sharps,flatsandduration.Thenotesarethelettersatog(orAtoG).Arestisp(forpause).Asharpis+andaflatis-.Thedurationsare1(wholenote),2(halfnote),4(quarternote),8(eightnote)and6(sixteenthnote).Thecharacter>raisestothenextoctaveand<lowers.Forexample,thisisthewaytoplayCandthenCsharponeoctaveabove

middleCwitharestbetweenthem,allinsixteenthnotes:Music.Play(">6cpc+").BlankscanbeusedforreadabilityandareignoredbyMusic.Play.

TheMusic.Playprocedurerequiresthatthemachinehaveasoundcardinordertoplaytones.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.Play,notbycallingPlay.

SeealsotheMusic.Soundprocedure,whichmakesasoundofagivenfrequency(Hertz)andduration(milliseconds).

Music.PlayFile PartofMusicmodule

Syntax Music.PlayFile(fileName:string)

Description

TheMusic.PlayFileprocedureisusedtoplayafileofmusic.Thefilemustbeinoneoftheacceptableformatsandthemachine,musthavetheappropriatehardware.

ThefileNameparametermustgivetheformatofthefile:

WAVfiles "WAV:filename"or"filename.WAV" MP3files "MP3:filename"or"filename.MP3" MIDIfiles "MIDI:filename"or"filename.MIDI"

Soundsareproducedsynchronouslyonaperprocessbasis.ThismeansthatwhenaprocessexecutesaMusic.Sound,Music.PlayorMusic.PlayFilecommand,itstopsuntilthecommandisfinished.However,otherprocesseswillcontinueexecuting.

Details

Toplaymusicwhileperforminganyotheractivity,thecalltoMusic.PlayFilemustbeexecutedinitsownprocess.Theprocessisthencalledusingtheforkcommand.Whenaforkcommandisgiven,executionstartsontheprocess(likeaprocedurecall)andcontinuesfollowingtheforkcommandatthesametime.

Example

Thisprogramplaysthemusicinthefile"branden3.wav"whiledrawingovalsonthescreen.

processDoMusic

Music.PlayFile("branden3.wav")

endloop

endDoMusic

forkDoMusic

varx,y,clr:int

x:=Rand.Int(0,maxx)

y:=Rand.Int(0,maxy)

Draw.FillOval(x,y,30,30,clr)

endloop

Execute

DetailsToplayasoundfilerequiresthatthecomputerbeequippedwithasoundcardandspeakers.

Details

TheTuring4.1softwarecanplayfilesinthefollowingaudioformats:WAVE(.wav)files,MIDIfiles(.midior.mid),andMP3files(.mp3).Ingeneral,MIDIfilesarethemostefficientandthusarethepreferredformforlongermusicpieceslikebackgroundmusic.WAVEfilescanrecordanything,notjustmusic,soareoftenusedforsoundeffects.

Details

TheTuring4.1softwarecanalsoplaymusiconacompactdisk.Toplaythecompletecontentsofthecompactdisk,thefilenameis“cd”.Toplayasingletrackfromacompactdisk,thefilenameis“cd:[tracknumber]”.

Music.PlayFile("cd")%PlaytheentireCD

Music.PlayFile("cd:3")%PlaythethirdtrackontheCD

Details

OnthePC,differentformatsofmusiccanplaysimultaneously.ThismeansthataprogrammightuseaMIDIfileasabackgroundsoundtrackandthenuseWAVEfilesforindividualsoundeffects.Thesoundeffectswouldnotinterferewiththebackgroundmusic.Playingasecondmusicfilewiththesameformatasanalreadyplayingpieceimmediatelyhaltsthefirstpieceandstartsthesecond.Thiscanbeusedtostopasingletypeofmusicbyplayingashortsilentpieceofmusic.

Thisprogrambouncesamapleleafaroundthescreenwithbackgroundmusicandasoundeffectwhenthemapleleafhitsanedge.Whentheuserpressesanykey,theprogramimmediatelyexits.

Example

constSTAR_SIZE:int:=80

varpic,x,y,dx,dy:int

varfinished:boolean:=false

%Playsoundeffectonce.

processBoing

Music.PlayFile("boing.wav")

endBoing

%Loopplayingbackgroundmusicuntil'finished'istrue.

processBackgroundMusic

exitwhenfinished

Music.PlayFile("background.mid")

endloop

endBackgroundMusic

%Gettheoriginalpicture

Draw.FillStar(3,3,STAR_SIZE-3,STAR_SIZE-3,

pic:=Pic.New(0,0,STAR_SIZE,STAR_SIZE)

%Settheinitiallocationanddirectionofmovement

x:=Rand.Int(0,maxx-STAR_SIZE)

y:=Rand.Int(0,maxy-STAR_SIZE)

forkBackgroundMusic%Startbackgroundmusicplaying

ifx+dx<0orx+dx>maxx-STAR_SIZEthen

dx:=-dx

forkBoing

ify+dy<0ory+dy>maxy-STAR_SIZEthen

dy:=-dy

forkBoing

Pic.Draw(pic,x,y,picCopy)

exitwhenhasch

Time.Delay(5)

endloop

%Stopthebackgroundmusic.

finished:=true

Music.PlayFileStop

Execute

Seealso

Music.PlayFileStoptohaltamusicfilethatiscurrentplaying,Music.PlayFileReturnforaprocedurethatstartsamusicfileplayingandreturnsimmediately(meaningthatyoudonotneedtouseprocessandforkstatements),andMusic.PlayFileLoopthatstartsamusicfileplayingcontinuouslyuntilitisstoppedwithouttheuseofprocessorfork.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.PlayFile,notbycallingPlayFile.

Music.PlayFileLoop PartofMusicmodule

Syntax Music.PlayFileLoop(fileName:string)

Description

TheMusic.PlayFileLoopprocedureisusedtoplayafileofmusiccontinuously,loopinguntiltheprogramishaltedortheMusic.PlayFileStopcommandisgiven.Thefilemustbeinoneoftheacceptableformatsandthemachine,musthavetheappropriatehardware.

TheMusic.PlayFileLoopprocedureisusedtoprovidecontinuousbackgroundmusicforaprogram.Whencalled,themusicstartsplaying,andtheprocedurereturnsimmediately.

Details

UnlikeMusic.PlayFile,theMusic.PlayFileLoopproceduredoesnothavetobecalledinaseparateprocess.However,themusicwillnotstopplaying(norwillaprogramthatcallsthisprocedureterminate)untilMusic.PlayFileStop

Example

Thisprogramcontinuouslyplaysthemusicinthefile"branden3.wavdrawingovalsonthescreen.

Music.PlayFileLoop("branden3.wav")

varx,y,clr:int

x:=Rand.Int(0,maxx)

y:=Rand.Int(0,maxy)

exitwhenhasch

endloop

Music.PlayFileStop

Execute

Details

Music.PlayFileLoop("cd")%PlaytheentireCD

Music.PlayFileLoop("cd:3")%PlaythethirdtrackontheCD

Details

OnthePC,differentformatsofmusiccanplaysimultaneously.ThismeansthataprogrammightuseaMIDIfileasabackgroundsoundtrackandthenuseWAVEfilesforindividualsoundeffects.Thesoundeffectswouldnotinterferewiththebackgroundmusic.Playingasecondmusicfilewiththesameformatasanalreadyplayingpieceimmediatelyhaltsthefirstpieceandstartsthesecond.usedtostopasingletypeofmusicbyplayingashortsilentpieceofmusic.

Example

Music.PlayFileLoop("background.mid")%Startbackgroundmusicplaying

dx:=-dx

Music.PlayFileReturn("boing.wav")

dy:=-dy

exitwhenhasch

Time.Delay(5)

endloop

Music.PlayFileStop

Execute

Seealso Music.PlayFileStoptohaltamusicfilethatiscurrentplaying.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.PlayFileLoopbycallingPlayFileLoop.

Music.PlayFileReturn PartofMusicmodule

Syntax Music.PlayFileReturn(fileName:string)

Description

TheMusic.PlayFileReturnprocedureisusedtoplayafileofmusic.Thefilemustbeinoneoftheacceptableformatsandthemachine,musthavetheappropriatehardware.

UnlikeMusic.PlayFile,theMusic.PlayFileReturnprocedureshouldnotbecalledinaseparateprocess.Instead,theprocedurereturnsimmediately.ThismakesMusic.PlayFileReturneasiertouse,butmakesitunsuitableforplayingasetoffilessequentially.

Example

Thisprogramplaysthemusicinthefile"branden3.wav"oncewhiledrawingovalsonthescreen.Ifthemusichasnotfinishedwhentheuserpressesakey,itishaltedusingMusic.PlayFileStop

Music.PlayFileReturn("branden3.wav")

varx,y,clr:int

x:=Rand.Int(0,maxx)

y:=Rand.Int(0,maxy)

exitwhenhasch

endloop

Music.PlayFileStop

Execute

Details

Music.PlayFileReturn("cd")%PlaytheentireCD

Music.PlayFileReturn("cd:3")%PlaythethirdtrackontheCD

Details

OnthePC,differentformatsofmusiccanplaysimultaneously.ThismeansthataprogrammightuseaMIDIfileasabackgroundsoundtrackandthenuseWAVEfilesforindividualsoundeffects.Thesoundeffectswouldnotinterferewiththebackgroundmusic.Playingasecondmusicfilewiththesameformatasanalreadyplayingpieceimmediatelyhaltsthefirstpieceandstartsthesecond.usedtostopasingletypeofmusicbyplayingashortsilentpieceofmusic.

Example

Music.PlayFileLoop("background.mid")%Startbackgroundmusicplaying

dx:=-dx

dy:=-dy

exitwhenhasch

Time.Delay(5)

endloop

Music.PlayFileStop

Execute

Seealso Music.PlayFileStoptohaltamusicfilethatiscurrentplaying.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.PlayFileReturnnotbycallingPlayFileReturn.

Music.PlayFileStop PartofMusicmodule

Syntax Music.PlayFileStop

Description

TheMusic.PlayFileStopprocedureisusedtotostopallmusicfilescurrentlyplaying.ThisincludesprocessesthatareexecutingtheMusic.PlayFileprocedure(theyexitimmediatelyandstartexecutingthenextstatementintheprocess),andtheMusic.PlayFileReturnandMusic.PlayFileLoopstatements,whichsimplystopplayingthemusic.

Details

InTuring,aprogramwillnothaltexecutionuntilallprocesseshaveterminated.Thismeansthatifyouareplayingbackgroundmusic,theprogramwillnotterminate,evenifexecutionreturnsfromthemainprogramunlessthebackgroundmusicishalted.

Example

Thisprogramplaysthebackgroundmusicfor30secondsandthenterminates.Notethatitisimportanttosettheflag(finished)beforecallingMusic.PlayFileStop.IfMusic.PlayFileStopcomesfirst,itispossibleforprocesstoreturnfromMusic.PlayFile,looparound,skipovertheexitwhenandcallMusic.PlayFileagainbeforethefinishedflagisset.

varfinished:boolean:=false

%Loopplayingbackgroundmusicuntil'finished'istrue.

processBackgroundMusic

exitwhenfinished

Music.PlayFile("background.mid")

endloop

endBackgroundMusic

forkBackgroundMusic%Startthebackgroundmusic

Time.Delay(30000)%Waitfor30seconds

finished:=true%Theflagmustbesetfirst

Music.PlayFileStop%Music.PlayFilewillreturnimmediately

Execute

Seealso Music.PlayFileforplayingmusicfilesandalargerexample.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.PlayFileStop,notbycallingPlayFileStop.

Music.Sound PartofMusicmodule

Syntax Music.Sound(frequency,duration:int)

Description

TheMusic.Soundstatementisusedtocausethecomputertosoundanoteofagivenfrequencyforagiventime.Thefrequencyisincyclespersecond(Hertz).Thetimedurationisinmilliseconds.Forexample,middleAonapianois440Hertz,soMusic.Sound(440,1000)playsmiddleAforonesecond.

Soundsareproducedsynchronouslyonaperprocessbasis.ThismeansthatwhenaprocessexecutesaMusic.SoundorMusic.Playcommand,itstopsuntilthecommandisfinished.However,otherprocesseswillcontinueexecuting.

Example

Thisprogramplaysasirensoundinthebackground.

processsiren

fori:100..3000by100

Music.Sound(i,50)%Soundnote

endfor

fordecreasingi:2900..200by100

Music.Sound(i,50)%Soundnote

endfor

endloop

endsiren

forksiren

…therestoftheprogramgoesherewhilethesirencontinues…

Execute

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingMusic.SoundnotbycallingSound.

SeealsoMusic.Playstatement,whichplaysnotesbasedonmusicalnotation.Forexample,Music.Play("8C")playsaneighthnoteofmiddleC.

Music.SoundOff PartofMusicmodule

Syntax Music.SoundOff

DescriptionTheMusic.SoundOffprocedurestopsanysoundormusicthatiscurrentlyplayingoriswaitingtoplay.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingMusic.SoundOff,notbycallingSoundOff.

SeealsoMusic.Play,Music.PlayFile,andMusic.Soundprocedures,whichmakesoundsthatcanbeturnedoffwithMusic.SoundOff.

named type

Syntax

AnamedTypeisoneof:

(a) typeId (b) moduleId.typeId

DescriptionAtypecanbegivenaname(typeId)andlaterthisnamecanbeusedinsteadofwritingoutthetype.

Example

Inthisexample,phoneRecordisanamedtype.

typephoneRecord:

record

name:string(20)

phoneNumber:int

address:string(50)

endrecord

varoneEntry:phoneRecord

varphoneBook:array1..100ofphoneRecord

Details

Form(a)isthemostcommonkindofnamedtype.Form(b)isusedwhenthetypenamehasbeenexportedfromamodule.

Arrayswhoseboundsarenotknownatcompiletimecannotbenamed.

nargs numberofarguments

Syntax nargs:int

Description

Thenargsfunctionisusedtodeterminethenumberofargumentsthathavebeenpassedtoaprogramfromthecommandline.Forexample,iftheprogramisrunfromtheTuringenvironmentusing

:rfile1file2

thennargswillreturn2.Ifaprogramcalledprog.xisrununderUNIXusingthiscommand:

prog.xfile1file2

thevalueofnargswillsimilarlybe2.

Thenargsfunctionisusuallyusedtogetherwiththefetchargfunctiontoaccesstheargumentsthathavebeenpassedtotheprogram.

Seealso fetchargforanexampleoftheuseofnargs.

nat naturalnumbertype

Syntax nat

Description

Thenat(naturalnumber)typehasthevalues0,1,2,3…Naturalnumberscanbecombinedbyvariousoperators,suchasaddition(+)andmultiplication(*).Naturalnumberscanbecombinedwithintegers(typeint),inwhichcasetheresultisaninteger.Naturalnumberscanalsobecombinedwithrealnumbers,inwhichcasetheresultisgenerallyarealnumber.Naturalnumberscanalwaysbeassignedtorealvariables,withimplicitconversiontoreal.

Example varcounter:nat

varj:nat:=9

SeealsoexplicitIntegerConstant.Thenattypeisusedinsteadofintwhenthevaluesareknowntobenon-negative.

TheTuringoperatorsonnaturalnumbersarethesameasthoseforintegers:+,-,*(multiply),div(truncatingintegerdivision),mod(integerremainder),**(exponentiation),aswellascomparisons(+,not=,>,>=,<,<=).Theoperatorsand,orandxortobeappliedtonaturalnumbervalues.Thebit-wisebooleanresultisproducedasanaturalnumber.Theshr(shiftright)andshl(shiftleft)operatorsarealsointroduced.

Inthecurrentimplementation,therangeofnaturalnumbersisfrom0to4294967294.Inotherwords,themaximumvalueofanaturalnumberis2**32-2.Thisrangeexistsbecausenaturalnumbersarestoredin4bytes.Thetypesnat1,nat2andnat4specifynaturalnumbersthatfitinto1,2or4bytes.

Explicitconstantssuchas213and0areconsideredtobeintegers.Asaresultthetypeoftaxinthisdeclarationisint:

vartax:=0%Thetypeisint

Naturalnumbervaluescanbeusedwheneverintegervaluesare

Details

expectedandviceversa,giventhatthevaluedoesnotexceedtherangeoftheexpectedtype.

Whenintegerandnaturalnumbersarecombinedusingabinaryoperatorsuchas+,theresultisaninteger.Thismeans,forexample,thatifcounterisanaturalnumber,counter+1isconsideredtobeaninteger.Aslongastheresultfitsintotherangethatistheintersectionoftherangesofintandnat,theresultwillbeasexpected.Anomaliesoccurwhentheresultis(orwouldbe)greaterthanthelargestinteger(maxint=2147483647).Forexample,ifnaturalnumbernisgreaterthanmaxint,theexpressionn+1willoverflow,becauseitsresultisanint(because1isanint).Toavoidthisproblem,youmustbecarefulthatbothoperandsarenaturalnumbers.

Supposewehavethisdeclaration:

constnatOne:nat:=1

Wecansafelycomputen+natOnebecausebothoperandshavetypenat.

Naturalnumberscanbeconvertedtorealnumbersusingnatreal,butinpracticethisisrarelyused,becauseanaturalvalueusedinplaceofarealvaluewillbeautomaticallyconvertedtoreal.

Naturalnumberscanbeconvertedtostringsandbackusingnatstrandstrnat.

IntheClanguage,anaturalnumberissaidtobe"unsigned".

Seealso maxnat,int,natn,intn,natstr,strnatandnatreal.

natn n-bytenaturalnumbertype

Syntax (a) nat1 %1-bytenaturalnumber (b) nat2 %2-bytenaturalnumber (c) nat4 %4-bytenaturalnumber

Description

Thenatn(n-bytenaturalnumber)typesaremachine-dependenttypesthatoccupyaspecifiednumberofbytes.Bycontrast,thenattypeisinprincipleamachine-independentandmathematicaltype(itoverflows,however,whenthevalueistoolargeorsmall,thatis,whenthevaluedoesnotfitinto4bytes).

Examplevarcounter1:nat1%Rangeis0..255

varcounter2:nat2%Rangeis0..65536

varcounter4:nat4%Rangeis0..4294967295

Details

InTuring,therangeofthenatis0to4294967294,whichmeansthatthenat4typeallowsonemorevalue,4294967295.Thisextravalueisusedinnattorepresentthestateofbeinguninitialized.Thenatntypesallowuseofallpossiblevaluesthatfitintonbytesandtherebyeliminatescheckingforinitialization.

ThenatntypesareliketheClanguagetypesshortunsigned,unsigned,andlongunsigned,exceptthatthenumberofbytesoccupiedbytheCtypesdependsontheparticularCcompiler.

Seealsotheintntypeswhicharenbyteintegervalues.Seealsonatandint.

natreal naturalnumbertorealfunction

Syntax natreal(n:nat):real

Description

Thenatrealfunctionisusedtoconvertanaturalnumbertoarealnumber.Thisfunctionisrarelyused,becauseinTuring,anaturalnumbercanbeusedanyplacearealvalueisrequired.Whenthisisdone,thenatrealfunctionisimplicitlycalledtodotheconversionfromnattoreal.Thenatrealfunctionissimilartointreal,exceptthatnatrealhandlesvaluesthatarelargerthanintvaluesanddoesnothandlenegativevalues.

Seealso nat.Seealsotheintreal,floor,ceilandroundfunctions.

natstr natural-number-to-stringfunction

Syntax natstr(n:nat[,width:int[,base:int]]):string

Description

Thenatstrfunctionisusedtoconvertanaturalnumbertoastring.Thestringisequivalentton,paddedontheleftwithblanksasnecessarytoalengthofwidth,writteninthegivennumberbase.Forexample,natstr(14,4,10)="bb14"wherebrepresentsablank.Thewidthandbaseparametersarebothoptional.Ittheyareomitted,thestringismadejustlongenoughtoholdthevalueandthenumberbaseis10.Forexample,natstr(23)="23".

Thewidthparametermustbenon-negative.Ifwidthisnotlargeenoughtorepresentthevalueofi,thelengthisautomaticallyincreasedasneeded.

Thestringreturnedbynatstrisoftheform:

{blank}digit{digits}

where{blank}meanszeroormoreblanksanddigit{digit}meansoneormoredigits.Theleftmostdigitiseithernon-zero,orasinglezerodigit;inotherwords,leadingzerosaresuppressed.

ThelettersA,B,C…areusedtorepresentthedigitvalues10,11,12,…Thebasemustbeintherange2to36(36becausetherearetendigitsand26letters).Forexample,natstr(255,0,16)="FF".

Thenatstrfunctionistheinverseofstrnat,soforanynaturalnumbern,strnat(natstr(n))=n.

Seealso

chr,ordandstrnatfunctions.Seealsotheintstrandstrintfunctions.SeealsoexplicitIntegerConstantforthewaytowritevaluesinbase2andbase16inaprogram.

Description

TheNetmoduleallowsTCP/IPequippedmachinestocommunicate.Inthecurrentimplementation(WinOOT3.0),thisisavailableonlyunderWin32(Windows95,98,NTandlater).

Toallowtwomachinestocommunicate,theremustbeaserver(whichcallsNet,WaitForConnection)andaclient(whichcallsNet.OpenConnection).Theserverwaitsuntilaclientconnectsandthenstartscommunicationbetweenthetwo.Whenaconnectionisestablished,anetstreamisreturnedthatcanbeusedinthesamefashionasafilestream(i.e.usingputsandgets).Oncetheconnectionisfinished,theprogramscallNet.CloseConnection.

Foreaseofreadingwebpages,theNet.OpenURLConnectionopensupaURLforreadingwiththegetstatement.ItisuptotheuserprogramtointerprettheHTMLorfilelocatedattheURL.

AllsubprogramsintheNetunitareexportedqualified(andthusmustbeprefacedwith"Net.").

EntryPoints

WaitForConnection Waitsuntilaclientconnectstoaspecifiedport.

OpenConnection Opensaconnectiontoaspecifiedmachine.

OpenURLConnection OpensaconnectiontoafilespecifiedbyaURL.

CloseConnection Closesaspecifiedconnection.

BytesAvailable Returnsthenumberofbytesavailabletobereadfromanetstream.

CharAvailable Returnstrueifthereisacharacteravailabletobereadfromanetstream.

LineAvailable

Returnstrueifthereisalineoftextavailabletobereadfromanet

stream.

TokenAvailable Returnstrueifthereisatokenavailabletobereadfromanetstream.

HostAddressFromName Returnsahost'saddressgivenitshostname.

HostNameFromAddress Returnsahost'snamegivenitsaddress.

LocalAddress Returnsthehostnameofthelocalmachine.

LocalName ReturnstheTCP/IPaddressofthelocalmachine.

Net.BytesAvailable PartofNetmodule

Syntax Net.BytesAvailable(netStream:int):int

DescriptionReturnsthenumberofbytesavailableforreadingfromthenetstreamspecifiedbythenetStreamparameter.

Details

TheNetmodulerequiresaTCP/IPstacktobeinstalledandoperatinginordertofunction.Itdoesnotcommunicateusinganyotherprotocols

ItispossibleforFirewallstointerferewiththeactionsoftheNetmodule,preventingconnectionsfromtakingplace.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.BytesAvailable,notbycallingBytesAvailable.

SeealsoNet.CharAvailable,Net.LineAvailable,andNet.TokenAvailable.

Net.CharAvailable PartofNetmodule

Syntax Net.CharAvailable(netStream:int):boolean

Description

ReturnstrueifacharacteriswaitingtobereadfromthenetstreamspecifiedbythenetStreamparameter.IfNet.CharAvailablereturnstrue,thenasinglecharactercanbereadfromthestreamwithoutblocking.

Details

Example

ThefollowingprogramfragmentreadsacharacterfromnetStreamonlyifthereisonewaitingtoberead.

ifNet.CharAvailable(netStream)then

varch:char

get:netStream,ch

putch..

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.CharAvailable,notbycallingCharAvailable.

SeealsoNet.BytesAvailable,Net.LineAvailable,andNet.TokenAvailable.

Net.CloseConnection PartofNetmodule

Syntax Net.CloseConnection(netStream:int)

Description

ClosesanetworkconnectionmadewithNet.OpenConnectionorNet.WaitForConnection.Aftertheconnectionisclosed,thenetstreamcannotbeusedforanypurposeoneithersideoftheconnection.

Details

Example

Thefollowingprogramfragmentconnectstoport5300onthemachinespecifiedbynetAddress,sendstheworkOKtoitandclosestheconnection.

netStream:=Net.OpenConnection(netAddress,chatPort

ifnetStream<=0then

put"Unabletoconnectto",netAddress

return

put:netStream,"OK"

Net.CloseConnection(netStream)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.CloseConnection,notbycallingCloseConnection.

Seealso Net.OpenConnectionandNet.WaitForConnection.

Net.HostAddressFromName PartofNetmodule

SyntaxNet.HostAddressFromName(hostName:string):string

DescriptionReturnsthenumericTCP/IPaddressofthemachinewhosehostnameisspecifiedbythehostNameparameter.

Details

Example

Thefollowingprogramprintsoutthehostnameofthecurrentmachine.

varhostName:string:="www.holtsoft.com"

put"Themachineaddressof",hostName,"is",

Net.HostAddressFromName(hostName)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.HostAddressFromName,notbycallingHostAddressFromName.

Seealso Net.HostNameFromAddress.

Net.HostNameFromAddress PartofNetmodule

SyntaxNet.HostNameFromAddress(hostAddr:string):string

DescriptionReturnstheTCP/IPhostnameofthemachinewhosenumericaddressisspecifiedbythehostAddrparameter.

Details

Example

ThefollowingprogramprintsoutthehostnameofthemachinewhoseTCP/IPnumericaddressis"128.100.5.1".

varhostAddr:string:="128.100.5.1"

put"Themachinenameof",hostAddr,"is",

Net.HostNameFromAddress(hostAddr)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.HostNameFromAddress,notbycallingLocalName.

Seealso Net.HostAddressFromName.

Net.LineAvailable PartofNetmodule

Syntax Net.LineAvailable(netStream:int):boolean

Description

ReturnstrueifalineofinputiswaitingtobereadfromthenetstreamspecifiedbythenetStreamparameter.IfNet.LineAvailablereturnstrue,thenalineofinputcanbereadfromthestreamwithoutblocking.

Details

Example

ifNet.LineAvailable(netStream)then

varline:string

get:netStream,line:*

putline

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.LineAvailable,notbycallingLineAvailable.

SeealsoNet.BytesAvailable,Net.CharAvailable,andNet.TokenAvailable.

Net.LocalAddress PartofNetmodule

Syntax Net.LocalAddress:string

Description

ReturnstheTCP/IPnumericaddressofthemachinetheprogramisrunningon.Thenumericaddressisoftheformxxx.yyy.zzz.wwwwhereeachsegmentisanumberfrom0to255.

Details

Example

ThefollowingprogramprintsouttheTCP/IPnumericaddressofthecurrentmachine.

put"Yourmachineaddressis",Net.LocalAddress

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.LocalAddress,notbycallingLocalAddress.

Seealso Net.LocalName.

Net.LocalName PartofNetmodule

Syntax Net.LocalName:string

DescriptionReturnstheTCP/IPhostnameofthemachinetheprogramisrunningon.

Details

Example

Thefollowingprogramprintsoutthehostnameofthecurrentmachine.

put"Yourmachinenameis",Net.LocalName

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.LocalName,notbycallingLocalName.

Seealso Net.LocalAddress.

Net.OpenConnection PartofNetmodule

SyntaxNet.OpenConnection(netAddr:string,port:int):int

Description

AttemptstoopenaconnectiontoportspecifiedbytheportparameteronthemachinespecifiedbynetAddrparameter.Theremustbeaprogramlisteningtothatportfortheconnectiontobemade.InOOT,thisisdoneusingtheNet.WaitForConnectionfunction.

Ifsuccessful,Net.OpenConnectionreturnsanetworkstreamdescriptorwhichcanbeusedwiththeput,get,read,andwritestatementsandeoffunctiontosendandreceivedatatothelisteningprogram.ItisalsotheparameterusedfortheNet.CloseConnection,Net.BytesAvailable,Net.CharAvailable,Net.LineAvailable,andNet.TokenAvailablefunctions.

ThenetAddrparameterisastringspecifyingthenetaddressofthemachinetobeconnectedto.Thiscaneitherbethefullhostnameorthenumericaladdress.

Ingeneral,systemprogramlisteninonportswithnumbersbelow1024.Portnumbersabove1024aregenerallyavailableforusebyusercreatedprograms.

Theprogramwillwaitforanindeterminateamountoftimetomaketheconnection.Ifitfails,itwillreturnanon-positivevalue.

Details

Thefollowingprogramimplementsa"Chat"program.Oneuserrunstheprogramontheirmachineasaserver,whichwaitsfor

Example

anothermachinetoconnecttoit.Theseconduserspecifiesthemachinetoconnecttoandthenconnects.Thetwocanthentypeateachother.

%The"Chat"program

constchatPort:int:=5055

varchoice:int

put"Enter1torunchatserver"

put"Enter2torunchatsession"

put"Choice:"..

getchoice

exitwhenchoice=1orchoice=2

endloop

varnetStream:int

varnetAddress:string

ifchoice=1then

netStream:=Net.WaitForConnection(chatPort

put"Entertheaddresstoconnectto:"..

getnetAddress

netStream:=Net.OpenConnection(netAddress,

ifnetStream<=0then

put"Unabletoconnectto",netAddress

return

Draw.Cls

put"Connectedto",netAddress

varlocalRow:int:=2

varlocalCol:int:=1

varremoteRow:=maxrowdiv2

varremoteCol:int:=1

varch:char

View.Set("noecho")

ifhaschthen

ch:=getchar

put:netStream,ch

ifch='\n'then

localRow:=localRowmod(maxrowdiv

localCol:=1

Text.Locate(localRow,localCol)

put""%Cleartoendofline

Text.Locate(localRow,localCol)

putch..

localCol+=1

ifNet.CharAvailable(netStream)then

get:netStream,ch

ifch='\n'then

remoteRow:=remoteRowmod(maxrowdiv

1+(maxrowdiv2)

remoteCol:=1

Text.Locate(remoteRow,remoteCol)

putch..

remoteCol+=1

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.OpenConnection,notbycallingOpenConnection.

Seealso Net.WaitForConnectionandNet.CloseConnection.

Net.OpenURLConnection PartofNetmodule

Syntax Net.OpenURLConnection(urlAddr:string):int

Description

AttemptstoopenahttpconnectiontoptheURL(UniversalResourceLocator)specifiedbytheurlAddr.

Ifsuccessful,Net.OpenURLConnectionreturnsanetworkstreamdescriptorwhichcanbeusedwiththegetstatementandeoffunctiontoreadthewebpagelocatedattheURL.

Theprogramwillwaitforanindeterminateamountoftimetomaketheconnection.Ifitfails,itwillreturnanon-positivevalue.

Details

Example

Thefollowingprogramprintsoutthecontentsofthefilespecifiedbytheuser.

varurl:string

put"EntertheURLtoload:"..

geturl

varnetStream:int

varline:string

netStream:=Net.OpenURLConnection(url)

ifnetStream<=0then

put"Unabletoconnectto",url

return

exitwheneof(netStream)

get:netStream,line

putline

endloop

Net.CloseConnection(netStream)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.OpenURLConnection,notbycallingOpenURLConnection.

Seealso Net.CloseConnection.

Net.TokenAvailable PartofNetmodule

Syntax Net.TokenAvailable(netStream:int):boolean

Description

ReturnstrueifalineofinputiswaitingtobereadfromthenetstreamspecifiedbythenetStreamparameter.IfNet.TokenAvailablereturnstrue,thenasingletoken(charactersurroundedbywhitespace)canbereadfromthestreamwithoutblocking.

Details

Example

ifNet.TokenAvailable(netStream)then

vartoken:string

get:netStream,token

puttoken

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.TokenAvailable,notbycallingTokenAvailable.

SeealsoNet.BytesAvailable,Net.CharAvailable,andNet.LineAvailable.

Net.WaitForConnection PartofNetmodule

SyntaxNet.WaitForConnection(port:int,varnetAddr:string):int

Description

Listensforaconnectionattheportspecifiedbytheportparameter.Whenanotherprogramconnectstotheport,thenthefunctionreturns.TheaddressoftheconnectingmachineisspecifiedinthenetAddrparameterandtheNet.WaitForConnectionreturnsanetworkstreamdescriptorwhichcanbeusedwiththeput,get,read,andwritestatementsandeoffunctiontosendandreceivedatatotheconnectingprogram.ItisalsotheparameterusedfortheNet.CloseConnection,Net.BytesAvailable,Net.CharAvailable,Net.LineAvailable,andNet.TokenAvailablefunctions.

InOOT,theconnectiontoaportismadewiththeNet.OpenConnectionfunction.

ThenetAddrparameterisastringspecifyingthenetaddressofthemachinethatconnectedtotheport.Itisthemachinesnumericaladdress.

Ingeneral,systemprogramlisteninonportswithnumbersbelow1024.Portnumbersabove1024aregenerallyavailableforusebyusercreatedprograms.

Theprogramwillwaitforindefinitelyforaconnectiontomadetotheport.

Details

SeeNet.OpenConnectionforanexampleof

Example Net.WaitForConnection.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingNet.WaitForConnection,notbycallingWaitForConnection.

Seealso Net.OpenConnectionandNet.CloseConnection.

new statement

Syntax

AnewStatementis:

new[collectionOrClassId,]pointerVariableReference

Description

Anewstatementcreates(allocates)anewelementandassignsitslocationtothepointervariable.Thiselementcanbeanobjectofacollectionorclassoravalueofatype.IfthecollectionOrClassIdisomitted,thechoiceofelementisdeterminedbythetypeofthepointer.Forexample,ifthepointeristoclassC,anobjectofclasswillbeallocated.

Example

Usingacollection,declarealistofrecordsandallocateonerecord.

record

contents:string(10)

next:pointertolist%Shortform:next:^list

endrecord

varfirst:pointertolist%Shortform:var

newlist,first%Shortform:newfirst

Example

Usingaclass,createanobjectofthatclass.Theobjectislocatedbythe

classnode

exportvarnext,varname

name:string(25)

next:pointertonode%Shortform:next:^node

endnode

varstart:pointertonode%Shortform:varstart:^node

newnode,start%Shortform:newstart

Example

Usingarecordtype,declarealistofrecordsandallocateonerecord.

typeitem:

record

contents:string(10)

next:pointertoitem%Shortform:next:^item

endrecord

varfirst:pointertoitem%Shortform:var

newfirst

Details

Astheexamplesinthissectionshow,apointercanlocateoneofthreethings:anobjectofacollection,anobjectofaclassoravalueofatype.

Inthenewstatement,thecollectionOrClassIdcanbeomitted.Ifthepointerlocatesatype,itmustbeomitted.Thefreestatementisusedtodeallocateanelement.

Animportedclasscanhaveoneofitsobjectscreated(bythenewstatement)onlyiftheclassisimportedvar.

Ifthereisnomorespacetoallocateanelement,newwillsetthepointertobethevalue,andtheprogramwillcontinueexecuting.

IfthepointerlocatesclassCandCcontainsanimplementbylist,theobjectcreatedbynewistheinheritedobject(throughanynumberoflevelsofimplementpointer,however,remainsapointertoC.

TheformnewpisashortformfornewC,pwhenCistheclassorcollectiongiveninp'stype.

IfpisapointertoclassCandChasadescendant(expansion)classstatementcanbeusedtoallocateanobjectoftypeD,asin:

newD,p%AllocatesanobjectofclassD

IfDhasanimplementbyclause,theexpansioniscreated.

Details

Thenewstatementcanalsobeusedtoresizeaflexiblearray.Ifanarrayhasbeendeclaredflexibleusingthesyntax.

varname:flexiblearrayindexType{,indexType

Theindicesmayhavecompile-timeorrun-timeupperbounds(thelowerboundmustbecompile-time).Theupperboundscanbechangedbyusing:

Additionally,theupperbound(bothinthedeclarationandthenewstatement)canbe

madeonelessthanthelowerbound.Thiseffectivelymakesanarraythatcontains0elements.Itcanlaterbeincreasedinsizewithanothernew.

Currently,onlyvariablescanbedeclaredinthisform.Thereisnoflexiblearrayparametertype,althoughaflexiblearraycanbepassedtoanarrayparameterwith"*"astheupperbound.

Example Seearrayforanexampleofflexiblearrays.

Seealso

classandcollectiondeclarations,pointertype,freestatement,nilvalueandimplementbylist.

Forflexiblearrays,seealsoarrayandflexible.

nil pointertoacollection

Syntax nil[(collectionOrClassId)]

Description

Thenilpointerdoesnotlocateanyelement(object).Pointerslocateitemsincollections,classesandtypes.ThecollectionOrClassIdisoptional.

Thisnilpointerisdistinctfrompointerstoactualelements,anditcanbecomparedtothesepointers.Itisalsodistinctfromtheuninitializedpointervalue.

Example

Inthisexample,thepointercalledfirstissettothenilpointerofcollectionc,thatis,tonil(c).

varc:collectionof

record

name:string(50)

next:pointertoc

endrecord

varfirst:pointertoc:=nil(c)

Details

Seealsocollection,classandpointer.WhenniliswrittenwithoutthecollectionOrClassId,itcanbeassignedtoapointertoanycollection,classortype.

ThetypeofnilwithoutthecollectionOrClassIdiseffectivelyapointertoeveryClass,animaginaryclassthathasnoobjectsandisthedescendantofallclasses.Thisimpliesthatitcanbeassignedtoanyotherclasspointer,becauseitisadescendantofallclasses.

Turingallowsyoutowritenil(id)afteraforwarddeclarationofid(thenameofacollection,classortype)before(andafter)theresolutionoftheid.

not true/false(boolean)operator

Syntax not

DescriptionThenot(booleannegation)operatorproducestheoppositeofatrue/falsevalue.Forexample,not(x>y)isequivalenttox<=y.

Examplevarerror:boolean:=false

varsuccess:boolean

success:=noterror%successbecomestheoppositeoferror

Details

Thenotoperatortakestrueandproducesfalseandtakesfalseandproducestrue.Thenotoperatorcanbewrittenas~.Seealsothebooleantype,prefixoperators,andprecedenceofoperators.

Thenotoperatorcanbeappliedtosets.

objectclass ofapointer

Syntax objectclass(pointerExpn)

Description

Theobjectclassattributeisusedtofindtheclassofanobjectlocatedbyapointer.ThepointerExpnmustbeanexpressionthatisapointertoaclass.

Example

Seeclassforanexampleofclassesandinheritance,inwhichaclasscalledTextFileisinheritedbyaclasscalledDevice.TheDeviceclassaddsanewexportedprocedurecalledioCtl.Inthepresentexample,objectclassisusedtotesttomakesurethatthetextFilePtrcurrentlylocatesanobjectthatwascreatedasaDevice(orasadescendantofDevice).ThenotationDevice(textFilePtr)convertsthepointertobeapointertoaDevicesothatioCtlcanbecalled.

vartextFilePtr:^TextFile

ifobjectclass(textFilePtr)>=Devicethen

%CansafelytreatobjectasaDevice

Device(textFilePtr).ioCtl

Details

Thisexampleusestheclasscomparisonoperator>=whichmeans"isadescendantof".Seeclass.

Youcanonlyuseobjectclassinclasscomparisons.Inparticular,objectclasscannotbeusedtodeclarepointers.Forexample,this:

varp:^objectclass(q)

isnotallowed.

opaque type

Description

WhenatypeTisexportedfrommodule,monitororclassMusingthekeywordopaque,thetypeM.Tisdistinctfromallothertypes.OpaquetypesareusedtoguaranteethatupdatestovaluesofthetypearedonewithinM.

Seealso

moduledeclarationsforanexampleofanopaquetypeusedtoimplementcomplexarithmetic.Seealsoequivalenceoftypesforthedefinitionofthetypematchingrulesforopaquetypes.

open filestatement

Syntax

AnopenStatementisoneof:

(a) open:fileNumberVar,fileName,ioCapability {,ioCapability} (b) open:fileNumberVar,argNum,ioCapability {,ioCapability}

Description

Theopenstatementconnectstheprogramtoafilesotheprogramcanperformoperationssuchasreadonthefile.Inform(a),theopenstatementtranslatesafileName,suchas"Master",toafilenumbersuchas5.Form(b),whichisless-commonlyused,opensafilewhosenameisgivenbyaprogramargument.Thisisdescribedbelow.

Thereadstatementusesthefilenumber,notthefilename,toaccessthefile.Whentheprogramisfinishedusingthefile,itdisconnectsfromthefileusingthestatement.EachioCapabilityisthenameofanoperation,suchasreadperformedonthefile.

Example

Thisprogramsillustrateshowtoopen,readandthencloseafile.

varfileName:string:="Master"%Nameoffile

varfileNo:int%Numberoffile

varinputVariable:string(100)

open:fileNo,fileName,read

read:fileNo,inputVariable

close:fileNo

TheopenstatementalwayssetsthefileNumbertoapositivenumber.Ifthefails(generallybecausethefiledoesnotexist),thefileNumberissettoanon-positivenumber.Itiswisetocheckthatthestreamnumberisgreaterthanzerobeforeusingitfurther.

AnioCapabilityisoneof:

get,put,read,write,seek,mod

Details

Afilecanbeaccessedusingonlythestatementscorrespondingtotheinput/outputcapabilitieswithwhichitwasopened.Note:tellisallowedonlyiftheopenisforseek.

TheopenstatementtruncatesthefiletolengthzeroiftheioCapabilitiesputorwritebutnotmod(whichstandsformodify).Inallothercases,theexistingfileintact.ThemodioCapabilityspecifiesthatthefileistobemodifiedwithoutbeingtruncated.Eachopenpositionstothebeginningofafile.Thereisnomechanismtodeleteafile.

Toopenforappendingtotheendofthefile,onehastoopenforseekwriteorputandthenseektotheendofthefile.Seetheseekstatement.

Mixedmodefiles,whichcombinegetandread(orputandwrite),aresupportedbysomeoperatingsystems,suchasUNIX,butnotbyothers,suchasMicrosoftWindows.

OnMicrosoftWindows,oneshouldnotethatopeningfilesinotherdirectoriesusesthebackslashcharacter.ThisisbecausethebackslashisaspecialcharacterinTuring(asin\tfortaband\nforanewline).Togetasinglebackslash,use\\.

e.g.open:f,"C:\\STUDENTS\\SMITH\\ACCT.DAT",

Form(b)ofthesyntaxallowsyoutoopenafilewhosenameisgivenasaprogramargumentonthecommandline.Forexample,underUNIX,thecommandline:

prog.xinfileoutfile

specifiestoexecuteprog.xwithprogramargumentsinfileandoutfiletheTuringprogrammingenvironment,theruncommandcanacceptprogramarguments.TheargNumberisthepositionoftheargumentonthecommandline.(Thefirstargumentisnumber1.)Thenameofthefiletobeopenedisthecorrespondingprogramargument.Ifthereisnosuchargument,orifthefilecannotbeopenedsuccessfully,fileNumberVariableissettozero.Seealsogivesthenumberofarguments,andfetcharg,whichgivesthen-thargumentstring.

Programargumentfilesreferencedbyargumentnumberandusedinorwritestatementsneednotbeexplicitlyopened,butareimplicitlyopenedwiththecapabilitycorrespondingtotheinput/outputstatementinwhichtheyarefirstused.(ThefileNumbergivesthenumberoftheargument.)

Theoperatingsystemstandardfiles(error,outputandinput)areaccessedusingfilenumbers0,-1,and-2,respectively(althoughthismaybesubjecttochange).Thesefilesarenotopenedexplicitly,butareusedsimplybyusingform(b)withthenumber.Bewareoftheanomalouscaseofafailedopenthatgivesyoufilenumber0.Asubsequentuseofthisnumberinaputwillproduceoutputthatgoestothestandarderrorstream,withnowarningthatthefileyouattemptedtoopenisnotactuallybeingused.

Toappendtoafile,thefilemustbeopenedwiththemodandseekthentheremustbeaseektotheendoffile.Forexample:

varstreamnumber:int

open:streamnumber,"myfile",put,mod,seek

seek:streamnumber,*

put:streamnumber,"Thisappearsattheendofthefile"

Thereisanolderandstillacceptableversionofopenthathasthissyntax:

open(varfileNumber:int,fileName:string,

Themodemustbe"r"(forget)or"w"(forput).

Details

ThepathnamespecifiedintheopenstatementandelsewherecanalwaysbeinUNIXformat(i.e.withforwardslashes,aninitialforwardslashindicatinganabsolutedirectory).OnthePC,absolutepathswouldhavetheform:

a:/dir1/dir2/filename

OntheMacintosh,theywouldhavetheform:

/volumename/directory1/directory2/filename

NotethatinadditiontotheUNIXpathformat,onthePC,youcanalwaysusestandardPCpathnotationandontheMacintosh,youcanusestandardMacintoshpathnotation.OntheMacintoshvolume,directoryandfilenamescanhavespacesinthem.

Allroutines(suchastheFileandDirmoduleroutines)willreturnfilesnamesinUNIXformat,regardlessofthemachinetheprogramisrunon.

Seealso close,get,put,read,write,seekandtellstatements.

or operator

Syntax AorB

Description

Theor(boolean)operatoryieldsaresultoftrueifatleastone(orboth)oftheoperandsistrue.orisashortcircuitoperator.Forexample,ifAistrueinAorBthenBisnotevaluated.

Examplevarsuccess:boolean:=false

varcontinuing:=true%thetypeisboolean

continuing:=continuingorsuccess

Details

continuingissettofalse,ifandonlyif,bothcontinuingandsuccessarefalse.SinceTuringusesshortcircuitoperators,oncecontinuingistrue,successwillnotbelookedat.

Theoroperatorcanbeappliedtonaturalnumbers.Theresultisthenaturalnumberthatisthebit-wiseoroftheoperands.Seenat(naturalnumber).

Seealso

boolean(whichdiscussestrue/falsevalues),explicitTrueFalseConstant(whichdiscussesthevaluestrueandfalse),precedenceandexpn(expression).

ord character-to-integerfunction

Syntax ord(ch:char):int

Description

Theordfunctionacceptsanenumeratedvalue,char,orastringoflength1,andreturnsthepositionofthevalueintheenumeration,orofthecharacterintheASCII(orEBCDICforIBMmainframes)sequence.Valuesofanenumeratedtypearenumberedlefttorightstartingatzero.Forexample,ord("A")is65.Theordfunctionistheinverseofchr,soforanycharacterc,chr(ord(c))=c.

Seealso chr,intstrandstrintfunctions.

parallelget parallelportfunction

Syntax parallelget:int

Description

TheparallelgetprocedureisusedonaPCtoreadthevalueofcertainpinsontheparallelport.ThisportcorrespondstotheMS-DOSdevice"LPT1".Thisprocedurecanbeusedtocontrolrobotsandperipherals.

Example

ThisprogramreadsandprintsthevaluesofthefivedatapinsofthePC'sparallelport.

constval:int:=parallelget%Readinthesetofpinvalues

put"Pin10is:",(valdiv64)mod2

Details

Thefivepinsthatareusedforparallelinputarepins10-15.Theparallelgetprocedurereturnsthesumof

64 Pin10high 128 Pin11high 32 Pin12high 16 Pin13high 8 Pin15high

Themodanddivoperatorscanbeusedtodeterminewhichpinsarehighorlow.

Seealsotheparallelputprocedureforadiagramofthepins.Thatprocedurevaluesontheparallelport.

parallelput parallelportprocedure

Syntax parallelput(p:int)

Description

TheparallelputprocedureisusedonaPCtosetthevaluesonthedatapinsontheparallelport.ThisportcorrespondstotheMS-DOSdevice"LPT1".Thisprocedurecanbeusedtocontrolrobotsandperipherals.

Example

Thisprogramsetsdatabit0,databit1andsoontodatabit7.

fori:0..7

parallelput(2**i)%Setdatabitiontheparallelport

put"Databit",i,"orPin",i+2,"hasjustbeenset"

endfor

Details

TheparallelputprocedureisusedtosettheeightdatabitsonthePC'sparallelport.Thesedatabits0-7correspondtopins2-9ontheparallelport.

Thevaluesenttoparallelputisthesumofthefollowing:

1 Databit0 16 Databit4 2 Databit1 32 Databit5 4 Databit2 64 Databit6 8 Databit3 128 Databit7

Forexample,thecommandparallelput(97)setsdatabits0,5and6high(97=1+32+64)andsetstheotherdatapinslow.Becausethereareonly8datapinsintheparallelport,thevaluepassedtoparallelputmustbefrom0to255.

Theparallelputprocedureisnotmeantforsendingastreamofcharacterstotheparallelport(forexample,ifyouwanttosendthestring"Hello"totheprinter).Ifyouwanttodothis,openthefile"LPT1"using

theopenstatementandputtothefile.

Seealsotheparallelgetfunction,whichisusedtoreadthevaluesofpinsontheparallelport.

paramDeclaration parameterdeclaration

Syntax

AparamDeclarationisoneof:

(a) [var]id{,id}:typeSpec (b) subprogramHeader

Description

Aparameterdeclaration,whichispartoftheheaderofaprocedureorfunction,specifiesaformalparameter(seealsoprocedureandfunctiondeclarations).Form(a)aboveisthemostcommoncase.Form(b)specifiesproceduresandfunctionsthatarethemselvespassedasparameters.

Example

procedureputTitle(title:string)

%Theparameterdeclarationis:title:string

puttitle

endputTitle

procedurex(vars:array1..*ofstring(*))

%Seteachelementofstothenullstring

fori:1..upper(s)

s(i):=""

endfor

Details

Parameterstoaproceduremaybedeclaredusingvar,whichmeansthattheparametercanbechangedinsidetheprocedure.Forexample,sischangedintheprocedure.Ifaparameterisdeclaredwithoutvar,itcannotbechanged.(ThisdiffersfromPascal,wherenon-varparameterscanbechanged.)Parameterstofunctionscannotbedeclaredtobevar.

Parametersdeclaredvararepassedbyreference,whichmeansthatapointertothevalueispassedtotheprocedure,ratherthanpassingtheactualvalue.Thisimpliesthatinthecallp(a(i)),inwhicharrayelementa(i)ispassedtoprocedurep,achangetoiinpdoesnotchangetheelementreferredtobyp'sactualparameter.Everynon-scalar(notinteger,subrange,real,boolean,enumerated,pointerorthechartype)parameterispassedbyreferencewhetherornotitisdeclaredvar.Inallothercases(scalarnon-varparameters)theparameterispassedbyvalue(theactualvalueiscopiedtotheprocedure).

Theupperboundofanarrayorstringthatisaformalparametermaybespecifiedasanasterisk(*),asisdoneaboveforparametersinprocedurex.Thisspecifiesthatthesizeoftheupperboundisinheritedfromthecorrespondingactualparameter.Parametersdeclaredusingstararecalleddynamicparameters.

Thenamesoftheformalparametersmustbedistinctfromeachother,fromtheprocedureorfunctionname,andfrompervasiveidentifiers.However,theyneednotbedistinctfromnamesoutsideoftheprocedureorfunction.

Example

Findthezerooffunctionf.Thisexampleillustratesform(b),whichisaparameterthatisafunction.SeealsosubprogramHeader.

functionfindZero(functionf(x:real):real

left,right,accuracy:real):

presign(f(left))not=sign(f(right)

andaccuracy>0

varL:real:=left

varR:real:=right

varM:real

constsignLeft:=sign(f(left))

M:=(R+L)/2

exitwhenabs(R-L)<=accuracy

ifsignLeft=sign(f(M))then

endloop

resultM

endfindZero

Details

Form(b)ofparamDeclarationisusedtospecifyformalparametersthatarethemselvesproceduresorfunctions.Forexample,inthefindZerofunction,formalparameterthatisitselfafunction.Thesubprogramtypecanbeusedtoreplaceform(b).Inparticular,theheadertothefindZerofunctioncanbereplacedbythefollowingwithnochangeintheaction.Thenamesgandxservenopurpose,exceptasplaceholdersinthedeclarationoff.

functionfindZero(f:functiong(x:real):

left,right,accuracy:real):

Parametersthataredeclarednonvarshould,inprinciple,beconstant.

Details

Unfortunately,thereisananomaloussituationinwhichthesecanchange.Thisoccurswhentheparameterispassedbyreference,becauseitisanonscalarsuchasastring.Iftheactualparameterischangedwhilethesubprogramisexecuting,theformalparameterwillchangeaswell.

Youcanalsooptionallyusetheregisterkeywordtorequestthatthevariablebeplacedinamachineregister.Thischangesform(a)toallowtheoptionaluseoftheregisterkeyword.Thesyntaxforform(a)isactually:

[var][register]id{,id}:[cheat]typeSpec

Inthecurrent(1999)implementation,programsareruninterpretivelyusingpseudo-code,whichhasnomachineregisters,andtheregisterkeywordisignored.Seeregisterforrestrictionsontheuseofregisterparameters.

Theoptionalkeywordcheatmeansthattheparameterhasatypecheat.SeeAnyvariableorconstantnonscalar(inotherwords,itemspassedbyreference)canbepassedtoatypecheatparameter.Theinternalrepresentationwillbeinterpretedasavalueofthespecifiedtype.Thisisdangerousasitprovidesunconstrainedaccesstotheunderlyingcomputermemory.

Example

Thisprocedureoutputsthevaluesofnbytesstartingattheaddressofformalparametera,usingaparametertypecheat.

proceduredump(a:cheatarray0..10000ofnat1

fori:0..n-1

puti,a(i):4

endfor

enddump

vars:string:="abc"

dump(s,5)%Dumps5bytes,startingwith

pause statement

Syntax

ApauseStatementis:

pauseexpn

Description

Thepausestatementblockstheprogram(orjusttheprocessinthecaseofaconcurrentprogram)foragivennumberofsimulatedtimeunits.Theexpnmustbeanon-negativeintvaluegivingthenumberoftimeunits.Thisisanalogoustothedelaystatement,whichcausesblockingforagivenamountofrealtime(actualphysicaltime).

Theinterpretermaintainsacounterwhichitconsiderstobesimulatedtime.Theonlyexecutionthatcausesthiscountertoincreaseisthepausestatement.Theprocessexecutingthepauseisblockeduntilthecounterhascountedforwardthenumberofunitsgivenbyexpn.Allotherstatements(exceptwait)areconsideredtobeinfinitelyfast.Severalprocessescanbeexecutingpausestatementssimultaneously.

TheuseofsimulatedtimeallowsTuringtobeusedasasimulationlanguageinwhichthepausestatementsimulatesthepassageoftimeinthesimulatedsystem.

Description

ThisunitcontainsthepredefinedsubprogramsthatdealwithdirectaccesstothehardwareundertheIBMPCarchitecture.

AllroutinesinthePCunitareexportedqualified(andthusmustbeprefacedwith"PC.").

EntryPoints

ParallelGet Returnsthevalueofthepinssetontheparallelport.

ParallelPut Setsthevaluesofthepinsontheparallelport.

PC.ParallelGet PartofPCmodule

Syntax PC.ParallelGet(port:int):nat1

Description

ThePC.ParallelGetfunctionisusedtoreadthevalueofcertainpinsonaparallelport.Theportisspecifiedwiththeportparameterwhichcanhavethevalue1,2or3correspondingto"LPT1","LPT2"and"LPT3".Thisprocedurecanbeusedtocontrolrobotsandperipherals.

Example

ThisprogramreadsandprintsthevaluesofthefivedatapinsofthePC'sparallelport.

%ReadinthesetofpinvaluesfromLPT1

constval:int:=PC.ParallelGet(1)

Details

Thefivepinsthatareusedforparallelinputarepins10-15.ThePC.ParallelGetprocedurereturnsthesumof

64 Pin10high 128 Pin11high 32 Pin12high 16 Pin13high 8 Pin15high

Themodanddivoperatorscanbeusedtodeterminewhichpinsarehighorlow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPC.ParallelGet,notbycallingParallelGet.

PC.ParallelPutprocedureforadiagramofthepins.That

Seealso procedureisusedtosetthevaluesontheparallelport.

PC.ParallelPut PartofPCmodule

Syntax PC.ParallelPut(port:int,value:int)

Description

ThePC.ParallelPutprocedureisusedonaPCtosetthevaluesonthedatapinsontheparallelport.Theportisspecifiedwiththeportparameterwhichcanhavethevalue1,2or3correspondingto"LPT1","LPT2"and"LPT3".Thisprocedurecanbeusedtocontrolrobotsandperipherals.

Example

Thisprogramsetsdatabit0,databit1andsoontodatabit7.

fori:0..7

%SetdatabitionparallelportLPT2

PC.ParallelPut(2,2**i)

put"Databit",i,"orPin",i+2,"hasjustbeenset"

endfor

Details

ThePC.ParallelPutprocedureisusedtosettheeightdatabitsonthePC'sparallelport.Thesedatabits0-7correspondtopins2-9ontheparallelport.

ThevaluesenttoPC.ParallelPutisthesumofthefollowing:

1 Databit0 16 Databit4 2 Databit1 32 Databit5 4 Databit2 64 Databit6 8 Databit3 128 Databit7

Forexample,thecommandPC.ParallelPut(97)setsdatabits0,5and6high(97=1+32+64)andsetstheotherdatapinslow.Becausethereareonly8datapinsintheparallelport,thevaluepassedtoPC.ParallelPutmustbefrom0to255.

ThePC.ParallelPutprocedureisnotmeantforsendingastreamofcharacterstotheparallelport(forexample,ifyouwanttosendthestring"Hello"totheprinter).Ifyouwanttodothis,openthefile"LPT1"usingtheopenstatementandputtothefile.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPC.ParallelPut,notbycallingParallelPut.

SeealsoPC.ParallelGetfunction,whichisusedtoreadthevaluesofpinsontheparallelport.

pervasive declarationmodifier

Description

Whenavariable,constant,typeorsubprogramisdeclared,youcanspecifythatitistobepervasive,whichmeansthatitdoesnotneedtobeexplicitlyimportedintomodules,monitorsorclassesinthecurrentscope.Thekeywordcanbeabbreviatedasanasterisk(*).

Example

varpervasivecounter:int%Shortform:var*count:int

const*maxCounter:int:=100

procedure*p(x:real)

DetailsThekeywordpervasiveisalsousedinexportlistsalongwiththekeywordunqualified.Seeexportlistfordetails.

Seealsovardeclaration,constdeclaration,proceduredeclaration,functionsubprogramheaderandexportlistforusesofpervasive.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithtakingpicturesofpartofthescreen,displayingthemandmovingpicturesfromfiletoscreenandback.

AllroutinesinthePicunitareexportedqualified(andthusmustbeprefacedwith"Pic.").

EntryPoints

New Createsapicturefromaspecifiedportionofthescreen.

Draw Drawsapictureonthescreen.

DrawSpecial Drawsapictureonthescreenusingspecialeffects.

DrawSpecialBack Drawsapictureonthescreenwhilecontinuingexecutionusingspecialeffects.

Free FreesupthepicturecreatedbyusingNeworFileNew.

FileNew Createsapicturefromafileinanallowedformat.

Save Savesapictureasafileinanallowedformat.

ScreenLoad Displaysafileinanallowedformatonthescreendirectly.

ScreenSave Savesaspecifiedportionofthescreenasafileinanallowedformat.

Rotate Createsanewpicturebyrotatinganexistingpicture.

Scale Createsanewpicturebyscalinganexistingpicture.

Flip Createsanewpicturebyflippinganexistingpictureupside-down.

Mirror Createsanewmirror-imageofanexistingpicture.Createsanewpicturebyblending

Blend twoexistingpicturestogether.

Blur Createsanewpicturebyblurringanexistingpictures.

Width Returnsthewidthofapicture.Height Returnstheheightofapicture.

Frames Returnsthethenumberofframesinamulti-frameGIFfile.

FileNewFrames Createsanarrayofpicturesfromamulti-frameGIFfile.

DrawFrames Drawsaseriesofpicturesonthescreeninsequencewhilecontinuingexecution.

DrawFramesBack Drawsaseriesofpicturesonthescreeninsequence.

SetTransparentColor SetsthecolortobeignoredwhenusingpicMergemode.

SetTransparentColour SetsthecolortobeignoredwhenusingpicMergemode.

Pic.Blend PartofPicmodule

Syntax Pic.Blend(picID1,picID2,pct:int):int

Description

Pic.Blendisusedtocreateanewpicturebyblendingtwoidenticallysizedpictures.Theresultingpictureiscreatedbytakingpct%ofthefirstpictureandaddingitto(100-pct)%ofthesecondpicture.

Details

Notethattheblendedpictureisanewlycreatedpicture.Whenitisnolongerneeded,itsmemoryshouldbereleasedbyusingPic.Free.

Notethatifpctis100,thentheresultingpicturewillbeidenticaltois0,thentheresultingpicturewillbeidenticaltopicID2.

Example

Theprogramcreatestwoidenticallysizedpictures,blendsthemtogetheranddisplaysallthreepictures.Youcanvarytheblendpercentagetoobtaindifferentresults.

%Createtheoriginalpictures

varpic1,pic2,picBlended:int

Draw.FillOval(50,50,50,50,brightblue)

pic1:=Pic.New(0,0,100,100)

Draw.FillMapleLeaf(10,10,90,90,brightred)

pic2:=Pic.New(0,0,100,100)

%Createnewpicturebyblending30%frompic1,70%frompic2

picBlended:=Pic.Blend(pic1,pic2,30)

%Drawthethreeimages

Pic.Draw(pic1,10,10,picCopy)

Pic.Draw(picBlended,230,10,picCopy)

OutputfromtheProgram

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.BlendBlend.

Pic.Blur PartofPicmodule

Syntax Pic.Blur(picID,blurAmount:int):int

Description

Pic.Blurisusedtocreateanewpicturebyblurringanexistingpicture.Theresultingpictureiscreatedbymixingpixelsinapicturewithpixelsadjacenttoit.AstheblurAmountincreases,theimagegrowsmoreandmoreblurry.

Details

Notethattheblurredpictureisanewlycreatedpicture.Whenitisnolongerneeded,itsmemoryshouldbereleasedbyusingPic.Free.

NotethatthisisafairlyCPUintensiveroutine.Onslowmachines,toasecondormorewhenblurAmountislarge.Insuchcases,itisbettertoprecomputethepicturesbeforestartingtheprogram.Thesecondexampleshowsthisbeingdone.

Example

Theprogramcreatesapictureandthenprogressivelyblursit.

%Createtheoriginalpicture

varf:=Font.New("serif:60:bold,italic,noantialias")

Font.Draw("Turing",10,30,f,red)

Draw.FillBox(240,5,270,35,brightblue)

varoldPic:int

oldPic:=Pic.New(0,0,maxx,maxy)

varnewPic:int

%Createthenewpicturebyblurringtheoldpicture

newPic:=Pic.Blur(oldPic,10)

%Freetheoldpicturesowedon'trunoutofmemory

Pic.Free(oldPic)

Pic.Draw(newPic,0,0,picCopy)

delay(300)

oldPic:=newPic

endloop

Outputatstart Afterseveralloops

Execute

Byprecalculatingandsavingtheresultsoftheblurredpicture,youvisualeffectwhereanobjectseemstocomeintofocus.Theprogrambelowblursanimage,savingeachstep.Itthendrawstheimagesinreverseorder,makingitappearasiftheimageisbecomingsuccessivelysharper.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Blur,notbycallingBlur.

Pic.Draw PartofPicmodule

Syntax Pic.Draw(picID,x,y,mode:int)

Description

Pic.Drawisusedtodrawapictureonthescreen.Thepictureisdrawnwiththelowerleftcornerat(x,y).

Themodeparameterhasoneofthefollowingvalues:

picCopy Thisdrawsthepictureontopofwhatwasunderneath,obscuringitcompletely.

picXor

ThisdrawsthepictureXORingitwiththebackground.InDOS,youcanusethisfunctiontodoanimation.DrawinganobjectontopofitselfwithXORerasesitandrestoresthebackground.

picMerge

ThisdrawsthepicturelikepicCopyexceptthatanyoccurrenceofthebackgroundcolorinthepictureisnotdrawntothescreen.Thisallowsyoutodrawanirregularly-shapedobjectanddrawittothescreen.

picUnderMerge

Thisdrawsthepicture,butonlywherethebackgroundcolorwasdisplayedunderneathit.Theeffectofthisistomakethepictureappeartobedisplayedbehindthebackground.

Execute

IfthePic.Drawcallfails,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Details

DisplayModeswithPic.Draw

Example

Theprogramdrawsagraphiconthescreenandthenrepeatsit50timesinrandompositions.

varpicID:int

varx,y:int

Draw.FillBox(50,50,150,150,red)

Draw.FillStar(50,50,150,150,green)

picID:=Pic.New(50,50,150,150)

fori:1..50

Pic.Draw(picID,x,y,picCopy)

endfor

Pic.Free(picID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Draw,notbycallingDraw.

Seealso

View.Updateforinformationonhowtoproducesmoothanimation.

Pic.DrawSpecialforinformationonhowtomakepicturesappearusingspecialeffectssuchaswipesandslides.

Pic.DrawFramesforinformationonhowtodisplaymultipleframeimagessuchasareobtainedfromGIFfiles.

Pic.DrawFrames PartofPicmodule

Syntax

Pic.DrawFrames(picIds:array1..*ofint,x,y,mode:

numFrames,delayBetweenFrames:int,eraseAfterboolean)

Description

Pic.DrawFramesisusedtodrawasetofpicturesstoredinanarrayofpicturesaredisplayedoneatatime,andthereisadelayofdelayBetweenFramesmillisecondsbetweenframes.Thex,y,andmodeparametersarethesameasinPic.Draw.ThenumFramesparameterspecifiesthenumberofframestobedrawn(thepicIdsarraymustbeatleastthisbig).TheeraseAfterparameterspecifieswhetherthelastframeoftheanimationshouldbeleftontheRunwindowwhenthecallfinishes.IferaseAfterissettotrue,thenthebackgroundisrestoredafterthelastpicturehasbeendrawnanddelayBetweenFramesmillisecondshaspassed.

Details

GIFfilescancontainmultipleframes(pictures).AnimatedGIFsfunctionbyeachframeintheGIFoneafteranotherwithadelaybetweenthem.

TuringallowsuserstoloadmultipleframeGIFimagesintoaseriesintoanarrayusingthePic.FileNewFramesprocedure.TheusercandeterminehowmanyframesarefoundintheGIFfileusingPic.Frames.TheframescanbesequentiallydisplayedusingeitherPic.DrawFramesorPic.DrawFramesBackwhichdisplaytheimagesoneatatime.(Pic.DrawFramesreturnsimageshavebeendisplayed,Pic.DrawFramesBackreturnsimmediatelyallowingtheprogramtocontinueexecutionwhiletheframesarebeingdisplayed.

Pic.FramesisafunctionwhichreturnsthenumberofframesfoundintheGIF.itisusedonaGIFthatdoesnotcontainmultipleimages,oronanon-GIFimagefile,itreturns1.

TheprogramloadsamultipleframeGIFcalled"globe.gif"anddisplaysit.

%Determinethenumberofframesin"globe.gif"

varnumFrames:=Pic.Frames("globe.gif")

%Loadthepicture

vardelayTime:int

varpics:array1..numFramesofint

Example Pic.FileNewFrames("globe.gif",pics,delayTime)

Pic.DrawFrames(pics,10,10,picCopy,numFrames

fori:1..numFrames

Pic.Free(pics(i))

endfor

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.DrawFramesbycallingDrawFrames.

Seealso

Pic.FramesforinformationonhowtodeterminethenumberofframesinaGIFimage.

Pic.FileNewFramesforinformationonhowtoloadaGIFimagewithmultipleframesintoanarrayofints.

Pic.DrawFramesBackforinformationonhowtosequentiallydisplaytheimagesstoredinarrayofpictureswhilecontinuingtoexecutetheprogram.

Pic.DrawFramesBack PartofPicmodule

SyntaxPic.DrawFramesBack(picIds:array1..*ofint,x,y,mode numFrames,delayBetweenFrames:int,eraseAfter

Description

Pic.DrawFramesBackisverysimilartoPic.DrawFrames.TheonlyPic.DrawFramesBackreturnsimmediatelyafterbeingcalledandprogramexecutioncontinueswhiletheframesarebeingdrawn.Thisallowsyoutocontinuetodrawothergraphicsbeingdrawn.

Forexample,thisprocedureisnecessaryifyouwanttohavetwosetsofframesbeingdrawnsimultaneously.

Details

Ifyouarewishtohaveseveralsetsofimagesdisplayedatthesametime,youmustusePic.DrawFramesBacktodisplayeachsetofimagesbutthelastandthenusedisplaythelastsetsothatTuringwillwaituntiltheyarecompletedbefore

Ifyouwanttodrawthesamesetofframescontinuously,donotuse

fori:1..20

Pic.DrawFrames(pics,10,10,picCopy,10,50,false

%DonotusePic.DrawFramesBackinthepreviousstatement

endfor

Ifyoudo,Turingwillattempttoruneachofthecallsatthesametime,andtheanimationwillappeartoonlyrunonce.

Details

TuringallowsuserstoloadmultipleframeGIFimagesintoaseriesPic.FileNewFramesprocedure.TheusercandeterminehowmanyframesarefoundinusingPic.Frames.TheframescanbesequentiallydisplayedusingeitherPic.DrawFramesBackwhichdisplaytheimagesoneatatime.(Pic.DrawFramesimageshavebeendisplayed,Pic.DrawFramesBackreturnsimmediatelyallowingtheprogramtocontinueexecutionwhiletheframesarebeingdisplayed.

Pic.FramesisafunctionwhichreturnsthenumberofframesfoundintheGIF.thatdoesnotcontainmultipleimages,oronanon-GIFimagefile,

Example

%Loadthepicture

vardelayTime:int

Pic.FileNewFrames("globe.gif",pics,delayTime)

fori:1..50

Pic.DrawFramesBack(pics,10,10,picMerge,

Pic.DrawFramesBack(pics,20+Pic.Width(pics(1)),10,

%All50iterationswillexecuteatonceifthenextcallis

%Pic.DrawFramesBack,andnotPic.DrawFrames

Pic.DrawFrames(pics,30+2*Pic.Width(pics(1)),10,

endfor

fori:1..numFrames

Pic.Free(pics(i))

endfor

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.DrawFramesDrawFrames.

Seealso

Pic.DrawFramesBackforinformationonhowtosequentiallydisplaytheimagesstoredinarraypictureswhilecontinuingtoexecutetheprogram.

Pic.DrawSpecial PartofPicmodule

Syntax Pic.DrawSpecial(picID,x,y,mode,transition,duration:

Pic.DrawSpecialisusedtodrawapictureonthescreenwithaspecialeffectsuchasawipe,aslide,orafade-in.Thepictureisdrawnwiththelowerleftcorneratdurationspecifieshowlongthetransitionshouldtakeinmilliseconds.fade-incouldbespecifiedtolast1/2asecondbyusingadurationof500.

ThemodeparameteristhesameasinPic.Newandhasoneofthefollowingvalues:

picCopy Thisdrawsthepictureontopofwhatwasunderneath,completely.

picXor ThisdrawsthepictureXORingitwiththebackground.canusethisfunctiontodoanimation.DrawinganobjectontopofitselfwithXORerasesitandrestoresthebackground.

picMerge ThisdrawsthepicturelikepicCopyexceptthatanyoccurrenceofthebackgroundcolorinthepictureisnotdrawntothescreen.Thisallowsyoutodrawanirregularly-shapedobjectanddrawitto

picUnderMerge Thisdrawsthepicture,butonlywherethebackgrounddisplayedunderneathit.Theeffectofthisistomakethepictureappeartobedisplayedbehindthebackground.

Thetransitionparameterindicatesthespecialeffectandhasoneofthefollowingvalues:

picWipeLeftToRight

Thepictureappearsasasolidblackbarsweepsfromlefttoright,"revealing"thenewpictureasthescreenunderneathreplaced.

Inthepicturebelow,"toTuring"isreplacingthe"Welcome"underneathasthebarsweepsfromlefttoright.

picWipeLeftToRight-halfwaythrough

transition

picWipeRightToLeft,picWipeTopToBottom,picWipeBottomToTop

AspicWipeLeftToRight,exceptthebarsweepsindifferentdirections.

picWipeUpperLeftToLowerRight

Thepictureappearsasasolidblackbarsweepsfromtheupperleftcornerdowntothelowerright,"revealing"thenewpictureunderneaththepictureisreplaced.

Inthepicturebelow"toTuring"isreplacingthe"Welcome"underneathasthebarsweepsfromupper-lefttolower-right.

picWipeUpperLeftToLowerRight-halfwaythroughtransition

picWipeUpperRightToLowerLeft,picWipeLowerLeftToUpperRight,picWipeLowerRightToUpperLeft

AspicWipeLeftToRight,exceptthebarsweepsindifferentdirections.

picWipeCentreToEdge,picWipeCenterToEdge

Thepictureappearsinsideanexpandingblackoutlinedboxasitsweepsfromthecentreouttotheedges,"revealing"thenewscreenunderneaththepictureisreplaced.

Inthepicturebelow,"toTuring"isreplacingthe"Welcome"underneathastheboxexpandsfromthecentreout.

picWipeCentreToEdge-halfwaythroughtransition

picWipeLeftToRightNoBar,

Description

picWipeRightToLeftNoBar,picWipeTopToBottomNoBar,picWipeBottomToTopNoBarpicWipeUpperLeftToLowerRightNoBar,picWipeUpperRightToLowerLeftNoBar,picWipeLowerLeftToUpperRightNoBar,picWipeLowerRightToUpperLeftNoBar,picWipeCentreToEdgeNoBar,picWipeCenterToEdgeNoBar

Astheconstantsabove,expectthereisnobartomarkthesweepacross.Thebargenerallylooksbetterwhendisplayingofasimilarone.Nobarisusuallywhentheimagesarecompletelydifferent(asintwophotographs,andsoon).

picSlideLeftToRight

Thepicture"slidesin"fromtheleftasasolidblackbarsweepsfromlefttoright,"pushing"thescreenunderneathofftherightedgeofthedrawingarea.

Inthepicturebelow"toTuring"isreplacingthe"Welcome"originallypresent,"pushing"the"Welcome"totherightslidesinfromtheleft.

picSlideLeftToRight-halfwaythroughtransition

picSlideRightToLeft,picSlideTopToBottom,picSlideBottomToTop

AspicSlideLeftToRight,exceptthebarsweepsindifferentdirections.

picSlideLeftToRightNoBar,picSlideRightToLeftNoBar,picSlideTopToBottomNoBar,picSlideBottomToTopNoBar

Astheconstantsabove,expectthereisnobartomarkthesweepacross.Thebargenerallylooksbetterwhendisplayingofasimilarone.Nobarisoftenwhentheimagesarecompletelydifferent(asintwophotographs,andsoon).

Thepicture"grows"fromtheleftasasolidblackbarsweepsfromlefttoright,"squeezing"thescreenunderneathedgeofthedrawingarea.

picGrowLeftToRight

Inthepicturebelow"toTuring"isreplacingthe"Welcome"originallypresent,"squeezing"the"Welcome"totheright"grows"fromtheleft.

picGrowLeftToRight-halfwaythroughtransition

picGrowRightToLeft,picGrowTopToBottom,picGrowBottomToTop

AspicGrowLeftToRight,exceptthebarsweepsindifferentdirections.

picGrowCentreToEdge,picGrowCenterToEdge

Thepicture"grows"fromthecentreasaoutlinedblackboxsweepsfromoutward,replacingthescreenunderneath.

Inthepicturebelow"toTuring"isreplacingthe"Welcome"originallypresent,as"toTuring"growsforthecentre.

picGrowCentreToEdge-halfwaythroughtransition

picGrowLowerLeftToUpperRight

Thepicture"grows"fromthelower-leftcornerasaoutlinedblackboxsweepsrightandupward,replacingthescreen

Inthepicturebelow"toTuring"isreplacingthe"Welcome"originallypresent,as"toTuring""grows"fromthelower-left.

picGrowLowerLeftToUpperRight-halfwaythroughtransition

picGrowUpperLeftToLowerRight,picGrowLowerRightToUpperLeft,picGrowUpperRightToLowerLeft

AspicGrowLowerLeftToUpperRighttheboxsweepsindifferentdirections.

picGrowLeftToRightNoBar,picGrowRightToLeftNoBar,picGrowTopToBottomNoBar,picGrowBottomToTopNoBarpicGrowUpperLeftToLowerRightNoBar,picGrowLowerLeftToUpperRightNoBar,picGrowUpperRightToLowerLeftNoBar,picGrowLowerRightToUpperLeftNoBar,picGrowCentreToEdgeNoBar,picGrowCenterToEdgeNoBar

Astheconstantsabove,expectthereisnobartomarkthesweepacross.Thebargenerallylooksbetterwhendisplayingofasimilarone.Nobarisusuallywhentheimagesarecompletelydifferent(asintwophotographs,andsoon).

picFadeIn

Thepicture"fadesin"overtopoftheimageunderneathit.Attheendofthetransition,thenewimagecompletelyreplacestheimageunderneathit.

picFadeIn-halfwaythroughtransition

picBlend

Thistransitionissomewhatdifferentbecauseitdoesn'ttakeanytimetoexecute.picBlendcausesthenewimagetobeblendedwiththebackground.Thecanbeusedbyitself,inwhichcase,imageis70%thenewimage,30%theoldimage.Youcanalsoaddanumberfrom1to100topicBlend,inwhichcase,theblendiswhateverwasaddedfrom(1-100)ofimageovertopoftheoldimage.transitionofpicBlend+15woulddisplayanimagethatiscomposedof15%thenewimageand85%theoldimage.)

picBlend-redstarblendedwithbluecircle

Execute

Details

ThePic.DrawSpecialrequiresamoderatelyfastmachinetooperatesuccessfully(PentiumIIIorhigher).ThepicFadeInandpicBlendtransitionsdonotworkwellon8-bit(256color)displays.OnMicrosoftWindowsmachines,youcandeterminetheofthedisplay(thenumberofcolorsavailable)byselectingtheDisplayfromtheStartmenu.Youcanalsousethe

Config.Display(cdNumMaxColors)

functiontodeterminethebit-depthofthedisplay(anythingover256colorswillproduceacceptableresults).

Details

IfthePic.DrawSpecialcallfails,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramdrawsabluestaronthescreen,thenaredcircle,thenhavethetworeplaceeachotherwithavarietyoftransitions.

varredID,blueID:int

varx,y:int

redID:=Pic.New(50,50,150,150)

blueID:=Pic.New(50,50,150,150)

Pic.DrawSpecial(redID,50,50,picCopy,picWipeLeftToRight

Pic.DrawSpecial(blueID,50,50,picCopy,picWipeTopToBottom

Pic.DrawSpecial(redID,50,50,picCopy,picSlideLeftToRight

Pic.DrawSpecial(blueID,50,50,picCopy,picSlideTopToBottom

Pic.DrawSpecial(redID,50,50,picCopy,picFadeIn

Pic.DrawSpecial(blueID,50,50,picCopy,picBlend

Pic.Free(redID)

Pic.Free(blueID)

Execute

Thefollowingprogramdemonstrateseachofthedifferentspecialeffects,firstusingpicturescontainingtext,thenpicturesloadedfromphotographs,thenbothatonce.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.DrawSpecialDrawSpecial.

Seealso

Pic.Drawforinformationonthemeaningofthemodeargument.

Pic.DrawSpecialBackforinformationonhowtocontinueexecutingtheprogramwhileaspecialeffectisoccurring.Thisallowsonetoproduceseveralspecial

Pic.DrawSpecialBack PartofPicmodule

Syntax Pic.DrawSpecialBack(picID,x,y,mode,transition,duration

Description

Pic.DrawSpecialBackisverysimilartoPic.DrawSpecial.TheonlyPic.DrawSpecialBackreturnsimmediatelyafterbeingcalledandprogramexecutioncontinueswhilethespecialeffectcontinues.Thisallowsyoutocontinuetodrawothergraphicseffectiscontinuing.

Forexample,thisprocedureisnecessaryifyouwanttohavetwopicturesbeingdrawnusingspecialeffectssimultaneously.

Details

Ifyouarewishtohaveseveralimagesdisplayedatthesametimeusingspecialeffects,youmustusePic.DrawSpecialBacktodisplayalltheimagesbutthelastandthenusethelastimagesothatTuringwillwaituntilthespecialeffectsarecompletedbeforecontinuingexecution.

Ifyouwanttodrawtheseveralspecialeffectscontinuouslyoverthesamelocation,donotusePic.DrawSpecialBack.

Pic.DrawSpecial(pic1,10,10,picCopy,picWipeLeftToRight

Pic.DrawSpecial(pic2,10,10,picCopy,picFadeIn,1000)

Ifyoudo,Turingwillattempttoruneachofthecallsatthesametime,andmostofthespecialeffectswillnotbeseen.

Description

Pic.DrawSpecialBackisusedtodrawapictureonthescreenwithaspecialeffectsuchasawipe,aslide,orafade-in.NotethatalltheparametersareidenticaltotheparametersofThepictureisdrawnwiththelowerleftcornerat(x,y).Thedurationtransitionshouldtakeinmilliseconds.Forexample,afade-incouldbyusingadurationof500.

ThemodeparameteristhesameasinPic.Newandhasoneofthefollowingvalues:

picCopy Thisdrawsthepictureontopofwhatwasunderneath,

picXor ThisdrawsthepictureXORingitwiththebackground.functiontodoanimation.DrawinganobjectontopofitselfwithXORerasesandrestoresthebackground.

picMerge ThisdrawsthepicturelikepicCopyexceptthatanyoccurrenceofthebackgroundcolorinthepictureisnotdrawntothescreen.Thisallowsyouirregularly-shapedobjectanddrawittothescreen.

picUnderMerge Thisdrawsthepicture,butonlywherethebackgroundunderneathit.Theeffectofthisistomakethepictureappeartobedisplayedbehindthebackground.

SeePic.DrawSpecialforthelistofpossiblevaluesforthetransition

Details

ThePic.DrawSpecialBackrequiresamoderatelyfastmachinetooperatesuccessfully(PentiumIIIorhigher).ThepicFadeInandpicBlendtransitionsdonotworkwellon8-bit(256color)MicrosoftWindowsmachines,youcandeterminethebit-depthofthedisplay(thenumberofcolorsavailable)byselectingtheDisplaycontrolpanelfromtheStartmenu.

Config.Display(cdNumMaxColors)

functiontodeterminethebit-depthofthedisplay(anythingover256colorswillproduceacceptableresults).

DetailsIfthePic.DrawSpecialBackcallfails,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextual

Example

Theprogramdrawsabluestaronthescreen,thenaredcircle,thenreplaceeachsimultaneously,side-by-side.

varredID,blueID:int

redID:=Pic.New(0,0,100,100)

blueID:=Pic.New(0,0,100,100)

Pic.DrawSpecialBack(redID,10,10,picCopy,picWipeLeftToRightNoBar

Pic.DrawSpecial(blueID,160,10,picCopy,picWipeRightToLeftNoBar

Pic.DrawSpecialBack(blueID,10,10,picCopy,picSlideLeftToRightNoBar

Pic.DrawSpecial(redID,160,10,picCopy,picSlideRightToLeftNoBar

Pic.DrawSpecialBack(redID,10,10,picCopy,picGrowRightToLeftNoBar

Pic.DrawSpecial(blueID,160,10,picCopy,picGrowLeftToRightNoBar

Pic.DrawSpecialBack(blueID,10,10,picCopy,picWipeTopToBottomNoBar

Pic.DrawSpecial(redID,160,10,picCopy,picWipeTopToBottomNoBar

Pic.DrawSpecialBack(redID,10,10,picCopy,picFadeIn

Pic.DrawSpecial(blueID,160,10,picCopy,picFadeIn

Pic.Free(redID)

Pic.Free(blueID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.DrawSpecialBackDrawSpecialBack.

Seealso

Pic.Drawforinformationonthemeaningofthemodeargument.

Pic.DrawSpecialforinformationonhowtodrawspecialeffectsandwaitforcompletioneffect.

Pic.FileNew PartofPicmodule

Syntax Pic.FileNew(fileName:string):int

Description

Pic.FileNewisusedtoobtainapicturefromafile.ThePic.FileNewprocedureallocatesthememoryforthepicture,whichcanbeverylargeforpicturesoflargeareas.ThememoryisfreedupwhentheprogramcallsPic.FreewiththepictureID.ThepicturecanbeusedwiththePic.DrawandPic.Save.

GIFfiles "GIF:filename"or"filename.GIF" JPGfiles "JPG:filename"or"filename.JPG" BMPfiles "BMP:filename"or"filename.BMP"

DetailsVariousversionsofTuringcanconvertdifferentformatsoffiles.Turing4.1forWindowscanloadBMP,GIFandJPGfiles.

Details

For,multi-frameGIFfiles(GIFfilesthathaveseveralframesorpicturesandareusedforanimation),Pic.FileNewwillonlyloadthefirstframe.SeethePic.FileNewFramesandPic.Frameforinformationonloadinganddisplayingamulti-frameGIFfile.

Details

IfthePic.FileNewcallfails,thenitreturns0.AlsoError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramreadsagraphicfromthefilemypic.bmpandthendrawsit50times.

varpicID:int

varx,y:int

picID:=Pic.FileNew("mypic.bmp")

fori:1..50

endfor

Pic.Free(picID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.FileNew,notbycallingFileNew.

Pic.FileNewFrames PartofPicmodule

SyntaxPic.FileNewFrames(pathName:string,varpicIDs:arrayint,vardelayTime:int)

Description Pic.FileNewFramesloadsmultiplepicturesstoredinasinglemultiframeGIFimagefileintoanarrayofintegers.

Details

GIFfilescancontainmultipleframes(pictures).AnimatedGIFsfunctionbydisplayingeachframeintheGIFoneafteranotherwithadelaybetweenthem.ThisdelaycanalsobespecifiedintheGIFfile.

Pic.FileNewFramesreadstheseriesofframesfromthemultiframeGIFfile,andturnseachframeintoapicture.ThepictureisthenassignedtoanelementinthepicIDsarray.Ifthearrayisnotlargeenough,thenanerroroccursandnoareloaded.

Pic.FileNewFramesalsoreadsthedelayspecifiedintheGIFfileandsetsdelayTimetothedelayinmilliseconds.NotethatmanymultipleframeGIFfilesdonotspecifyadelay,inwhichcasedelayTimewillbesetto0.

InordertodeterminethenumberofframesinmultipleframeGIFfile,youmustusethePic.Framesfunction.ThisreturnsanumberthatcanbeusedtodeclarethearraythatwillbepassedtoPic.FileNewFrames.

varnumFrames=Pic.Frames("mypic.gif")

vardelayTime:int

Pic.FileNewFrames("mypic.gif",pics,delayTime)

TheframescanbesequentiallydisplayedusingeitherPic.DrawFramesPic.DrawFramesBackwhichdisplaytheimagesoneatatime.(Pic.DrawFramesreturnsoncealltheimageshavebeendisplayed,Pic.DrawFramesBackreturnsimmediatelyallowingtheprogramtocontinueexecutionwhiletheframesarebeingdisplayed.

Details

GIFfilescanhaveatransparentcolor.Thiscolorwillbeaddedtothecolorpalette,ifnotalreadypresent.ThusyoumaynoticethatmaxcolorchangesaftercallingPic.FileNeworPic.FileNewFrames.TheGIFimagewillbebedisplayedwithoutthetransparentcolorifmodeparameterinanyofthePic.Draw...

proceduresissettopicMerge.

Details

Eachpictureisinthearrayhasbeenallocatedbythesystemandshouldbefreedseparatelyoncetheprogramisfinishedwiththepictures.Failingtodosocanuseupthesystem'smemory.

Example

%Createtheoriginalpicture

%Loadthepicture

vardelayTime:int

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.FileNewFramesnotbycallingFileNewFrames.

Seealso

Pic.DrawFramesforinformationonhowtosequentiallydisplaytheimagesstoredinarrayofpictures.

Pic.Flip PartofPicmodule

Syntax Pic.Flip(picID:int):int

Description

Pic.Flipisusedtocreateanewpicturebyflippingthepicturevertically.Theresultingpictureisexactlythesamesizeastheoriginal,exceptitappears“upside-down”.

DetailsNotethattheupside-downpictureisanewlycreatedpicture.Whenlongerneeded,itsmemoryshouldbereleasedbyusingPic.Free.

Example

Theprogramloadsapicturefromafile,flipsitandthendrawstheoriginalandtheupside-downimagesidebysideinawindowafterresizingthewindowtofitthetwopictures.

varpic,newPic,width,height:int

pic:=Pic.FileNew("lighthouse.jpg")

newPic:=Pic.Flip(pic)

width:=Pic.Width(pic)

height:=Pic.Height(pic)

%Drawthetwoimages:originalandflipped

View.Set("graphics:"+intstr(2*width+30)+";"+

intstr(height+25)+",nobuttonbar")

Pic.Draw(pic,10,20,picCopy)

Draw.Text("Original",50,5,defFontID,black)

Pic.Draw(newPic,20+Pic.Width(pic),20,picCopy

Draw.Text("Flipped",60+Pic.Width(pic),5,defFontID

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Flip,notbycallingFlip.

Pic.Frames PartofPicmodule

Syntax Pic.Frames(pathName:string):int

DescriptionPic.FramesisusedtodeterminethenumberofframesfoundinamultipleframeGIFfile.

Details

TuringallowsuserstoloadmultipleframeGIFimagesintoaseriesintoanarrayusingthePic.FileNewFramesprocedure.TheusercandeterminehowmanyframesarefoundintheGIFfileusingPic.Frames.TheframescanbesequentiallydisplayedusingeitherPic.DrawFramesorPic.DrawFramesBackwhichdisplaytheimagesoneatatime.(Pic.DrawFramesreturnsimageshavebeendisplayed,Pic.DrawFramesBackreturnsimmediatelyallowingtheprogramtocontinueexecutionwhiletheframesarebeingdisplayed.

Pic.FramesisafunctionwhichreturnsthenumberofframesfoundintheGIF.itisusedonaGIFthatdoesnotcontainmultipleimages,oronanon-GIFimagefile,itreturns1.

Example

%Loadthepicture

vardelayTime:int

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.FramescallingFrames.

Seealso

Pic.DrawFramesforinformationonhowtosequentiallydisplaytheimagesstoredinarrayofpictures.

Pic.Free PartofPicmodule

Syntax Pic.Free(picID:int)

Description

Pic.FreeisusedtoreleasethememoryallocatedbyPic.New.ItfreesupthememoryallocatedtotheparameterpicID.ThismeansthatpicIDcannotbeusedinaorDraw.SaveprocedureafterPic.Freeiscalled.

Turinghasalimitednumberofpicturesthatareavailableatanyonetime(approximately1,000).Aprogramthatcontinuouslyallocatespictures(usingorPic.FileNew)willeventuallyfailifitdoesnotfreethepicturesusingwell,ifaprogramallocateshundredsofpicturesanddoesnotfreeanyofthem,thememorydevotedtothepictureswillnotbefreedandeventuallytheprogrammayexhaustthememoryonthemachine.

Details

IfPic.FreeispassedaninvalidpictureID,afatalerroroccurs.Iftheforother(non-fatal)reasons,Error.Lastwillreturnanon-zerovalueindicatingreasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Theprogramanimatesapicturemovingacrossabackground.Eachabouttomovetoanewlocation,apictureofthebackgroundatthatlocationistaken.Whenthepictureistobemovedtothenextlocation,thebackgroundpictureisdrawnovertopofthepicture,thus"erasing"it.ThePic.Freecommandfreesbackgroundpictureonceitisnolongerinuse.Withoutit,theprogramwoulduseupallthepictureidentifiersandcrashafteroneortwomovesacrossthewindow.

Theanimationintheexampleflickersslightly.SeeView.Updateforinformationontoproduceflicker-freeanimation.

varpicID,bgID:int

varx,y,c,direction:int

%Createthepicturebeingmoved

picID:=Pic.New(50,50,150,150)

%Createabackground

Example fori:1..1000

x:=Rand.Int(0,maxx)

y:=Rand.Int(0,maxy)

c:=Rand.Int(9,15)%Usebrightcolors

Draw.FillBox(x,y,x+30,y+30,c)

endfor

y:=100

direction:=1

%Mainloop

%Takeapictureofthebackground

bgID:=Pic.New(x,y,x+100,y+100)

Pic.Draw(picID,x,y,picCopy)%Drawthepicture

delay(20)%Delay20milliseconds

Pic.Draw(bgID,x,y,picCopy)%Drawthebackgroundoverthepicture

Pic.Free(bgID)%Freethebackground

ifx<=0or(x+100)>=maxxthen

direction:=-direction

x+=direction

endloop

Execute

ThismeansthatyoucanonlycallthefunctionbycallingPic.Free,notbycalling

Pic.Height PartofPicmodule

Syntax Pic.Height(picID:int):int

Description

Pic.HeightreturnsthewidthinpixelsofthepicturerepresentedbypicID.

ThisfunctionisoftenusedinconjunctionwithPic.WidthtoobtainthedimensionsofapictureloadedusingPic.FileNew.

Example

Theprogramdrawsloadsapicturefromthefilelighthouse.jpgandproceedstotiletheentirerunwindowwithcopiesofthepicture.

varpic:int:=Pic.FileNew("lighthouse.jpg")

varwidth:int:=Pic.Width(pic)

varheight:int:=Pic.Height(pic)

varx,y:int:=0

exitwheny>maxy

exitwhenx>maxx

x:=x+width

endloop

y:=y+height

endloop

OutputofExampleProgram

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Height,notbycallingHeight.

SeealsoPic.Widthtoobtainapicture'swidthandPic.FileNewtoloadapicturefromagraphicsfile.

Pic.Mirror PartofPicmodule

Syntax Pic.Mirror(picID:int):int

Description

Pic.Mirrorisusedtocreateanewpicturebyflippingthepicturehorizontally.Theresultingpictureisexactlythesamesizeastheoriginal,exceptitappearsasa“mirrorimage”.

Details

Notethatthemirror-imagedpictureisanewlycreatedpicture.Whenitisnolongerneeded,itsmemoryshouldbereleasedbyusingPic.Free.

Example

Theprogramdrawsacrescentonthescreen,takesapictureofitandthencreatesasecondpicturebymirror-imagingthecrescent.Itthendrawsboththeoriginalpictureandthemirror-imagedversion.

varpic,newPic:int

Draw.FillOval(50,50,50,50,brightred)

Draw.FillOval(70,50,50,50,colorbg)

Draw.Text("BLUE",40,60,defFontID,brightblue

Draw.Text("MOON",40,40,defFontID,brightblue

pic:=Pic.New(0,0,100,100)

newPic:=Pic.Mirror(pic)

%Drawthetwoimages:originalandflipped

Pic.Draw(pic,10,20,picCopy)

Draw.Text("Original",10,5,defFontID,black)

Pic.Draw(newPic,110,20,picCopy)

Draw.Text("Flipped",140,5,defFontID,black)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Mirror,notbycallingMirror.

Pic.New PartofPicmodule

Syntax Pic.New(x1,y1,x2,y2:int):int

Description

Pic.Newisusedtoobtainapictureofaportionofthescreen.ThePic.Newprocedureallocatesthememoryforthepicture,whichcanbeverylargeforpicturesoflargeareas.ThememoryisfreedupwhentheprogramcallsPic.FreewiththepictureID.ThepicturecanbeusedwiththePic.DrawandPic.Save.

Thepictureisofthescreenareadefinedbytherectangle(x1,y1)-(x2,y2).

Details

IfthePic.Newcallfails,thenitreturns0.AlsoError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

Theprogramdrawsagraphiconthescreenandthendrawsit50times.

varpicID:int

varx,y:int

picID:=Pic.New(50,50,150,150)

fori:1..50

endfor

Pic.Free(picID)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.New,notbycallingNew.

Pic.Rotate PartofPicmodule

Syntax Pic.Rotate(picID,angle,x,y:int):int

Description

Pic.Rotateisusedtocreateanewpicturebyrotatinganalreadyexistingpicture.Rotationcaneitherbearoundaspecificpointinthepicture(oftenusedforrotatingapicureinplace)orjustageneralrotation.

Theangleisspecifiedindegrees.Therotationisdoneinacounter-clockwisedirection.TheoriginalpictureisnotmodifiedbythecalltoPic.Rotateandmuststillbefreedwhennolongerused.ThepictureproducedbyPic.Rotatemaybeadifferentsizethantheoriginalpicture.

The(x,y)pointisthepointaroundwhichtherotationistotakeplaceandisrelativetothepicturebeingrotated.Ifitisnotimportanttorotatethepictureinplace,xandyshouldbesetto-1,whichmakethenewpicturetheminimumsizerequiredtofittherotatedimage.

Details

ThePic.Rotatecommandcanfail,inwhichcaseitreturns0.TheError.LastMsgfunctioncanthenbeusedtoobtainmoreinformationaboutthefailure.

Details

Ifxandyaresettoapointinthepicture(ratherthan1),itispossibleforpartsoftheoriginalpicturetoberotatedofftheleftandbottomedgeofthenewpicture.ThisoccursbecausePic.Rotateguaranteesthatthepointspecifiedby(x,y)intheoriginalpicturewillbelocatedat(x,y)intherotatedpicture.Youcanavoidlosingpartsofthepicturebymakingcertainthereisamarginofbackgroundcolorontheleftandbottomsidesofthepicture.

Aswell,anypixelsintherotatedpicturethatwerenotpartoftheoriginalpicturearesettothebackgroundcolor.

Details

Rotationcanbeslowonoldermachines.Programsthatareusinganimationshouldcreateandstorealltherotatedimagesthatmaybeneeded.Oftenpicturesofanobjectatvariousanglesarestoredinanarray.

Example

Thisprogramdraws“Hello”onthescreenrotatedat0,45and90degrees.

varf:int:=Font.New("Serif:36")

Font.Draw("Hello",10,10,f,black)

varpic:int:=Pic.New(5,5,120,45)

varpic45:int:=Pic.Rotate(pic,45,-1,-1)

varpic90:int:=Pic.Rotate(pic,90,-1,-1)

OutputfromProgram

Execute

Example

Thisprogrammovesaspinning“Hello”aroundthescreen,bouncingitofftheedgesoftheoutputwindow.Noticethattheoriginalpicturecontainsadequatespaceontheleftandbottomsidestocontaintherotation.

varpic:array0..35ofint

varf:int:=Font.New("Serif:36")

constCTR:int:=57

Font.Draw("Hello",5,45,f,black)

Draw.FillOval(CTR,CTR,3,3,brightred)

pic(0):=Pic.New(0,0,115,115)

forangle:1..35

pic(angle):=Pic.Rotate(pic(0),angle*10,

endfor

varx:int:=CTR

vary:int:=CTR

vardx:int:=1

vardy:int:=1

forangle:0..35

Pic.Draw(pic(angle),x-CTR,y-CTR

ifx+dx<CTRorx+dx>maxx-CTRthen

dx:=dx

ify+dy<CTRory+dy>maxy-CTRthen

dy:=dy

delay(50)

endfor

endloop

Execute

DetailsNotethattherotatedpictureisanewlycreatedpicture.Whenitisnolongerneeded,itsmemoryshouldbereleasedbyusingPic.Free

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Rotate,notbycallingRotate.

Pic.Save PartofPicmodule

Syntax Pic.Save(picID:int,fileName:string)

Description

Pic.Saveisusedtosaveapictureonthescreentoafile.

BMPfiles "BMP:filename"or"filename.BMP"

Details

VariousversionsofTuringcansavedifferentformatsoffiles.Turing4.1forWindowscansaveonlyBMPformatfiles,astheyareloss-lessandcanhandle24-bitdepthimages.

Details

IfPic.SaveispassedaninvalidpictureID,afatalerroroccurs.Ifthecallfailsforother(non-fatal)reasons,Error.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

TheprogramdrawsagraphiconthescreenandthensavesitasaBMPfile.

varpicID:int

varx,y:int

picID:=Pic.New(50,50,150,150)

Pic.Save(picID,"BMP:mypic.dat")

Pic.Free(picID)

ThefollowingtwoprogramssaveandloadafileinBMPformat.

%Programtosaveapictureinmypic.bmp

varpicID:int

varx,y:int

picID:=Pic.New(50,50,150,150)

Pic.Save(picID,"mypic.bmp")

Pic.Free(picID)

Example %Programtoloadthepicturebackagainanddraw50copies

varpicID:int

varx,y:int

picID:=Pic.FileNew("mypic.bmp")

fori:1..50

endfor

Pic.Free(picID)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Save,notbycallingSave.

Pic.Scale PartofPicmodule

Syntax Pic.Scale(picID,newWidth,newHeight:int):int

Description

Pic.Scaleisusedtocreateanewpicturebyscaling(resizing)analreadyexistingpicture.Rotationcaneitherbearoundaspecificpointinthepicture(oftenusedforrotatingapicureinplace)orjustageneralrotation.

ThenewWidthandnewHeightparametersarethedesiredwidthandheightofthenewpicture.ThenewWidthandnewHeightparametersmaybenegative,inwhichcasepictureismirrorimage(newWidthisnegative)orupside-down(newHeightnegative)andtheabsolutevaluesareusedforthenewwidthandheightvalues.

DetailsThePic.Scalecommandcanfail,inwhichcaseitreturns0.TheError.LastMsgfunctioncanthenbeusedtoobtainmoreinformationaboutthefailure.

Details

Creatingalargerpicturebyscalingasmallerpicturewillresultina"grainy"imagewitheachpixelbeingscaledupinto2or3pixels.Ingeneralimagequalityalargepictureisscaleddown.However,whenalargepictureisscaleddown,thinone-pixelwidelinescan"disappear".

Inordertoscaleapicturewhileretainingitsoriginalaspectratio,scalewithmultiplesoftheoriginalwidthandheight.ThewidthandheightofapicturecanbeobtainedusingPic.WidthandPic.Height.

Details

Scalingcanbeslowonoldermachines.Programsthatareusinganimationshouldcreateandstoreallthescaledimagesthatmaybeneeded.Oftenpicturesofanobjectatvarioussizesarestoredinanarray.

DetailsNotethatthescaledpictureisanewlycreatedpicture.Whenitisnolongerneeded,itsmemoryshouldbereleasedbyusingPic.Free.

Thisprogramdrawsasetofstarsscaledat50%,100%and150%onNotehowsomesingle-pixellinesareremovedwhenthepictureisscaleddown..

%The"Pic.ScaleExample"program.

varpic:int

Example

varnewPic:int

varpicWidth,picHeight:int

Draw.FillStar(0,0,STAR_SIZE,STAR_SIZE,brightred

Draw.Box(0,0,STAR_SIZE,STAR_SIZE,green)

picWidth:=Pic.Width(pic)

picHeight:=Pic.Height(pic)

forx:1..3

fory:1..3

newPic:=Pic.Scale(pic,x*picWidthdiv

y*picHeightdiv2)

Pic.Draw(newPic,(x-1)*maxxdiv3+5,

(y-1)*maxydiv3+20,picCopy)

Pic.Free(newPic)

Draw.Text(realstr(x/2,0)+"x"+

(x-1)*maxxdiv3+5,(y

defFontID,black)

endfor

OutputfromProgram

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.ScaleScale.

Pic.ScreenLoad PartofPicmodule

Syntax Pic.ScreenLoad(fileName:string,x,y,mode:int)

Description

Pic.ScreenLoaddisplaysapicturefromafilestraighttothescreen.

JPGfiles "JPG:filename"or"filename.JPG" BMPfiles "BMP:filename"or"filename.BMP"

Thexandyparameterssetthelowerlefthandcornerofthepicture.

Themodeparameterhasoneofthefollowingvalues:

picCopy Thisdrawsthepictureontopofwhatwasunderneath,obscuringitcompletely.

picXOR

ThisdrawsthepictureXORingitwiththebackground.InDOS,youcanusethisfunctiontodoanimation.DrawinganobjectontopofitselfwithXORerasesitandrestoresthebackground.

picMerge

ThisdrawsthepicturelikepicCopyexceptthatanyoccurrenceofthebackgroundcolorinthepictureisnotdrawntothescreen.Thisallowsyoutodrawanirregularly-shapedobjectanddrawittothescreen.

picUnderMerge

Thisdrawsthepicture,butonlywherethebackgroundcolorwasdisplayedunderneathit.Theeffectofthisistomakethepictureappeartobedisplayedbehindthebackground.

VariousversionsofTuringcanconvertdifferentformatsoffiles.Turing4.1forWindowscanloadBMPfilesandJPGfiles.Unfortunately,duetostrictlyenforcedpatentsontheGIF

Details compressionalgorithm,TuringwillnotimplementimportationofGIFpicturesuntilthepatentsexpireinJune2004.

Details

Atthetimeofwriting,MacOOTsupportedonlyPICTfiles.Consultthereleasenotestofindoutwhichfileformatsarecurrentlysupported.

Details

IfthePic.ScreenLoadfails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

TheprogramdisplaysapictureonthescreenfromthePCXfilemypic.BMP.

Pic.ScreenLoad("mypic.bmp",0,0,picCopy)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.ScreenLoad,notbycallingScreenLoad.

Pic.ScreenSave PartofPicmodule

Syntax Pic.ScreenSave(x1,y1,x2,y2:int,fileName:string)

Description

Pic.ScreenSavesavesaportionofthescreenintoafileinaformatspecifiedbythefilename.

Thepicturesavedtothefileistheportionofthescreendefinedbytherectangle(x1,y1)-(x2,y2).

BMPfiles "BMP:filename"or"filename.BMP"

Details

VariousversionsofTuringcansavedifferentformatsoffiles.Turing4.1forWindowscansaveBMP.Unfortunately,duetostrictlyenforcedpatentsontheGIFcompressionalgorithm,TuringwillnotimplementsavingofGIFpicturesuntilthepatentsexpireinJune2004.

Details

IfthePic.ScreenSavefails,thenError.Lastwillreturnanon-zerovalueindicatingthereasonforthefailure.Error.LastMsgwillreturnastringwhichcontainsthetextualversionoftheerror.

Example

TheprogramdrawsagraphicandsavesitasaPICTfilecalleddraw.

picID:=Pic.ScreenSave(50,50,150,150,"PICT:draw")

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.ScreenSave,notbycallingScreenSave.

Pic.SetTransparentColor PartofPicmodule

Syntax Pic.SetTransparentColor(colorNumber:int)

Description

ThePic.SetTransparentColorproceduresetsthecolorinthepicturethatshouldbeconsideredtransparentwhenthepictureisdrawnusingthepicMergeorpicUnderMergemodes.Ifnocolorisspecified,thenthedefaultbackgroundcolor(colorbg,usuallywhite)isusedasthetransparentcolor.

Details

ThiscallisoftenusedwhendisplayingimagesthatwereoriginallystoredasGIFsandtranslatedintoanotherformat.ManyGIFshaveatransparentcolorthatcanbenon-white.Tousethiscall,youmustknowthecolornumberthatrepresentsthecolorintheimagethatistobetransparent.

Example

Thisprogramdisplaystwoimagesloadedfromthesamefile.Inthesecondimage,thetransparentcolorhasbeensettobrightred(thatis,thepartsoftheimagethataremeanttobetransparentareinbrightred).

varpic1:int:=Pic.FileNew("airplane.bmp")

varpic2:int:=Pic.FileNew("airplane.bmp")

Pic.SetTransparentColor(pic2,brightred)

setscreen("offscreenonly")

forx:100..maxx-100

put"Thelowerimagehasthetransparentcolorsettobrightred"

Pic.Draw(pic1,x,150,picMerge)

Pic.Draw(pic2,x,50,picMerge)

View.Update

delay(5)

endfor

Execute

Pic.SetTransparentColourisanalternatespellingfor

Details Pic.SetTransparentColor.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.SetTransparentColor,notbycallingSetTransparentColor.

Seealso Pic.DrawandPic.FileNew.

Pic.Width PartofPicmodule

Syntax Pic.Width(picID:int):int

Description

Pic.WidthreturnsthewidthinpixelsofthepicturerepresentedbypicID.

ThisfunctionisoftenusedinconjunctionwithPic.HeighttoobtainthedimensionsofapictureloadedusingPic.FileNew.

Example

Theprogramdrawsloadsapicturefromthefilelighthouse.jpgandproceedstotiletheentirerunwindowwithcopiesofthepicture..

varpic:int:=Pic.FileNew("lighthouse.jpg")

varwidth:int:=Pic.Width(pic)

varheight:int:=Pic.Height(pic)

varx,y:int:=0

exitwheny>maxy

exitwhenx>maxx

x:=x+width

endloop

y:=y+height

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingPic.Width,notbycallingWidth.

SeealsoPic.Heighttoobtainapicture'sheightandPic.FileNewtoloadapicturefromagraphicsfile.

play procedure

Syntax play(music:string)

DescriptionTheplayprocedureisusedtosoundmusicalnotesonthecomputer.

ExampleThisprogramsoundsthefirstthreenotesoftheCscale.

play("cde")

Example

ThisprogramplaysfrommiddleCtooneoctaveabovemiddleCanddownagainin8thnotes.

play("8cdefgab>c")

play("<bagfedc")

Details

Theplayproceduretakesstringscontainingcharactersthatspecifynotes,rests,sharps,flatsandduration.Thenotesarethelettersatog(orAtoG).Arestisp(forpause).Asharpis+andaflatis-.Thedurationsare1(wholenote),2(halfnote),4(quarternote),8(eightnote)and6(sixteenthnote).Thecharacter>raisestothenextoctaveand<lowers.Forexample,thisisthewaytoplayCandthenCsharponeoctaveabovemiddleCwitharestbetweenthem,allinsixteenthnotes:play(">6cpc+").Blankscanbeusedforreadabilityandareignoredbyplay.

UndersomesystemssuchasUNIX,theplayproceduremayhavenoeffect.

Thecurrent(1999)implementationdoesnotsupportplay.

Seealso

theplaydonefunction,whichisusedtoseeifanotehasfinishedsounding.Seealsothesoundprocedure,whichmakesasoundofagivenfrequency(Hertz)andduration(milliseconds).

SeealsopredefinedunitMusic.

playdone function

Syntax playdone:boolean

DescriptionTheplaydonefunctionisusedtodeterminewhennotesplayedbytheplayprocedurehavefinishedsounding.

Example

ThisprogramsoundsthefirstthreenotesoftheCscaleandoutputs"Alldone"assoonastheyarefinished.Withouttheloop,themessagewouldcomeoutbeforethenotesarefinished.

play("cde")

exitwhenplaydone

endloop

put"Alldone"

DetailsUndersomesystemssuchasUNIX,theplaydoneproceduremaybemeaningless.

Seealso

theplayprocedure.Seealsothesoundprocedurewhichmakesasoundofagivenfrequency(Hertz)andduration(milliseconds).

pointer type

Syntax ApointerTypeisoneof:

(a) [unchecked]pointertocollectionId %Shortform:^collectionId (b) [unchecked]pointertoclassId %Shortform:^classId (c) [unchecked]pointertotypeSpec %Shortform:^typeSpec

Description

Avariabledeclaredasapointertypeisusedtolocateanelementofacollectionorclassoravalueofatype.Thenewstatementcreatesanewelement(orvalue)andplacestheelement'slocationinapointervariable.Thefreestatementdestroysanelementlocatedbyapointervariable.

Example

Usingacollection,declarealistorrecordsandallocateonerecord.

record

contents:string(10)

next:pointertolist

endrecord

varfirst:pointertolist

newlist,first

Example

Createacollectionthatwillrepresentabinarytree.

vartree:collectionof

record

name:string(10)

left,right:pointertotree

endrecord

varroot:pointertotree

newtree,root

tree(root).name:="Adam"

Usingaclass,createanobjectofthatclass.Theobjectislocatedbythe

Example

startpointer.ThenamefieldoftheobjectissettoEd.

classnode

exportvarnext,varname

name:string(25)

next:pointertonode%Shortform:next:^node

endnode

varstart:pointertonode%Shortform:varstart:^node

newnode,start%Shortform:newstart

node(start).name:="Ed"%Shortform:start->name:=

Forcollectionsandclasses,apointeriseffectivelyasubscript(anindex)forthatcollectionorclass.Pointerscanbeassigned,comparedforequalityandpassedasparameters.

Thekeywordspointertocanbereplacedbytheshortform^,asin

varfirst:^item

GivenapointerpthatlocatesanobjectofclassorcollectionC,theobjectisreferencedasC(p)orastheshortform^p.AfieldfoftheobjectisreferencedasC(p).for^p.forastheshortformp->f.Forexample,intheclassgivenabove,thenamefieldoftheobjectlocatedbythestartcanbesettoAliceby:

start->name:="Alice"

Pointerstotypesusethesamenotation,exceptthatpointerstotypesarenotallowedtousetheformtypeSpec(p).Seeclassforanexampleoftheuseofaclasswithpointers.

Thecarat^iscalledthedereferencingoperatorandhasthehighestprecedence.Forexample,in^p.a,thecaratappliestopandnottoapply^toallofp.a,useparentheses:^(p.a).Severalcaratscanappearinarow,forexample,

varr:^^int

declaresapointertoapointertoanintegerand^^risthenotationforreferencingtheinteger.

Areferencecannotbeginwithaleftparenthesis,butcanbesurroundedby^(…),asin^(q.b).Iffisaparameterlessfunctiondeclaredwithout

Details parenthesesthatreturnsapointer,theform^fcallsfbeforedereferencingthepointer.

Bydefault,allpointersarechecked.ThismeansthereisaruntimetesttomakesurethatreferencessuchasC(p)actuallylocateelements,i.e.,thatisinitialized,isnotnilandisnotdangling(locatinganobjectthathasbeenfreed).Thischeckingrequiresextraspace(theimplementationattachesatimestamptoeachpointerandobject)andtime.Inhigh-performanceprogramsinwhichthisextraspaceandtimearenotacceptable,thepointercanbedeclaredtobeunchecked.Whenthisisdone,theprogrambecomesdangerousanditistheprogrammer'sresponsibilitytomakesurethatallpointerusageisvalid.

Ifthisisnotthecase,theprogrambecomessusceptibletouncontrolledcrashes.

Checkedpointerscannotbeassignedtouncheckedpointersnorviceversa.However,youmay,atyourperil,useanimplementation-dependentcheat,toconvertacheckedpointertoauncheckedpointer,asin:

typecheckedPtr:^R

typeuncheckedPtr:unchecked^R

varc:checkedPtr%cisancheckedpointer

varu:uncheckedPtr%uisanunchecked

u:=cheat(uncheckedPtr,d)%Thisisatype

UncheckedpointersareequivalenttothepointersoftheClanguage,whichareinherentlyerrorproneandcausedifficulttolocatebugs.Anentirecollection(butnotaclass)canbedeclaredunchecked,inwhichcaseallofitspointersareimplicitlyunchecked.Seecollection.

Seealso

inheritlistsforadescriptionoftheassignabilityrulesforpointers.Seeclassesandcollectionsformoredetailsabouttheuseofpointers.Seealsonewandfreestatements.Seealsonil,objectclassandanyclass.

post assertion

Syntax

AnpostAssertionis:

posttrueFalseExpn

Description

Apostassertionisaspecialformofanassertstatementthatisusedinaprocedureorfunction.Itisusedtogiverequirementsthatthebodyoftheprocedureorfunctionissupposedtosatisfy.TheserequirementsaregivenbythetrueFalseExpn.Afterthebodyhasexecutedandjustbeforetheprocedureorfunctionreturns,thetrueFalseExpnisevaluated.Ifitistrue,alliswellandexecutioncontinues.Ifitisfalse,executionisterminatedwithanappropriatemessage.Seeassertstatementsandprocedureandfunctiondeclarationsformoredetails.Seealsopreandinvariantassertions.

Example

Thisfunctionissupposedtoproduceanintegerapproximationofthesquarerootofintegeri.Thepostconditionrequiresthatthisresult,whichiscalledanswer,mustbewithinadistanceof1fromthecorrespondingrealnumbersquareroot.

functionintSqrt(i:int)answer:int

prei>=0

postabs(answer-sqrt(i))<=1

…statementstoapproximatesquareroot…

endintSqrt

Details

Apostassertioncanalsobeusedinamodule,monitor,classorprocessdeclarationtomakesurethattheinitializationsatisfiesitsrequirements.

Seealso moduleandprocess.

pre assertion

Syntax

AnpreAssertionis:

pretrueFalseExpn

Description

Apreassertionisaspecialformofanassertstatementthatisusedatthebeginningofaprocedureorfunction.Itisusedtogiverequirementsthatthecalleroftheprocedureorfunctionsissupposedtosatisfy.TheserequirementsaregivenbythetrueFalseExpn.ThetrueFalseExpnisevaluated.Ifitistrue,alliswellandexecutioncontinues.Ifitisfalse,executionisterminatedwithanappropriatemessage.Seeassertstatementsandprocedureandfunctiondeclarationsformoredetails.Seealsopostandinvariantassertions.

Example

Thisfunctioncomputestheaverageofnvalues.Itspreconditionrequiresthatmustbestrictlypositive,toavoidthepossibilityofdividingbyzerowhencomputingtheaverage.

functionaverage(a:array1..*ofreal,n:

pren>0

varsum:real:=0

fori:1..n

sum:=sum+a(i)

endfor

resultsum/n

endaverage

DetailsApreassertioncanalsobeusedinamodule,monitor,classorprocessdeclarationtomakesurethatrequirementsforinitializationaremet.

Seealso moduleandprocess.

precedence ofoperators

Description

Turing'sprecedencerulesdeterminetheorderofapplyingoperatorsinanexpressionsuchas3+4*5.Theserulesstate,forexample,thatmultiplicationisdonebeforeaddition,sothisexpressionisequivalentto3+(4*5).

Parenthesizedpartsofanexpressionareevaluatedbeforebeingused.Forexample,in(1+2)*3,theadditionisdonebeforethemultiplication.

Theprecedencerulesaredefinedbythistable,inwhichoperatorsappearingearlierinthetableareappliedfirst.Forexample,multiplicationisappliedbeforeaddition:

(1) **,^,# (2) prefix+and- (3) *,/,div,mod,rem,shr,shl (4) infix+,-,xor

(5) <,>,=,<=,>=,not=,in,notin (6) not (7) and (8) or

(9) => (booleanimplication)

Operatorsappearingonasinglelineinthistableareappliedfromlefttoright.Forexample,abcisthesameis(ab)c.

Herearesomeexamplesillustratingprecedence,inwhichtheleftandrightexpressionsareequivalent:

1**2 (1**2) a+b*c a+(b*c) a*b/c (a*b)/c

borcandd bor(candd) x<yandy<z (x<y)and(y<z)

ThefinalexampleillustratesthefactthatinTuring,parenthesesarenotrequiredwhencombiningcomparisonsusingandandor.ThesewouldberequiredinthePascallanguage.

Thetypecheatoperator#isappliedaftersubscripting,subprogramcalling,dotting,and>.Forexample,ineachofthefollowing,#appliestotheentirereferencetotheright.

#a(i) #r.y #p->x

Thepointerfollowingoperator^isappliedbeforesubscripting,subprogramcalling,dotting,and->.Forexample,inthefollowing,^appliestoa,randp.

^a(i) ^r.y ^p->x

Useparenthesestoforce^toapplytomoreofthereference.Forexample,in^(a(i)),the^appliestoa(i).

Seealsoinfixandprefixoperators.Seetheint,real,string,boolean,set,enum,charandchar(n)types.

pred predecessorfunction

Syntax pred(expn)

Description

Thepredfunctionacceptsaninteger,character,oranenumeratedvalueandreturnstheintegerminusone,thepreviouscharacter,orthepreviousvalueintheenumeration.Forexample,pred(7)is6.

Example

ThispartofaTuringprogramfillsuparrayawiththeenumeratedvaluesred,yellow,green,red,yellow,green,etc.

typecolors:enum(green,yellow,red)

vara:array1..100ofcolors

fori:1..100

a(i):=c

ifc=colors.greenthen

c:=colors.red

c:=pred(c)

endfor

Details Itisillegaltoapplypredtothefirstvalueofanenumeration.

Seealso succ,lowerandupperfunctions.

prefix operator

Syntax

AprefixOperatorisoneof:

(a) + %Integerandrealidentity

%(doesnotchangevalue)

(b) %Integerandrealnegation

(c) not %Not(Booleannegation)

(d) # %Typecheat

(e) ^ %Pointerfollowing

Description

Aprefixoperatorisplacedbeforeavalueoroperandtoproduceanothervalue.Forexample,ifthevalueofxisseven,then-xisnegativeseven.Therearealsoinfixoperatorssuchasmultiplication(*)andaddition(+),whichareplacedbetweentwovaluestoproduceathirdvalue.Seeinfixoperator.

The+andprefixoperatorscanbeappliedonlytonumericvalues(integer,realandnaturalnumbers).Thenotprefixcanbeappliedonlytotrue/false(boolean)values.Forexamplenot(x>y)isequivalenttox<=y.Thenotoperatorproducestruefromfalseandfalsefromtrue.

The#operatorsisatypecheat(seecheat),andthe^operatorispointerfollowing(seepointer).

Seealso

int,realandbooleantypes,aswellasprecedence(fortheorderofapplyingoperators)andinfixoperators.

procedure declaration

Syntax

AprocedureDeclarationis:

procedureid[(paramDeclaration{,paramDeclaration})]

statementsAndDeclarations endid

Description

Aproceduredeclarationcreates(butdoesnotrun)anewprocedure.Thenameoftheprocedure(id)isgivenintwoplaces,justafterprocedureandjustafterend.

Example

proceduregreetings

put"Helloworld"

endgreetings

greetings%ThisoutputsHelloworld

proceduresayItAgain(msg:string,n:int)

fori:1..n

putmsg

endfor

endsayItAgain

sayItAgain("Toot",2)%Tootisoutputtwice

proceduredouble(varx:real)

x:=2*x

enddouble

vary:real:=3.14

double(y)%Thisdoublesthevalueofy

Thesetofparametersdeclaredwiththeprocedurearecalledformalparameters.Inthedoubleprocedure,forexample,xisaformalparameter.Aprocedureiscalled(invoked)byaprocedurecallstatementwhichconsistsoftheprocedure'snamefollowedbytheparenthesizedlistofactualparameters(ifany).Forexample,double(y)isacallhavingyasanactualparameter.Ifthereareno

Details

parameters(seethegreetprocedureabove),thecalldoesnothaveparentheses.Thekeywordprocedurecanbeabbreviatedtoproc.

Ordinarily,aprocedurereturns(finishesandgoesbacktotheplacewhereitwascalled)byreachingitsend.However,thereturnstatementinaprocedurecausesittoreturnimmediately.Notethatreturncanalsobeusedinthemainprogramtocauseittohaltimmediately.

Onlyparametersdeclaredusingvarmaybechangedintheprocedure,forexample,xischangedinthedoubleprocedure.Theupperboundsofarraysandstringsthatareparametersmaybedeclaredtobeanasterisk(*).Thismeansthattheboundisthatoftheactualparameter.SeeparamDeclarationfordetailsaboutparameters.

Proceduresandfunctionscannotbedeclaredinsideotherproceduresandfunctions.

ThesyntaxofaprocedureDeclarationpresentedabovehasbeensimplifiedbyleavingouttheoptionalimportlist,precondition,initclause,postconditionandexceptionhandler.Thefullsyntaxis

procedure[pervasive]id

[:deviceSpecification]

[pretrueFalseExpn]

[posttrueFalseExpn]

[exceptionHandler]

Aproceduremustbedeclaredbeforebeingcalled.Toallowformutuallyrecursiveprocedures,thereareforwarddeclarationsofprocedureswithlaterdeclarationofeachprocedurebody.Seeforwardandbodydeclarationsforexplanations.

importlist,precondition,initclause,postconditionandexceptionHandlerforexplanationsofthesefeatures.Seepervasiveforinformationonpervasiveprocedures.See

Seealso exceptionHandler.TheoptionaldeviceSpecificationisusedonlyinproceduresdeclaredinmonitorsandisusedtocreateaninterrupthandlingprocedure.Seemonitorfordetails.

procedureCall statement

Syntax

AprocedureCallis:

procedureId[([expn{,expn}])]

Description

Aprocedurecallisastatementthatcalls(invokesoractivates)aprocedure.Iftheprocedurehasparameters,aparenthesizedlistofexpressions(expns)mustfollowtheprocedure'sname(procedureId).

Example

proceduregreet

put"Hello"

endgreet

greet%Thisisacalltothegreetprocedure

proceduretimes(vari:int,factor:int)

i:=factor*i

endtimes

varj:int

times(j,4)%Multiplyjby4

Aparameterdeclaredintheheaderofaprocedureisaformalparameter.Forexample,iandfactoraboveareformalparameters.Eachexpressioninthecallisanactualparameter.Forexample,jand4aboveareactualparameters.

Ifaformalparameterisdeclaredusingvar,thentheexpressionpassedtothatparametermustbeavariablereference(soitsvaluecanpotentiallybechangedbytheprocedure).Thismeans,forexample,thatitwouldbeillegaltopassj+3asthefirstparametertotimes.Thevariablereferenceandtheformalparametermusthaveequivalenttypes(seeequivalencefordetails).

Eachactualparameterpassedtoanon-varformalparametermustbeassignabletothatparameter(seeassignabilityfordetails).SeealsoprocedureDeclaration.

Details InthisexplanationofprocedureCall,wehaveuptothispointignoredthepossibilityofproceduresexportedfrommodules,monitorsandclasses.IftheprocedureisbeingcalledfromoutsideofamoduleormonitorMfromwhichithasbeenexported,thesyntaxoftheprocedureCallis:

M.procedureId[([expn{,expn}])]

Inotherwords,themoduleormonitornameandadotmustprecedetheprocedure'sname.Iftheprocedureisbeingcalledfromoutsideofaclassfromwhichithasbeenexported,thesyntaxoftheprocedureCallisoneof:

(a)classId(p).procedureId[([expn{,expn

(b)p->procedureId[([expn{,expn}])]

Inthese,pmusttheapointervaluethatlocatesanobjectintheclass.Form(b)isashortformforform(a).

Seealso class.

process declaration

Syntax

AprocessDeclarationis:

processid[([paramDeclaration{,paramDeclaration}])]

statementsAndDeclarations endid

Description

Aprocessdeclarationismuchlikeaproceduredeclaration,butisactivatedbyaforkstatementratherthanbyacall.Theforkstatementstartsconcurrent(parallel)executionoftheprocesswhilethestatementsfollowingtheforkcontinuetoexecute.

Example

Thisprograminitiates(forks)twoconcurrentprocesses,oneofwhichrepeatedlyoutputsHiandtheotherHo.TheresultingoutputisanunpredictablesequenceofHi'sandHo'sasgreetingsexecutestwiceconcurrently,oneinstancewithwordsettoHiandtheotherwithwordsettoHo.

processgreetings(word:string)

putword

endloop

endgreetings

forkgreetings("Hi")

forkgreetings("Ho")

Theprocessdeclarationcreatesatemplateforaprocess(aconcurrentactivity),whichisactivatedbyaforkstatement.

Aprocessdeclarationcanappearwhereveramoduledeclarationisallowedexceptthataprocessdeclarationisnotallowedinaclass.Thedeclarationsandstatementsinaprocessdeclarationarethesameasthoseinaprocedure.

SeeparamDeclarationfordetailsaboutparameters.Thereisananomalyinparameterstoprocesses,thatcanleadtoerrors.In

Details

particular,non-varparametersthatarenon-scalars(suchasstringsandarrays)arepassedbyreference.Theresultisthatthetargetofthereferencemaychangevaluewhiletheprocessisexecuting,whichinturnmeansthattheseeminglyconstantparameterisnotreallyconstant.Forexample,ifthestringvariableswerepassedtothegreetingsprocessandsubsequentlychanged,thevalueofgreetings'formalparameterwouldchange.

ThesyntaxofaprocessDeclarationpresentedabovehasbeensimplifiedbyleavingouttheoptionalstacksize(compileTimeExpn),importlist,precondition,initclause,postconditionandexceptionhandler.

Thefullsyntaxis:

process[pervasive]id

[([paramDeclaration{,paramDeclaration

[:compileTimeExpn]

[pretrueFalseExpn]

[posttrueFalseExpn]

[exceptionHandler]

Seepervasiveforinformationonpervasiveprocesses.TheoptionalcompileTimeExpnfollowingtheparameterlist(ifany)isusedtospecifythenumberofbytesfortheprocess'stack.

Seealsoimportlist,precondition,initclause,postconditionandexceptionHandlerforexplanationsoftheseadditionalfeatures.

program a(main)program

Syntax

Aprogramis:

DescriptionATuringprogramconsistsofalistofstatementsanddeclarations.

ExampleThisisacompleteTuringprogram.ItoutputsAlanM.Turing.

put"AlanM.Turing"

Example

ThisisacompleteTuringprogram.Itoutputsatriangleofstars.

varstars:string:="*"

putstars

stars:=stars+"*"

endloop

Example

ThisisacompleteTuringprogram.ItoutputsHelloonceandGoodbyetwice.

proceduresayItAgain(what:string,n:int)

fori:1..n

putwhat

endfor

endsayItAgain

sayItAgain("Hello",1)

sayItAgain("Goodbye",2)

Details

Inaprogramtherecanbemanyunits(seeunit),oneofwhichistheprogram(calledthemainprogram),theothersofwhicharemodules,monitorsandclasses.Themainprogramisoptionallyprecededbyanimportlist,whichliststheunitsthatituses.

Seealso importlist.

put statement

Syntax

AputStatementis:

put[:fileNumber,]putItem{,putItem}[..]

Description

TheputstatementoutputseachoftheputItems.Usually,anewlineisstartedintheoutputafterthefinalputItem.Iftheoptionaldot-dot(..)ispresent,though,subsequentoutputwillbecontinuedonthecurrentoutputline.Withcharactergraphics,theomissionofdot-dotcausestheremainderoftheoutputlinetobeclearedtoblanks.

Ordinarily,theoutputgoestothescreen.However,ifthefileNumberispresent,theoutputgoestothefilespecifiedbythefilenumber(seetheopenstatementfordetails).Also,outputcanberedirectedfromthescreentoafile,inwhichcaseallputstatementswithoutafilenumberaresenttothefileinsteadofthescreen.

Example

varn:int:=5

put"Aliceowesme$",n

%Outputis:Aliceowesme$5

%Notethatnoextraspaceis

%outputbeforeanintegersuchasn.

Example

StatementOutputNotes

put2424

put1/100.1%Trailingzerosomitted

put100/1010%Decimalpointomitted

put5/31.666667%6fractiondigits

putsqrt(2)1.414214%6fractiondigits

put4.86*10**94.86e9%Exponentfor=1e6

put121:5bb121%Width5;bisblank

put1.37:6:3b1.370%Fractionwidthof3

put1.37:11:3:2bb1.370e+00%Exponentwidthof2

put"Say\"Hello\""Say"Hello"

put"XX":4,"Y"XXbbY%Blankshownasb

puttrueandfalsefalse%Putoutabooleanvalue

put1<2true%Putoutabooleanvalue

Example

Asingleblanklineisoutputthisway:

put""%Outputnullstringthennewline

Thisputstatementissometimesusedtocloseoffalinethathasbeenoutputpiecebypieceusingputwithdot-dot.

Details

ThegeneralformofaputItemisoneof:

(a) expn[:widthExpn[:fractionWidth[:exponentWidth]]] (b) skip

SeetheaboveexamplesforusesofwidthExpn,fractionWidthandexponentWidth.Fortheexactmeaningofthesethreewidths,seethedefinitionsofthefunctionsrealstr,frealstranderealstr.Theskipitemisusedtoendthecurrentoutputlineandstartanewline.

Details

Theputsemanticsallowput'sofenumvalues.Thevaluesprintedaretheelementnamesthemselves,casesensitive.Forexample:

typecolors:enum(red,green,blue)

putc%outputs"red"(withoutthequotes)

Details

Theputsemanticsallowput'sofbooleanvalues.Thevaluesprintedareeither“true”or“false”(withoutthequotes).Forexample:

varc:boolean:=trueorfalse

putc%outputs"true"(withoutthequotes)

quit failstatement

Syntax

AquitStatementis:

quit[guiltyParty][:quitReason]

Description

Thequitstatementcausesaprogram(orconcurrentprocess)tofail.Thefailure(calledanexception)eitherabortstheprogram(orprocess)orcausescontroltobepassedtoanexceptionhandler.

Example

IntheinputLinesprocedure,halttheprogramifendoffileisencounteredbeforethestring"stop"isread.Notethatareturnstatementintheprocedurewouldterminatetheprocedurebutnottheentireprogram.

varline:array1..50ofstring

procedureinputLines

vari:int:=0

ifeofthen

put"Missing'stop'ininput"

quit%Haltentireprogram

i:=i+1

getline(i)

exitwhenline(i)="stop"

endloop

endinputLines

inputLines

Inthesimplecase,theoptionalguiltyPartyandquitReasonareomitted.TheguiltyPartyoptionisusedtospecifythepositionoffailure.SeeexceptionHandlerforanexampleofaquitstatementusedinconjunctionwithahandler.Ahandler,whichislocatedatthebeginningofasubprogrambody,isgivencontrolwhenaquitisexecutedorafailure,suchasdivisionbyzero,occursinthesubprogram.

Details

TheguiltyPartyoptionisusedtodesignatethelocationofthefailure,forexample,totellthedebuggerwhatlineisconsideredtobethelocationofthefailure.AguiltyPartyisoneof:

(a) < (b) >

IfguiltyPartyisomitted,thefailureisconsideredtooccuratthequitstatement.Ifitis<,thefailureisconsideredtooccuratthecalltothepresentsubprogram.Forexample,ifthepresentsubprogramimplementssquarerootsqrtandispassedanegativeargument,itcanuse<tospecifythatthecallerprovidedafaultyargument.IfguiltyPartyis>,thismeansthefailurehasalreadyoccurredandisbeingpassedontothenexthandlerortothesystem.Tosummarize,thethreepossibilitiesfordesignatingthelocationofthefailureare:

(a) < Calleriscauseoffailure

(b) > Theexceptionbeinghandledisthecause.

(c) (omittedguiltyParty)Thepresentquitisthecause.

ThequitReasonisanintegerexpressionwhichisusedtoidentifythekindoffailure.Ifitisomitted,adefaultvalueischoseninthefollowingmanner.IfguiltyPartyisomittedoris<,thedefaultis1.IfguiltyPartyis>andanexceptionhandlerisactive,thedefaultisthequitReasonoftheexceptionbeinghandled.Ifnoexceptionisbeinghandled,thedefaultis1.Inthecaseofprogramabortion,theimplementationmaypassthequitReasontotheoperatingsystemorprogrammingenvironment.

Seealso exceptionHandler,returnandresult.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwithrandomnumbers.

AllroutinesintheRandunitareexportedqualified(andthusmustbeprefacedwith"Rand.").

EntryPoints

Real Returnsarandomrealnumber.Int Returnsarandominteger.Reset Setstheseedinthedefaultsequencetoadefaultvalue.

Set Setstheseedinthedefaultsequencetoaspecifiedvalue.

Next Returnsarandomrealnumberfromasequence.Seed Setsaseedinasequence.

Rand.Int PartofRandmodule

Syntax Rand.Int(low,high:int):int

Description

TheRand.Intstatementisusedtocreateapseudo-randomintegerintherangelowtohigh,inclusive.Forexample,ifiisaninteger,afteri:=Rand.Int(i,1,10),iwouldhaveavaluesuchas7or2or10.

Example

Thisprogramsimulatestherepeatedrollingofasixsideddie.

put"Rolled",Rand.Int(1,6)

endloop

Details

TheRand.Intstatementsetsitsparametertothenextvalueofasequenceofpseudo-randomintegersthatapproximatesauniformdistributionovertherangelow=i=high.Itisrequiredthatlow=high.

Eachtimeaprogramruns,Rand.Intusesadifferentpseudo-randomnumbersequence.Toalwaysgetthesamesequence(actually,tostartthesequenceatthesamepoint),usetheRand.Setprocedure.

Touseseveralsequencesofrepeatablepseudo-randomnumbersequences,usetheRand.SeedandRand.Nextprocedures.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Int,notbycallingInt.

Seealso Rand.Real,Rand.Set,Rand.SeedandRand.Next.

Rand.Next PartofRandmodule

Syntax Rand.Next(seq:1..10):real

Description

TheRand.Nextprocedureisusedwhenyouneedseveralsequencesofpseudo-randomnumbers,andyouneedtobeabletoexactlyrepeatthesesequencesforanumberofsimulations.TheRand.Nextprocedureisthesameasrand,exceptseqspecifiesoneoftenindependentandrepeatablesequencesofpseudo-randomrealnumbers.

TheRand.Seedprocedureisusedtostartoneofthesesequencesataparticularpoint.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Next,notbycallingNext.

Seealso Rand.Seed,Rand.Int,Rand.RealandRand.Next.

Rand.Real PartofRandmodule

Syntax Rand.Real:real

Description

TheRand.Realfunctionreturnsapseudo-randomnumberintherangezerotoone.Forexample,ifxisarealnumber,afterx:=Rand.Real,xwouldhaveavaluesuchas0.729548or0.352879.

Example

ThisprogramrepeatedlyandrandomlyprintsoutHiho,hihoorIt'sofftoworkwego.

ifRand.Real>0.5then

put"Hiho,hiho"

put"It'sofftoworkwego"

endloop

Details

TheRand.Realfunctionsetsitsparametertothenextvalueofasequenceofpseudo-randomrealnumbersthatapproximatesauniformdistributionovertherange0<r<1.

Eachtimeaprogramruns,Rand.Realusesadifferentpseudo-randomnumbersequence.Toalwaysgetthesamesequence(actually,tostartthesequenceatthesamepoint),usetheRand.Setprocedure.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Real,notbycallingReal.

Seealso Rand.Int,Rand.Set,Rand.SeedandRand.Next.

Rand.Reset PartofRandmodule

Syntax Rand.Reset

Description

Thisisaprocedurewithnoparametersthatresetsthesequencesofpseudo-randomnumbersproducedbyRand.RealandRand.Int.Thisallowsidenticalexecutionsofthesameprogramtoproduceidenticalresults.

Example

Thisprogramsimulatestherepeatedrollingofasixsideddie.Eachtimetheprogramruns,thesamesequenceofrollsoccurs.

Rand.Reset

endloop

Details

IfRand.ResetandRand.Setarenotused,eachtimeaprogramrunsRand.RealandRand.Intuseadifferentpseudo-randomnumbersequence.Togetthesamesequenceeachtime(actually,tostartthesequenceatadifferentpoint),useRand.ResetorRand.Set.

TheRand.Resetprocedurecanbecalledanytime.However,tomakeitwork,itshouldonlybecalledonceperprogram.AnycalltoRand.Resetafterthefirstoneisignored.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Reset,notbycallingReset.

Seealso Rand.Set,Rand.Int,Rand.Real,Rand.SeedandRand.Next.

Rand.Seed PartofRandmodule

Syntax Rand.Seed(seed:nat4,seq:1..10)

Description

TheRand.SeedprocedurerestartsoneofthesequencesgeneratedbyRand.Next.EachrestartwiththesameseedcausesRand.Nexttoproducethesamesequenceforthegivensequence.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Seed,notbycallingSeed.

Seealso Rand.Next,Rand.Int,Rand.Real,andRand.Set.

Rand.Set PartofRandmodule

Syntax Rand.Set(seed:nat4)

Description

Thisproceduresetstheseedforsequencesofpseudo-randomnumbersproducedbyRand.RealandRand.Int.Thisallowsidenticalexecutionsofthesameprogramtoproduceidenticalresults.

Example

Thisprogramsimulatestherepeatedrollingofasixsideddie.Eachtimetheprogramruns,thesamesequenceofrollsoccurs.

Rand.Set(16#1234ABCD)

endloop

Details

IfRand.ResetandRand.Setarenotused,eachtimeaprogramrunsRand.RealandRand.Intuseadifferentpseudo-randomnumbersequence.Togetthesamesequenceeachtime(actually,tostartthesequenceatadifferentpoint),useRand.ResetorRand.Set.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRand.Set,notbycallingSet.

Seealso Rand.Reset,Rand.Int,Rand.Real,Rand.SeedandRand.Next.

rand randomrealnumberprocedure

Syntax rand(varr:real)

Description

Therandstatementisusedtocreateapseudo-randomnumberintherangezerotoone.Forexample,ifxisarealnumber,afterrand(x),xwouldhaveavaluesuchas0.729548or0.352879.

Example

ThisprogramrepeatedlyandrandomlyprintsoutHiho,hihoorIt'sofftoworkwego.

varr:real

rand(r)

ifr>0.5then

put"Hiho,hiho"

put"It'sofftoworkwego"

endloop

Details

Therandstatementsetsitsparametertothenextvalueofasequenceofpseudo-randomrealnumbersthatapproximatesauniformdistributionovertherange0<r<1.

Eachtimeaprogramruns,randusesadifferentpseudo-randomnumbersequence.Togetthesamesequence(useRand.Set).

Touseseveralsequencesofrepeatablepseudo-randomnumbersequences,usetherandseedandrandnextprocedures.

Inmanylanguages,randwouldbeafunctionratherthanaprocedure.IthasbeendesignedasaprocedureinTuringtorespectthemathematicalideathateverycalltoafunctionusingthesamearguments(ornoargumentsatall)shouldreturnthesamevalue.Ifrandwereafunction,thiswouldnotbetrue.

Seealsorandint,randomize,randseedandrandnext.

SeealsopredefinedunitRand.

randint randomintegerprocedure

Syntax randint(vari:int,low,high:int)

Description

Therandintstatementisusedtocreateapseudo-randomintegerintherangelowtohigh,inclusive.Forexample,ifiisaninteger,afterrandint(i,1,10),iwouldhaveavaluesuchas7or2or10.

Example

Thisprogramsimulatestherepeatedrollingofasixsideddie.

varroll:int

randint(i,1,6)

put"Rolled",i

endloop

Details

Therandintstatementsetsitsparametertothenextvalueofasequenceofpseudo-randomintegersthatapproximatesauniformdistributionovertherangelow=i=high.Itisrequiredthatlow=high.

Eachtimeaprogramruns,randintusesthesamepseudo-randomnumbersequence.Togetadifferentsequence(actually,tostartthesequenceatadifferentpoint),usetherandomizeprocedure.

Touseseveralsequencesofrepeatablepseudo-randomnumbersequences,usetherandseedandrandnextprocedures.

Seealso rand,randomize,randseedandrandnext.

randnext procedure

Syntax randnext(varv:real,seq:1..10)

Description

Therandnextprocedureisusedwhenyouneedseveralsequencesofpseudo-randomnumbers,andyouneedtobeabletoexactlyrepeatthesesequencesforanumberofsimulations.Therandnextprocedureisthesameasrand,exceptseqspecifiesoneoftenindependentandrepeatablesequencesofpseudo-randomrealnumbers.

Therandseedprocedureisusedtostartoneofthesesequencesataparticularpoint.

Seealso randseed,randint,randandrandnext.

randomize procedure

Syntax randomize

Description

Thisprocedureisobsolete.Itwasoriginallyusedtoproduceadifferentsequenceofrandomnumberseachtimeaprogramexecuted.WithcurrentversionsofTuring,therandomnumbersequenceis“randomized”eachtimeaTuringprogramisexecuted,eliminatingtheneedforthisprocedure.

Toresettherandomnumbersequenceandthusallowforapredeterminedsequenceofpseudo-randomnumbers,useRand.Set.

Seealsorandint,rand,randseedandrandnext.

SeealsopredefinedunitRand.

randseed procedure

Syntax randseed(seed:int,seq:1..10)

Description

Therandseedprocedurerestartsoneofthesequencesgeneratedbyrandnext.Eachrestartwiththesameseedcausesrandnexttoproducethesamesequenceforthegivensequence.

Seealso randnext,randint,rand,andrandomize.

read filestatement

Dangerousparts

Syntax

AreadStatementis:

read:fileNumber[:status],readItem{,readItem}

Description

ThereadstatementinputseachofthereadItemsfromthespecifiedfile.Theseitemsareinputdirectlyusingthebinaryformatthattheyhaveonthefile.Inotherwords,theitemsarenotinsource(ASCIIorEBCDIC)format.Inthecommoncase,theseitemshavebeenoutputtothefileusingthewritestatement.

Bycontrast,thegetandputstatementsusesourceformat,whichapersoncanreadusinganordinarytexteditor.

Example

Thisexampleshowshowtoinputacompleteemployeerecordusingareadstatement.

varemployeeRecord:

record

name:string(30)

pay:int

dept:0..9

endrecord

varfileNo:int

open:fileNo,"payroll",read

read:fileNo,employeeRecord

ThefileNumbermustspecifyafilethatisopenwithreadcapability(oraprogramargumentfilethatisimplicitlyopened).

Theoptionalstatusisanintvariablethatissettoimplementation-dependentinformationabouttheread.Ifstatusisreturnedaszero,thereadwassuccessful.Otherwisestatusgivesinformationabouttheincompleteorfailedread(whichisnotdocumentedhere).Youcommonlyusestatuswhenyouarereadingarecordorarrayfromafileandyouarenotsureiftheentireitemexistsonthefile.Ifitdoesnot

Details

exist,thereadwillfailpartwaythrough,butyourprogramcancontinueanddiagnosetheproblembyinspectingstatus.

AreadItemis:

variableReference[:requestedSize[:actualSize

EachreadItemspecifiesavariabletobereadininternalform.TheoptionalrequestedSizeisanintegervaluegivingthenumberofbytesofdatatoberead.TherequestedSizeshouldbelessthanorequaltothesizeoftheitem'sinternalforminmemory(elseawarningmessageisissued).IfnorequestedSizeisgiven,thesizeoftheiteminmemoryisused.TheoptionalactualSizeisanintvariablethatissettothenumberofbytesactuallyread.

Anarray,recordorunionmaybereadandwrittenasawhole.

Itisdangeroustoreadintopointervariables,asthisallowsthepossibilityofcreatingincorrectaddressesinthepointers.ItisalsodangeroustoreadmorebytesthanareinthereadItem.

Seealso thewrite,open,close,seek,tell,getandputstatements.

real therealnumbertype

Syntax real

Description

Therealnumbertypeisusedfornumbersthathavefractionalparts,forexample,3.14159.Realnumberscanbecombinedbyvariousoperatorssuchasaddition(+)andmultiplication(*).Realnumberscanalsobecombinedwithintegers(wholenumbers,suchas23,0and-9),inwhichcasetheresultisgenerallyarealnumber.Anintegercanalwaysbeassignedtoarealvariable,withimplicitconversiontoreal.

Examplevarweight,x:real

varx:real:=9.83

vartax:=0.7%Thetypeisimplicitlyrealbecause

%0.7isarealnumber

Details

SeealsoexplicitRealConstant.Theinttypeisusedinsteadofreal,whenvaluesarewholenumbers.Seeintfordetails.

Realnumberscanbeconvertedtointegersusingceil(ceiling),floor,orround.Realnumberscanbeconvertedtostringsusingerealstr,frealstr,andrealstr.Theseconversionfunctionscorrespondexactlytotheformattingusedfortheputstatementwithrealnumbers.Stringscanbeconvertedtorealnumbersusingstrreal.Seedescriptionsoftheseconversionfunctions.

Thepredefinedfunctionsforrealnumbersincludemin,max,sqrt,sin,cons,arctan,sind,cosd,arcand,lnandexp.Seethedescriptionsofthesefunctions.

Pseudo-randomsequencesofrealnumberscanbegeneratedusingrand.Seethedescriptionofthisprocedure.

TheTuringReportgivesaformaldefinition(notrepeatedhere)ofimplementedrealnumbersintermsoftheirrequiredaccuracyrelativetoinfinitelyaccurate(mathematical)realnumbers.

Turingimplementsrealnumbersusing8bytefloatingpointrepresentation.Thisprovides14to16decimaldigitsofprecisionandanexponentrangeofatleast-38..38.ThePCandMacintoshversionsofTuringhave16decimaldigitsofaccuracybecausetheyuseIEEEstandardfloatingpointrepresentation.

Seealso realn.

realn n-byterealnumbertype

Syntax (a) real4 %4-byterealnumber (b) real8 %8-byterealnumber

Description

Therealn(n-byterealnumber)typesaremachine-dependenttypesthatoccupyaspecifiednumberofbytes.Bycontrast,therealtypeis,inprinciple,amachine-independentandmathematicaltype(however,itoverflowswhentheexponentofthevalueistoolargeorsmallandithasonlyalimitedamountofprecision).

Example varwidth:real4

varheight:real8

Details

Turingimplementsthetyperealusing8bytefloatingpointrepresentation.Thisprovides14to16decimaldigitsofprecisionandanexponentrangeofatleast-38..38.ThePCandMacintoshversionsofTuringhave16decimaldigitsofaccuracybecausetheyuseIEEEstandardfloatingpointrepresentation.

Thisimpliesthatreal8andrealareessentiallythesametype,soinpracticethereisnoadvantagetousingreal8ratherthanreal.However,real4hastheadvantageofoccupyinghalfasmuchspace(withcorrespondinglyreducedprecision).

Arithmeticforallrealtypes(real,real4andreal8)iscarriedoutwiththeaccuracyandexponentrangeof8-bytereals.

Thetypereal4issometimescalledsingleprecision(becauseitoccupiesasingle4-byteword)andreal8issometimescalleddoubleprecision.

realstr real-to-stringfunction

Syntax realstr(r:real,width:int):string

Description

Therealstrfunctionisusedtoconvertarealnumbertoastring.Forexample,realstr(2.5e1,4)="bb25"wherebrepresentsablank.Thestringisanapproximationtor,paddedontheleftwithblanksasnecessarytoalengthofwidth.

Thewidthparametermustbenon-negative.Ifthewidthparameterisnotlargeenoughtorepresentthevalueofritisimplicitlyincreasedasneeded.Thedisplayedvalueisroundedtothenearestdecimalequivalentwiththisaccuracy.Inthecaseofatie,thedisplayvalueisroundedtothenextlargervalue.

Thestringrealstr(r,width)isthesameasthestringfrealstr(r,width,defaultfw)whenr=0orwhen1e-3<abs(r)<1e6,otherwisethesameaserealstr(r,width,defaultfw,defaultew),withthefollowingexceptions.Withrealstr,trailingfractionzeroesareomitted,andthedecimalpointisomittediftheentirefractioniszero.(Theseomissionstakeplaceeveniftheexponentpartisprinted.)Ifanexponentisprinted,anyplussignandleadingzeroesareomitted.Thus,wholenumbervaluesareingeneraldisplayedasintegers.

Defaultfwisanimplementation-definednumberoffractionaldigitstobedisplayed.Formostimplementations,defaultfwwillbe6.

Defaultewisanimplementation-definednumberofexponentdigitstobedisplayed.Formostimplementations,defaultewwillbe2.

Therealstrfunctionapproximatestheinverseofstrreal,althoughround-offerrorskeepthesefrombeingexactinverses.

Seealso theerealstr,frealstr,strreal,intstrandstrintfunctions.

record type

Syntax

ArecordTypeis:

record id{,id}:typeSpec {id{,id}:typeSpec} endrecord

Description

Eachvalueofarecordtypeconsistsoffields,onefieldforeachname(id)declaredinsidetherecord.Inthefollowingexample,thefieldsarename,phoneNumberandaddress.

Example

typephoneRecord:

record

name:string(20)

phoneNumber:int

address:string(50)

endrecord

varoneEntry:phoneRecord

varphoneBook:array1..100ofphoneRecord

vari:int

oneEntry.name:="Turing,Alan"

phoneBook(i):=oneEntry%Assignwholerecord

Details

Inarecord,id'soffieldsmustbedistinct.However,theseneednotbedistinctfromidentifiersoutsidetherecord.Recordscanbeassignedasawhole(torecordsofanequivalenttype),buttheycannotbecompared.AsemicoloncanoptionallyfolloweachtypeSpec.

Anyarraycontainedinarecordmusthaveboundsthatareknownatcompiletime.

Thenotation>canbeusedtoaccessrecordfields.Forexample,ifpisapointertophoneRecord,p>namelocatesthenamefield.Seepointer.

register usemachineregister

Description

Whenavariable,constantorparameterisdeclared,youcanrequestthattheitembeplacedinamachineregister.Thisshouldbedoneonlyforprogramsrequiringconsiderableefficiency.

Example

varregistercounter:int

constregistermaxCounter:int:=100

procedurep(registerx:real)

Details

Itemscanberequestedtobeinregistersonlyiftheyarelocaltoasubprogram(notglobalvariables,declaredinthemainprogram,amodule,monitororclass).Itemsrequestedtobeinregisterscannotbeboundto,passedtoreferenceparameters,havetheiraddresstakenbyaddr,orhavecertaintypecheatsappliedtothem(sinceamachineregisterhasnoaddress).

Therequesttousearegistermaybeignored.Forexample,thecurrent(1999)interpretiveimplementationusespseudo-code,whichhasnomachineregisters,andsoignorestheregisterkeyword.Forthesyntaxofusingthiskeyword,seevardeclaration,constdeclarationandparamDeclaration.

rem remainderoperator

Syntax rem

Description

Therem(remainder]operatorproducestheremainderofonenumberdividedbyanother.Forexample,7rem2produces1and-12rem5produces-2.

Example

Inthisexample,eggCountisthetotalnumberofeggs.Thefirstputstatementdetermineshowmanydozeneggsthereare.Thesecondputstatementdetermineshowmanyextraeggstherearebeyondthelastdozen.

vareggCount:int

geteggCount

put"Youhave",eggCountdiv12,"dozeneggs"

put"Youhave",eggCountrem12,"leftover"

Seealsoinfixoperators,precedenceofoperatorsandthemodanddivoperators.

repeat makecopiesofstring

function

Syntax repeat(s:string,i:int):string

DescriptionTherepeatfunctionreturnsicopiesofstringscatenatedtogether.Forexample,repeat("X",4)isXXXX.

Example

ThisprogramoutputsHoHoHo.

varword:string:="Ho"

putrepeat(word,3)

Details

Ifiislessthanorequaltozero,thenullstring""isreturned.Therepeatfunctionisoftenusedforspacingofoutput.Forexample,thisstatementskips20blanksbeforeoutputtingx.

putrepeat("",20),x

result statement

Syntax

AresultStatementis:

resultexpn

DescriptionAresultstatement,whichmustappearonlyinafunction,isusedtoprovidethevalueofthefunction.

Example

Thisfunctiondoublesitsparameter.

functiondouble(x:real):real

result2*x

enddouble

putdouble(5.3)%Thisoutputs10.6

Example

Thisfunctionfindsthepositionofanameinalist.

functionfind(a:array1..100ofstring):

fori:1..100

ifa(i)=namethen

resulti

endfor

endfind

Details

Theexecutionofaresultstatementcomputesthevalueoftheexpression(expn)andterminatesthefunction,returningthevalueasthevalueofthefunction.

Theexpressionmustbeassignabletotheresulttypeofthefunction,forexample,indouble,2*xisassignabletoreal.(SeetheassignmentStatementforthedefinitionofassignable.)

Afunctionmustterminatebyexecutingaresultstatementandnotbyreachingtheendofthefunction.

return statement

Syntax

AreturnStatementis:

return

Description

Areturnstatementterminatestheprocedure(ormainprogram)inwhichitappears.Ordinarily,aprocedure(ormainprogram)terminatesbyreachingitsend;thereturnstatementisusedtocauseearlytermination.

Example

ThisproceduretakesnoactioniftheerrorHasOccurredflaghasbeensettotrue.

proceduredouble

iferrorHasOccurredthen

return%Terminatethisprocedure

…handleusualcaseinthisprocedure…

enddouble

DetailsAreturnmustnotappearasastatementin(theoutermostlevelof)amodule,norcanitappearinafunction.

Description

Thisunitcontainsthepredefinedconstantsforthebasiccolorsandthesubprogramstochangethecolorpalette.

AllsubprogramsintheRGBunitareexportedqualified(andthusmustbeprefacedwith"RGB.").AllthecolorconstantsareexportedunqualifiedandthusdonotneedtheRGBprefix.

Details

Foraprogramthatdisplaysthe256predefinedcolors(andtheirassociatedcolornumbers)inTuring,runthe"Colors.t"program.

Details

Thefollowingnamescanbeusedforcolors.TheyrepresentcolornumbersandthuswillnotbeaccurateifRGB.SetColorhasbeenusedtochangecolornumbers0through15.

black,blue,green,cyan,red,magenta,purple,brown,white,gray,grey,brightblue,brightgreen,brightcyan,brightred,brightmagenta,brightpurple,yellow,brightwhite,darkgray,darkgrey

Theremainingfourcolorsrepresenttheforegroundcolor(blackonWindowsortheMacintosh,whiteonaDOSsystem)andthebackgroundcolor(whiteonWindowsorMacintosh,blackonaDOSsystem).UsingthesefourcolorsallowsyoutowriteprogramsthatworkonbothWindowsandDOSversionsofTuring.

colorfg,colourfg,colorbg,colourbg

Turingusesapalettetoaccesscolorsfordisplay.Thispaletteisa

Details

listofcolornumbersandtheirassociatedactualcolor.TheTuringpalettestartswith256entries(thecolornumbersfrom0to255).With16,24,and32-bitcolordisplays,however,aTuringprogramcandisplaythousandsofcolorsatonce.Thesecolors,however,willallhavecolornumbersassociatedwiththem.Forexample,ifaTuringprogramloadsaJPEGimage,theremaybethousandsofcolorsonthescreen,butthenumberofcolornumberswillstayat256.Likewise,16,24,and32-bitcolordisplays,ifyouloadapictureinGIFformatthathasa256colorsthataredifferentfromtheinitialTuringcolorpalette,theywillappearintherunwindow.However,theywillnotbeaddedtoTuring'scolorpalette.

IfyouattempttodeterminethecolornumberofaparticularpixelthatdoesnotmatchanyofthecolorsinTuring'scolorpalette,thenTuringwillreturnthecolornumberofthecolorintheTuringpalettethatmostcloselymatchesthatcolorofthepixel.

EntryPoints

GetColorGetColour Getsthecurrentred,greenandbluevaluesofa

specifiedcolornumber.SetColorSetColour Setsthered,greenandbluevaluesofa

specifiedcolornumber.AddColorAddColour Createsanewcolornumberwithaspecified

red,greenandbluevalue.

RGB.AddColor PartofRGBmodule

Syntax RGB.AddColor(redComp,greenComp,blueComp:real):int

Description

TheRGB.AddColorfunctionattemptstocreateanewcolorwiththered,greenandbluecomponentsspecified.Ifsuccessful,thefunctionreturnsanewcolornumber(usuallyonegreaterthanmaxcolor)andmaxcolorisupdatedbyadding1toit.Ifitisunsuccessful,thefunctionreturns1andError.LastandError.LastMsgcanbeusedtodeterminethecauseoftheproblem.

Thered,greenandbluevaluesmustnormalizedtobebetween0and1.Thustoaddthepureredtothecolorpalette,youwouldcall:

newColor:=RGB.AddColor(1.0,0.0,0.0)

newColorwouldbesettothecoloradded,or1iftheattempttoaddacolorfailed.

Example

Thisprogramaddsapaletteof16bluestotheendofthecolorpalette.

varclr:int

forblueShade:0..15

clr=RGB.AddColor(0,0,blueShade/15)

ifclr=1then

put"Coloraddfailedonshadenumber",

put"Addedcolornumber",clr

endfor

Details RGB.AddColourisanalternatespellingforRGB.AddColor.

Status

Exportedqualified.

RGB.AddColor,notbycallingAddColor.

Seealso RGB.GetColorandRGB.SetColor.

RGB.GetColor PartofRGBmodule

SyntaxRGB.GetColor(colorNumber:int, varredComp,greenComp,blueComp:real)

Description

TheRGB.GetColorprocedurereturnsthered,greenandbluecomponentstothecolorassociatedwiththecolorNumberparameter.Thered,greenandbluevaluesarenormalizedtobebetween0and1.Thuscolorwhitereturns1.0fortheredComp,greenCompandblueCompvaluesandcolorblackreturns0.0forallthree.

Example

Thisprogramgetsthecomponentsofalltheavailablecolors.

put"ColorRedGreenBlue"

forclr:0..maxcolor

varredComp,greenComp,blueComp:int

RGB.GetColor(clr,redComp,greenComp,blueComp

putclr:4,"",redComp:6:4,"",greenComp

blueComp:6:4

endfor

Details RGB.GetColourisanalternatespellingforRGB.GetColor.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRGB.GetColor,notbycallingGetColor.

Seealso RGB.SetColorandRGB.AddColor.

RGB.maxcolor PartofRGBmodule

Syntax maxcolor:int

Description

Example

put"Themaximumcolornumberis",maxcolor

Details

Thescreenshouldbeina"screen"or"graphics"mode.Ifitisnot,itwillautomaticallybesetto"screen"mode.SeeView.Setfordetails.

ForIBMPCcompatiblesin"screen"mode,maxcolor=15.ForthedefaultIBMPCcompatible"graphics"mode(CGA),maxcolor=3.

Status

ThismeansthatyoucancallthefunctionbycallingmaxcolororbycallingRGB.maxcolor.

Seealso

Draw.Dotforexamplesoftheuseofmaxcolor.SeetheText.Colorprocedurewhichisusedforsettingthecurrently-activecolor.

RGB.SetColor PartofRGBmodule

SyntaxRGB.SetColor(colorNumber:int, redComp,greenComp,blueComp:real)

Description

TheRGB.SetColorfunctionsetsthered,greenandbluecomponentsofthecolorassociatedwiththecolorNumberparameter.Thered,greenandbluevaluesmustnormalizedtobebetween0and1.ThustosetthecolorassociatedwiththecolorNumberparametertopurered,youwouldcall:

RGB.SetColor(colorNumber,1.0,0.0,0.0)

ItiswisetouseError.LastandError.LastMsgtochecktoseeifthecolorchangeissuccessful.

Example

Thisprogramsetsalltheavailablecolorstoshadesofred

forclr:0..maxcolor

ifnotRGB.SetColor(clr,clr/maxcolor,0,0)

put"Colorsetfailedoncolornumber",

endfor

Details RGB.SetColourisanalternatespellingforRGB.SetColor.

Details

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingRGB.SetColor,notbycallingSetColor.

Seealso RGB.GetColorandRGB.AddColor.

round real-to-integerfunction

Syntax round(r:real):int

Description

Theroundfunctionisusedtoconvertarealnumbertoaninteger.Theresultisthenearestintegertor.Inthecaseofatie,thenumericallylargervalueisreturned.Forexample,round(3)is3,round(2.85)is3andround(-8.43)is-8.

Seealso thefloorandceilfunctions.

scalar type

Syntax

AscalarTypeisoneof:

(a) standardType %int,real,booleanorstring

(b) enumeratedType (c) subrangeType (d) pointerType (e) char (f) intn (g) natn (h) realn

(i) namedType %Mustnameoneoftheabovetypes

Description

Scalartypesaresometimescalledsimpleorprimitivetypes.Thenon-scalartypesarestrings,sets,arrays,records,unionsandinOOTchar(n).Theyaredefinedusingscalartypes.Scalartypesarepassedbyvaluetoparameters,whilenon-scalarsarepassedbyreference(bypassinganimplicitpointertothenon-scalarvalue).

Description

IncurrentTuringimplementationsscalartypesaredirectlyrepresentedin1,2,4or8bytesinacomputer'smemory.Thisimpliesthattheycanbeefficientlypassedbyvalue.

seek (file)statement

Syntax

AseekStatementisoneof:

(a) seek:fileNumber,filePosition (b) seek:fileNumber,*

Description

Randomaccessofbothsource(ASCIIorEBCDIC)andinternalform(binary)filesisprovidedbytheseekandtellstatements.Theseekstatementrepositionsthespecifiedfilesothatthenextinput/outputoperationwillbeginatthespecifiedpoint(filePosition)inthefile.

ThefileNumbermustspecifyafilethatisopenwithseekcapability.ThefilePositionisanon-negativeintegeroffsetinbytesfromthebeginningofthefile.Usually,thisisanumberreturnedbythetellstatement.(Thefirstpositioninthefileispositionzero.)

Form(b)specifiesthatthenextoperationistobeginatthepositionimmediatelyfollowingthecurrentendofthefile.AfilePositionofzerospecifiesthatthenextoperationistostartatthebeginningofthefile.Seekingtoapositionbeyondthecurrentendofthefileandthenwriting,automaticallyfillstheinterveningpositionswiththeinternalrepresentationofzero.

Example

Thisexampleshowshowtouseseektoappendtotheendofafile.

varemployeeRecord:

record

name:string(30)

pay:int

endrecord

varfileNo:int

open:fileNo,"payroll",write,seek,mod

seek:fileNo,*%Seektotheendofthefile

write:fileNo,employeeRecord

%Thisrecordisaddedtotheendofthefile

Seealsoread,write,open,close,tell,getandputstatements.Anotherexampleuseofseekisgivenwiththeexplanationofthetellstatement.

self pointertocurrentobject

Syntax self

DescriptionTheselffunctionproducesapointertothecurrentobject.Thisfunctioncanbeusedonlyinsideaclassdeclaration.Seeclass.

Example

Enterthecurrentobjectontoalistofdisplayableobjects.Themodulecalleddisplayablehasexportedaprocedurecalledenterwhoseparametertypeispointertoanyclass.SinceselfisapointertoCandCisadescendantofanyclass,itislegaltopassselftodisplayable.enter.

classC

importdisplayable

displayable.enter(self)…

Details

Itisillegaltocalltheexportedentriesofaclassuntilthecurrentobjecthasbeencompletelyinitialized,so,manycallstothecurrentobjectusingselfwillnotbelegal.

ThenotationtocallexportedsubprogrampofanenclosingclassCorofitsancestorD,isC.porD.p.Callsofthisform,whichcanappearonlywithinclassC,callthesubprograminC(orinDinthecaseofD.p)regardlessoftheobjecttype,orofanyoverriding,orofthestatusofinitialization.

separator betweentokensinaprogram

Description

ATuringprogramismadeupofasequenceoftokens(seetokens),suchasvar,x,:,andint.Thesetokensmayhaveseparatorsbetweenthem.Aseparatorisacomment(seecomment),blank,tab,formfeedoranendofline.

set type

Syntax

AsetTypeis:

setoftypeSpec

Description

Eachvalueofasettypeconsistsofasetofelements.ThetypeSpec,whichisrestrictedtobeingasubrangeoranenumeratedtype,givesthetypeoftheseelements.

Example

ThesmallSettypeisdeclaredsothatitcancontainanyandallofthevalues0,1and2.Variablesisinitializedtobethesetcontaining1and2.

typesmallSet:setof0..2

vars:smallSet:=smallSet(0,1)

if2insthen…

Details

Inclassicalmathematics,thesetconsistingof0and1iswrittenas{0,1}.ThisiswritteninTuringusingasetconstructorconsistingofthenameofthesettypefollowedbyaparenthesizedlistofelements,whichinthisexampleissmallInt(0,1).Theemptysetiswritten,forexample,assmallInt().ThefullsetiswrittenassmallInt(all),sosmallInt(all)=smallInt(0,1,2).

Setscanbeassignedasawhole(tosetsofanequivalenttype).Seealsoequivalenceoftypes.

Theoperatorstocombinetwosetsareunion(+),intersection(*),setsubtraction(-),equality(=),inequality(not=),subset(<=),strictsubset(<),superset(>=),strictsuperset(>),andxor("exclusiveor"alsoknownassymmetricdifference).Onlysetswithequivalenttypes(equalboundsontheirindextypes)canbecombinedbytheseoperators.Theoperatorswhichdetermineifanelementis,orisnot,inasetareinandnotin.Forexample,thetesttoseeif2isinsetsiswrittenintheaboveexampleas:2ins.

TheindexTypeofasettypemustcontainatleastoneelement.For

example,therange1..0wouldnotbeallowed.SeealsoindexType.InTuring,setsarelimitedtoatmost31elements.OOTallowsaverylargenumberofelements.

Details

Itisillegaltodeclarean"anonymous"set.Theonlylegaldeclarationforansetisinatypedeclaration.Forexample,thefollowingisnowillegal:

vara:array1..10ofsetof0..3

Giventhatthereisno(easy)wayofgeneratingasetvaluewithoutitbeinganamedtype,thisshouldnotimpactanybutthemostbizarrecode.

Seealso precedenceofoperatorsfortheorderofapplyingsetoperations.

setConstructor

Syntax

AsetConstructoris:

setTypeId(membersOfSet)

Description

Eachvalueofasettypeconsistsofasetofelements.Inclassicalmathematics,thesetconsistingof0and1iswrittenas{0,1}.ThisiswritteninTuringusingasetconstructorconsistingofthenameofthesettype(setTypeId)followedbyaparenthesizedlistofelements.

Example

ThesmallSettypeisdeclaredsothatitcancontainanyandallofthevalues0,1and2.Variablesisinitializedtobethesetcontaining1and2.Theset{0,1}iswritteninthisTuringexampleassmallInt(0,1).

typesmallSet:setof0..2

vars:smallSet:=smallSet(0,1)

if2insthen…

Details

TheformofmembersOfSetisoneof:

(a)expn{,expn}%Listofmembersofset

(b)all%Allmemberofindextypeofset

(c)%Nothing,meaningtheemptyset

Theemptysetiswritten,forexample,assmallInt().ThefullsetiswrittenassmallInt(all),sosmallInt(all)=smallInt(0,1,2).Seealsothesettype.

ThesyntaxofsetConstructorasgivenabovehasbeensimplifiedbyignoringthefactthatsettypescanbeexportedfrommodules.Whenasettypeisexportedandusedoutsideofamodule,youmustwritethemodulename,adotandthenthetypename.Forexample,thesetconstructorabovewouldbewrittenasm.smallSet(1,2),wheremisthemodulename.

setpriority procedure

Syntax setpriority(p:nat)

Description

Thesetpriorityprocedureisusedtosetthepriorityofaprocessinaconcurrentprogram.Thisprioritycannotbecountedontoguaranteecriticalaccesstosharedvariables.Asmallervalueofpmeansincreasedspeed.Theargumenttosetprioritymaybelimitedtotherange0to2**15-1.

Seealsogetpriority,forkandmonitor.

setscreen graphicsprocedure

setscreen("graphics:300;100")

Thisprogramoutputsthesquarerootsforthefirst200numbers.Theusercaninspectalltheoutputandprintthevaluesaftertheprogramhasfinishedexecution

setscreen("text")

forvalue:1..200

putvalue:3,"",sqrt(value)

endfor

Thisprogramcreatesawindowwithoutabuttonbaratthetopthatissizedtofitthescreen.Itthendrawsan“X”inredinthewindow.

setscreen("graphics:max;max,nobuttonbar")

drawline(0,0,maxx,maxy,red)

drawline(maxx,0,0,maxy,red)

Syntax setscreen(s:string)

Example

Hereareexampleusesofthesetscreenprocedure.Inmanycases,thesewillappearasthefirststatementoftheprogram.Theycan,however,appearanyplaceinaprogram.

setscreen("graphics")%Entergraphicsmode

setscreen("graphics:400;300")%Changewindowto400x300

setscreen("nocursor")%Turnoffcursor

setscreen("noecho")%Donotechokeys

Description

Thesetscreenstatementisusedtochangethemodeofthescreen,aswellasthewayinwhichTuringdoesinputandoutput.Theparametertosetscreenastring,suchas"graphics".Thestringcontainsoneormoreoptionsseparatedbycommas,suchas"text,noecho".

UsersshouldlookatView.Setinordertofindouttheimplementationspecifieddetailsofsetscreenontheirsystems.

Therearetwoscreenmodes,textandgraphics.Intextmode,outputtothewindowisonlyallowedusingputandget.Attemptingtousegraphicsormovingthecursorusinglocatewillresultinanerror.However,awindowin

Details

textmodewillkeepalltextoutputsenttoit.Anyoutputthatscrollsofftheedgeofthewindowcanbereadbyadjustingthescrollbarsofthewindow.Printingatextoutputwindowprintsalltheoutputsenttothewindow,notjusttheoutputcurrentlyvisibleinthewindow.Programsoftenusewhentheyaredisplayinglargeamountsoftextdatathattheusermaywishtovieworprintlater.Savingthecontentsofatextoutputwindowcreatesatextfilecontainingalltheoutputsenttothewindow.

Ingraphicsmode,aprogramcanusebothputandget,locateandgraphicscommandstosendoutputtothewindow.However,anyoutputthatscrollsoffthewindowislost.Printingthewindowoutputsthecurrentcontentsofthewindow.SavingagraphicsoutputwindowsavesthecurrentcontentsofthewindowasaBMPfile.

Wheretheoptionstosetscreenaremutuallyexclusive,theyarelistedherewiththedefaultunderlined.Herearetheoptions:

"graphics","text",Setsthemodeofthewindowtothegivenmode.Asizecanforthewindowcanbespecifiedatthesametime.Ifthewindowmodeorsizechanges,thenthewindowwillbecleared.

Tospecifythesizeofawindowingraphicsmode,thegraphicscanhaveamodifierintheform"graphics:<width>;<height>".Thissetsthewindowtobe<width>pixelsby<height>pixelsinsize.Themaximumsizeofawindowisthesizeofthescreen.

Tospecifythesizeofawindowintextmode,thetextcanhaveamodifierintheform"text:<rows>;<columns>".Thissetsthewindowtobe<rowslinesinheightby<columns>charactersinwidth.Themaximumsizeofawindowisthesizeofthescreen.

Tosetawindowtothemaximumsizeavailableonthescreen,you"max"forthe<width>,<height>,<rows>or<columns>parameters.

"cursor","nocursor"Causesthecursortobeshown(orhidden).Thecursoronlyappearswhentheprogramiswaitingforkeyboardinputfromtheuser.

"echo","noecho"Causes(orsuppresses)echoingofcharactersthataretyped.Echoingiscommonlyturnedoffininteractiveprogramstokeeptypedcharactersfrombeingechoedatinappropriateplacesonthescreen.

"nooffscreenonly","offscreenonly"Causesor(suppresses)outputfrombeingsenttothevisiblewindow.Whentheoffscreenonlyoptionisactive,anytextandgraphicsoutputisdrawntotheoffscreenbufferthatismaintainedforeveryRunwindowbutnotdrawntothescreen.View.Updateisthenusedtocopytheentirecontentsoftheoffscreenbuffertothewindow.Byallowingnumerousdrawingcommandstobesenttotheoffscreenbufferandthenupdatingthewindowatonetime,itispossibletogetsmootheranimation.

"msdos","nomsdos"CausesthewindowtousetheMS-DOScharacterset(withlinedrawingcharacters)insteadoftheWindowsANSIcharacterset.The"nomsdos"optioncausesthewindowtousetheWindowsANSIcharacterset.Notethatthe"msdos"optiononlyworksiftheWindowsfont(usuallyCourierNew)supportsit.

"buttonbar","nobuttonbar"Causesor(suppresses)thedisplayofabuttonbaratthetopoftheoutputwindowwhichallowstheusertoeasilystopprogramexecutionorsaveandprinttheoutputwindow.

Example Thisprogramcreatesagraphicswindowthatis300pixelsby100pixels.

Seealso

theDrawmodule,thedraw…subprogramsandtheView.Updateprocedurefordoingsmoothanimation.SeealsoView.Setforfurthersetscreenincludingpositioningtheoutputwindowonthescreen.

shl shiftleftoperator

Syntax AshlB

Description

Theshl(shiftleft)operatorproducesthevalueofAshiftedBbitstotheleft.BothAandBmustbenon-negativeintegers(naturalnumbers).

Example

Assignthebase2value11toiandthenshiftitleftby2placesandassigntheresultingbase2value1100toj.

vari,j:int

i:=2#11%2#11=3(base10)

j:=ishl2%jbecomes2#1100=12(base10)

Details

Theshloperatorisdefinedmathematically(inamachine-independentway)asfollows:AshlB=A*(2**B).Overflowoccurswhentheresultexceedsthemaximumvalueofthenat4(4-bytenaturalnumber)type.

ValueAcanbeofanyintegertype(aslongasitisnon-negative)oranynaturalnumbertype.

Theshloperatorhasthesameprecedenceasthe*operator.

Seealso

shr(shiftright),or,andandxor,whichalsoarebitmanipulationoperatorsthatactonnon-negativevalues.SeealsoexplicitIntegerConstantwhichdescribesvaluessuchas2#1100.

shr shiftrightoperator

Syntax AshrB

Description

Theshr(shiftright)operatorproducesthevalueofAshiftedBbitstotheright.BothAandBmustbenon-negativeintegers(naturalnumbers).

Example

Assignthebase2value1101toiandthenshiftitrightby2placesandassigntheresultingbase2value11toj.

vari,j:int

i:=2#1101%2#1101=13(base10)

j:=ishr2%jbecomes2#11=3(base10)

Details

Theshroperatorisdefinedmathematically(inamachine-independentway)asfollows:AshrB=Adiv2**B.

ValueAcanbeofanyintegertype(aslongasitisnon-negative)oranynaturalnumbertype.

Theshroperatorhasthesameprecedenceasthe*operator.

Seealso

shl(shiftleft),or,andandxor,whichalsoarebitmanipulationoperatorsthatactonnon-negativevalues.SeealsoexplicitIntegerConstantwhichdescribesvaluessuchas2#1101.

sign function

Syntax sign(r:real):-1..1

Description

Thesignfunctionisusedtodeterminewhetheranumberispositive,zeroornegative.Itreturns1ifr>0,0ifr=0,and-1ifr<0.Forexample,sign(5)is1andsign(-23)is-1.

Example

Thisprogramreadsinnumbersanddeterminesiftheyarepositive,zeroornegative:

varx:real

casesign(x)of

label1:put"Positive"

label0:put"Zero"

label-1:put"Negative"

endcase

signal wakeupaprocessstatement

Syntax

AsignalStatementis:

signalvariableReference

Description

Asignalstatementisusedinaconcurrentprogramtowakeupaprocessthatisblocked(waitingonaconditionvariable).Thestatementcanonlybeusedinsideamonitor(aspecialkindofmodulethathandlesconcurrency).Asignalstatementoperatesonaconditionvariable(thevariableReference),whichisessentiallyaqueueofsleepingprocesses.Seeconditionforanexampleofasignalstatement.

Details

Asignalstatementwakesuponeprocessthatisdoingawaitonthespecifiedconditionqueue,ifsuchaprocessexists.Iftheconditionisdeferred(ortimeout;seecondition),thesignalercontinuesinthemonitor,andtheawakenedprocessisallowedtocontinueonlywhenthemonitorbecomesinactive.Asignaltoanimmediate(non-deferred)conditioncausesthesignaledprocesstobeginrunninginthemonitorimmediately.Thesignalingprocesswaitstore-enterthemonitorwhenthemonitorbecomesinactive.

Seealsoconditionandwait.Seealsomonitorandfork.Seealsoempty.Seealsopause.

simutime simulatedtimefunction

Syntax simutime:int

DescriptionThesimutimefunctionreturnsthenumberofsimulatedtimeunitsthathavepassedsinceprogramexecutionbegan.

Details

Simulatedtimeonlypasseswhenallprocessareeitherpausedorwaiting.ThissimulatesthefactthatCPUtimeiseffectivelyinfinitelyfastwhencomparedto"pause"time.

Example

Thisprintsoutthesimulatedtimepassingbetweentwoprocesses.Thiswillprintout3,5,6,9,10,12,15,15,18,20,21,…

processp(t:int)

pauset

putsimutime

endloop

forkp(3)

forkp(5)

Execute

Seealso SeealsopredefinedunitConcurrency.

sin sinefunction(radians)

Syntax sin(r:real):real

DescriptionThesinfunctionisusedtofindthesineofananglegiveninradians.Forexample,sin(0)is0.

Example

Thisprogramprintsoutthesineofp/6,2p/6,3p/6,upto12p/6radians.

constpi:=3.14159

fori:1..12

constangle:=i*pi/6

put"Sinof",angle,"is",sin(angle)

endfor

Execute

Seealso

thecosandtanfunctionsforcalculatingcosineandtangent.

thesindfunctionwhichfindsthesineofananglegivenindegrees.(2pradiansarethesameas360degrees.)

sind sinefunction(degrees)

Syntax sind(r:real):real

DescriptionThesindfunctionisusedtofindthesineofananglegivenindegrees.Forexample,sind(0)is0.

Example

Thisprogramprintsoutthesineof30,60,90,upto360degrees.

fori:1..12

constangle:=i*30

put"Sinof",angle,"is",sind(angle)

endfor

Execute

Seealso

thecosdandtandfunctionsforcalculatingcosineandtangent.

thesinfunctionwhichfindsthesineofananglegiveninradians.(2pradiansarethesameas360degrees.)

sizeof sizeofatype

Syntax sizeof(typeNameOrVariableReference)

Description

Thesizeofattributeisusedtofindthenumberofbytesusedtorepresentthetypeorvariable.Thisisimplementation-dependent(dirty).

Example

Thesizeofint2andnat2is2.

vari:int2

constnat2size:=sizeof(i)%sizeis2

Details

ThetypeNameOrVariableReferencemustbethenameofauser-definedtype,avariablereference,abasictype(suchasreal),oraconstant.

Inprinciple,sizeofreturnsthenumberofstorageunitswhichwouldnotnecessarilybe8-bitbytes.Forexample,insomeoldermachines,suchastheCDC6000series,thestorageunitsare60bitwords.However,almostallmoderncomputersuse8-bitbytessothesearetheunitsofsizeof.

Bewarethatsizesmayreflectalignmentconstraintsintheunderlyingcomputer.Forexample,stringsizesmayberoundeduptoevenvalues(2-bytewordalignments).

Seealso

theindirectionoperator@,cheat,explicitIntegerConstant(howtowritehexadecimalconstants),andpointers(inparticularuncheckedpointers).Seealsoaddr,whichreturnstheaddressofavariable.

sizepic graphicsfunction

Syntax sizepic(x1,y1,x2,y2:int):int

Description

Thesizepicfunctionisusedtodeterminethesizebufferneededtorecordapicturefromthescreen(seedescriptionoftakepic).Thisgivestheminimumnumberofelementsoftheintarrayusedbytakepic.Thebufferisusedbydrawpictomakecopiesofthepictureonthescreen.

Example

Thisprogramoutputsthesizeofarrayneededtoholdapicturewithleftbottomcorneratx=10,y=20andrighttopcorneratx=50,y=60.

put"Thesizeofthearrayneedstobe",

sizepic(10,20,50,60)

Details

Seetakepicforanexampleoftheuseofsizepicandforfurtherinformationaboutbuffersfordrawingpictures.

Seealso

drawpic.Seealsosetscreen,maxx,maxy,drawdot,drawline,drawbox,anddrawoval.

SeealsopredefinedunitPic.

skip usedingetstatement

Syntax skip

Description

Usingskipasaninputiteminagetstatementcausesthecurrentinputtobeskippeduntilanon-whitespacetokenisencountered.Whitespaceincludesallblanks,tabs,formfeedsandnewlines.

Example

Theskipinputitemwasoriginallyintendedtobeusedtoseeifmoreinputexistsinaninputfile.ThisusehasbeenlargelymaderedundantbyachangeintheTuringlanguage.ThenewversionofTuringreadsatoken,asingetsbutnotingets:*orgets:3,andautomaticallyskipsanywhitespacefollowingtheinputvalue,butwillnotgobeyondthebeginningofthenextinputline.Originallythisautomaticskippingdidnottakeplace,soskipwasrequired.Theformofaninputloopthatusedskipwasasfollows:

getskip%Thisislinenowredundant

exitwheneof

get…

endloop

Details

Theskipbypassesallwhitespacecharactersincludinganytrailingnewlinesandblanklines.Byskippingthesecharacters,atrueend-of-fileconditionwasdetected.Otherwise,theend-of-filecouldhavebeenhiddenbyanywhitespacefollowingthelastinputitem.WiththechangeinTuring,thelinegetskipisnolongerneeded(althoughitstillworkscorrectly).

Example

Theskipcanalsobeusedtocorrectlyidentifythestartofalongstring(usuallytobereadinlineorcountedmode).Here,itskipsthewhitespaceandtrailingnewlineasfollows:

vari:int

varline:string

geti,skip,line:*

endloop

Details

Thefirstiteminthegetstatementreadsanintegerbyskippingallwhitespaceandreadingdigitsuntilwhitespaceisencountered.Theinputstreamisthenleftwiththewhitespaceasthenextinputcharacter.Theskipthenskipspastthewhitespace,effectivelybeginningthenextinputatthenextnon-whitespacecharacter.Thistruncatesleadingblanksandhasanother,potentiallymoreimportant,effect.Iftheintegeristhelastdataonalineandthestringisonafollowingline,theskipisnecessarytoavoidsettinglinetoanullstringvalue.

Seealso getstatementandloopstatement.

skip usedinputstatement

Syntax skip

DescriptionUsingskipasanoutputiteminaputstatementcausesthecurrentoutputlinetobeendedandanewlinetobestarted.

Example

Thisexample,TobeisoutputononelineandOrnottobeonthenext.

put"Tobe",skip,"Ornottobe"

Details Usingskipisequivalenttooutputtingthenewlinecharacter"\n".

sound statement

Syntax sound(frequency,duration:int)

Description

Thesoundprocedureisusedtocausethecomputertosoundanoteofagivenfrequencyforagiventime.Thefrequencyisincyclespersecond(Hertz).Thetimedurationisinmilliseconds.Forexample,middleAonapianois440Hertz,sosound(440,1000)playsmiddleAforonesecond.

Example

Thisprogramsoundsthefrequencies100,200upto1000eachforhalfasecond.

fori:1..10

sound(100*i,500)%Soundnotefor1/2second

endfor

Details

OnIBMPCcompatibles,thehardwareresolutionofdurationisinunitsof55milliseconds.Forexample,sound(440,500)willdelaytheprogrambyabouthalfasecond,butmaybeoffbyasmuchas55milliseconds.

Details ThesoundproceduredoesnotcurrentlyworkunderMacOOT.

Seealso

playstatement,whichplaysnotesbasedonmusicalnotation.Forexample,play("8C")playsaneighthnoteofmiddleC.Seealsothedelay,clock,sysclock,wallclock,timeanddatestatements.

Sprite

Description

SpritesareawayofdoinganimationinTuringbypassingthePicmodule.Aspriteisessentiallyapicturewithaspecificlocationand"depth".YoucreateaspritebycallingSprite.NewwithapicIDreceivedfromPic.New.YoucanthenmovethespritearoundbycallingSprite.SetPosition.Whenyouarefinishedwiththesprite,youcallSprite.Free.

Notethatspritesworkbestwhentheyaremoderatelysmall.Ifyouhavelargesprites,youwillcontinuetohaveflashing.

AllsubprogramsintheSpriteunitareexportedqualified(andthusmustbeprefacedwith"Sprite.").

EntryPoints

New Createsanewspritefromapicture.Free Disposesofaspriteandfreeupitsmemory.

SetHeight

Setstheheightofasprite.Spriteswithagreaterheightappearabovespriteswithalesserheight.Thebackgroundisconsideredheight0.Theheightmaybenegative.

SetPosition Setsthelocationofthesprite.Canspecifythecenterofthespriteorthelower-leftcorner.

SetFrameRate Setsthemaximumnumberoftimesasecondthespriteswillbemovedonscreen.

ChangePic Changesthepictureassociatedwithasprite.

Animate Changesthelocationandthepictureassociatedwithasprite.Usedforanimatingamovingchangingimage.

Show Showsapreviouslyhiddensprite.Hide Hidesavisiblesprite.

Sprite.Animate PartofSpritemodule

SyntaxSprite.Animate(spriteID,picID,x,y:int,centered:boolean)

Description

MovesthespritespecifiedbyspriteIDtothelocationspecifiedby(true,thenthespriteiscenteredon(x,y).Otherwise(x,y)specifiesthelower-leftcornerofthesprite.Atthesametime,itchangesthepictureassociatedwiththesprite.

AsimpleexampleoftheSprite.Animateprocedurewouldbeofapictureassociatedwiththespritewouldconstantlychangeasthefigurewaswalking.Atthesametime,thelocationofthefigurewouldalsochange.

Example

HereisaprogramthatloadsaseriesofimagesfromananimatedGIFfilecalled"mypic.gif".ItworksbyloadingtheimagesfromtheGIFfileintoanarray(seePic.FileNewFramesformoreinformation)andthendisplaystheimagessequentiallyonthescreen,movingtheimageeightpixelseachtime.

varnumFrames:=Pic.Frames("mypic.gif")

%Loadthepicture

vardelayTime:int

Pic.FileNewFrames("mypic.gif",pics,delayTime)

varsprite:int

sprite:=Sprite.New(pics(1))

Sprite.SetPosition(sprite,0,100,false)

Sprite.Show(sprite)

forx:8..maxxby8

Sprite.Animate(sprite,pics((xdiv8)mod

delay(40)%Stopspritefrommovingtooquickly

endfor

Sprite.Free(sprite)

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.AnimateAnimate.

Seealso Sprite.New,Sprite.SetPositionandSprite.ChangePic.

Sprite.ChangePic PartofSpritemodule

Syntax Sprite.ChangePic(spriteID,picID:int)

Description

Changesthepictureassociatedwithaspritewhilemaintainingthespritesheightandvisibilitystatus.AtypicaluseSprite.ChangePicwouldbetoanimateaspritethatstaysinposition.

Example

HereisaprogramthattthatloadssiximagesfromfilesPic1.bmpthroughPic6.bmpandthendisplaysthemsequentiallyinthecenterofthescreen.

varpics:array0..5ofint

varsprite:int

fori:1..6

pics(i1):=Pic.FileNew("Pic"+intstr(

ifError.Lastnot=0then

put"Errorloadingimage:",Error.LastMsg

return

endfor

figure:=Sprite.New(pics(0))

Sprite.SetPosition(sprite,maxxdiv2,maxydiv

Sprite.Show(sprite)

fori:1..100

Sprite.ChangePic(sprite,pics(imod6))

endfor

Sprite.Free(sprite)

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.ChangePic,notbycallingChangePic.

Seealso Sprite.New.

Sprite.Free PartofSpritemodule

Syntax Sprite.Free(spriteID:int)

DescriptionDestroysthespriteandfreesupthememorythespriteused.ItisanerrortousethespriteIDafterthespritehasbeenfreed.

Example SeeSprite.AnimateforanexampleofSprite.Free.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.Free,notbycallingFree.

Seealso Sprite.New.

Sprite.Hide PartofSpritemodule

Syntax Sprite.Hide(spriteID:int)

DescriptionHidesapreviouslyvisiblesprite.Sprite.Hidehasnoeffectifthespriteisalreadyinvisible.

Example

Thefollowingprogramanimatesfourballsonthescreen.Whentheballsareclosetoeachotherortoawall,theyappear,otherwisetheyarehidden.

varpic,sprite,x,y,dx,dy,radius:array1..6

varvisible:array1..6ofboolean

setscreen("nocursor")

%Createallthesprites.

fori:1..6

radius(i):=Rand.Int(10,25)

Draw.FillOval(25,25,radius(i),radius(i

Font.Draw(intstr(i),20,20,0,black)

pic(i):=Pic.New(0,0,50,50)

Draw.FillBox(0,0,50,50,0)

x(i):=Rand.Int(radius(i),maxx‹radius

y(i):=Rand.Int(radius(i),maxy‹radius

dx(i):=Rand.Int(3,3)

dy(i):=Rand.Int(3,3)

sprite(i):=Sprite.New(pic(i))

Sprite.SetPosition(sprite(i),x(i),y(i),

Sprite.SetHeight(sprite(i),i)

visible(i):=false

endfor

%Nowmoveallthespritesaroundthescreen.

fori:1..6

ifx(i)+dx(i)<radius(i)or

x(i)+dx(i)>maxxradius(i

dx(i):=dx(i)

x(i):=x(i)+dx(i)

ify(i)+dy(i)<radius(i)or

y(i)+dx(i)>maxyradius(i

dy(i):=dy(i)

y(i):=y(i)+dy(i)

endfor

fori:1..6

varnear:boolean:=false

if(x(i)<50)or(x(i)>maxx50)or

(y(i)<50)or(y(i)>maxy50)

near:=true

ifnotnearthen

forj:1..6

ifinot=jthen

ifsqrt((x(i)‹x(j))**2+

(y(i)‹y(j))**2)<100

near:=true

endfor

ifnearandnotvisible(i)then

Sprite.Show(sprite(i))

visible(i):=true

elsifnotnearandvisible(i)then

Sprite.Hide(sprite(i))

visible(i):=false

Sprite.SetPosition(sprite(i),x(i),y

endfor

Time.Delay(40)

exitwhenhasch

endloop

fori:1..6

Sprite.Free(sprite(i))

endfor

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.HidecallingHide.

Seealso Sprite.Show.

Sprite.New PartofSpritemodule

Syntax Sprite.New(picID:int):int

Description

CreatesanewspritefromapicturespecifiedbypicID.ThespritestartsinvisibleandshouldbegivenadepthusingSprite.SetHeightandaposition,givenSprite.SetPositionbeforebeingmadevisibleusingSprite.Show.Whenyouarefinishedusingthesprite,thespriteshouldbefreedusingSprite.Free.

Spritesworkbestwhentheyareofmoderatesize.Largespriteswillcauseflashingwhenmovedacrossthescreen.

Anythingthatisiscolor0inthepicturewillnotappearwhenthespriteisdrawn.Inotherwords,color0istransparent.(Thisisbydefault.Youcansetthetransparentcolorforaspritebysettingthepicture'stransparentcolourusingPic.SetTransparentColor.

Example SeeSprite.AnimateforanexampleofSprite.New.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.New,notbycallingNew.

SeealsoSprite.SetHeight,Sprite.SetPosition,Sprite.ShowandSprite.Free.

Sprite.SetFrameRate PartofSpritemodule

Syntax Sprite.SetFrameRate(framesPerSec:int)

Description

Specifiesthemaximumnumberoftimespersecondthatspritepositionswillbechangedonthescreen.Thehigherthenumber,thesmoothertheanimationwillappear(andthemoreprocessortimewillbeusedtoperformtheanimation).

Details

Whenyouchangethepositionorappearanceofasprite,Turingdoesnotupdatethewindowimmediately.Instead,itwaitsacertainlengthoftimeandthenupdatesallspritesthathavemovedsincethelastupdate.Thisallowsforrelativelysmoothanimation.

ThismeansthatyouhaveasimpleloopthatcallsSprite.SetPosition200timesasecond,theimageofthespriteonthescreenisstillonlybeingmoved(bydefault)33timesasecond.

YoucanspecifyhowmanytimesasecondTuringcheckstoseeifaspritehasmovedbyusingtheSprite.SetFrameRateprocedure.Ratesof5-10willmakethemovementofthespritesseemverychoppy.Ratesof100aremoreorlesscompletelysmooth(themaximumis120)andmostCRT'swillnotnoticeanydifferenceafter60.Thedefaultrateis33framespersecond.Youshouldnotethatifyousettheratehigherthanyourcomputercanhandle,everyotherpartofyourprogramwillslowdownasTuringwillbecheckingforspritemovementratherthanexecutingyourprogram.

AmodernPC(2+GHzwithadecentgraphicscard)canprobablyhandleaframerateof60+,dependingonthenumberofsprites.APentiumIIIshouldprobablyusethedefaultrate.Slowermachinesshouldprobablyusealowerrate(around20).Experimentationisthebestwaytodeterminetheidealframerate.

Status

Exportedqualified.

Sprite.SetFrameRate,notbycallingSetFrameRate.

Sprite.SetHeight PartofSpritemodule

Syntax Sprite.SetHeight(spriteID,newHeight:int)

Description

SetstheheightofthespritespecifiedbyspriteIDtothevaluespecifiedbynewHeight.

Theheightofaspritedetermineswhichspriteappearsaboveanotherwhentheyoverlap.The"higher"sprite(theonewiththegreaterheight)willappearontopofthespritewiththelowerheight,evenifthelowerspriteisdrawnsecond.

Thebackground(i.e.anynon-sprite)isconsideredtobeinheight0.Spriteswithanegativeheightwillappear"behind"thebackground.Notethatiftwospriteshavethesameheight,theonedrawnlastwillappearabovethefirstone.

Example SeeSprite.HideforanexampleofSprite.SetHeight.

Details

Itshouldbenotedthatalotmorecomputationmustbedonetodisplayspriteswithanegativeheight.Ifyouareonaslowermachineandperformanceisnotsufficient,considertryingtoeliminatetheuseofspritesmovingbehindthebackground.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.SetPosition,notbycallingSetPosition.

Seealso Sprite.New.

Sprite.SetPosition PartofSpritemodule

SyntaxSprite.SetPosition(spriteID,x,y:int,centered:boolean)

Description

MovesthespritespecifiedbyspriteIDtothelocationspecifiedby(x,y).Ifcenteredistrue,thenthespriteiscenteredon(x,y).Otherwise(x,y)specifiesthelower-leftcornerofthesprite.

Example SeeSprite.HideforanexampleofSprite.SetPosition.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.SetPosition,notbycallingSetPosition.

Seealso Sprite.New.

Sprite.Show PartofSpritemodule

Syntax Sprite.Show(spriteID:int)

DescriptionDisplaysapreviouslyhiddensprite.Sprite.Showhasnoeffectifthespriteisalreadyvisible.

Example SeeSprite.HideforanexampleofSprite.Show.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSprite.Show,notbycallingShow.

Seealso Sprite.Hide.

sqrt squarerootfunction

Syntax sqrt(r:real):real

DescriptionThesqrtfunctionisusedtofindthesquarerootofanumber.Forexample,sqrt(4)is2.

Example

Thisprogramprintsoutthesquarerootsof1,2,3,…upto100.

fori:1..100

put"Squarerootof",i,"is",sqrt(i)

endfor

Details

Itisillegaltotrytotakethesquarerootofanegativenumber.Theresultofsqrtisalwayspositiveorzero.

Theoppositeofasquarerootisthesquare.Forexample,thesquareofxiswrittenisx**2.

standardType

Syntax

AstandardTypeisoneof:

(a) int (b) real

(c)string[(maximumLength)]

(d) boolean

(e) nat %naturalnumber

(f) intn %n-byteinteger(n=1,2,4)

(g) natn %n-bytenatural(n=1,2,4)

(h) realn %n-bytereal(n=4,8)

(i) char %singlecharacter

(j) char(n) %ncharacters

DescriptionThestandardtypescanbeusedthroughoutaprogram.Theyshouldnotbeincludedinanimportlist.

Seealsoint,real,stringandboolean.Seealsonat,intn,natn,realn,char,char(n)

statement

Syntax

Astatementisoneof:

(a) assignmentStatement %variableReference:=expn

(b) openStatement %open… (c) closeStatement %close… (d) putStatement %put… (e) getStatement %get… (f) readStatement %read… (g) writeStatement %write… (h) seekStatement %seek… (i) tellStatement %tell… (j) forStatement %for…endfor

(k) loopStatement %loop…endloop

(l) exit[whentrueFalseExpn] (m) ifStatement %if…endif

(n) caseStatement %case…endcase

(o) asserttrueFalseExpn (p) begin statementsAndDeclarations end

(q) procedureCall %procedureId[(parameters)]

(r) return (s) resultexpn

(t) new[collectionId,]pointerVariableReference

(u) free[collectionId,]pointerVariableReference

(v) tagunionVariableReference,expn

(w) forkStatement %fork… (x) signalvariableReference

(y) waitvariableReference[,expn]

(z) pauseexpn

(aa) quit[guiltyParty][:quitReason] (bb) unchecked (cc) checked

Description

Astatement(orcommand)causesaparticularaction,forexample,theputStatement:

put"Hello"

outputsHello.Seethedescriptionsoftheindividualstatementsforexplanationsoftheiractions.Eachstatementcanoptionallybyfollowedbyasemicolon(;).

Examplewidth:=24%Assignmentstatement

put"Helloworld"%Putstatement

exitwheni=100%Exitstatement

assertwidth<320%Assertstatement

Details

Youcanusearesultstatementonlyinafunction.Youcanuseareturnstatementonlytoterminateaprocedureorthemainprogram(butnottoterminatetheinitializationofamodule).Seealsoresultandreturn.

Thereareanumberofpredefinedprocedures,suchasdrawline,whicharenotlistedasstatementsabove.Theseareconsideredprocedurecalls,whichisoneformofstatement.

Syntax

StatementsAndDeclarationsare:

{statementOrDeclaration}

Description

StatementsAndDeclarationsarealistofstatementsanddeclarations.Forexample,aTuringprogramconsistsofalistofstatementsanddeclarations.Thebodyofaprocedureisalistofstatementsanddeclarations.

EachstatementOrDeclarationisoneof:

(a)statement

(b)declaration

Seealsostatementanddeclaration.

Example

ThislistofstatementsanddeclarationsisaTuringprogramthatoutputsHelloFrank.

varname:string

name:="Frank"

put"Hello",name

Description

Thisunitcontainsthepredefinedconstantsformanipulatingstrings.

SeveralroutinesintheStrmoduleareexportedunqualified.

EntryPoints

Lower Convertastringtolowercase.Upper Convertastringtouppercase.Trim Removeleadingandtrailingblanks.index Findsaspecifiedstringinanotherstring.length Returnsthelengthofastring.

repeat Createsastringbyrepeatingaspecifiedstringanumberoftimes.

Str.Lower PartofStrmodule

Syntax Str.Lower(s:string):string

Description

TheStr.Lowerfunctiontakesthestringsandreturnsastringinwhichalltheuppercaselettersareconvertedtolowercase.Forexample,Str.Lower("ABC123def")returns"abc123def".

Example

Thisprogramobtainslinesoftextfromtheuserandoutputsthelinesconvertedtolowercase.

varline:string

put"Enteralineoftext(emptytoquit):"..

getline:*

exitwhenline=""

put"Thelowercaseversion:",Str.Lower(line

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingStr.Lower,notbycallingLower.

Seealso Str.UpperandStr.Trim.

Str.Trim PartofStrmodule

Syntax Str.Trim(str:string):string

Description

TheStr.Trimfunctiontakesthestringstrandreturnsastringinalltheleadingandtrailingspaces(thespacesatthebeginningandtheend)aredeleted.Forexample,Str.Trim("Thisisatest")returns"Thisisatest".Ifstronlyhasspacesinit,thenStr.Trimwillreturnanemptystring.

Example

Thisprogramobtainsinputfromtheuseruntiltheuserentersalinewithnon-whitespacecharactersinit.

varline:string

put"Enteranon-emptylineoftext:"..

getline:*

exitwhenStr.Trim(line)not=""

endloop

put"Youentered",line

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingStr.Trim,notbycallingTrim.

Seealso Str.LowerandStr.Upper.

Str.Upper PartofStrmodule

Syntax Str.Upper(s:string):string

Description

TheStr.Upperfunctiontakesthestringsandreturnsastringinwhichallthelowercaselettersareconvertedtouppercase.Forexample,Str.Upper("ABC123def")returns"ABC123DEF".

Example

Thisprogramobtainslinesoftextfromtheuserandoutputsthelinesconvertedtouppercase.

varline:string

put"Enteralineoftext(emptytoquit):"..

getline:*

exitwhenline=""

put"Theuppercaseversion:",Str.Upper(line

endloop

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingStr.Upper,notbycallingUpper.

Seealso Str.LowerandStr.Trim.

Stream

Description

ThisunitcontainsthepredefinedsubprogramsthatdealwithI/Ostreams.ThebasicI/OinTuringisdonewithI/Ostatements.However,extrafunctionsareallpartoftheStreamunit.

AllroutinesintheStreamunitareexportedqualified(andthusmustbeprefacedwith"Stream."),withtheexceptionofeofwhichispartofthelanguagebutconceptuallypartofthisunitandisconsideredtobeexportedunqualified.

EntryPoints

eof* Determinesiftheendoffilehasbeenreached.Flush Flushesaspecifiedstream.FlushAll Flushesallopenoutputstreams.

*Partofthelanguage,conceptuallypartoftheStreamunit.

Stream.eof PartofStreammodule

Syntax eof(streamNumber:int):boolean

Description

Theeof(endoffile)functionisusedtodetermineifthereisanymoreinput.Itreturnstruewhentherearenomorecharacterstoberead.Theparameteranditsparenthesesareomittedwhenreferringtothestandardinput(usuallythisisthekeyboard);otherwisetheparameterspecifiesthenumberofastream.Thestreamnumberhasbeendetermined(inmostcases)byanopenstatement.

Example

Thisprogramreadsandoutputsallthelinesinthefilecalled"info".

varline:string

varfileNumber:int

open:fileNumber,"info",get

exitwheneof(fileNumber)

get:fileNumber,line:*

putline

endloop

Details

Seealsothedescriptionofthegetstatement,whichgivesmoreexamplesoftheuseofeof.Seealsotheopenandreadstatements.

Whentheinputisfromthekeyboard,theusercansignalend-of-filebytypingcontrol-ZonaPC(orcontrol-DonUNIX).Ifaprogramtestsforeofonthekeyboard,andtheuserhasnottypedcontrol-Z(orcontrol-D)andtheuserhastypednocharactersbeyondthosethathavebeenread,theprogrammustwaituntilthenextcharacteristyped.Oncethischaracteristyped,theprogramknowswhetheritisattheendoftheinput,andreturnsthecorrespondingtrueorfalsevalueforeof.

Status

PartofthelanguageandonlyconceptuallypartoftheStreamunit.

Thismeansthatyoucanonlycallthefunctionbycallingeof,notbycallingStream.eof.

Stream.Flush PartofStreammodule

Syntax Stream.Flush(streamNumber:int)

DescriptionTheStream.FlushprocedureisusedtoflushanybufferedoutputassociatedwiththestreamNumberparameter.

Details

Turingautomaticallyflushesanybufferedoutputwhenastreamisclosed.Turingalsoautomaticallyclosesanyopenfileswhenexecutionisterminated.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingStream.Flush,notbycallingFlush.

Stream.FlushAll PartofStreammodule

Syntax Stream.FlushAll

DescriptionTheStream.FlushAllprocedureisusedtoflushanybufferedoutputinanyopenfile.

Details

Turingautomaticallyflushesanybufferedoutputwhenastreamisclosed.Turingalsoautomaticallyclosesanyopenfileswhenexecutionisterminated.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingStream.FlushAll,notbycallingFlushAll.

string type

Syntax

AstringTypeis:

string[(maximumLength)]

Description

EachvariablewhosetypeisastringTypecancontainasequence(astring)ofcharacters.ThelengthofthissequencemustnotexceedthestringType'smaximumlength.

Examplevarname:string

name:="Nancy"

varlicenceNumber:string(6)

licenceNumber:="175AJN"

Details

Stringscanbeassignedandtheycanbecomparedforbothequalityandforordering.Seealsostringcomparisonandassignmentstatement.

Stringscanbecatenated(joinedtogether)usingthe+operatorandseparatedintosubstrings.Seecatenationandsubstring.Stringfunctionsareprovidedtofindthelengthofastring,tofindwhereonestringappearsinsideanother,andtomakerepeatedcopiesofastringalljoinedtogether.Seelength,index,andrepeat.

Astringtypewrittenwithoutamaximumlengthislimitedtoholdingamaximumof255characters.

ThemaximumLengthofastring,ifgivenasapartofthetype,mustbeknownatcompiletime,andmustbeatleast1andatmost255.Themaximumlengthofastringisgivenbyupper,forexample,upper(licenceNumber)is6.Seealsoupper.

Inthedeclarationofastringthatisavarformalparameterofaprocedureorfunction,themaximumLengthcanbewrittenasanasterisk(*).Here,themaximumlengthistakentobethatofthecorrespondingactualparameter,asin:

proceduredeblank(vars:string(*)).

Thestarcanalsobeusedwhentheparameterisanarrayofstrings.

SeealsoexplicitStringConstantsforexactrulesforwritingstringvaluessuchas"Nancy".Seealsochar(n)andchartypes.

string comparison

Syntax

AstringComparisonisoneof:

(a) stringExpn=stringExpn (b) stringExpnnot=stringExpn (c) stringExpn>stringExpn (d) stringExpn<stringExpn (e) stringExpn>=stringExpn (f) stringExpn<=stringExpn

DescriptionStrings(stringExpns)canbecomparedforequality(=andnot=)andforordering(>,<,>=and<=).

Examplevarname:string:="Nancy"

varlicenceNumber:string(6)

licenceNumber:="175AJN"

Details

Twostringsareconsideredtobeequal(=)iftheyhavethesamelengthandaremadeup,characterbycharacter,ofthesamecharacters.Iftheydiffer,theyareconsideredtobeunequal(not=).

Orderingamongstringsisessentiallyalphabeticorder.StringSisconsideredtocomebeforestringT,thatisS<T,ifthetwoareidenticaluptoacertainpositionandafterthatposition,eitherthenextcharacterofScomesbeforethenextcharacterofT,orelsetherearenomorecharactersinSwhileTcontainsmorecharacters.

S>T(ScomesafterT)meansthesamethingasT<S.S>=TmeansthesamethingasS>TorS=T.S<=TmeansthesamethingasS<TorS=T.

ASCIIgivestheorderingamongindividualcharacters.Itspecifies,amongotherthings,thatlettercapitalLcomes

alphabeticallybeforecapitalletterMandsimilarlyforsmall(lowercase)letters.

OnIBMmainframecomputers,theEBCDICspecificationofcharactersmaybeusedinsteadofASCII.

strint string-to-integer

function

Syntax strint(s:string[,base:int]):int

Description

Thestrintfunctionisusedtoconvertastringtoaninteger.Theintegerisequivalenttostrings.Thenumberbaseparameterisoptional,forexample,strint("47")=47.InTuringproper,thebaseisnotallowedandisassumedtobe10.

Stringsmustconsistofapossiblynullsequenceofblanks,thenanoptionalplusorminussign,andfinallyasequenceofoneormoredigits.Fornumberbaseslargerthan10,thedigitscanincludea,b,c…(alternatelyA,B,C…)whichrepresentthedigitvalues10,11,12…Thebase,ifgiven,mustbeintherange2to36(36becausethereare10basetendigitsand26letters).Forexample,strint("FF",16)=255.

Theintstrfunctionistheinverseofstrint,soforanyintegeri,

strint(intstr(i))=i.

Seealso chr,ord,intstrandstrnatfunctions.

strintok string-to-integer

function

Syntax strintok(s:string[,base:int]):boolean

Description

Thestrintokfunctionisuseddeterminewhetherthestrintfunctioncanbeusedtoconvertthestringtoanintegerwithoutcausinganerror.Ifthestringcanbesuccessfullyconverted,thenstrintokreturnstrue,otherwiseitreturnsfalse.

Stringsshouldconsistofapossiblynullsequenceofblanks,thenanoptionalplusorminussign,andfinallyasequenceofoneormoredigits.Fornumberbaseslargerthan10,thedigitscanincludea,b,c…(alternatelyA,B,C…)whichrepresentthedigitvalues10,11,12…Ifsiscorrectlyconstructed,thenstrnatokwillreturntrue,otherwiseitreturnsfalse.Thebase,ifgiven,mustbeintherange2to36(36becausethereare10basetendigitsand26letters).Forexample,strintok("FF",16)=true.

Seealso strintfunctionthatdoestheactualconversion.

strnat stringtonaturalnumberfunction

Syntax strnat(s:string[,base:int]):nat

Description

Thestrnatfunctionisusedtoconvertastringtoanaturalnumber.Thenaturalnumberisequivalenttostrings.Thenumberbaseparameterisoptional,forexample,strnat("47")=47.

Stringsmustconsistofapossiblynullsequenceofblanks,thenanoptionalplussign,andfinallyasequenceofoneormoredigits.Fornumberbaseslargerthan10,thedigitscanincludea,b,c…(alternatelyA,B,C…)whichrepresentthedigitvalues10,11,12…Thebase,ifgiven,mustbeintherange2to36(36becausethereare10basetendigitsand26letters).Forexample,strnat("FF",16)=255.

Thenatstrfunctionistheinverseofstrnat,soforanynaturalnumbern,strnat(natstr(n))=n.

Thestrnatfunctionissimilartostrint,exceptthatstrnathandlesvaluesthatarelargerthanintvaluesanddoesnothandlenegativevalues.

Seealso thechr,ord,intstrandstrintfunctions.

strnatok stringtonaturalnumberfunction

Syntax strnatok(s:string[,base:int]):boolean

Description

Thestrnatokfunctionisuseddeterminewhetherthestrnatfunctioncanbeusedtoconvertthestringtoanaturalnumberwithoutcausinganerror.Ifthestringcanbesuccessfullyconverted,thenstrnatokreturnstrue,otherwiseitreturnsfalse.

Stringsshouldconsistofapossiblynullsequenceofblanks,thenanoptionalplussign,andfinallyasequenceofoneormoredigits.Fornumberbaseslargerthan10,thedigitscanincludea,b,c…(alternatelyA,B,C…)whichrepresentthedigitvalues10,11,12…Ifsiscorrectlyconstructed,thenstrnatokwillreturntrue,otherwiseitreturnsfalse.Thebase,ifgiven,mustbeintherange2to36(36becausethereare10basetendigitsand26letters).Forexample,strnatok("FF",16)=true.

Seealso strnatfunctionthatdoestheactualconversion.

strreal string-to-realfunction

Syntax strreal(s:string):real

Description

Thestrrealfunctionisusedtoconvertastringtoarealnumber.Forexample,strreal("2.5e1")willproduceanapproximationtothenumber25.0.

Stringsmustconsistofapossiblynullsequenceofblanks,thenanoptionalplusorminussignandfinallyanexplicitunsignedrealorintegerconstant.

Therealstr,erealstrandfrealstrfunctionsapproximatetheinverseofstrreal,althoughround-offerrorskeepthesefrombeingexactinverses.

Seealso realstr,erealstr,frealstr,intstrandstrintfunctions.

strrealok string-to-realfunction

Syntax strrealok(s:string):boolean

Description

Thestrrealokfunctionisuseddeterminewhetherthestrrealfunctioncanbeusedtoconvertthestringtoarealnumberwithoutcausinganerror.Ifthestringcanbesuccessfullyconverted,thenstrrealokreturnstrue,otherwiseitreturnsfalse.

Stringsshouldconsistofapossiblynullsequenceofblanks,thenanoptionalplusorminussignandfinallyanexplicitunsignedrealorintegerconstant.Ifitdoesso,thenstrrealokwillreturntrue,otherwiseitreturnsfalse.

Seealso strrealfunctionthatdoestheactualconversion.

subprogramHeader

Syntax

AsubprogramHeaderisoneof:

(a) procedure[pervasive]id

(b) function[pervasive]id

[id]:typeSpec

Description

Asubprogramheaderisusedtodescribetheinterfacetoasubprogram.Subprogramheadersareusedwithinotherlanguagefeaturessuchassubprogramtypesandexternaldeclarations.

Parameterlesssubprogramsmayuseparentheses(withnothingbetweenthem),asisrequiredintheCprogramminglanguage.Theseparenthesescanbeusedtodisambiguatebetweenthecalltothesubprogram(parenthesespresent)andareferencethesubprogram(parenthesesmissing).

Supposefisaparameterlesssubprogramdeclaredwithoutparenthesesandgisaparameterlesssubprogramdeclaredwithparentheses.Theirheadersare:

proceduref

procedureg()

Inaprogram,fandg()arecallstothesefunctions,whilegisareferenceto(notacallto)theprocedure.Thereisnowaytowriteareferencetof.Whenindoubt,useparenthesesinthedeclaration,asinthecaseforg,sothatcallsalwayshaveparenthesesandreferencesalwaysdonot.Areferencetoasubprogramcanbeassignedtoasubprogramvariable.Seesubprogramtype.

ExampleSpecifythattisthetypeofprocedurewithavarintegerparameterandarealparameter.SeealsosubprogramType.

typet:procedureq(varj:int,y:real)

Details

Thekeywordpervasivecanbeinsertedjustafterprocedureorfunction.Whenthisisdone,thesubprogramisvisibleinsideallsubconstructsofthesubprogram'sscope.Withoutpervasive,thesubprogramisnotvisibleinsidemodulesunlessexplicitlyimported.Pervasivesubprogramsneednotbeimported.Youcanabbreviatepervasiveasanasterisk(*).

Seealso pervasive.

subprogramType

Syntax

AsubprogramTypeis:

subprogramHeader

Description

Avariableorconstantcancontainareferencetoasubprogram.ThetypeofthevariableorconstantisasubprogramType.SeealsosubprogramHeader.

Example

Inthefollowingtisasubprogramtype,anduisavariableoftypetinitializedtorefertoprocedurernd.

procedurernd(vari:int,x:real)

i:=round(x)

endrnd

typet:procedureq(varj:int,y:real)

varu:t:=rnd%Procedurevariableureferstornd

varj:int

u(j,24.6)%Callprocedureureferringtornd

varv:=u%Subprogramvariablevinitializedtou

Details

Thenameofthesubprogram,forexampleq,andtheparameters,forexampleiandx,havenomeaninginasubprogramtype.Theyarepresentonlybecauseoftheformofsubprogramheaders.

Ifvisavariableorconstantthatreferstoasubprogram,vcanbecalled,comparedforequalitytoothersubprogramvariables,assignedandpassedasaparameter.Variablevisnotaninteger,stringorpointerandcannotparticipateintheircorrespondingoperations.

Areferencetoasubprogram,ratherthatthecodeofthesubprogram,iscontainedinavariablevwhosetypeisasubprogramtype.Thisimpliesthataddr(v)istheaddressofthereferencetosubprogram,ratherthantheaddressofthesubprogram.Theaddressofthecodeisgivenby#v.Seecheatforanexplanationofthe#operator.

Youcannotassignareferencetoasubprogramexportedfromaclass.Thisrestrictionexistsbecausethesesubprogramsaremeaninglesswithoutanaccompanyingreferencetoanobject.

Manypotentialusesofsubprogramvariablesarebetterprogrammedusingclassesandoverridingexportedsubprograms.Seeclass.

subrangeType

Syntax

AsubrangeTypeis:

expn..expn

DescriptionAsubrangetypedefinesasetofvalues,forexample,thesubrange1..4consistsof1,2,3and4.

Example

vari:1..10%icanbe1,2…upto10

typexRange:0..319%Defineintegersubrange

varpixels:arrayxRangeofint

%Arrayelementsare

%numbered0,1,…319

fork:xRange%krangesfrom0to319

pixels(k):=0

endfor

Details

Asubrangemustcontainatleastoneelement.Inotherwords,thesecondexpression(expn)mustbeatleastaslargeasthefirstexpression.

Thelowerboundofasubrangemustbeknownatcompiletime.Theupperboundisallowedtobearuntimevalueonlyinonesituationandthatiswhenitgivestheupperboundofanarraybeingdeclaredinavariabledeclaration,inotherwordswhendeclaringadynamicarray.

Subrangesareusuallyasubsetoftheintegers,asin1..10.Youcanalsohavesubrangesofenumeratedtypesandcharacters(thechartype).

Youcanapplyloweranduppertosubrangetypes.

substring ofanotherstring

Syntax

Asubstringisoneof:

(a) stringReference(leftPosition..rightPosition) (b) stringReference(charPosition)

Description

Asubstringselectsapartofanotherstring.Inform(a)thesubstringstartsattheleftpositionandrunstotherightposition.Inform(b),thesubstringisonlyasinglecharacter.Turingsupportsubstringsofchar(n)values.

Example

varword:string:="bring"

putword(2..4)%Outputsrin

putword(3)%Outputsi

putword(2..*)%Outputsring;thestar

%theendofthestring.

putword(*-2..*-1)%Outputsin

Details

Theleftmostpossiblepositioninastringisnumbered1.Thelastpositioninastringcanbewrittenasanasterisk(*).Forexample,word(2..*)isequivalenttoword(2..length(word)).

EachofleftPosition,rightPosition,andcharPositionmusthaveoneoftheseforms:

(a)expn (b)* (c)*-expn

TheexactrulesfortheallowedvaluesofleftPositionandrightPositionare:

(1)leftPositionmustbeatleast1, (2)rightPositionmustbeatmostlength(stringReference),and (3)thelengthoftheselectedsubstringmustzeroormore.

Thisspecificallyallowsnullsubstringssuchasword(1,0)inwhichrightPositionis0andword(6,5)inwhichleftPositionisonemorethatlength(stringReference).

Notethatsubstringsarenotassignable.Forexample,ifsisastring,thestatements(3):="a"isillegalinTuring.

Turingsupportssubstringsofchar(n)values.Seechar(n).Ifasubstringofchar(n)valuethastwooperands,asint(2..77),theresulttypeofthisoperationisastring.Ifthesubstringhasoneoperand,asint(7),thisbecomes,ineffect,asubscriptintoanarrayofcharacters.Theresultisareferencetoachar,whichcanbeassignedtoorpassedtoavarparameter.

Seealsostring,char,char(n),explicitStringConstant,explicitCharConstantcatenationandlength.

succ successorfunction

Syntax succ(expn)

Description

Thesuccfunctionacceptsaninteger,characteroranenumeratedvalueandreturnstheintegerplusone,thenextcharacter,orthenextvalueintheenumeration.Forexample,succ(7)is8.

Example

ThispartofaTuringprogramfillsuparrayawiththeenumeratedvaluesgreen,yellow,red,green,yellow,red,etc.

typecolors:enum(green,yellow,red)

vara:array1..100ofcolors

varc:colors:=colors.green

fori:1..100

a(i):=c

ifc=colors.redthen

c:=colors.green

c:=succ(c)

endfor

Details Youcannotapplysucctothelastvalueofanenumeration.

Seealso thepred,lowerandupperfunctions.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwiththeoperatingsystemdirectly(gettingtheprocessid,gettingruntimeargumentsandexecutingcommandsintheoperatingsystem,etc.).

AllroutinesintheSysunitareexportedqualified(andthusmustbeprefacedwith"Sys.").

EntryPoints

GetComputerName Getsthenameofthecomputer.

GetEnv Getsastringassociatedwithanenvironmentvariable.

GetPid GetsthecurrentprocessIDforTuring.

GetUserName Getsthenameoftheusercurrentlyloggedon.

Exec Executesaprogramoropensadatafileusingtheoperatingsystem.

Nargs Getsthenumberofruntimearguments(exportedunqualified).

FetchArg Getsaspecifiedruntimeargument(exportedunqualified).

Sys.Exec PartofSysmodule

Syntax Sys.Exec(command:string):boolean

Description

TheSys.Execfunctionisusedtoexecuteanapplicationormoreoften,openadatafilewithitsassociatedapplication.Sys.ExeccanbeusedtolaunchsuchprogramsastheInternetBrowserbyspecifyingaURL.Sys.Execlaunchestheapplicationassociatedwithfile'ssuffix.(Inessence,itperformsthesameoperationasifauserdoubleclickedonthefile.)

Example

ThisprogramlaunchesaninternetbrowserandpointsittoHoltSoftware'shomepage.Itthenlaunchesamovieusingthedefaultvideoplayer.

ifnotSys.Exec("http://www.holtsoft.com/turing/support")

put"TheSys.Execcallfailed"

ifnotSys.Exec("skate.avi")then

put"TheSys.Execcallfailed"

DetailsWhentheSys.Execprocedureisused,theexecutingprogramcontinuesexecutionimmediatelywhilethelaunchedapplicationisrunning.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.ExecExec.

Seealso Sys.Nargs,Sys.FetchArgandSys.GetEnvfunctions.

Sys.FetchArg PartofSysmodule

Syntax System.FetchArg(i:int):string

Description

TheSys.FetchArgfunctionisusedtoaccessthei-thargumentthathasbeenpassedtoaprogramfromthecommandline.Forexample,iftheprogramisrunfromtheTuringenvironmentusing

:rfile1file2

thenSys.FetchArg(2)willreturn"file2".Ifaprogramcalledprog.xunderUNIXusingthiscommand:

prog.xfile1file2

thevalueofSys.FetchArg(2)willsimilarlybe"file2".

TheSys.Nargsfunction,whichgivesthenumberofargumentspassedtotheprogram,isusuallyusedtogetherwiththeSys.FetchArgfunction.ParameteripassedtoSys.FetchArgmustbeintherange0..Sys.Nargs

The0-thargumentisthenameoftherunningprogram.

Example

Thisprogramlistsitsownnameanditsarguments.

put"Thenameofthisprogramis:",Sys.FetchArg

fori:1..Sys.Nargs

put"Argument",i,"is",Sys.FetchArg(i

endfor

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.FetchArgbycallingFetchArg.

Seealso Sys.Nargs

Sys.GetComputerName PartofSysmodule

Syntax Sys.GetComputerName:string

Description

TheSys.GetComputerNamefunctionisusedtodeterminethenameofthecomputer.OnthePC,thisistheNetBIOSname.Itreturns“NoName”ifanamecouldnotbedetermined.

Example

Thisprogramoutputsagreetingtotheuser.

varcomputerName,userName:string

computerName:=Sys.GetComputerName

userName:=Sys.GetUserName

put"Hello",userName,"on",computerName

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.GetComputerName,notbycallingGetComputerName.

SeealsoSys.GetUserNametoobtaintheusernameoftheusercurrentlyloggedin.

Sys.GetEnv PartofSysmodule

Syntax Sys.GetEnv(symbol:string):string

Description

TheSys.GetEnvfunctionisusedtoaccesstheenvironmentstringwhosenameissymbol.Thesestringsaredeterminedbytheshell(commandprocessor)ortheprogramthatcausedyourprogramtorun.SeealsotheSys.NargsandSys.FetchArgfunctions.

Example

OnaPC,thisretrievestheenvironmentvariableUSERLEVELandprintsextrainstructionsifUSERLEVELhadbeensettoNOVICE.USERLEVELcanbesettoNOVICEwiththecommandSETUSERLEVEL=NOVICEintheautoexec.batfileorinanybatchfile.

constuserLevel:string

userLevel:=Sys.GetEnv("USERLEVEL")

ifuserLevel="NOVICE"then

…%putasetofinstructions

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.GetEnv,notbycallingGetEnv.

Sys.GetPid PartofSysmodule

Syntax Sys.GetPid:int

Description

TheSys.GetPidfunctionisusedtodeterminetheI.D.(number)thatidentifiesthecurrentoperatingsystemtask(process).Bewarethatthereareprocesses,activatedbytheforkstatement,thatareindependentoftheoperatingsystemstasks.

UnderUNIX,thenumberisused,forexample,forcreatingauniquenameofafile.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.GetPid,notbycallingGetPid.

Seealso Sys.Nargs,Sys.FetchArgandSys.GetEnv.

Sys.GetUserName PartofSysmodule

Syntax Sys.GetUserName:string

Description

TheSys.GetUserNamefunctionisusedtodeterminethenameofthecurrentuser.Itreturns“Unknown”ifanamecouldnotbedetermined.

Example

Thisprogramoutputsagreetingtotheuser.

varcomputerName,userName:string

computerName:=Sys.GetComputerName

userName:=Sys.GetUserName

put"Hello",userName,"on",computerName

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.GetUserName,notbycallingGetUserName.

Seealso Sys.GetComputerNametoobtainthenameofthecomputer.

Sys.Nargs PartofSysmodule

Syntax Sys.Nargs:int

Description

TheSys.Nargsfunctionisusedtodeterminethenumberofargumentsthathavebeenpassedtoaprogramfromthecommandline.Forexample,iftheprogramisrunfromtheTuringenvironmentusing

:rfile1file2

thenSys.Nargswillreturn2.Ifaprogramcalledprog.xisrununderUNIXusingthiscommand:

prog.xfile1file2

thevalueofSys.Nargswillsimilarlybe2.

TheSys.NargsfunctionisusuallyusedtogetherwiththeSys.FetchArgfunctiontoaccesstheargumentsthathavebeenpassedtotheprogram.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingSys.Nargs,notbycallingNargs.

Seealso Sys.FetchArgforanexampleoftheuseofSys.Nargs.

sysclock millisecsusedprocedure

Syntax sysclock(varc:int)

Description

ThesysclockstatementisusedonamultitaskingsystemsuchasUNIXtodeterminetheamountoftimethathasbeenusedbythisprogram(process).Variablecisassignedthenumberofcentralprocessormillisecondsassignedtothisprogram.Thisisoflittleuseonapersonalcomputer,wheresysclockreturnsthesamevalueasclock.

Example

OnaUNIXsystem,thisprogramtellsyouhowmuchtimeithasused.

vartimeUsed:int

sysclock(timeUsed)

put"Thisprogramhasused",timeUsed,

"millisecondsofCPUtime"

Seealsodelay,time,clock,wallclockanddatestatements.

system statement

Syntax system(command:string,varret:int)

Description

Thesystemstatementisusedtoexecutetheshell(operatingsystem)ifitweretypedattheterminal.Thereturncodeisinret.Areturncodeof0(zero)meansnodetectederrors.Areturncodeof127meansthecommandprocessorcouldnotbeaccessed.Areturncodeof126meansthecommandprocessordidnothaveroomtorunonthePC.

Example

ThisprogramcreatesadirectorylistingwhenrununderDOSonanIBMPCcompatiblecomputer.ThesameprogramwillrununderUNIXbychanging"to"ls".

varsuccess:int

system("dir",success)

ifsuccessnot=0then

ifsuccess=127then

put"Sorry,can'tfind'command.com'"

elsifsuccess=126then

put"Sorry,noroomtorun'dir'"

put"Sorry,'dir'didnotwork"

Details

Whenthesystemprocedureisused,theexecutingprogramusuallyremainsinmemorywhilethesystemcommandisexecuting,andonceexecutionofthesystemcommandisfinished,controlreturnstotheoriginalprogram.However,onthePC,thereisvariantofthesystemprocedurethatallows"chaining".Thismeansthatwhenthesystemcommandisexecuted,theoriginallyrunningprogramis"thrownaway"(i.e.removedfrommemory).Whentheexecutedprogramterminates,oneisreturnedtoDOS.

Tochainanotherprogram,oneprepends"chain:"tothestartcommand

i.e.system("chain:myprog.exe",retCode)

Notethatthiscommandis"hazardous".Specifically,ifyoucallitfromTuring(asopposedtoaprogramcompiledwithTComp)andyouhavenotsavedyoursourcefile,youwillloseit!Turingwillberemovedfrommemorywithoutanywarning

whenthesystemprocedureisexecuted.Likewiseanyopenfileswillbeclosedinstantly.Thismeansthereisadangerifallfileswerenotproperlyclosedbeforethesystemprocedurewascalled.

The"chain:"commandisoftenusedforstartingmenuprograms,wheretheuserselectsaprogramtorunanddoesn'twantTuringtoremaininmemory.ItcanalsobeusedwithextraordinarilylargeTuringprogramsthatcanbesplitintodifferentparts.ByusingTCompandcompilingeachpartseparately,onecanhaveeachprogramcalltheotherandneverhaveallpartsinmemoryatonce.

Example

Thisprogramuseschainingtolaunchoneofseveralpossibleprogramsbasedonuserchoice.Itgivesanerrorifforsomereasonthesystemcommandfailstowork.Itassumesthatc:\chemistry.exe,c:\math.exe,c:\english.exeandc:\history.exealreadyexist.

varchoice,success:int

put"Enterthesubject(1-4):"..

getchoice

varcommand:string

casechoiceof

%Notetheuseofthedoublebackslashinthefilename

%isbecausethebackslashisaspecialcharacterinTuring(as

%in\tfortaband\nforanewline).Togetasinglebackslash

%oneuses\\.

label1:command:="c:\\chemistry.exe"

label2:command:="c:\\math.exe"

label3:command:="c:\\english.exe"

label4:command:="c:\\history.exe"

label:put"Choicemustbefrom1-4."

assertfalse%Wasn'ta1-4.Terminate.

endcase

system("chain:"+command,success)

%IfIreachthisline,thesystemcommandfailedandoneshouldgive

%anerrormessage.

put"Systemcalledfailed."

put"Program\"",command,"\"couldn'tberun."

assertfalse%Terminatetheprogram

Details

HerearethepossibleerrorsunderPC-Turing

-1 NotenoughmemorytoloadCOMMAND.COM -2 Notenoughmemorytoruncommand -3 Argumentlistgreaterthan128bytesorenvironmentinfo

-4 Couldn'tfindCOMMAND.COM -5 COMMAND.COMcorrupt -6 -noshelloptionisselected,thesystemprocedureis disallowed

Seealsonargs,fetchargandgetenvfunctions.

SeealsopredefinedunitSys.

tag statement

Syntax

AtagStatementis:

tagunionVariableReference,expn

DescriptionAtagstatementisaspecial-purposeassignmentthatisusedforchangingthetagofaunionvariable.

Example

Inthisexample,thetagfieldofunionvariablevissettobepassenger,therebyactivatingthepassengerfieldofv.

typevehicleInfo:

unionkind:passenger..recreational

labelpassenger:

cylinders:1..16

labelfarm:

farmClass:string(10)

label:%Nofieldsfor"otherwise"clause

endunion

varv:vehicleInfo

tagv,passenger%Activatepassengerpart

Details

Atagstatementistheonlywaytomodifythetagfieldofaunionvariable(otherthanbyassigninganentireunionvaluetotheunionvariable).

Youcannotaccessaparticularsetoffieldsofaunionunlessthetagissettomatchthecorrespondinglabelvalue.

Seealso uniontypes.

takepic graphicsprocedure

…drawhappyfaceinthebox(0,0)to(100,100)…

%Createbufferbigenoughtoholdhappyface

varface:array1..sizepic(0,0,100,100)ofint

%Copypictureintothebuffer,whichisthefacearray

takepic(0,0,100,100,face)

%Redrawthepicturewithitsleftbottomat(200,0)

drawpic(200,0,face,0)

Syntax takepic(x1,y1,x2,y2:int,varbuffer:array1..*ofint)

Description

Thetakepicprocedureisusedtorecordthepixelvaluesinarectangle,withleftbottomandrightcornersof(x1,y1)and(x2,y2),inthebufferarray.Thisrequiresasufficiently-largebuffer(seesizepic).Thedrawpicprocedureisusedtomakecopiesoftherecordedrectangleonthescreen.

Example

Afterdrawingahappyface,thisprogramcopiesthefacetoanewlocation.

Execute

Theintegervaluesthattakepicplacesinthebuffercanbereadorwritten(usingthereadandwritestatements).Unfortunately,ifa

Details

valuehappenstobethepatternusedtorepresenttheuninitializedvalue(thelargestnegativenumberthehardwarecanrepresent)assignment(by:=)andputoftheindividualintegervaluesinthebufferwillfail.

Details

Thedrawpic,takepic,andsizepicsubprogramshavebeenmadeobsoletebythesubprogramsPic.DrawandPic.NewofthePicmodule.Usersarestronglysuggestedtousethoseroutinesinstead.ThePicmodulealsocontainssubprogramstoloadimagesfromfiles.

Seealso

sizepicanddrawpic.Seealsosetscreen,maxx,maxy,drawdot,drawline,drawbox,anddrawoval.

SeealsopredefinedunitPic.

tan tangentfunction(radians)

Syntax tan(r:real):real

DescriptionThetanfunctionisusedtofindthetangentofananglegiveninradians.Forexample,tan(p/4)is0.5.

Example

Thisprogramprintsoutthetangentof0,p/6,2p/6,3p/6,upto12p/6radians.

fori:0..12

constangle:=i*Math.PI/6

put"Tangentof",angle,"is",tan(angle

endfor

Execute

Details

Anargumenttotanofp/2,3*p/2,etc.mayresultinanoverflow(andhaltoftheprogram)astheresultistechnically¥.(Itmaynotcauseanoverflowduetorounding,inwhichcasetheresultwillsimplybeaverylargenumber.)

Seealso

thesinandcosfunctionsforcalculatingsineandcosine.

thetandfunctionwhichfindsthetangentofananglegivenindegrees.(2pradiansarethesameas360degrees.)

tand tangentfunction(degrees)

Syntax tand(r:real):real

DescriptionThetandfunctionisusedtofindthetangentofananglegivenindegrees.Forexample,tand(45)is1.

Example

Thisprogramprintsoutthetangentof0,30,60,90,upto360degrees.

fori:0..12

constangle:=i*30

put"Tanof",angle,"is",tand(angle)

endfor

Execute

Details

Anargumenttotanof90,270,etc.mayresultinanoverflow(andhaltoftheprogram)astheresultistechnically¥.(Itmaynotcauseanoverflowduetorounding,inwhichcasetheresultwillsimplybeaverylargenumber.)

Seealso

thesindandcosdfunctionsforcalculatingsineandcosine.

thetanfunctionwhichfindsthetangentofananglegiveninradians.(2pradiansarethesameas360degrees.)

tell filestatement

Syntax

AntellStatementis:

tell:fileNumber,filePositionVar

Description

ThetellstatementsetsfilePositionVar,whosetypemustbeint,tothecurrentoffsetinbytesfromthebeginningofthespecifiedfile.ThefileNumbermustspecifyafilethatisopenwithseekcapability(orelseaprogramargumentfilethatisimplicitlyopened).Thetellstatementisusefulforrecordingthefilepositionofacertainpieceofdataforlateraccessusingseek.

Example

Thisexampleshowshowtousetelltorecordthelocationofarecordinafile.Thislocationislaterusedbyseektoallowtherecordtoberead.

varemployeeRecord:

record

name:string(30)

pay:int

dept:0..9

endrecord

varfileNo:int

varlocation:int

open:fileNo,"payroll",write,seek

tell:fileNo,location%Makenoteofthislocation

write:fileNo,employeeRecord%Writerecordatthislocation

seek:fileNo,location%Gobacktolocation

read:fileNo,employeeRecord%Readtherecord

%thatwaspreviouslywritten

Seealso theread,write,open,close,seek,getandputstatements.

Description

Thisunitcontainsthepredefinedsubprogramsthathandlecharacter(text)outputonthescreen(i.e.outputusingput).

AllroutinesintheTextunitareexportedqualified(andthusmustbeprefacedwith"Text.")withtheexceptionofmaxrowandmaxcolwhichareexportedunqualified.

EntryPoints

Cls Clearsthescreentothetextbackgroundcolor.

Color Setsthetextcolorusedbyput.Colour Setsthetextcolorusedbyput.

ColorBack Setsthetextbackgroundcolorusedbyput.

ColourBack Setsthetextbackgroundcolorusedbyput.

Locate Movesthecursortothespecifiedrowandcolumn.

LocateXY Movesthecursortothecursorlocationclosesttoaspecifiedpixelposition.

maxcol Thenumberofcolumnsonthescreen(exportedunqualified).

maxrow Thenumberofrowsonthescreen(exportedunqualified).

WhatRow Returnsthecurrentcursorrow.WhatCol Returnsthecurrentcursorcolumn.WhatColor Returnsthecurrenttextcolor.WhatColour Returnsthecurrenttextcolor.WhatColorBack Returnsthecurrenttextbackgroundcolor.WhatColourBack Returnsthecurrenttextbackgroundcolor.

Text.Cls PartofTextmodule

Syntax Text.Cls

Description

TheText.Cls(clearscreen)procedureisusedtoblankthescreentothetextbackgroundcolor.Thecursorissettothetopleft(torow1,column1).

Details

Thescreenshouldbeina"screen"or"graphics"mode.Ifthescreenmodehasnotbeenset,itwillautomaticallybesetto"screen"mode.SeeView.Setfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.Cls,notbycallingCls.

Text.Color PartofTextmodule

Syntax Text.Color(Color:int)

Description

TheText.Colorprocedureisusedtochangethecurrently-activecolor.Thisisthecolorofcharactersthataretobeputonthescreen.ThealternatespellingisText.Colour.

Example

Thisprogramprintsoutthemessage"Bravo"threetimes,eachinadifferentcolor.

fori:1..3

Text.Color(i)

put"Bravo"

endfor

Example

Thisprogramprintsoutamessage.Thecolorofeachletterisdifferentfromtheprecedingletter.Forletternumberithecolornumberisimodmaxcolor+1.Thiscyclesrepeatedlythroughalltheavailablecolors.

View.Set("screen")

constmessage:="HappyNewYear!!"

fori:1..length(message)

Text.Color(imodmaxcolor+1)

putmessage(i)..

endfor

Details

In"screen"modeontheIBMPC,thecolorspecifiedcanactuallyrangefrom0-31.Theupper16colors(16-31)arethesameasthelower16,exceptthattheyblink.

SeeView.Setforthenumberofcolorsavailableinthevarious"graphics"modes.

Thescreenshouldbeina"screen"or"graphics"mode.Ifthescreenmodehasnotbeenset,itwillautomaticallybesetto"screen"mode.SeeView.Setfordetails.

ThismeansthatyoucanonlycallthefunctionbycallingText.Color,notbycallingColor.

SeealsoText.ColorBack,Text.WhatColor,Text.WhatCharandView.maxcolor.

Text.ColorBack PartofTextmodule

Syntax Text.ColorBack(Color:int)

Description

TheText.ColorBackprocedureisusedtochangethecurrenttextbackgroundcolor.ThealternatespellingisText.ColourBack.

TheText.ColorBackproceduresetsthetextbackgroundcolortothespecifiedcolor.Thisisthecolorthatsurroundscharacterswhentheyareputontothescreen.OnanIBMPCin"screen"mode,thecolorcanbefrom0-7.(Youcannothavetheupper8colorsastextbackgroundcolors.OnUNIXdumbterminals,Text.ColorBack(1)turnsonhighlightingandText.ColorBack(0)turnsitoff.Onothersystems,thisproceduremayhavenoeffect.

Example

Sincethisprogramisin"screen"mode,changingthebackgroundcolorhasnoimmediatelyobservableeffect.Whenthemessage"Greetings"isoutput,thebackgroundsurroundingeachletterwillbered.

View.Set("screen")

Text.ColorBack(red)

put"Greetings"

Details

Thescreenshouldbeina"screen"or"graphics"mode.Ifthescreenmodehasnotbeenset,itwillautomaticallybesetto"screen"mode.SeeView.Setfordetails

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.ColorBack,notbycallingColorBack.

Seealso Text.ColorandText.WhatColorBack.

Text.Locate PartofTextmodule

Syntax Text.Locate(row,column:int)

Description

TheText.Locateprocedureisusedtomovethecursorsothatthenextoutputfromputwillbeatthegivenrowandcolumn.Row1isthetopofthescreenandcolumn1istheleftsideofthescreen.

Example

Thisprogramoutputsstarsofrandomcolorstorandomlocationsonthescreen.Thevariablecolrispurposelyspelleddifferentlyfromthewordcolortoavoidtheprocedureofthatname(usedtosetthecolorofoutput).Therownumberispurposelychosensothatitisonelessthanmaxrow.Thisavoidsthescrollingofthescreenwhichoccurswhenacharacterisplacedinthelastcolumnofthelastrow.

View.Set("screen")

varrow,column,colr:int

row:=Rand.Int(1,maxrow)

column:=Rand.Int(1,maxcol)

colr:=Rand.Int(0,maxcolor)

Text.Color(colr)

Text.Locate(row,column)

put"*"..%Usedot-dottoavoidclearingendofline

endloop

Details

TheText.Locateprocedureisusedtolocatethenextoutputbasedonrowandcolumnpositions.SeealsotheText.LocateXYprocedurewhichisusedtolocatetheoutputbasedxandypositions,wherex=0,y=0istheleftbottomofthescreen.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.Locate,notbycallingLocate.

Seealso View.SetandDraw.Dot.

Text.LocateXY PartofTextmodule

Syntax Text.LocateXY(x,y:int)

Description

TheText.LocateXYprocedureisusedtomovethecursorsothatthenextoutputfromputwillbeatapproximately(x,y).Theexactlocationmaybesomewhattotheleftofxandbelowytoforcealignmenttoacharacterboundary.

Example

ThisprogramoutputsHellostartingatapproximately(100,50)onthescreen.

Text.LocateXY(100,50)

put"Hello"

Details

TheText.LocateXYprocedureisusedtolocatethenextoutputbasedonxandypositions,wherethepositionx=0,y=0istheleftbottomofthescreen.SeealsotheText.Locateprocedurewhichisusedtolocatetheoutput-basedrowandcolumnpositions,whererow1isthetoprowandcolumn1istheleftcolumn.

Thescreenshouldbeina"graphics"mode.SeetheView.Setprocedurefordetails.Ifthescreenisnotina"graphics"mode,itwillautomaticallybesetto"graphics"mode.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.LocateXY,notbycallingLocateXY.

Seealso View.SetandDraw.Dot.

Text.maxcol PartofTextmodule

Syntax maxcol:int

DescriptionThemaxcolfunctionisusedtodeterminethenumberofcolumnsonthescreen.

ExampleThisprogramoutputsthemaximumcolumnnumber.

put"Numberofcolumnsonthescreenis",maxrow

Details

ForIBMPCcompatiblesaswellasmostUNIXdumbterminals,in"text"or"screen"mode,maxcol=80.ForthedefaultIBMPCcompatible"graphics"mode(CGA),maxcol=40.

Status

ThismeansthatyoucancallthefunctionbycallingmaxcolorbycallingText.maxcol.

Seealso Text.Locateprocedureforanexampleoftheuseofmaxcol.

Text.maxrow PartofTextmodule

Syntax maxrow:int

DescriptionThemaxrowfunctionisusedtodeterminethenumberofrowsonthescreen.

ExampleThisprogramoutputsthemaximumrownumber.

put"Numberofrowsonthescreenis",maxrow

DetailsForIBMPCcompatibles,maxrow=25.FormanyUNIXdumbterminals,maxrow=24.

Status

ThismeansthatyoucancallthefunctionbycallingmaxroworbycallingText.maxrow.

Seealso Text.Locateprocedureforanexampleoftheuseofmaxrow.

Text.WhatCol PartofTextmodule

Syntax Text.WhatCol:int

DescriptionTheText.WhatColfunctionisusedtodeterminethecursorposition'scolumn.

Example

ThisprogramoutputsThecurrentrowis5,thecurrentcolumnis15.

Text.Locate(5,10)

put"12345"..

put"Thecurrentrowis",Text.WhatRow

put"Thecurrentcolumnis",Text.WhatCol

DetailsThescreenshouldbeina"screen"or"graphics"mode.Text.WhatColfunctionsproperlyevenifthecursorisinvisible.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.WhatCol,notbycallingWhatCol.

Seealso

theText.WhatRowfunction,whichisusedtodeterminethecursorrow.SeealsotheText.Locate,Text.maxrowandText.maxcolprocedure.

Text.WhatColor PartofTextmodule

Syntax Text.WhatColor:int

Description

TheText.WhatColorfunctionisusedtodeterminethecurrenttext(foreground)color,ie.,thecolorusedforcharactersthatareoutputusingput.ThealternatespellingisText.WhatColour.

Example

Thisprogramoutputsthecurrently-activecolornumber.Themessageisalsogiveninthecurrently-activecolor.

put"Thiswritingisincolornumber",Text.WhatColor

DetailsThescreenshouldbeina"screen"or"graphics"mode.SeeView.Setfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.WhatColor,notbycallingWhatColor.

SeealsotheText.Colorprocedure,whichisusedtosetthecolor.SeealsoText.ColorBackandText.WhatColorBack.

Text.WhatColorBack PartofTextmodule

Syntax Text.WhatColorBack:int

Description

TheText.WhatColorBackfunctionisusedtodeterminethecurrenttextbackgroundcolor.Thealternatespellingiswhatcolourback.

Example

Thisprogramoutputsthecurrently-activebackgroundcolornumber.Thebackgroundcolorofthemessageisdeterminedbythisnumber.

View.Set("screen")

put"Thebackgroundofthiswriting"

put"isincolornumber",Text.WhatColorBack

Details

Thescreenshouldbeina"screen"or"graphics"mode.Bewarethatthemeaningofbackgroundcolorisdifferentinthesetwomodes.SeeText.ColorBackfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.WhatColorBack,notbycallingWhatColorBack.

Seealso Text.ColorandText.WhatColor.

Text.WhatRow PartofTextmodule

Syntax Text.WhatRow:int

DescriptionTheText.WhatRowfunctionisusedtodeterminethecursorposition'srow.

Example

Text.Locate(5,10)

put"12345"..

put"Thecurrentrowis",Text.WhatRow

put"Thecurrentcolumnis",Text.WhatCol

DetailsThescreenshouldbeina"screen"or"graphics"mode.Text.WhatRowfunctionsproperlyevenifthecursorisinvisible.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingText.WhatRow,notbycallingWhatRow.

Seealso

theText.WhatColfunction,whichisusedtodeterminethecursorcolumn.SeealsotheText.Locate,Text.maxrowandText.maxcolprocedure.

Description

Thisunitcontainsthepredefinedsubprogramsthathandleanythingtodowithtime,eitherasadateorasatimer.

AllroutinesintheTimeunitareexportedqualified(andthusmustbeprefacedwith"Time.").

EntryPoints

Sec Returnsthenumberofsecondssince1/1/197000:00:00GMT.

Date Returnsthecurrentdateandtimeasastring.

SecDate Convertsanumberofsecondsintoadate/timestring.

DateSec Convertsadate/timestringtoanumberofseconds.

SecParts

Convertsthenumberofsecondssince1/1/197000:00:00GMTintoadayofmonth,month,year,dayofweek,hour,minuteandsecondintegers.

PartsSec Convertsadayofmonth,month,year,hour,minuteandsecondintegersintothenumberofsecondssince1/1/197000:00:00GMT.

SecStr Convertsthenumberofsecondssince1/1/197000:00:00GMTintoauserspecifiedformattedstringrepresentingthedate.

Elapsed Returnsthenumberofmillisecondselapsedsincetheprogramstartedtorun.

ElapsedCPU ReturnsthenumberofmillisecondsofCPUtimeelapsedsincetheprogramstartedtorun.

Delay Sleepsforaspecifiednumberofmilliseconds.

DelaySinceLast SleepsuntilaspecifiednumberofmillisecondssincethelastcalltoTime.DelaySinceLast.

Time.Date PartofTimemodule

Syntax Time.Date:string

Description

TheTime.Datefunctionreturnsthecurrentdateandtimeasastring.Thereturnedstringintheformat"ddmmmyyhh:mm:ss",wheremmmisthefirst3charactersofthemonth,e.g.,"Apr".Forexample,ifthedateisChristmas1989at9:02:37inthemorning,Time.Datewillreturn"25Dec8909:02:37".Twenty-fourhourtimeisused,soeleventhirtyatnightthesamedaywouldreturn"25Dec8923:30:00"

Example

Thisprogramgreetsyouandtellsyouthedateandtime.

vartheDateTime,theDate,theTime:string

theDateTime:=Time.Date

theDate:=theDateTime(1..9)

theTime:=theDateTime(11..*)

put"Greetings!!Thedateandtimetodayis",

Details

Bewarnedthatonsomecomputers,suchasIBMPCcompatiblesorAppleMacintoshes,thedatemaynotbesetcorrectlyintheoperatingsystem;inthatcase,theTime.Dateprocedurewillgiveincorrectresults.

ThestringformofthedatecanbeconvertedtoanumericformforcomparisonpurposesusingtheTime.DateSecfunction.ThenumericformcanbeconvertedtoastringusingtheTime.SecDatefunction.ThenumericformofthetimecanbeobtainedusingtheTime.Secfunction.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.Date,notbycallingDate.

Seealso Time.Sec,Time.DateSecandTime.SecDatefunctions.

Time.DateSec PartofTimemodule

Syntax Time.DateSec(dateString:string):int

Description

TheTime.DateSecfunctionisusedtoconvertadateandtimestringintoanumber,specifically,thenumberofsecondssince00:00:00GMTJan1,1970.

Thefunctioncanalsoconvertjustthedate("ddmmmyy"),inwhichcaseitreturnsthenumberofsecondssince00:00:00GMTJan1,1970frommidnightoftheenteredday.Itwillalsoconvertatimewithoutthedate("hh:mm:ss"),inwhichcaseitreturnsthenumberofsecondsthathavepassedsincemidnightofthatday.

Iftheformatisincorrectorcan'tbeinterpreted,thenTime.DateSecwillreturn1andError.LastandError.LastMsgwillbesettotheappropriateerror.

Example

Thisprogramgivesthenumberofsecondssince00:00:00GMTJan1,1970.

vartheDateTime,theDate,theTime:string

theDateTime:=Time.Date

theDate:=theDateTime(1..9)

theTime:=theDateTime(11..*)

put"Thenumberofsecondsfrom00:00:00GMTJan1,1970",

"frommidnight",theDate,"is",Time.DateSec

put"Thenumberofsecondsfrommidnightto",theTime

Time.DateSec(theTime)

"from",theDateTime,"is",Time.DateSec(theDateTime

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.DateSec,notbycallingDateSec.

Seealso Time.Sec,Time.DateandTime.SecDatefunctions.

Time.Delay PartofTimemodule

Syntax Time.Delay(duration:int)

DescriptionTheTime.Delayprocedureisusedtocausetheprogramtopauseforagiventime.Thetimedurationisinmilliseconds.

Example

Thisprogramprintstheintegers1to10withaseconddelaybetweeneach.

fori:1..10

Time.Delay(1000)%Pausefor1second

endfor

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.Delay,notbycallingDelay.

Seealso Time.ElapsedandTime.ElapsedCPU.

Time.DelaySinceLast PartofTimemodule

Syntax Time.DelaySinceLast(duration:int)

Description

TheTime.DelaySinceLastprocedureisusedtocausetheprogramtopauseforagiventimesincethelastcalltoTime.DelaySinceLast.Thetimedurationisinmilliseconds.

Example

Thisprogramoutputsfrom1to100,000,thenoutputshowlongittooktodothis(inmilliseconds).ItthencallsTime.DelaySinceLasttowaituntil10secondshaspassedsincethebeginningoftheprogram(regardlessofhowlongittooktoexecutetheloop).Finallyitoutputshowmanymillisecondshaspassedsincetheprogramstarted.Thisshouldbecloseto10,000milliseconds.

vart:int:=Time.Elapsed

put"Startingnow,countto100,000"

fori:1..100000

puti..

locate(whatrow,1)

endfor

put"Finishedcountingto100,000"

put"Elapsedtime:",Time.Elapsed-t,"milliseconds"

Time.DelaySinceLast(10000)

put"Elapsedtime:",Time.Elapsed-t,"milliseconds"

Execute

TheTime.DelaySinceLastisusuallyusedtotimeaprocesssothatitoperatesonthesamespeednomatterwhatthemachine.Forexample,intheaboveexample,theprogramwillalwyastake10secondstoexecute,regardlessofthespeedofthemachine(up

Details

toapoint).FastmachineswillspendlittletimeintheforloopandlongerwaitingtoreturnfromTime.DelaySinceLast.SlowermachineswilltakelongertoexecutetheloopandwillconsequentlywaitlesstimebeforereturningfromTime.DelaySinceLast.

TheTime.DelaySinceLastprocedureisoftenusedtotimethespeedofanimationingames.

Notethatthisonlyworksuptoapoint.Onaveryslowmachine,theforloopmaytakelongerthan10secondstoexecute,inwhichcasethecalltoTime.DelaySinceLastwillreturninstantly.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.DelaySinceLast,notbycallingDelaySinceLast.

Seealso Time.ElapsedandTime.ElapsedCPU.

Time.Elapsed PartofTimemodule

Syntax Time.Elapsed:int

Description

TheTime.Elapsedfunctionreturnstheamountoftimesinceaprogram(process)startedrunning.Thenumberofmillisecondssincetheprogramstartedrunningisreturned.

Example

Thisprogramtellsyouhowmuchtimeithasused.

vartimeRunning:int

timeRunning:=Time.Elapsed

put"Thisprogramhasrun",timeRunning,"milliseconds"

Details

OnIBMPCcompatibles,thisisthetotaltimesincetheTuringsystemwasstartedup.Thehardwareresolutionofdurationisinunitsof55milliseconds.Forexample,Time.Elapsedmaybeoffbyasmuchas55milliseconds.

OnAppleMacintoshes,thisisthetotaltimesincethemachinewasturnedon.Thehardwareresolutionofdurationisinunitsof17milliseconds(1/60-thofasecond).

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.Elapsed,notbycallingElapsed.

Seealso Time.ElapsedCPUandTime.Delaysubprograms.

Time.ElapsedCPU PartofTimemodule

Syntax Time.ElapsedCPU:int

Description

TheTime.ElapsedCPUfunctionisusedonamultitaskingsystemsuchasUNIXtodeterminetheamountoftimethathasbeenusedbythisprogram(process).Thenumberofcentralprocessormillisecondsassignedtothisprogramisreturned.Thisisoflittleuseonapersonalcomputer,whereTime.ElapsedCPUreturnsthesamevalueasTime.Elapsed.

Example

OnaUNIXsystem,thisprogramtellsyouhowmuchtimeithasused.

vartimeUsed:int

timeUsed:=Time.ElapsedCPU

put"Thisprogramhasused",timeUsed,

"millisecondsofCPUtime"

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.ElapsedCPU,notbycallingElapsedCPU.

Seealso Time.ElapsedandTime.Delaysubprograms.

Time.PartsSec PartofTimemodule

SyntaxTime.PartsSec(year,month,day,hour,minute,second:int):int

Description

TheTime.PartsSecfunctionisusedtoconvertthenumericpartsofadate(specificallytheyear,month,day,hour,minuteandsecond)intothenumberofsecondssince00:00:00GMTJan1,1970andthedatespecifiedbytheparts.

Thefunctioncanalsoconvertatimewithoutadate(year,monthanddayareall0),inwhichcaseitreturnsthenumberofsecondsthathavepassedsincemidnightofthecurrentday.

Ifthenumbersdon'tmakeanysenseorcan'tbeinterpreted,thenTime.PartsSecwillreturn1andError.LastandError.LastMsgwillbesettotheappropriateerror.

Example

Thisprogramgivesthenumberofsecondsbetween00:00:00GMTJan1,1970and9:27inthemorning,ChristmasDay,1989).

"is",Time.PartsSec(1989,12,25,9,27,0

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.PartsSec,notbycallingPartsSec.

Seealso Time.SecParts,Time.DateandTime.Secfunctions.

Time.Sec PartofTimemodule

Syntax Time.Sec:int

Description

TheTime.Secfunctionreturnsthecurrentdateandtimeasanumber.Thereturnedintegeristhetimeinsecondssince00:00:00GMT(GreenwichMeanTime)January1,1970.

ExampleThisprogramtellsyouhowmanysecondssince1970.

put"Thenumberofsecondssince1970is",Time.Sec

Details

Bewarnedthatonsomecomputers,suchasIBMPCcompatiblesorAppleMacintoshes,thedatemaynotbesetcorrectlyintheoperatingsystem;inthatcase,theTime.Dateprocedurewillgiveincorrectresults.

ThestringformofthedatecanbeconvertedtoanumericformforcomparisonpurposesusingtheTime.DateSecfunction.ThenumericformcanbeconvertedtoastringusingtheTime.SecDatefunction.ThenumericformofthetimecanbeobtainedusingtheTime.Secfunction.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.SecbycallingSec.

Seealso Time.Date,Time.DateSecandTime.SecDatefunctions.

Time.SecDate PartofTimemodule

Syntax Time.SecDate(timeInSecs:int):string

Description

TheTime.SecDatefunctionisusedtoconvertthenumberofsecondssince00:00:00GMTJan1,1970intoadateandtimestring.

IftimeInSecsisincorrectorcan'tbeinterpreted,thenTime.SecDatewillreturntheemptystringandError.LastandError.LastMsgwillbesettotheappropriateerror.

Example

Thisprogramgivesthenumberofsecondssince00:00:00GMTJan1,1970andthedateinstringform.

vartimeInSecs:int:=Time.Sec

vartheDateTime:string

theDateTime:=Time.SecDate(timeInSecs)

put"Thenumberofsecondssince1970is",timeInSecs

put"Greetings!!Thedateandtimetodayis",theDateTime

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.SecDate,notbycallingSecDate.

Seealso Time.Sec,Time.DateandTime.DateSecfunctions.

Time.SecParts PartofTimemodule

SyntaxTime.SecParts(sec:int,varyear,month,day, dayOfWeek,hour,minute,second:int)

Description

TheTime.SecPartsfunctionisusedtoconvertasinglenumberformofthetime(thenumberofsecondssince00:00:00GMTJan1,1970)intoadatewithnumericcomponentparts.

ThedayOfWeekparameteris1forMonday,2forTuesdaythrough7forSunday.

Ifthesecparameterdoesn'tmakeanysenseorcan'tbeinterpreted,thenTime.PartsSecwillsetallthevarparametersto1andError.LastError.LastMsgwillbesettotheappropriateerror.

Example

Thisprogramreturnsthecurrentdayoftheweek.

varyear,month,day,dayOfWeek,hour,minute,second

Time.SecParts(Time.Sec,year,month,day,dayOfWeek

hour,minute,second)

vardays:array1..7ofstring(10):=init("Monday","Tuesday",

"Wednesday","Thursday","Friday","Saturday","Sunday")

put"Thecurrentdayoftheweekis",days(dayOfWeek

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.SecPartscallingSecParts.

Seealso Time.PartsSec,Time.DateandTime.Secfunctions.

Time.SecStr PartofTimemodule

Syntax Time.SecStr(timeInSecs:int,formatString:string):string

Description

TheTime.SecStrfunctionisusedtoconvertthenumberofsecondssince00:00:00GMTJan1,1970intoadateandtimestring.

IftimeInSecsisincorrectorcan'tbeinterpreted,thenTime.SecStrwillreturntheemptystringandError.LastandError.LastMsgwillbesettotheappropriateerror.

Detailsn

TheformatStringparameterspecifieshowtheoutputstringwilllook.TheformatStringconsistsofdifferentlettersspecifyingthedifferentformatsandspacesorcommasbetweentheseletters.Thedifferentletterscanbecombinedtoprovidedifferentdateformats.

Herearetheletters:

a AbbreviatedweekdaynameA Fullweekdaynameb AbbreviatedmonthnameB Fullmonthnamec Dateandtimerepresentationappropriateforlocaled Dayofmonthasdecimalnumber(01-31)H Hourin24-hourformat(00-23)I Hourin12-hourformat(01-12)j Dayofyearasdecimalnumber(001-366)m Monthasdecimalnumber(01-12)M Minuteasdecimalnumber(00-59)p Currentlocale’sA.M./P.M.indicatorfor12-hourclockS Secondasdecimalnumber(00-59)

U Weekofyearasdecimalnumber,withSundayasfirstdayofweek(00-53)

w Weekdayasdecimalnumber(0-6;Sundayis0)

W Weekofyearasdecimalnumber,withMondayasfirstdayofweek(00-53)

x DaterepresentationforcurrentlocaleX Timerepresentationforcurrentlocaley Yearwithoutcentury,asdecimalnumber(00-99)Y Yearwithcentury,asdecimalnumberz,Z Time-zonename

Example

Thisprogramoutputsthecurrentdateandthedaynumberintheyear.Exampleoutput:ThursdayNovember13,2003isdaynumber317of2003

putTime.SecStr(Time.Sec,"ABd,Y"),"isdaynumber",

Time.SecStr(Time.Sec,"j"),"of",Time.SecStr

Execute

Thisexampledemonstrateseachoftheformattingletters.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingTime.SecStrcallingSecStr.

Time.SecandTime.SecPartsfunctions.

Seealso

time timeofdayasastringprocedure

Syntax time(vart:string)

Description

Thetimestatementisusedtodeterminethecurrenttimeofday.Variabletisassignedastringintheformat"hh:mm:ss".Forexample,ifthetimeistwominutesand47secondsafternineA.M.,twillbesetto"09:02:47".Twenty-fourhourtimeisused.Forexample,eleventhirtyP.M.givesthestring"23:30:00".

Example

Thisprogramgreetsyouandtellsyouthetimeofday.

vartimeOfDay:string

time(timeOfDay)

put"Greetings!!Thetimeis",timeOfDay

Details

BewarnedthatonsomecomputerssuchasIBMPCcompatiblesorAppleMacintoshes,thetimemaynotbesetcorrectlyintheoperatingsystem.Inthiscase,thetimeprocedurewillgiveincorrectresults.

Seealsodelay,clock,sysclock,wallclockanddatestatements.

token ininput

Description

Atokenisessentiallyaword,anumberoraspecialsymbolsuchas:=.InaTuringprogramtherearefourkindsoftokens:keywordssuchasget,identifierssuchasincomeTax,operatorsandspecialsymbols,suchas+and:=,andexplicitconstants,suchas1.5and"Hello".Somekeywords,suchasindex,arereservedandcannotbeusedinprogramstonamevariables,procedures,etc.

Agetstatement,suchas

getincomeTax

usestoken-orientedinput.Thismeansthatwhitespace(blanks,tabs,etc.)isskippedbeforereadingtheinputitemandaftertheitem(uptothebeginningofthenextline).Seethegetstatementfordetails.

Example

Inthisexample,thetokensarevar,x,:,real,x,:=and9.84.

varx:real

x:=9.84

true booleanvalue(notfalse)

Syntax true

DescriptionAboolean(true/false)variablecanbeeithertrueorfalse(seebooleantype).

Example

varpassed:boolean:=true

varmark:int

fori:1..10

getmark

passed:=passedandmark>=60

endfor

ifpassed=truethen

put"Youpassedalltensubjects"

DetailsThelineifpassed=truethencanbesimplifiedtoifpassedthenwithnochangetothemeaningoftheprogram.

type declaration

Syntax

AtypeDeclarationisoneof:

(a) typeid:typeSpec (b) typeid:forward

DescriptionAtypedeclarationgivesanametoatype.Thisnamecanbeusedinplaceofthetype.

Example

typenameType:string(30)

typerange:0..150

typeentry:

record

name:nameType

age:int

endrecord

Details

Thekeywordpervasivecanbeinsertedjustaftertype.Whenthisisdone,thetypeisvisibleinsideallsubconstructsofthetypescope.Withoutpervasive,thetypeisnotvisibleinsidemodules,monitorsandclassesunlessexplicitlyimported.Pervasivetypesneednotbeimported.Youcanabbreviatepervasiveasanasterisk(*).

Aforwardtypeallowspointerstobedeclaredtothetypebeforethetypeisresolved.Toresolveatype,youmustfollowaforwardwithadeclarationofthesamenameandinthesamescope.ThistypedeclarationmustincludeatypeSpec.

TypeConv

Description

ThisunitcontainsthepredefinedsubprogramsthatconvertbetweendifferentTuringstandardtypes.Therearealsosixroutinesthatarepartofthelanguage,ratherthanpartoftheunit,butareconceptuallypartofthisunit.

AllroutinesintheTypeConvunitareexportedunqualified.

DescriptionoftheroutinesintheTypeConvmodulecanbefoundinthischapter.

EntryPoints

intreal Convertsanintegertoareal.intstr* Convertsanintegertoastring.natreal Convertsanaturalnumbertoareal.natstr* Convertsanaturalnumbertoastring.round Convertsarealtoaninteger(rounding).floor Convertsarealtoaninteger(rounddown).ceil Convertsarealtoaninteger(roundup).realstr Convertsarealtoastring.erealstr Convertsarealtoastring(exponentialnotation).frealstr Convertsarealtoastring(noexponent).strint* Convertsastringtoaninteger.

strintok* Returnswhetherastringcanlegallybeconvertedtoaninteger.

strnat* Convertsastringtoanaturalnumber.

strnatok* Returnswhetherastringcanlegallybeconvertedtoanaturalnumber.

strreal Convertsastringtoareal.

strrealok Returnswhetherastringcanlegallybeconvertedtoareal.

chr* ReturnstheASCIIvalueofaspecifiedstringoflengthone.

ord* ReturnsastringoflengthonewiththeASCIIvaluespecified.

*Partofthelanguage,conceptuallypartoftheTypeConvunit.

typeSpec typespecification

Syntax

AtypeSpec(typespecification)isoneof:

(a) int (b) real (c) boolean (d) stringType %Example:string(20) (e) subrangeType %Example:1..150

(f) enumeratedType %Example:enum(red,green,blue)

(g) arrayType %Example:array1..150ofreal

(h) setType %Example:setof1..10

(i) recordType %Example:record…endrecord

(j) unionType %Example:union…endunion

(k) pointerType %Example:pointertocollectionVar

(l) namedType %Example:colorRange (m) nat %naturalnumber

(n) intn %n-byteinteger(n=1,2,4)

(o) natn %n-bytenatural(n=1,2,4)

(p) realn %n-bytereal(n=4,8) (q) char %singlecharacter (r) char(n) %ncharacters (s) subprogramType

Description

Atypespecificationdeterminestheallowedvaluesforavariableorconstant.Forexample,ifvariablexisaninteger(itstypeSpecisint),thepossiblevaluesforxarenumberssuchas-15,0,3and348207.Ifxisarealnumber(itstypeSpecisreal),thenitspossiblevaluesinclude7.8,-35.0,and15e12.Ifxisaboolean,itspossiblevaluesaretrueandfalse.Ifxisastring,itspossiblevaluesincludeHelloandGood-bye.

Example

varnumberOfSides:int

varx,y:real

typerange:0..150%ThetypeSpechereis0

typeentry:%HereisarecordtypeSpec

record

name:string(25)

age:range

endrecord

Seealso

int,real,boolean,string,subrangeType,enum,array,set,record,union,pointer,named,nat,intn,natn,realn,char,andchar(n)types.

unchecked compilerdirective

Dangerous

Description

OOTaddstheconceptof"unchecked"toTuring.Here,youcanrequestthatcertainruntimetests,whichtakeplacebydefault,canbeeliminated.Thismakestheprogrammoreefficientattheriskofunreliability.

Example

Declareptobeanuncheckedpointertoaninteger(seepointersfordetails).Pointerpwillbedangeroustouse,becausetheruntimesystemwillnotchecktoseeifitactuallylocatesaninteger,asopposedtoarbitrarycomputermemory.Inotherwords,uncheckedpointersarelikeClanguagepointers.

varp:unchecked^int

Example

DeclareCtobeanuncheckedcollectionofrecordsoftypeR(seecollectionsfordetails).PointerstoCwillbeunchecked.

varC:uncheckedcollectionofR

Example

Removecheckingfromthebodyofaloop.

fori:1..500

unchecked

ifa(i)=keythen

endfor

Details

Intheaboveexample,theuncheckedkeywordrequeststhatallchecking,inparticular,arrayboundscheckingforarraya,aretobeomitted.Thedisablinglastsfromtheoccurrenceofthekeyworduncheckedtotheendofthesurroundingconstruct,inthiscase,untilendfor.Inasimilarway,thecheckedkeywordwillrequestthatcheckingbere-enabledfromtheoccurenceofcheckedtotheendofthesurroundingconstruct.

Inthecurrent(1999)implementation,theuseofuncheckedto

turnoffcheckinginablockofstatementsisignored.Ingeneral,animplementationmaychoosetoignorerequeststodisablechecking.

union type

Syntax

AunionTypeis:

union[id]:indexTypeof

labellabelExpn{,labelExpn}:

{id{,id}:typeSpec}

{labellabelExpn{,labelExpn}:

{id{,id}:typeSpec}}

[label:{id{,id}:typeSpec}]

endunion

Description

Auniontype(alsocalledavariantrecord)islikearecordinwhichthereisaruntimechoiceamongsetsofaccessiblefields.Thischoiceismadebythetagstatement,whichdeletesthecurrentsetoffieldsandactivatesanewset.

Example

Thisuniontypekeepstrackofvariousinformationaboutavehicle,dependingonthekindofvehicle.

constpassenger:=0

constfarm:=1

constrecreational:=2

typevehicleInfo:

unionkind:passenger..recreationalof

labelpassenger:

cylinders:1..16

labelfarm:

farmClass:string(10)

label:%Nofieldsfor"otherwise"clause

endunion

varv:vehicleInfo

tagv,passenger%Activatepassengerpartv.cylinders

Theoptionalidentifierfollowingthekeywordunionisthenameofthetagoftheuniontype.Iftheidentifierisomitted,thetagisstillconsideredtoexist,althoughitsvaluecannotbeaccessed.Thetagmustbeofanindextype,forexample1..7.Youshouldlimittherangeofthisindextype,asthecompilermayhavealimit(atleast255)onthemaximumrangeitcanhandle.

Details

EachlabelExpnmustbeknownatcompiletimeandmustliewithintherangeofthetag'stype.Thefields,includingthetag,ofaunionvaluearereferencedusingthedotoperator,asinv.cylindersandthesecanbeusedasvariablesorconstants.Afieldcanbeaccessedonlywhenthetagmatchesoneofthelabelexpressionscorrespondingtothefield.Thetagcanbechangedbythetagstatementbutitcannotbeassignedto,passedtoavarparameter,orboundtousingvar.

Inaunion,id'soffields,includingthetag,mustbedistinct.However,theseneednotbedistinctfromidentifiersoutsidetheunion.Unionscanbeassignedasawhole(tounionsofanequivalenttype),buttheycannotbecompared.AsemicoloncanoptionallyfolloweachtypeSpec.

Anyarraycontainedinaunionmusthaveboundsthatareknownatcompiletime.

Thenotation>canbeusedtoaccessunionfields.Forexample,ifppointertovehicleRecord,p>farmClasslocatesthefarmClassfield.

Seealso pointer.

unit filecontainingmodule,monitor,orclass

Syntax

AcompilationUnitisoneof:

(a) [importList]mainProgram (b) unitmoduleDeclaration (c) unitmonitorDeclaration (d) unitclassDeclaration

Description

Aprogramcanbedividedupintounits,eachinaseparatefile.Allfilesexceptthemainprogrambeginwiththekeywordunit.Theunitcontainsthemainprogram,amodule,amonitororaclass.

Example

Hereisstackmodulethatisseparatedoutintoafilewhosenameis

unit%Thekeywordunitbeginseachseparatefile

modulestack

exportpush,pop

vartop:int:=0

varcontents:array1..100ofint

procedurepush(i:int)

top+=1

contents(top):=i

endpush

procedurepop(i:int)

i:=contents(top)

top-=1

endpop

endstack

Themainprogram,whichisinanotherfile,gainsaccesstothestackbyimportingit.Hereisthemainprogram:

importvarstack%Usethestack

varn:int

stack.push(n)

stack.pop(n)

Details

Inthisexample,thekeywordvarintheimportlistisrequiredbecausethemainprogramcausesachangeinthestack,bycallingpushandpopimportlistsofunitsthataremodules,monitorsandclassesareusedtogainaccesstofurtherunits.

Ifthestackwereinafilewithadifferentname,saystk.t,theimportlistwouldberewrittentouseaninclause,asfollows:

importvarstackin"stk.t"

AmainProgramissimplyaprogram.Seeprogram.

Seealsomodule,monitorandclass.Seealsoexportlist,importlist,inheritimplementlistandimplementbylist.

unqualified export

Description

Whenanidentifierxisexportedfromamodule,monitororclassMusingthekeywordunqualified,itcanbeusedoutsideofMwithoutthequalification"M.".Inotherwords,outsideofM,itcanbereferredtoassimplyx.Thekeywordunqualifiedcanbewritteninitsshortformas~.whichispronounced"notdot",asin:

export~.x

Seeals o exportlist.

upper bound

Syntax upper(reference[,dimension]):int

Description

Theupperattributeisusedtofindtheupperboundofanarray,string,char(n)ornon-opaquesubrangetype.(Seelowerforfindingthelowerbound.)

Example

Inaprocedure,seeiftheboundofarrayparameteraislargeenoughthatitcanbesubscriptedbyi.Ifitislargeenough,itisseta(i)tozero.

proceduretest(vara:array1..*ofreal)

ifi<=upper(a)then

a(i):=0.0

endtest

Details

Inasimilarway,ifsisastring,itsupperbound(notlength!)isgivenbyupper(s).Ifanarrayhasmorethanonedimension,asinvarb:array1..10,1..60ofint,youmustspecifythedimension.Forexample,upper(b,2)returns60.

var declaration

Syntax

AvariableDeclarationisoneof:

(a) varid{,id}[:typeSpec][:=initializingValue] (b) collectionDeclaration

Description

Avariabledeclarationcreatesanewvariable(orvariables).Onlyform(a)willbeexplainedhere.SeecollectionDeclarationforexplanationofform(b).ThetypeSpecofform(a)canbeomittedonlyiftheinitializingvalueispresent.

Examplevarj,k:int:=1%jandkareassignedvalue1

vart:="Sample"%Thetypeoftisstring

varv:array1..3ofstring(6):=

init("George","Fred","Alice")

Details

Theinitializingvalue,ifpresent,mustbeanexpressionorelsealistofitemsseparatedbycommasinsideinit(…).ThesyntaxofinitializingValueisoneof:

(a) expn (b) init(initializingValue{,initializingValue})

Eachinit(…)correspondstoanarray,recordorunionvaluethatisbeinginitialized.Thesemustbenestedforinitializationofnestedtypes.

IfthetypeSpecisomitted,thevariable'stypeistakentobethe(root)typeoftheinitializingexpression,forexample,intorstring.ThetypeSpeccannotbeomittedfordynamicarraysorwhentheinitializingvalueisoftheforminit(…).Thevaluesinsideinit(…)mustbeknownatcompiletime.

Thekeywordpervasivecanbeinsertedjustaftervar.Whenthisisdone,thevariableisvisibleinsideallsubconstructsofthevariable'sscope.Withoutpervasive,thevariableisnotvisibleinsidemodulesunlessexplicitlyimported.Pervasivevariablesneednotbeimported.Youcanabbreviateanasterisk(*).

OOTextendsTuringinthefollowingway.OOTchangesform(a)toallowtheoptionaluseoftheregisterkeywordtorequestthatthevariablebeplacedinamachineregister.TheOOTsyntaxforform(a)isactually:

var[pervasive][register]id{,id}[:typeSpec

Inthecurrent(1994)OOTimplementation,programsareruninterpretivelyusingpseudo-code,whichhasnomachineregisters,andtheregisterkeywordisignored.Seeofregistervariables.

Seealsocollection,bind,procedureandfunctiondeclarations,parameterdeclarations,importlistsforotherusesofthekeywordvar.

variableReference useofavariable

Syntax

AvariableReferenceis:

variableId{componentSelector}

Description

InaTuringprogram,avariableisdeclaredandgivenaname(variableId)andthenused.Eachuseiscalledavariablereference.

Ifthevariableisanarray,collection,recordorunion,itsparts(components)canbeselectedusingsubscriptsandfieldnames(usingcomponentSelectors).TheformofacomponentSelectorisoneof:\

(a) (expn{,expn}) (b) .fieldId

Form(a)isusedforsubscripting(indexing)arraysandcollections.Thenumberofarraysubscriptsmustbethesameasinthearray'sdeclaration.Acollectionhasexactlyonesubscript,whichmustbeapointertothecollection.Form(b)isusedforselectingafieldofarecordorunion.

Example

Followingthedeclarationsofk,aandr,eachofk,a(k)andr.namearevariablereferences.

vark:int

vara:array1..100ofreal

record

name:string(20)

phone:string(8)

endrecord

a(k):=3.14159

r.name:="SteveCook"

Avariablereferencecancontainmorethanonecomponent

Detailsselector,forexample,whenthevariableisanarrayofrecords.Foranexample,seetherecordtype.SeealsoconstantReferenceandvardeclaration.

Description

Thisunitcontainsthepredefinedsubprogramsthatdealwiththecurrentoutputsurface,whichisawindow.

AllroutinesintheViewunitareexportedqualified(andthusmustbeprefacedwith"View.")withtheexceptionofmaxx,maxy,maxcolorandmaxcolourwhichareexportedunqualified.

Returnsthemaximumxcoordinate(width1)(exportedunqualified).

Returnsthemaximumycoordinate(height1)(exportedunqualified).

maxcolor

Returnsthemaximumcolornumber(#colors1)(exportedunqualified).

maxcolour

Returnsthemaximumcolornumber(#colors1)(exportedunqualified).

Set Changestheconfigurationoftheoutputsurface.

ClipSet Clipsoutputtoaspecifiedrectangle.

ClipAdd

Addsanotherspecifiedrectangletotheclipping

EntryPoints

region.

ClipAddOval Addsanotherspecifiedovaltotheclippingregion.

ClipOff Stopsallclipping.

WhatDotColor

Getsthecolorofthepixelataspecifiedlocation.

WhatDotColour Getsthecolorofthepixelataspecifiedlocation.

Update

Updatestheonscreenwindowfromtheoffscreenbitmap.

UpdateArea

Updatespartoftheonscreenwindowfromtheoffscreenbitmap.

SetTransparentColor

SetsthetransparentcolortobeignoredwhenusingpicUnderMerge

SetTransparentColour

SetsthetransparentcolourtobeignoredwhenusingpicUnderMerge

View.ClipAdd PartofViewmodule

Syntax View.ClipAdd(x1,y1,x2,y2:int)

Description

TheView.ClipAddprocedureaddsanotherrectanglespecifiedby(x1,y1)-(x2,y2)totheclippingregion.Thisonlyworksonsystemsthatsupportcomplexclippingregions.Ifnoclippingregionhasbeenspecified,thentherectanglebecomesthecompleteclippingregion.

Aclippingregionistheregionthattheoutputwillappearin.Iftherectangleisspecifiedastheclippingregion,anydrawingdoneoutsidetherectanglewillnotappear.

Tosettheinitialclipping,orremovetheoldregionandreplaceitwithanewone,useView.ClipSet.Tosettheclippingregionbacktotheentirescreenorwindow,useView.ClipOff.

Thesecommandsonlyworkin"graphics"mode.

Example

Thisprogramsetstheclippingregiontofiverectanglesandthendrawsrandomcircles.Thecircleswillonlyappear(orpartiallyappear)intherectangles.

constmaxx13:int:=maxxdiv3

constmaxx23:int:=2*maxxdiv3

constmaxy13:int:=maxydiv3

constmaxy23:int:=2*maxydiv3

View.ClipSet(0,0,maxx13,maxy13)

View.ClipAdd(maxx23,0,maxx,maxx13)

View.ClipAdd(maxx13,maxy13,maxx23,maxy23)

View.ClipAdd(0,maxy23,maxx13,maxy)

View.ClipAdd(maxx23,maxy23,maxx,maxy)

%Drawtherandomovalsinthebox

varx,y,clr:int

clr:=Rand.Int(0,maxcolor)%Randomcolor

endloop

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.ClipAdd,notbycallingClipAdd.

Seealso View.ClipSetandView.ClipOfffunctions.

View.ClipAddOval PartofViewmodule

Syntax View.ClipAddOval(x,y,xradius,yradius:int)

Description

TheView.ClipAddOvalprocedureaddsanotherovalspecifiedby(x,y)andxradiusandyradius)totheclippingregion.Ifnoclippingregionhasbeenspecified,thentheovalbecomesthecompleteclippingregion.

Aclippingregionistheregionthattheoutputwillappearin.Iftherectangleisspecifiedastheclippingregion,anydrawingdoneoutsidetheovalwillnotappear.

Tosettheinitialclipping,orremovetheoldregionandreplaceitwithanewrectangle,useView.ClipSet.Tosettheclippingregionbacktotheentirescreenorwindow,useView.ClipOff.

Example

Thisprogramsetstheclippingregiontofivecirclesandthendrawsrandomsquares.Thesquareswillonlyappear(orpartiallyappear)intheovals.

constc1:int:=maxydiv4

constc2:int:=3*maxydiv4

constradius:int:=maxydiv4

View.ClipAddOval(c1,c1,radius,radius)

%Drawtherandomsquaresinthebox

varx,y,clr:int

x:=Rand.Int(0,maxx-30)%Randomx

y:=Rand.Int(0,maxy-30)%Randomy

Draw.FillBox(x,y,x+30,y+30,clr)

endloop

Execute

BycombininganimationusingView.UpdateandView.ClipAddOval,youcanachieveamovingspotlighteffect.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.ClipAddOval,notbycallingClipAddOval.

Seealso View.ClipSet,View.ClipAddandView.ClipOfffunctions.

View.ClipOff PartofViewmodule

Syntax View.ClipOff

Description

TheView.ClipOffprocedureturnsoffclipping.Thismeansthatanydrawingcommandscanappearontheentiredrawingsurface(thescreenorthewindow,dependingonthesystem).

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.ClipOff,notbycallingClipOff.

Seealso View.ClipAddandView.ClipSetfunctions.

View.ClipSet PartofViewmodule

Syntax View.ClipSet(x1,y1,x2,y2:int)

Description

TheView.ClipSetproceduresetstheclippingregiontotherectanglespecifiedby(x1,y1)-(x2,y2).Ifaclippingregionalreadyexist,itisreplacedbythespecifiedrectangle.

Aclippingregionistheregioninwhichtheoutputwillappear.Iftherectangleisspecifiedastheclippingregion,anydrawingdoneoutsidetherectanglewillnotappear.

Tosettheinitialclipping,orremovetheoldregionandreplaceitwithanewone,useView.ClipSet.Tosettheclippingregionbacktotheentirescreenorwindow,useView.ClipOff.

Example

Thisprogramsetstheclippingregiontofiverectanglesandthendrawsrandomcircles.Thecircleswillonlyappear(orpartiallyappear)intherectangles.

constmaxx13:int:=maxxdiv3

constmaxx23:int:=2*maxxdiv3

constmaxy13:int:=maxydiv3

constmaxy23:int:=2*maxydiv3

View.ClipSet(0,0,maxx13,maxy13)

View.ClipAdd(maxx23,0,maxx,maxy13)

View.ClipAdd(maxx13,maxy13,maxx23,maxy23)

View.ClipAdd(0,maxy23,maxx13,maxy)

View.ClipAdd(maxx23,maxy23,maxx,maxy)

varx,y,clr:int

endloop

Exportedqualified.

Status ThismeansthatyoucanonlycallthefunctionbycallingView.ClipSet,notbycallingClipSet.

Seealso View.ClipAddandView.ClipOfffunctions.

View.maxcolor PartofViewmodule

Syntax View.maxcolor:int

Description

Example

put"Themaximumcolornumberis",View.maxcolor

Details

Thescreenshouldbeina"screen"or"graphics"mode.Ifitisnot,itwillautomaticallybesetto"screen"mode.SeeView.Setfordetails.

ForIBMPCcompatiblesin"screen"mode,maxcolor=15.ForthedefaultIBMPCcompatible"graphics"mode(VGA),maxcolor=15.

DetailsView.maxcolorisidenticaltoRGB.maxcolor.Itisplacedhereforconsistencywithotherscreeninformationroutines.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.maxcolor.NotethatRGB.maxcolorisexportedunqualified,sothatonecancallmaxcolor.

Seealso

Draw.Dotforexamplesoftheuseofmaxcolor.SeetheText.Colorprocedurewhichisusedforsettingthecurrently-activecolor.

View.maxx PartofViewmodule

Syntax maxx:int

DescriptionThemaxxfunctionisusedtodeterminethemaximumvalueofxforthecurrentgraphicsmode.

Example

Thisprogramoutputsthemaximumxvalue.

put"Themaximumxvalueis",maxx

Details

ForthedefaultIBMPCcompatiblegraphicsmode(CGA),maxx=319.

Status

ThismeansthatyoucancallthefunctionbycallingmaxxorbycallingView.maxx.

SeealsoDraw.Dotforanexampleoftheuseofmaxxandforadiagramillustratingxandypositions.

View.maxy PartofViewmodule

Syntax maxy:int

DescriptionThemaxyfunctionisusedtodeterminethemaximumvalueofyforthecurrentgraphicsmode.

Example

Thisprogramoutputsthemaximumyvalue.

put"Themaximumyvalueis",maxy

Details

ForthedefaultIBMPCcompatiblegraphicsmode(CGA),maxy=199.

Status

ThismeansthatyoucancallthefunctionbycallingmaxyorbycallingView.maxy.

SeealsoDraw.Dotforanexampleoftheuseofmaxyandforadiagramillustratingxandypositions.

View.Set PartofViewmodule

Syntax View.Set(s:string)

Example

HereareexampleusesoftheView.Setprocedure.Inmanycases,thesewillappearasthefirststatementoftheprogram.However,theycanappearanyplaceinaprogram.

View.Set("graphics")%Switchtographicsmode

View.Set("screen")%Switchtoscreenmode

View.Set("nocursor")%Turnoffcursor

View.Set("noecho")%Donotechokeystrokes

Description

TheView.Setstatementisusedtochangethemodeofthescreen,aswellasthewayinwhichTuringdoesinputandoutput.TheparametertoView.Setisastring,suchas"graphics".Thestringcontainsoneormoreoptionsseparatedbycommas,suchas"text,noecho".View.Setaffectstheactivewindow.

Details

Therearetwowindowmodes,textandgraphics.

textmodedoesnotallowanygraphicswhatsoever(includingcursorpositioning,etc.).Onlyputandgetareallowed.Anyoutputthatscrollsoffthetopofthewindowispreservedandcanviewedorprintedlater.

graphicsmodeallowscharactergraphicsandpixelgraphicscommandssuchandText.LocateandDraw.Box.

ThedefaultgraphicsmodeisdefinedintheTuringpreferences.Itisgoodpracticetosetthedesiredmodesothattheprogramwillfunctionproperlyregardlessofthedefaultgraphicsmode.Notethatiftheuserprintstheoutputwindow,intextmode,alloutputsenttothewindowisprinted.Ingraphicsmode,onlythecurrentoutputofthewindowisprinted.Iftheusersavestheoutputwindow,atextmodewindowwillproduceatextfilecontainingalltheoutputsenttothewindow.AgraphicswindowwillproduceaBMPgraphicsfilecontainingthecurrentcontentsofthewindow.

WheretheoptionstoView.Setaremutuallyexclusive,theyarelisted

Details

herewiththedefaultunderlined.Herearetheoptions:

"cursor","nocursor"-Causesthecursortobeshown(orhidden).Thecursorisonlydisplayedwhentheprogramisawaitinginput.

"echo","noecho"-Causes(orsuppresses)echoingofcharactersthataretyped.Echoingiscommonlyturnedoffininteractiveprogramstokeeptypedcharactersfrombeingechoedatinappropriateplacesonthescreen.

"noxor","xor"-noxormodemeansthatalldrawingisdonenormally.Inxormode,allpixelgraphicsaredrawnXOR'edonthebackground(withtheexceptionofthePicroutines,wherethedrawingmodeisspecified).ThemostimportantpropertyofanXOR'edobjectisthatitcanbeerasedandthebackgroundrestoredbyXOR'ingtheobjectontopofitself.

"msdos","nomsdos"-CausesthewindowtousetheMS-DOScharacterset(withlinedrawingcharacters)insteadoftheWindowsANSIcharacterset.The"nomsdos"optioncausesthewindowtousetheWindowsANSIcharacterset.Notethatthe"msdos"optiononlyworksiftheWindowsfont(usuallyCourierNew)supportsit.

"visible","invisible","popup"-Causestheactivewindowtobecomevisible(invisibleor,forpopup,invisibleuntilinputoroutputoccursinthewindow).

"title:<text>"-Causesthetitleoftheactivewindowtobesetto<text

"position:<x>;<y>"-Causesthepositionoftheupperleftcorneroftheactivewindowtobesetto(x,y).The<x>parametercanalsobeoneof:“left”,“center”,“center”or“right”,inwhichcasethewindowwillbeplacedontheleft,centerorrightsideofthescreen.The<y>parametercanalsobeoneof:“top”,“middle”,“truemiddle”,or“bottom”inwhichcasethewindowwillbeplacedatthetop,middleabout1/3fromthetop,middleorbottomofthescreen.Notethatwhenawindowissupposedtobecenteredinthemiddleofthescreen,“middle”usuallylooksbetterthan“truemiddle”.

"nooffscreenonly","offscreenonly"Causesor(suppresses)outputfrom

beingsenttothevisiblewindow.Whentheoffscreenonlyoptionisactive,anytextandgraphicsoutputisdrawntotheoffscreenbufferthatismaintainedforeveryRunwindowbutnotdrawntothescreen.View.UpdateisthenusedtocopytheentirecontentsoftheoffscreenbuffertotheRunwindow.Byallowingnumerousdrawingcommandstobesenttotheoffscreenbufferandthenupdatingthewindowatonetime,itispossibletogetsmootheranimation.

"buttonbar","nobuttonbar"Causesor(suppresses)thedisplayofabuttonbaratthetopoftheoutputwindowwhichallowstheusertoeasilystopprogramexecutionorsaveandprinttheoutputwindow.

"text","screen","graphics"-Setswindowtothegivenmodeandalwayserasesthescreen,evenwhenalreadyintherequestedmode.

Thetextmodecanhaveamodifierintheform"text:<rows>;<cols>".Thissetsthewindowtobe<rows>by<cols>oftextinsize.

Thescreenmodeactuallysetsthewindowtographicsmode.Itcanhaveamodifierintheform"screen:<rows>;<cols>".Thissetsthewindowtobe<rows>by<cols>oftextinsize.

Thegraphicsmodecanhaveamodifierintheform"graphics:<width<height>".Thissetsthewindowtobe<width>by<height>pixelsinsize.

Tosetawindowtothemaximumsizeavailableonthescreen,youcanuse“max”forthe<width>,<height>,<rows>or<columns>parameters.Ifthewindowrequestedislargerthanwillfitonthescreen,thewindowwillfilltheentirescreenandscrollbarswillbeaddedtotheoutputwindowtoallowthewindowusertoseetherestofthewindow.

Thisprogramcreatesagraphicswindowthatis300pixelsby100pixels.

Thisprogramoutputsthesquarerootsforthefirst200numbers.Theusercaninspectalltheoutputandprintthevaluesaftertheprogramhasfinishedexecution

Example

View.Set("text")

forvalue:1..200

putvalue:3,"",sqrt(value)

endfor

Thisprogramcreatesawindowwithoutabuttonbaratthetopthatissizedtofitthescreen.Itthendrawsan“X”inredinthewindow.

View.Set("graphics:max;max,nobuttonbar")

Draw.Line(0,0,maxx,maxy,red)

Draw.Line(maxx,0,0,maxy,red)

Thisprogramresizesthewindowto200x200,movestheoutputwindowtothebottom-leftofthescreenandhidesthebuttonbar.Itthensetsthewindowtitleto“BottomLeftWindow”andoutputstheword“Hello”.

View.Set("graphics:200;200,position:bottom;left,nobuttonbar")

View.Set("title:BottomLeftWindow")

put"Hello"

Seealso setscreenforfurtherinformation.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.Set,notbycallingSet.

View.SetTransparentColor PartofViewmodule

Syntax View.SetTransparentColor(colorNumber:int)

Description

TheView.SetTransparentColorproceduresetsthecolorintheRunwindowthatshouldbeconsideredtransparentwhenapictureisdrawnonthewindowusingthepicUnderMergemode.Ifnocolorisspecified,thenthedefaultbackgroundcolor(colorbg,usuallywhite)isusedasthetransparentcolor.YoucanchangethisbackgroundcolorusingRGB.SetColoroncolor0.

DetailsThiscallisoftenusedwhenyouwanttheRunwindowtohaveabackgroundcolorotherthancolor0.

Example

Thisprogramdisplaystwoimagesloadedfromthesamefile.Inthesecondimage,thetransparentcolorhasbeensettobrightred(thatis,thepartsoftheimagethataremeanttobetransparentareinbrightred).

constSIZE:int:=20

procedureDrawCheckerBoard

forx:0..maxxbySIZE

fory:0..maxybySIZE

if((x+y)divSIZE)mod2=0then

Draw.FillBox(x,y,x+SIZE,y+

endfor

endDrawCheckerBoard

varpic:int:=Pic.FileNew("datafiles/airplane.bmp")

Pic.SetTransparentColor(pic,brightred)

RGB.SetColor(0,1.,0.,0.)

DrawCheckerBoard

Pic.Draw(pic,100,100,picUnderMerge)

View.SetTransparentColor(brightgreen)

Pic.Draw(pic,400,100,picUnderMerge)

Execute

DetailsView.SetTransparentColourisanalternatespellingforView.SetTransparentColor.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.SetTransparentColor,notbycallingSetTransparentColor.

Seealso Pic.SetTransparentColor.

View.Update PartofViewmodule

Syntax View.Update

Description

TheView.UpdateprocedureupdatesaRunwindowfromanoffscreenbitmap.ItisusedwiththecommandView.Set("offscreenonly")whichpreventstheRunwindowfrombeingupdateduntiltheView.Updatecommandisgiven.

Example

Thisprogramdisplays30circlesbouncingaroundthescreen.ToseetheeffectwithoutView.Update,commentoutthelineView.Set("offscreenonly")

%Placesomecirclesaroundthescreen

constRADIUS:int:=30

constNUM_BALLS:int:=20

varx,y,dx,dy,clr:array1..NUM_BALLSofint

fori:1..NUM_BALLS

x(i):=Rand.Int(RADIUS,maxx-RADIUS)

y(i):=Rand.Int(RADIUS,maxy-RADIUS)

dx(i):=Rand.Int(-3,3)

dy(i):=Rand.Int(-3,3)

clr(i):=Rand.Int(1,15)

endfor

%Now,anydrawingtothescreenwon'tappearuntila

%View.Updateisgiven.

View.Set("offscreenonly")

cls%Cleartheoffscreenwindow

fori:1..NUM_BALLS

ifx(i)+dx(i)<RADIUSor

x(i)+dx(i)>maxx-RADIUSthen

dx(i):=-dx(i)

ify(i)+dy(i)<RADIUSor

y(i)+dy(i)>maxy-RADIUSthen

dy(i):=-dy(i)

x(i):=x(i)+dx(i)

y(i):=y(i)+dy(i)

Draw.FillOval(x(i),y(i),RADIUS,RADIUS

endfor

%Allthecircleshavebeendrawn.Nowupdatethescreen.

View.Update

Time.Delay(5)

endloop

Execute

Details

AllTuringRunwindowshavebothanonscreenvisiblewindowandanoffscreenwindow.Wheneveranyoutputissenttothescreen,boththeonscreenwindowandtheoffscreenwindowareupdated.WhentheRunwindowneedstobeupdated(forexamplewhenanotherwindowismovedovertopofitandthenremoved),Turingcopiestheoffscreenwindowontotheonscreenwindow.

WhentheView.Set("offscreenonly")commandisgiven,Turingnolongerdrawstotheonscreenwindowwhenanydrawingcommandisgiven.However,itdoesupdatetheoffscreenwindow.WhentheView.Updatecommandisgiven,theentireoffscreenwindowiscopiedtotheonscreenwindow.

Thiscanbeusedtoprovidesmooth,flicker-freeanimation.Animatedobjectsflickerwhentheobjectbeinganimateddisappearsfromtheonscreenwindowforaperiodoftime.ByusingView.Set("offscreenonly")/View.Update,theonscreenwindowisneverblank.Instead,theoffscreenwindowdrawnovertopofftheonscreenwindow,replacingit.Thismeansthattheon-screenwindowisneverblankedout,eliminatingtheflickeringfoundintheanimation.

Details

It'sveryeasytoforgetthatnooutputwillappearintheRunwindowwhenusingView.Update.RemembertouseView.Set("nooffscreenonly")toturnoffthisfeaturesendingoutputfordebuggingpurposes.

Details

View.UpdateshouldnotbeusedinconjunctionwiththeSpritemodule.Spritescanbeconsideredalimitedversionofthistechnique.View.Updatealsoworkswellwhentheentirebackgroundis

changing.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.Update,notbycallingUpdate.

SeealsoView.Setforthe"offscreenonly"and"nooffscreenonly"options.

View.UpdateAreaforupdatingpartofthewindowatatime.

View.UpdateArea PartofViewmodule

Syntax View.UpdateArea(x1,y1,x2,y2)

Description

TheView.UpdateAreaprocedureupdatesarectanglularareaRunwindow,specifiedby(x1,y1)-(x2,y2)fromtheoffscreenbitmap.ItisusedwiththecommandView.Set("offscreenonly")whichpreventstheRunwindowfrombeingupdateduntiltheView.UpdateAreaorView.Updatecommandisgiven.

Becausetheentirescreenisnotupdatedeachtime,theanimationcanbemuchfaster,especiallyonslowmachines.ThisproceduredoestakemoreefforttousethanView.Updateasitrequirestheprogrammertocalculatewhichportionofthescreenmustbeupdated.

Example

Thisprogrammovesastarbackandforthacrossthescreen.TocomparethespeedupView.UpdateAreawithView.Update,replacethecallstoView.UpdateAreawithView.Update.

View.Set("offscreenonly")

varSIZE:int:=50

forx:0..maxx-SIZE

Draw.FillStar(x,100,x+SIZE,100+SIZE

View.UpdateArea(x-1,100,x+SIZE,100+

endfor

fordecreasingx:maxx-SIZE..0

View.UpdateArea(x,100,x+SIZE+1,100+

endfor

endloop

Execute

Details

Iftheentirescreenisbeingupdatedeachtimethroughtheanimationloop(forexampleifthebackgroundimageischanging),thenuseView.Updateinstead.

WhenusingView.UpdateArea,itisimportanttocorrectlycalculatetheregiontobeupdated.Thisregionmustnotonlycontaintheitembeingdrawn,butalsoanyareawherethebackgroundshouldbereplaced.Forexample,intheprogramabove,theareaupdatedincludedtheonepixeltotheleftofthestarwhenthestarwasmovingright-wardandonepixeltotherightofthestarwhenthestarwasmovingleft-ward.

Execute

HereisanexampleprogramthatallowsyoutocomparethespeedofanimationusingView.UpdatewithView.UpdateArea.Theprogramanimatesanobjectonabackgroundofstars.Pressinganykeyswitchesbetweenthetwocalls.

AllTuringRunwindowshavebothanonscreenvisiblewindowandanoffscreenwindow.Wheneveranyoutputissenttothescreen,boththeonscreenwindowandtheoffscreenwindowareupdated.WhentheRunwindowneedstobeupdated(forexamplewhenanotherwindowismovedovertopofitandthenremoved),Turingcopiestheoffscreenwindowontotheonscreenwindow.

Details

WhentheView.Set("offscreenonly")commandisgiven,Turingnolongerdrawstotheonscreenwindowwhenanydrawingcommandisgiven.However,itdoesupdatetheoffscreenwindow.WhentheView.Updatecommandisgiven,theentireoffscreenwindowiscopiedtotheonscreenwindow.

Thiscanbeusedtoprovidesmooth,flicker-freeanimation.Animatedobjectsflickerwhentheobjectbeinganimateddisappearsfromtheonscreenwindowforaperiodoftime.ByusingView.Set("offscreenonly")/View.Update,theonscreenwindowisneverblank.Instead,theoffscreenwindowdrawnovertopofftheonscreenwindow,replacingit.Thismeansthattheon-screenwindowisneverblankedout,eliminatingtheflickeringfoundintheanimation.

Details

It'sveryeasytoforgetthatnooutputwillappearintheRunwindowwhenusingView.UpdateArea.RemembertouseView.Set("nooffscreenonly")toturnoffthisfeaturesendingoutputfordebuggingpurposes.

Details

View.UpdateAreashouldnotbeusedinconjunctionwiththeSpritemodule.Spritescanbeconsideredalimitedversionofthistechnique.View.UpdateAreaalsoworkswellwhentheentirebackgroundischanging.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.UpdateArea,notbycallingUpdateArea.

SeealsoView.Setforthe"offscreenonly"and"nooffscreenonly"options.

View.Updateforproceduretoupdatetheentirescreenatonetime.

View.WhatDotColor PartofViewmodule

Syntax View.WhatDotColor(x,y:int):int

Description

TheView.WhatDotColorfunctionisusedtodeterminethecolornumberofthespecifiedpixel.ThealternatespellingisView.WhatDotColour.

Example

Thisprogramdrawsalinewhichbouncesofftheedgesofthescreenandmakesabeepwhenitfindsapixelthathasalreadybeencolored.

varx,y:int:=0

vardx,dx:int:=1

ifView.WhatDotColor(x,y)not=0and

View.WhatDotColor(x,y)not=brightred

Draw.FillOval(x,y,10,10,brightred)

Draw.Dot(x,y,1)

x:=x+dx

y:=y+dy

ifx=0orx=maxxthen

dx:=-dx

ify=0ory=maxythen

dy:=-dy

endloop

Execute

AnotherexampleillustratestheuseofView.WhatDotColortodeterminethecolorofpixelsinawindowpaintedwithmulti-colorblocks.Theactualcolornumberappearsintheblock.The

Example

colorofthedotunderthemousecursorappearsintheupper-leftcornerofthewindow.Notethatyoucanalsoplacethemousecursorovertheblacktextindicatingthecolornumber.

Details

Thescreenshouldbeina"graphics"mode.Ifisnotsetto"graphics"mode,itwillautomaticallybesetto"graphics"mode.SeeView.Setfordetails.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingView.WhatDotColor,notbycallingWhatDotColor.

Seealso

Draw.Dot,whichisusedforsettingthecolorofapixel.Seealsomaxxandmaxy,whichareusedtodeterminethenumberofpixelsonthescreen.

wait blockaprocessstatement

Syntax

AwaitStatementis:

waitvariableReference[,expn]

Description

Thewaitstatementisusedinaconcurrentprogramtocausetheexecutingprocesstobeblocked(togotosleep)untilitisawakenedbyasignalstatement.Thestatementcanonlybeusedinsideamonitor(aspecialkindofmodulethathandlesconcurrency).Awaitstatementoperatesonaconditionvariable(thevariableReference),whichisessentiallyaqueueofsleepingprocesses.Seeconditionforanexampleofawaitstatement.

Details

Awaitstatementforapriorityconditionmustincludetheoptionalexpn,.Thisexpressionmustbeanon-negativeintvaluewhichisusedtoorderprocesseswaitingforthecondition,lownumbersfirst.

Awaitstatementforatimeoutconditionmustincludetheoptionalexpn,whichmustbeanon-negativeintvaluewhichgivesthetimeoutinterval.Aprocesswaitingforatimeoutconditionisimplicitlyawakenedifitwaitslongerthanitstimeoutinterval.

Seealsoconditionandsignal.Seealsomonitorandfork.Seealsoempty.Seealsopause.

wallclock secondssince1/1/1970procedure

Syntax wallclock(varc:int)

DescriptionThewallclockstatementisusedtodeterminethetimeinsecondssince00:00:00GMT(GreenwichMeanTime)January1,1970.

Example

Thisprogramtellsyouhowmanysecondssince1970.

varseconds:string

wallclock(seconds)

put"Thenumberofsecondssince1970is",seconds

Details

BewarnedthatonsomecomputerssuchasIBMPCcompatiblesorAppleMacintoshes,thetimemaynotbesetcorrectlyintheoperatingsystem;inthatcase,thewallclockprocedurewillgiveincorrectresults.Also,onIBMPCcompatibles,thecallisdependentonhavingthetimezoneTZvariablecorrectlyset.OnanIBMPC,thedefaulttimezoneissettoPST(6hoursfromGMT).

OntheAppleMacintosh,thewallclockprocedurereturnsthenumberofsecondssince00:00:00localtimeJan.1,1970.

Seealsodelay,time,clock,sysclockanddatestatements.

whatcol cursorpositionfunction

Syntax whatcol:int

DescriptionThewhatcolfunctionisusedtodeterminethecursorposition'scolumn.

Example

locate(5,10)

put"12345"..

put"Thecurrentrowis",whatrow

put"Thecurrentcolumnis",whatcol

DetailsThescreenshouldbeina"screen"or"graphics"mode.whatcolfunctionsproperlyevenifthecursorisinvisible.

Seealso

thewhatrowfunction,whichisusedtosetthedeterminethecursorrow.Seealsothelocate,maxrowandmaxcolprocedure.

whatcolor textcolorgraphicsfunction

Syntax whatcolor:int

Description

Thewhatcolorfunctionisusedtodeterminethecurrent(foreground)color,ie.,thecolorusedforcharactersthatareoutputusingput.Thealternatespellingiswhatcolour.

Example

Thisprogramoutputsthecurrently-activecolornumber.Themessageisalsogiveninthecurrently-activecolor.

put"Thiswritingisincolornumber",whatcolor

DetailsThescreenshouldbeina"screen"or"graphics"mode.Seesetscreenfordetails.

Seealso

thecolorprocedure,whichisusedtosetthecolor.Seealsocolorbackandwhatcolorback.

whatcolorback colorofbackgroundfunction

Syntax whatcolorback:int

DescriptionThewhatcolorbackfunctionisusedtodeterminethecurrentbackgroundcolor.Thealternatespellingiswhatcolourback.

Example

Thisprogramoutputsthecurrently-activebackgroundcolornumber.Thebackgroundcolorofthemessageisdeterminedbythisnumber.

setscreen("screen")

put"Thebackgroundofthiswriting"

put"isincolornumber",whatcolorback

Details

Thescreenshouldbeina"screen"or"graphics"mode.Bewarethatthemeaningofbackgroundcolorisdifferentinthesetwomodes.Seecolorbackfordetails.

Seealsocolorandwhatcolor.

whatdotcolor graphicsfunction

Syntax whatdotcolor(x,y:int):int

DescriptionThewhatdotcolorfunctionisusedtodeterminethecolornumberofthespecifiedpixel.Thealternatespellingiswhatdotcolour.

Example

Thisprogramdrawsalinewhichbouncesofftheedgesofthescreenandmakesabeepwhenitfindsapixelthathasalreadybeencolored.

varx,y:int:=0

vardx,dx:int:=1

ifwhatdotcolor(x,y)not=0then

sound(400,50)

drawdot(x,y,1)

x:=x+dx

y:=y+dy

ifx=0orx=maxxthen

dx:=-dx

ify=0ory=maxythen

dy:=-dy

endloop

Details

Thescreenshouldbeina"graphics"mode.Ifisnotsetto"graphics"mode,itwillautomaticallybesetto"graphics"mode.Seesetscreenfordetails.

Seealso

drawdot,whichisusedforsettingthecolorofapixel.Seealsomaxxandmaxy,whichareusedtodeterminethenumberofpixelsonthescreen.Seealsosound,whichcausesthecomputertomakeasound.

SeealsopredefinedunitView.

whatrow cursorpositionfunction

Syntax whatrow:int

DescriptionThewhatrowfunctionisusedtodeterminethecursorposition'srow.

Example

locate(5,10)

put"12345"..

put"Thecurrentrowis",whatrow

put"Thecurrentcolumnis",whatcol

DetailsThescreenshouldbeina"screen"or"graphics"mode.whatrowfunctionsproperlyevenifthecursorisinvisible.

Seealso

thewhatcolfunction,whichisusedtosetthedeterminethecursorcolumn.Seealsothelocate,maxrowandmaxcolprocedure.

Window

Description

Thisunitcontainsthepredefinedsubprogramsthathandlewindows.Thereareroutinestoopen,close,hide,showandselectwindows.

AllroutinesintheWindowunitareexportedqualified(andthusmustbeprefacedwith"Window.").

Details

ThepredefinedsubprogramsoftheWindowmoduleallusewindowidentifierstoindicatewhichwindowtoactupon.ThedefaultRunwindowcanbespecifiedbyusingdefWindID.Forexample,thefollowingcodecausesthemainRunwindowtoappearandthenblinkonandoffthreetimes.

%OutputsomedatatomaketheRunwindowappear.

put"Hello,World!"

fori:1..3

delay(1000)

Window.Hide(defWinID)

delay(1000)

Window.Show(defWinID)

endfor

put"Howareyou?"

EntryPoints

Open Opensanewexecutionwindow.Close Closesanexecutionwindow.Select Selectsanexecutionwindowforoutput.GetSelect Returnsthecurrently-selectedexecutionwindow.

SetActive Selectsandactivate(makefront-most)anexecutionwindow.

GetActive Getsthecurrentactivewindow.GetPosition Getthescreenpositionofanexecutionwindow.SetPosition Setthescreenpositionofanexecutionwindow.Hide Hidesanexecutionwindow.Show Showsthecurrentexecutionwindow.Set Setstheconfigurationoftheexecutionwindow.

Update Updatestheonscreenwindowfromtheoffscreenbitmap.

Window.Close PartofWindowmodule

Syntax Window.Close(windowID:int)

DescriptionTheWindow.CloseprocedureclosesthewindowspecifiedbythewindowIDparameter.

Example

Thefollowingprogramopensawindow,makesitactiveandthenclosesthewindowaftergettingakeystrokefromtheuser.

%Openthewindow

varwinID:int

winID:=Window.Open("position:300;300,graphics:200;200")

varx,y,clr:int

for:1..20

endfor

varch:char:=getchar%Waitforinput

Window.Close(winID)%Closethewindow

DetailsIfawindowisselected(i.e.outputisgoingtothatwindow)whenitisclosed,themainRunwindowbecomestheselectedwindow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Close,notbycallingClose.

Seealso Window.OpenandWindow.Select.

Window.GetActive PartofWindowmodule

Syntax Window.GetActive:int

Description

TheWindow.GetActivefunctionreturnsthewindowIDoftheactivewindow.IftheactivewindowisaTuringrunwindow,thenWindow.GetActivereturnsdefWinID(whichis-1)ifthewindowisthedefaultrunwindow,orwhatevernumberwasreturnedfromWindow.Openforanyotherrunwindow.Iftheactivewindowisnotarunwindow,thenitreturns-5andsetsError.LastandError.LastMsgtoindicatethefact.

Anactivewindowisdefinedasthewindowthathastheinputfocus.Thismeansthatanytypingwillbesenttotheactivewindow.Undermostsystemsanactivewindowisindicatedbyachangeintheappearanceofthewindow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.GetActive,notbycallingGetActive.

Seealso Window.SetActive.

Window.GetPosition PartofWindowmodule

Syntax Window.GetPosition(windowID:int,varx,y:int)

Description

TheWindow.GetPositionprocedurereturnsthelocationofthespecifiedexecutionwindowonthescreenintheyparameters.Thexandyparametersspecifythelowerleftcornerofthewindowinscreencoordinates.(0,0)isthelowerleftcornerofthescreen.

Example

Thefollowingprogramoutputsthecurrentpositionoftherunwindow.

%Constantsforwindows

%Calculatetheactualsizeofawindow

varwindowWidth:int:=maxx+windowEdgeSize

varwindowHeight:int:=maxy+windowEdgeSize+

%Getthescreensize

varscreenWidth:int:=Config.Display(cdScreenWidth

varscreenHeight:int:=Config.Display(cdScreenHeight

%Openthewindow

varwinID:int:=Window.Open("title:UpperRight")

Window.SetPosition(winID,screenWidthwindowWidth

%Returnthecurrentposition

varwindowXPosition,windowYPosition:int

Window.GetPosition(winID,windowXPosition,windowYPosition

put"Windowlocatedat",windowXPosition,",",

ThismeansthatyoucanonlycallthefunctionbycallingWindow.GetPosition

Seealso Window.SetPositiontosetthecurrentwindowpositionandConfig.Display

Window.GetSelect PartofWindowmodule

Syntax Window.GetSelect:int

Description

TheWindow.GetSelectfunctionreturnsthewindowIDoftheselectedwindow.Iftheselectwindowisthemain(default)runwindow,thenitreturnsdefWinID(whichis-1).

Aselectedwindowisdefinedasthewindowthatoutputwillbesentto.Itcanbeinvisible.Whenaprogramstartsexecution,theselectedwindowisthemainRunwindow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.GetSelect,notbycallingGetSelect.

Seealso Window.Select.

Window.Hide PartofWindowmodule

Syntax Window.Hide(windowID:int)

Description

TheWindow.Hideprocedurehidesthespecifiedwindow.Thismeansitdisappearsfromtheuser'sscreen.However,itisstillpossibletoselectanddrawthewindowwhileitremainshidden.Iftheuseractivatesit(usingWindow.GetActive)itwillautomaticallyappear.

Tomakeawindowappearafterit'shidden,youuseWindow.Show.

Details

Whenawindowishidden,outputtoitisfaster.Itisquitepossiblefortheyoutohideawindow,docomplicateddrawingtoitandthenmakeitappearinordertohavetheprogramexecutefaster.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Hide,notbycallingHide.

Seealso Window.SelectandWindow.SetActive.

Window.Open PartofWindowmodule

Syntax Window.Open(setUpString:string):int

Description

TheWindow.Openfunctionisusedtocreateawindow.AwindowIDisreturnedifthewindowissuccessfullycreated.Ifthewindowisnotcreatedthenitreturns0.Error.LastandError.LastMsgcanthenbeusedtodeterminethecauseofthefailure.

ThesetUpStringparameterisidenticaltothatofView.Set.SeeView.Setforthelistofoptionsavailable.

Whenthewindowiscreated,itisautomaticallyselected(i.e.alloutputwillbesenttothatwindowunlessredirectedbyaWindow.Selectcommand).

Example

Thefollowingprogramopensawindow,makesitactiveandthenclosethewindowaftergettingakeystrokefromtheuser.

%Openthewindow

varwinID:int

winID:=Window.Open("position:top;center,graphics:200;200")

varx,y,clr:int

for:1..20

endfor

varch:char:=getchar%Waitforinput

Window.Close(winID)%Closethewindow

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Open,notbycallingOpen.

SeealsoView.SetforthesyntaxofstartUpString.SeealsoWindow.SelectandWindow.SetActive.

Window.Select PartofWindowmodule

Syntax Window.Select(windowID:int)

Description

TheWindow.Selectselectsthewindowthatoutputistobesentto.

Aselectedwindowisdefinedasthewindowthatoutputwillbesentto.Itcanbeinvisible.Whenaprogramstartsexecution,theselectedwindowisthemainRunwindow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Select,notbycallingSelect.

Window.Set PartofWindowmodule

Syntax Window.Set(windowID:int,setUpString:string)

Description

TheWindow.SetproceduresetstheconfigurationofthewindowspecifiedbythewindowIDparameter.SeeView.Setforacompletelistofavailableoptions.ThesetUpStringparametercanbeanycombinationoptions,separatedbycommas.Hereisaselectionoftheavailableoptions.

text:<rows>;<cols>-Setstheoutputwindowtotextmodeandchangesthewindowsizetobe<rows>rowsby<cols>columnsinsize.

graphics:<xsize>;<ysize>-Setstheoutputwindowtographicsmodeandchangesthewindowsizetobe<xsize>pixelsacrossand<ysize>pixelsinheight.

visible|invisible|popup-Setsthescreentobevisible,invisibleorpopup.Apopupwindowishiddenuntiloutputissenttothatwindow.ThemainRunwindowisapopupwindow.Ifyouneversendanyoutputtoit,itneverappears.

noxor|xor-SetswhetheralldrawingoperationsdrawusingXOR.

nocursor|cursor-Setswhetherthecursorisvisibleornot.

noecho|echo-Setswhethertheinputfromthekeyboardisechoedtothescreen.

title:<text>-Setsthewindowtitlebarto<text>.

position:<x>;<y>-Setsthepositionofthetopleftcornerofthewindowtobe(<x>,<y>).

offscreenonly|nooffscreenonly-Setswhetheroutputtothewindowgoestooffscreenwindowalone,orboththeonscreenandoffscreenwindow.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Set,notbycallingSet.

Seealso

View.SetforacompletelistoftheoptionsavailablewithWindow.Set.SeeWindow.Openforhowtocreateanewwindow.

Window.SetActive PartofWindowmodule

Syntax Window.SetActive(windowID:int)

Description

TheWindow.SetActiveprocedureactivatesthewindowspecifiedbythewindowIDparameter.

Anactivewindowisdefinedasthewindowthathastheinputfocus.Thismeansthatanytypingwillbesenttotheactivewindow.Undermostsystemsanactivewindowisindicatedbyachangeintheappearanceofthewindow.

Details

Ingeneral,itisunwisetochangetheactivewindow.IftheuserisworkingonanotherprogramatthesametimetheprogramisrunningandtheprogramexecutestheWindow.SetActiveprocedure,sheorhewillsuddenlybereturnedtoOOTwithoutwarning.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.SetActive,notbycallingSetActive.

Seealso Window.GetActiveandWindow.Select.

Window.SetPosition PartofWindowmodule

Syntax Window.SetPosition(windowID:int,x,y:int)

DescriptionTheWindow.SetPositionproceduremovesthelocationofthespecifiedexecutionwindowonthescreen.specifythelowerleftcornerofthewindowinscreencoordinates.(0,0)isthelowerleftcornerofthescreen.

Example

Thefollowingprogramopensfourwindows,oneateachcornerofthescreen.

%Constantsforwindows

%Calculatetheactualsizeofawindow

varwindowWidth:int:=maxx+windowEdgeSize

varwindowHeight:int:=maxy+windowEdgeSize+

%Getthescreensize

varscreenWidth:int:=Config.Display(cdScreenWidth

varscreenHeight:int:=Config.Display(cdScreenHeight

%Openthewindow

varwinID1:int:=Window.Open("title:UpperRight")

Window.SetPosition(winID1,screenWidthwindowWidth

varwinID2:int:=Window.Open("title:UpperLeft")

Window.SetPosition(winID2,0,screenHeightwindowHeight

varwinID3:int:=Window.Open("title:LowerLeft")

Window.SetPosition(winID3,0,0)

varwinID4:int:=Window.Open("title:LowerRight")

Window.SetPosition(winID4,screenWidthwindowWidth

ThismeansthatyoucanonlycallthefunctionbycallingWindow.SetPosition

Seealso Window.GetPositiontogetthecurrentwindowpositionandConfig.Display

Window.Show PartofWindowmodule

Syntax Window.Show(windowID:int)

Description

TheWindow.Showproceduremakesthespecifiedwindowappearifitwasinvisible.

Tomakeawindowdisappearafterit'svisible,youuseWindow.Hide.

Details

Whenawindowishidden,outputtoitisfaster.Itisquitepossiblefortheyoutohideawindow,docomplicateddrawingtoitandthenmakeitappearinordertohavetheprogramexecutefaster.

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingWindow.Show,notbycallingShow.

Window.Update PartofWindowmodule

Syntax Window.Update(windowID:int)

Description

TheWindow.UpdateprocedureupdatesaspecifiedRunwindowfromanoffscreenbitmap.ItisusedwiththecommandView.Set("offscreenonly")whichpreventstheRunwindowfrombeingupdateduntiltheWindow.Updatecommandisgiven.

ThiscommandisidenticaltotheView.Updatecommandexceptthatitupdatesthespecifiedwindow.Itshouldbeusedwhendoinganimationwithmorethanonewindow.

Seealso View.Updateforinformationonflicker-freeanimation.

write filestatement

Syntax

AwriteStatementis:

write:fileNumber[:status],writeItem{,writeItem}

Description

ThewritestatementoutputseachofthewriteItemstothespecifiedfile.Theseitemsareoutputdirectlyusingthebinaryformatthattheyhaveinthecomputer.Inotherwords,theitemsarenotinsource(ASCIIorEBCDIC)format.Inthecommoncase,theseitemswilllaterbeinputfromthefileusingthereadstatement.Bycontrast,thegetandputstatementsusesourceformat,whichapersoncanreadusingatexteditor.

Example

Thisexampleshowshowtooutputacompleteemployeerecordusingawritestatement.

varemployeeRecord:

record

name:string(30)

pay:int

dept:0..9

endrecord

varfileNo:int

open:fileNo,"payroll",write

write:fileNo,employeeRecord

Anarray,recordorunionmaybereadandwrittenasawhole.ThefileNumbermustspecifyafilethatisopenwithwritecapability(orelseaprogramargumentfilethatisimplicitlyopened).

Theoptionalstatusisanintvariablethatissettoimplementation-dependentinformationaboutthewrite.Ifstatusisreturnedaszero,thewritewassuccessful.Ifstatusisnotreturnedaszero,statusgivesinformationabouttheincompleteorfailedwrite(whichisnotdocumentedhere).Programmersoftenusestatuswhentheyarewritingarecordorarraytoafileandare

Details

notsureifthereisenoughroomonthedisktoholdtheitem.Ifthereisnotenoughroom,thewritewillfailpartwaythrough,buttheprogramcancontinueanddiagnosetheproblembyinspectingstatus.

AwriteItemis:

reference[:requestedSize[:actualSize]]

EachwriteItemisavariableorconstant,tobewrittenininternalform.TheoptionalrequestedSizeisanintegerexpressiongivingthenumberofbytesofdatatobewritten.TherequestedSizeshouldbelessthanorequaltothesizeoftheitem'sinternalforminmemory(ifitisnot,awarningmessageisissued).IfnorequestedSizeisgiven,thesizeoftheiteminmemoryisused.TheoptionalactualSizeissettothenumberofbytesactuallywritten.

Seealso write,open,close,seek,tell,getandputstatements.

xor exclusive"or"operator

Syntax AxorB

Description

Whenappliedtosetvalues,xor(symmetricdifference)yieldsasetwhichincludeselementeifandonlyifeiscontainedinexactlyoneoftheoperands.Whenappliedtonon-negativeintegervalues,xoryieldsanaturalnumberwhosebitsarethexorofthecorrespondingbitsoftheoperands.BothoperandsAandBareevaluated.

Example

Statuss3willcontainelementsthatareins1ors2butnotboth.Herexorisasetoperator.Seeenumandsettypesforexplanationsofthesetypes.

typestatus:enum(ready,sending,repeating)

typestatusSet:setofstatus

vars1,s2,s3:statusSet

s1:=statusSet(status.read,status.sending)

s2:=statusSet(status.read,status.repeating)

s3:=s1xors2%Sameas(s1+s2)-(s1*s2)

Example

Eachbitofnaturalnumbern3willbe1ifexactlyoneofthecorrespondingbitsofn1andn2are1.Forexample,ifn1=2#110(6)andn2=2#010(2),n3willbesetto2#100(4).Herexorisanintegeroperator.

varn1,n2,n3:nat

n3:=n1xorn2

Details

Thexoroperatorisnotashortcircuitoperator;inotherwords,bothofitsoperandsarealwaysevaluated.Theprecedenceofxoristhesameasthatofplus(+).

Seealsoset.SeealsoexplicitIntegerConstantwhichdescribesvaluessuchas2#110.

TuringLanguageElements#if-usedforconditionalcompilationaddressint-typeall-allmembersofasetand-operatoranyclass-theancestorofallclassesarray-typeassert-statementassignability-ofexpressiontovariableassignment-statementbegin-statementbind-declarationbody-declarationboolean-true-falsetypebreak-debuggerpausestatementcase-selectionstatementcatenation(+)-joiningtogetherstringschar-typechar(n)-typechecked-compilerdirectiveclass-declarationclose-filestatementcollection-declarationcomment-remarkstatementcomparisonOperatorcondition-declarationconst-constantdeclarationconstantReference-useofaconstantdeclaration-createavariabledeferred-subprogramdeclarationdiv-integertruncatingdivisionoperatorenum-enumeratedtypeenumeratedValue-enumeratedvalueequivalence-oftypesexit-statement

explicitCharConstant-characterliteralexplicitConstant-literalexplicitIntegerConstant-integerliteralexplicitRealConstant-realliteralexplicitStringConstant-stringliteralexplicitTrueFalseConstant-booleanliteralexpn-expressionexport-listexternal-declarationfalse-booleanvalue(nottrue)flexible-arrayinitializationfor-statementfork-statementforward-subprogramdeclarationfree-statementfunction-declarationfunctionCallget-filestatementhandler-exceptionhandlerid-(identifier)nameofaniteminaprogramif-statementimplement-clauseimplementby-clauseimport-listin-memberofasetinclude-sourcefilesindexTypeindirection-operator(@)infix-operatorinherit-inheritanceclauseinit-arrayinitializationint-integertypeintn-n-byteintegertypeinvariant-assertionloop-statementmod-modulooperatormodule-declarationmonitor-declarationnamed-type

nat-naturalnumbertypenatn-n-bytenaturalnumbertypenew-statementnil-pointertoacollectionnot-true/false(boolean)operatoropaque-typeopen-filestatementor-operatorparamDeclaration-parameterdeclarationpause-statementpervasive-declarationmodifierpointer-typepost-assertionpre-assertionprecedence-ofoperatorsprefix-operatorprocedure-declarationprocedureCall-statementprocess-declarationprogram-a(main)programput-statementquit-failstatementread-filestatementreal-therealnumbertyperealn-n-byterealnumbertyperecord-typeregister-usemachineregisterrem-remainderoperatorresult-statementreturn-statementscalar-typeseek-(file)statementseparator-betweentokensinaprogramset-typesetConstructorshl-shiftleftoperatorshr-shiftrightoperatorsignal-wakeupaprocessstatementskip-usedingetstatement

skip-usedinputstatementstandardTypestatementstatementsAndDeclarationsstring-typestring-comparisonsubprogramHeadersubprogramTypesubrangeTypesubstring-ofanotherstringtag-statementtell-filestatementtoken-ininputtrue-booleanvalue(notfalse)type-declarationtypeSpec-typespecificationunchecked-compilerdirectiveunion-typeunit-filecontainingmodule,monitor,orclassunqualified-exportvar-declarationvariableReference-useofavariablewait-blockaprocessstatementwrite-filestatementxor-exclusive"or"operator

BasicPredefinedSubprogramsTypeConversion

FromIntegerintreal-integer-to-realfunctionintstr-integer-to-stringfunction

FromRealceil-real-to-integerfunctionerealstr-real-to-stringfunctionfloor-real-to-integerfunctionfrealstr-real-to-stringfunctionrealstr-real-to-stringfunctionround-real-to-integerfunction

FromNatnatreal-naturalnumbertorealfunctionnatstr-natural-number-to-stringfunction

FromStringstrint-string-to-integer:functionstrintok-string-to-integer:functionstrnat-stringtonaturalnumberfunctionstrnatok-stringtonaturalnumberfunctionstrreal-string-to-realfunctionstrrealok-string-to-realfunction

To/FromASCIIchr-integer-to-characterfunctionord-character-to-integerfunction

MaximumNumbersmaxint-maximumintegerfunctionmaxnat-maximumnaturalnumberfunctionminint-minimumintegerfunctionminnat-minimumnaturalnumberfunction

Mathabs-absolutevaluefunctionarctan-arctangentfunction(radians)arctand-arctangentfunction(degrees)cos-cosinefunction(radians)

cosd-cosinefunction(degrees)exp-exponentiationfunctionln-naturallogarithmfunctionmax-maximumfunctionmin-minimumfunctionsign-functionsin-sinefunction(radians)sind-sinefunction(degrees)sqrt-squarerootfunction

Stringsindex-findpatterninstringfunctionlength-ofastringfunctionrepeat-makecopiesofstring:function

EnumeratedTypespred-predecessorfunctionsucc-successorfunction

Fileseof-end-of-filefunction

Arrayslower-boundupper-bound

RandomNumbersrand-randomrealnumberprocedurerandint-randomintegerprocedurerandnext-procedurerandomize-procedurerandseed-procedure

Timeclock-millisecsusedproceduredate-proceduresysclock-millisecsusedproceduretime-timeofdayasastringprocedurewallclock-secondssince1/1/1970procedure

Soundplay-procedureplaydone-functionsound-statement

Systemdelay-procedure

fetcharg-fetchargumentfunctiongetenv-getenvironmentfunctiongetpid-getprocessidfunctionnargs-numberofargumentssystem-statement

ParallelPortparallelget-parallelportfunctionparallelput-parallelportprocedure

Mousebuttonchoose-switchmousemodesbuttonmoved-hasamouseeventoccurredbuttonwait-getamouseeventproceduremousewhere

CharacterGraphicscls-clearscreengraphicsprocedurecolor-textcolorgraphicsprocedurecolorback-backgroundcolorprocedurecolour-textcolorgraphicsprocedurecolourback-backgroundcolorprocedurelocate-proceduremaxcol-maximumcolumnfunctionmaxcolor-graphicsfunctionmaxcolour-graphicsfunctionmaxrow-maximumrowfunctionsetscreen-graphicsprocedurewhatcol-cursorpositionfunctionwhatcolor-textcolorgraphicsfunctionwhatcolorback-colorofbackgroundfunctionwhatcolour-textcolorgraphicsfunctionwhatcolourback-colorofbackgroundfunctionwhatrow-cursorpositionfunction

PixelGraphicscls-clearscreengraphicsprocedurecolor-textcolorgraphicsprocedurecolorback-backgroundcolorprocedurecolour-textcolorgraphicsprocedurecolourback-backgroundcolorproceduredrawarc-graphicsproceduredrawbox-graphicsprocedure

drawdot-graphicsproceduredrawfill-graphicsproceduredrawfillarc-graphicsproceduredrawfillbox-graphicsproceduredrawfillmapleleaf-graphicsproceduredrawfilloval-graphicsproceduredrawfillpolygon-graphicsproceduredrawfillstar-graphicsproceduredrawline-graphicsproceduredrawmapleleaf-graphicsproceduredrawoval-graphicsproceduredrawpic-graphicsproceduredrawpolygon-graphicsproceduredrawstar-graphicsprocedurelocate-procedurelocatexy-graphicsproceduremaxcol-maximumcolumnfunctionmaxcolor-graphicsfunctionmaxcolour-graphicsfunctionmaxrow-maximumrowfunctionmaxx-graphicsfunctionmaxy-graphicsfunctionsetscreen-graphicsproceduresizepic-graphicsfunctiontakepic-graphicsprocedurewhatcol-cursorpositionfunctionwhatcolor-textcolorgraphicsfunctionwhatcolorback-colorofbackgroundfunctionwhatcolour-textcolorgraphicsfunctionwhatcolourback-colorofbackgroundfunctionwhatdotcolor-graphicsfunctionwhatdotcolour-graphicsfunctionwhatrow-cursorpositionfunction

CharacterInputgetch-getcharacterproceduregetchar-getcharacterfunctionhasch-hascharacterfunction

Concurrencyempty-conditionfunction

getpriority-functionsetpriority-proceduresimutime-simulatedtimefunction

AddressesandSizesaddr-addressofavariablesizeof-sizeofatype

BitManipulationbits-extraction

Classesobjectclass-ofapointerself-pointertocurrentobject

TypeCheatscheat-typecheating

PredefinedModulesConcurrency

Concurrency.emptyConcurrency.getpriorityConcurrency.setpriorityConcurrency.simutime

ConfigConfig.DisplayConfig.LangConfig.Machine

DirDir.ChangeDir.CloseDir.CreateDir.CurrentDir.DeleteDir.GetDir.GetLongDir.Open

DrawDraw.ArcDraw.BoxDraw.ClsDraw.DotDraw.FillDraw.FillArcDraw.FillBoxDraw.FillMapleLeafDraw.FillOvalDraw.FillPolygonDraw.FillStarDraw.LineDraw.MapleLeafDraw.OvalDraw.Polygon

Draw.StarDraw.Text

ErrorError.LastError.LastMsgError.LastStrError.MsgError.StrError.Trip

ErrorNumExceptionsFile

File.CopyFile.DeleteFile.DiskFreeFile.ExistsFile.RenameFile.Status

FontFont.DrawFont.FreeFont.GetNameFont.GetSizeFont.GetStyleFont.NameFont.NewFont.SizesFont.StartNameFont.StartSizeFont.Width

GUIGUI.AddLineGUI.AddTextGUI.AlertGUI.Alert2GUI.Alert3GUI.AlertFullGUI.ChooseGUI.ChooseFull

GUI.ClearTextGUI.CloseWindowGUI.CreateButtonGUI.CreateButtonFullGUI.CreateCanvasGUI.CreateCanvasFullGUI.CreateCheckBoxGUI.CreateCheckBoxFullGUI.CreateFrameGUI.CreateHorizontalScrollBarGUI.CreateHorizontalScrollBarFullGUI.CreateHorizontalSliderGUI.CreateLabelGUI.CreateLabelFullGUI.CreateLabelledFrameGUI.CreateLineGUI.CreateMenuGUI.CreateMenuItemGUI.CreateMenuItemFullGUI.CreatePictureGUI.CreatePictureButtonGUI.CreatePictureButtonFullGUI.CreatePictureRadioButtonGUI.CreatePictureRadioButtonFullGUI.CreateRadioButtonGUI.CreateRadioButtonFullGUI.CreateTextBoxGUI.CreateTextBoxFullGUI.CreateTextFieldGUI.CreateTextFieldFullGUI.CreateVerticalScrollBarGUI.CreateVerticalScrollBarFullGUI.CreateVerticalSliderGUI.DisableGUI.DisposeGUI.Draw...GUI.EnableGUI.FontDrawGUI.GetCheckBox

GUI.GetEventTimeGUI.GetEventWidgetIDGUI.GetEventWindowGUI.GetHeightGUI.GetMenuBarHeightGUI.GetScrollBarWidthGUI.GetSliderValueGUI.GetTextGUI.GetVersionGUI.GetWidthGUI.GetXGUI.GetYGUI.HideGUI.HideMenuBarGUI.OpenFileGUI.OpenFileFullGUI.Pic...GUI.ProcessEventGUI.QuitGUI.RefreshGUI.SaveFileGUI.SaveFileFullGUI.SelectRadioGUI.SetActiveGUI.SetBackgroundColorGUI.SetBackgroundColourGUI.SetCheckBoxGUI.SetDefaultGUI.SetDisplayWhenCreatedGUI.SetKeyEventHandlerGUI.SetLabelGUI.SetMouseEventHandlerGUI.SetNullEventHandlerGUI.SetPositionGUI.SetPositionAndSizeGUI.SetScrollAmountGUI.SetSelectionGUI.SetSizeGUI.SetSliderMinMax

GUI.SetSliderReverseGUI.SetSliderSizeGUI.SetSliderValueGUI.SetTextGUI.SetXORGUI.ShowGUI.ShowMenuBar

InputInput.KeyDown-getkeyboardstateInput.Pause-pauseforkeystrokeInput.getchInput.getcharInput.hasch

JoystickJoystick.GetInfo

KeyboardLimits

maxint-maximumintegerfunctionmaxnat-maximumnaturalnumberfunctionminint-minimumintegerfunctionminnat-minimumnaturalnumberfunction

Mathabs-absolutevaluefunctionarctan-arctangentfunction(radians)arctand-arctangentfunction(degrees)cos-cosinefunction(radians)cosd-cosinefunction(degrees)exp-exponentiationfunctionln-naturallogarithmfunctionmax-maximumfunctionmin-minimumfunctionsign-functionsin-sinefunction(radians)sind-sinefunction(degrees)sqrt-squarerootfunction

MouseMouse.ButtonChooseMouse.ButtonMovedMouse.ButtonWait

Mouse.WhereMusic

Music.PlayMusic.PlayFileMusic.PlayFileStopMusic.SoundMusic.SoundOff

NetNet.BytesAvailableNet.CharAvailableNet.CloseConnectionNet.HostAddressFromNameNet.HostNameFromAddressNet.LineAvailableNet.LocalAddressNet.LocalNameNet.OpenConnectionNet.OpenURLConnectionNet.TokenAvailableNet.WaitForConnection

PCPC.ParallelGetPC.ParallelPutparallelget-parallelportfunctionparallelput-parallelportprocedure

PicPic.BlendPic.BlurPic.DrawPic.DrawFramesPic.DrawFramesBackPic.DrawSpecialPic.DrawSpecialBackPic.FileNewPic.FileNewFramesPic.FlipPic.FramesPic.FreePic.Height

Pic.MirrorPic.NewPic.RotatePic.SavePic.ScalePic.ScreenLoadPic.ScreenSavePic.SetTransparentColorPic.SetTransparentColourPic.Width

RGBRGB.AddColorRGB.AddColourRGB.GetColorRGB.GetColourRGB.SetColorRGB.SetColourRGB.maxcolorRGB.maxcolour

RandRand.IntRand.NextRand.RealRand.ResetRand.SeedRand.Set

SpriteSprite.AnimateSprite.ChangePicSprite.FreeSprite.HideSprite.NewSprite.SetFrameRateSprite.SetHeightSprite.SetPositionSprite.Show

Strindex-findpatterninstringfunctionlength-ofastringfunction

repeat-makecopiesofstring:functionStream

Stream.FlushStream.FlushAllStream.eofeof-end-of-filefunction

SysSys.ExecSys.FetchArgSys.GetComputerNameSys.GetEnvSys.GetPidSys.GetUserNameSys.Nargsgetenv-getenvironmentfunctiongetpid-getprocessidfunction

TextText.ClsText.ColorText.ColorBackText.ColourText.ColourBackText.LocateText.LocateXYText.WhatColText.WhatColorText.WhatColorBackText.WhatColourText.WhatColourBackText.WhatRowText.maxcolText.maxrow

TimeTime.DateTime.DateSecTime.DelayTime.ElapsedTime.ElapsedCPUTime.PartsSec

Time.SecTime.SecDateTime.SecParts

TypeConvFromInteger

intreal-integer-to-realfunctionintstr-integer-to-stringfunction

FromNatnatreal-naturalnumbertorealfunctionnatstr-natural-number-to-stringfunction

FromRealceil-real-to-integerfunctionerealstr-real-to-stringfunctionfloor-real-to-integerfunctionfrealstr-real-to-stringfunctionrealstr-real-to-stringfunctionround-real-to-integerfunction

FromStringstrint-string-to-integer:functionstrintok-string-to-integer:functionstrnat-stringtonaturalnumberfunctionstrnatok-stringtonaturalnumberfunctionstrreal-string-to-realfunctionstrrealok-string-to-realfunction

To/FromASCIIchr-integer-to-characterfunctionord-character-to-integerfunction

ViewView.ClipAddView.ClipOffView.ClipSetView.SetView.Update-flicker-freeanimationView.WhatDotColorView.WhatDotColourView.maxcolorView.maxcolourView.maxxView.maxy

WindowWindow.CloseWindow.GetActiveWindow.GetPositionWindow.GetSelectWindow.HideWindow.OpenWindow.SelectWindow.SetWindow.SetActiveWindow.SetPositionWindow.ShowWindow.Update

MiscellaneousSubprogramsAddressesandSizes

addr-addressofavariablesizeof-sizeofatype

Arrayslower-boundupper-bound

BitManipulationbits-extraction

Classesobjectclass-ofapointerself-pointertocurrentobject

EnumeratedTypespred-predecessorfunctionsucc-successorfunction

TypeCheatscheat-typecheating

TheGUIModuleIntroduction

SincetheintroductionoftheMacintosh,graphicaluserinterfaces(GUI)havebeenbecomingmoreandmorecommon.MostcommercialprogramswrittenforeithertheMacintoshorMicrosoftWindowsmakeuseofGUIelementstomaketheirprogrameasiertouse.

Forsometime,studentshavebeenrequestingmethodsofputtingGUIelementssuchasbuttons,checkboxes,radiobuttons,etc,intotheirTuringprograms.TuringnowincludesanewsetofpredefinedsubprogramsthatallowstudentstoaddnumerousGUIelementstotheirprogramsquicklyandeasily.Thesesubprogramsallowstudentstocreate:buttons,checkboxes,radiobuttons,sliders,scrollbars,picturebuttons,radiopicturebuttons,textfields,lines,textlabels,andframes.

TheentireGUILibraryiswritteninTuringandthesourceisincludedwiththeTuringdistribution.TheGUIlibraryiscompletelyprocedure-oriented.Thismeansthatitisnotnecessarytoknowobject-orientedprogrammingorconceptsinordertobeabletousethelibrary.Advancedstudentsarewelcome(infact,encouraged)tolookattheprogramsasanexampleofalargeprojectwritteninTuring.WehopethattherewillbeenterprisingstudentswhowillbeinspiredtoaddnewwidgetstothelibraryandencouragethosewhodosotosubmitthemtoHoltSoftwareforpossibleinclusionintothenextversionofthelibrary.

Hereisawindowwithafewwidgets.

SomeGUIWidgets(OutputofExample.dem)

TheGUIlibraryisusablebystudentswhounderstandtheconceptofsubprograms.InordertousetheGUIlibrary,studentsmustwriteprocedures(althoughtheymaybeassimpleasthestudentdesires).WethereforesuggestthatteachersintroducestudentstotheGUIlibraryinaGrade11computersciencecourse.

Note:Turinghasnotchanged.Itisnotavisualbuildinglanguage.StudentswishingtousetheGUIlibrarywillbewritingprogramstocreateandusetheseGUIelement,notspendingtheirtimevisuallybuildinguserinterfaces(whichmaybefun,butteachesverylittle).InkeepingwiththetraditionofTuring,themorethestudentslearnaboutcomputerscience,themoreinterestingtheir

programswillbe,GUIornoGUI!

Terminology

Theterm"Widget"meansanygraphicaluserinterfaceelement.Abutton,acheckboxorradiobuttonareallexamplesofwidgets.

Theterm"Event"meanseitherakeystrokeoramousebuttonbeingpressedinawindow.

ExamplePrograms

Allexampleprogramsshownherearelocatedinthe[TuringDirectory]/Examples/GUIdirectory.(Inotherwords,startinthesamedirectoryastheTuringexecutable,movetotheExamplesfolderandthentheGUIfolder.)AlltheavailableGUIwidgetshaveexampleprogramstodemonstratetheiruse.

GeneralPrinciplesoftheGUILibrary

HerearesomegeneralinstructionsfortheuseoftheGUIlibrary.Readthissectionbeforelookingatthespecificsofvariousroutines.

AllthesubprogramsfortheGUIlibraryareplacedinamodulecalledGUI.Tocallanyofthesubprograms,prefacethenameofthesubprogramwithGUI..Forexample,theCreateLabelsubprogramwouldbecalledusingGUI.CreateLabel.Ingeneral,mostwidgetshaveaCreatesubprogram.Forexample,buttonshaveaCreateButtonsubprogram,radiobuttonshaveaCreateRadioButtonsubprogram,andsoon.TheCreatesubprogramtakesasparametersthingssuchasthelocation,thesizeoftheGUIelement,andthenameofaproceduretobecalledwhenthewidgetisclicked.ThisproceduremustbedeclaredbeforethecalltotheCreatesubprogram.Formostwidgets,therearetwoformsoftheCreatesubprogram.TheCreatesubprogramandtheCreateFullsubprogram.ThedifferencebetweenthetwoisthattheCreateFullsubprogramallowstheusertodefinemoreparametersthatareotherwisesettodefaultvalues.Forexample,theGUI.CreateButtonprocedureallowstheusertospecifythexandylocationofthebutton,thewidthofthebutton,thetextthatappearsinthebutton,andtheproceduretocallwhenthebuttonisclicked.TheGUI.CreateButtonFullroutinespecifiesthoseandalsoallowstheusertospecifytheheightofthebutton(otherwisesettoaheightthatwillfitthelabel),ashortcutkeyboardcharacterthatallowstheuserto"press"thebuttonusingakeyboardandaparametertoallowtheusertospecifyifthisbuttonisthe"default"button(theone"pressed"iftheuserpressestheEnterkey).AllCreatesubprogramsreturnaninteger.ThisnumberistheIDofthewidgetthathasbeencreated.YouneedtousethisIDifyouwanttodoanythingtothewidgetlater,suchasmoveit,changeitssize,hideit,andsoon.MostsimpleprogramscansafelyignorethewidgetID,althoughtheywillneedtohandlethereturnvaluefromthefunction.Afterallthewidgetshavebeencreated,theprogrammustrepeatedlycallGUI.ProcessEventuntilthefunctionreturnstrue.

%Nowprocesseventsuntiltheuserabortstheprogram.

endloop

GUI.ProcessEventchecksforuserinputfromthemouseorthekeyboardandthencheckstoseeiftheuserhasclickedonawidget.Iftheuserhas,thenitrespondsappropriately(togglingthecheckbox,pressingthebutton,etc.)andthenifappropriate,callstheproceduretheusersuppliedintheCreatesubprogram.GUI.ProcessEventreturnstruewhentheGUI.Quithasbeencalled,otherwiseitreturnsfalse.

Whenaprogramisfinishedexecution(forexampleiftheuserselected"Quit"or"Exit"fromthefilemenu),itshouldcalltheGUI.Quitprocedure.ThiswillcausetheGUI.ProcessEventlooptoexit.Theprogramshouldhaveanycleanupcodeplacedaftertheendloop.

Hereisaverysimpleexampleofaprogramthatputs"Hello"everytimeabuttonispressed.

%The"Hello"program.

importGUI

View.Set("graphics:200;200")%Shrinktherunwindow

%Theprocedurecalledwhenthebuttonispushed.

procedurePutHello

put"Hello"

endPutHello

%Createthebutton.ThenumberreturnedistheIDnumberofthebutton.

varb:int:=GUI.CreateButton(100,100,0,"SayHello",PutHello)

%Nowprocesseventsuntiltheuserabortstheprogram.

endloop

Hereistheoutputwindowaftertheuserhaspressedthebuttontwice.

OutputofHello.dem

ActiveandPassiveWidgets

Widgetscomeintwoforms.Activewidgetsareonesthatrespondtokeystrokesandbuttonclicks.Passivewidgetsdonotrespondtoanything.Examplesofpassivewidgetsarelines,frames,labels,labelledframesandpictures.Passivewidgetsaregenerallyusedtoorganizetheoutputwindow.

Hereisanexampleofasmallprogramthatshowsomepassivewidgets.

%The"Passive"program

%Thisdemonstratessomeofthepassivewidgetssuchas:

%Lines,Frames,LabelledFrames,LabelsandPictures.

importGUI

%We'llneedapictureforourPicturewidget.Mostlikely

%youwouldnormallyhaveitsavedinanexternalfileand

%usePic.FileNewtoreaditintoapicture.Fortheexample

%programwe'llconstructitbyhand.

Draw.FillMapleLeaf(37,37,63,63,brightpurple)

varpic:=Pic.New(0,0,100,100)

%Thebackgroundmustbegrayforindentedandexdented

%itemstobevisible.

%Nowplacethewidgets.

%Threelinesofthedifferenttypeswithlabels

varline1:=GUI.CreateLine(70,10,maxx-10,10,GUI.LINE)

varlabel1:=GUI.CreateLabelFull(60,10,"Line",0,0,

GUI.RIGHT+GUI.MIDDLE,0)

varline2:=GUI.CreateLine(70,30,maxx-10,30,GUI.INDENT)

varlabel2:=GUI.CreateLabelFull(60,30,"Indent",0,0,

varline3:=GUI.CreateLine(70,50,maxx-10,50,GUI.EXDENT)

varlabel3:=GUI.CreateLabelFull(60,50,"Exdent",0,0,

%Nowplacetheframes

varframe1:=GUI.CreateFrame(10,70,100,120,GUI.LINE)

varlabel4:=GUI.CreateLabelFull(10,70,"Line",90,50,

varframe2:=GUI.CreateFrame(110,70,200,120,GUI.INDENT)

varlabel5:=GUI.CreateLabelFull(110,70,"Indent",90,50,

varframe3:=GUI.CreateFrame(210,70,300,120,GUI.EXDENT)

varlabel6:=GUI.CreateLabelFull(210,70,"Exdent",90,50,

%Nowplacethelabelledframes

varframe4:=GUI.CreateLabelledFrame(10,140,100,190,GUI.LINE,"Line")

varframe5:=GUI.CreateLabelledFrame(110,140,200,190,GUI.INDENT,

"Indent")

varframe6:=GUI.CreateLabelledFrame(210,140,300,190,GUI.EXDENT,

"Exdent")

%Placethepicture

varlabel7:=GUI.CreateLabel(30,315,"Picturewithoutmerge")

varpic1:=GUI.CreatePicture(30,210,pic,false)

varlabel8:=GUI.CreateLabel(maxx-130,315,"Picturewithmerge")

varpic2:=GUI.CreatePicture(maxx-130,210,pic,true)

%Thisloopdoesn'tdomuchsincenoneofthewidgetshaveanyactions.

endloop

Hereistheoutputwindowfromtheprogramwithsomelabels,aline,apicture,andalabelledframe.

OutputofPassive.dem

Whenanactivewidgetisinitialized,usuallyanactionproceduremustbespecified.Thisisthenameofaprocedurethatwillbecalledwhenthewidgetisselected.Forexample,intheHelloprogram,thePutHelloprocedurewasspecifiedastheactionprocedureofthebutton.Wheneverthebuttonwaspressed,thePutHelloprocedurewascalled.

Someactionprocedureshavearguments.Forexample,theactionprocedureforasliderhasaparameterofthecurrentvalue.ThisallowstheproceduretousethecurrentvaluewithouthavingtocallaGUIsubprogramtogetthecurrentslidervalue.

KeyboardShortcuts

Severaltypesofwidgetscanhave"shortcuts".Ashortcutissimplyakeystrokethathasthesameeffectasclickingonthewidget.WhenyouspecifyashortcuttoawidgetintheCreateFullprocedureforthewidget,youmustspecifyasinglecharacter.TheeasiestwaytodothisistousethechrfunctionwiththeASCIIvalueofthecharactertobeusedastheshortcut.Youcanalsospecifycontrolcharactersusingthe"^"notation.Forexample,thecharacterCtrl+Fcanbeexpressedas"^F"inTuring.

ThefollowingcharacterscannotbeusedasshortcutsbecausetheTuringenvironmentusesthemforvariouspurposes(stoppingorrerunningprograms,andsoon.):Ctrl+C,Ctrl+D,Ctrl+Z,F1,F11andF12.

BackgroundColor

Itiscommonforwindowstohaveadifferentbackgroundcolorfromthestandardwhite.Tochangethebackgroundcolorofawindow,usetheGUI.SetBackgroundColorprocedure.Thisproceduretakesoneparameter,thenewbackgroundcolor.Itredrawsthewindowinthebackgroundcolorandthenredrawsallthewidgets.Italsonotifiesthewidgetsaboutthenewbackgroundcolorsothatwhenthewidgetiserasedormoved,thelocationofthewidgetisfilledwiththenewbackgroundcolorinsteadofwhite.

NotethatMicrosoftWindowsdialogboxesoftenhaveabackgroundcolorofgray.Inordertosimulatethat,youshouldgivethecommandGUI.SetBackgroundColor(gray)beforecreatingwidgets.

Severalwidgets(Canvas,Frame,LabelledFrame,TextFieldandTextBox)canhavebordersofeithertypeINDENTorEXDENT.Thesebordersgiveasortof3-Dappearancetothewidget.However,theyrequirethatthebackgroundbesettogray.

HereisanexampleofasmallprogramthatcreatesaCanvaswitha3-Dappearanceandthendrawscirclesinthecorner.

%The"Canvas1"program.

%Createacanvasanddrawfourcirclesonit.

importGUI

%Necessaryfora3-Dlookforthecanvas

%ThisprocedureisneededasanargumenttoCreateCanvasFull.

procedureDoNothing(mx,my:int)

endDoNothing

%Createalabelforthecanvas.WecoulduseCreateLabelFullformore

%precisealignment.

varlabel1:=GUI.CreateLabel(70,182,"FourCircles")

%Createthecanvas.WeneedtouseCreateCanvasFullinorderto

%specifythetypeofborder.

varcanvas:=GUI.CreateCanvasFull(20,20,160,160,GUI.INDENT,

DoNothing,DoNothing,DoNothing)

%Drawthefourovals.Noticethattheydon'textendoffthecanvas

%andtheco-ordinatestheyusearerelativetothecanvas,notthewindow.

constradius:=70%Halfthewidth-10

GUI.DrawFillOval(canvas,0,0,radius,radius,brightred)

GUI.DrawFillOval(canvas,160,0,radius,radius,brightgreen)

GUI.DrawFillOval(canvas,0,160,radius,radius,brightblue)

GUI.DrawFillOval(canvas,160,160,radius,radius,brightpurple)

Hereistheoutputwindow.

OutputofCanvas1.dem

WidgetSizes

Thesizethatyouspecifyawidgettobeisnotnecessarilytheactualsizethatthewidgetwillappear.Infactformanywidgets,youcanspecifyawidthandheightof0forthewidgetandletstheinitializerdecidehowlargethewidgetshouldbe.Anotherexampleiswithcheckboxes,whereifyouspecifythecheckboxtoberightjustified,thexandycoordinatesindicatethelower-rightcornerinsteadofthelower-leftcornerasusual.Thismeansthatyoumayhavetodosomeexperimentationtodeterminewhereyouwantthewidgetstobeplaced.Readthepageoneachsubprogramthatyouusetofindoutexactlywhatyouarespecifyingwiththex,y,widthandheightparameters.

Ifyouaretryingtoalignwidgetstogether(forexamplealigningscrollbarswithacanvas),usetheGUI.GetX,GUI.GetY,GUI.GetWidth,andGUI.GetHeightfunctionstodeterminethesizeoftheobject.

PositioningTextLabels(AligningLabelswithWidgets)

Itisverycommontowanttoaligntextlabelswithwidgetsonthescreen.Thereareafewtipsandtrickstodoingsosuccessfully.Toalignatextlabelwithawidget,itissimplyamatterofusingtheGUI.CreateLabelFullfunctionwiththeappropriatex,y,width,heightandalignmentarguments.

Ifyouareleftorrightaligningalabel,thengenerallyyouwillwantthexcoordinatetospecifytheedgetobealignedfromandthewidthparametershouldbesetto0.Similarly,ifyouaretoporbottomaligningalabel,thentheycoordinateshouldspecifytheedgetobealignedfromandtheheightparametershouldbesetto0.

Toalignawidgethorizontallywithawidget,chooseGUI.CENTERforthehorizontalalignmentandtheusethexcoordinateandwidthofthewidgetasthelabel'sxcoordinateandwidth.YoucangetthexcoordinateandwidthofawidgetusingGUI.GetXandGUI.GetWidth.

Likewise,toalignawidgetverticallywithawidget,chooseGUI.MIDDLEfortheverticalalignmentandtheusetheycoordinateandheightofthewidgetasthelabel'sycoordinateandheight.YoucangettheycoordinateandheightofawidgetusingGUI.GetYandGUI.GetHeight.

Hereisanexampleillustratingtheplacementofalabelatthecenterofeachoffoursidesofawidgetcalledw:

importGUI

procedureDoNothing(text:string)

endDoNothing

varw:int:=GUI.CreateTextField(50,15,100,"",DoNothing)

%Thesefollowinglinesaretheimportantpartoftheprogram.

varleft:=GUI.CreateLabelFull(GUI.GetX(w)-2,GUI.GetY(w),

"Left",0,GUI.GetHeight(w),GUI.RIGHT+GUI.MIDDLE,0)

varabove:=GUI.CreateLabelFull(GUI.GetX(w),

GUI.GetY(w)+GUI.GetHeight(w)+2,"Above",GUI.GetWidth(w),0,

GUI.CENTER+GUI.BOTTOM,0)

varright:=GUI.CreateLabelFull(GUI.GetX(w)+GUI.GetWidth(w)+2,

GUI.GetY(w),"Right",0,GUI.GetHeight(w),GUI.LEFT+GUI.MIDDLE,0)

varbelow:=GUI.CreateLabelFull(GUI.GetX(w),GUI.GetY(w)-2,

"Below",GUI.GetWidth(w),0,GUI.CENTER+GUI.TOP,0)

Here'stheresult.Notethattheformulaforaligningalabelwithawidgetisthesameforanytypeofwidget.

TextBoxAlignedwithFourLabels

Here'sanexampleillustratingaligningawidgetwiththetopofthewindow.Noticethatthelabeliscenteralignedwithxof0andwidthofmaxx,andtopalignedwithayofmaxyandaheightof0.

vartitle:=GUI.CreateLabelFull(0,maxy,"Title",maxx,0,

Finally,here'sanexampleillustratingtheplacementofalabelinthecenterofthescreen.Noticethatthelabeliscenteralignedwithxof0andwidthofmaxx,andmiddlealignedwithayof0andaheightofmaxy.

vartitle:=GUI.CreateLabelFull(0,0,"Title",maxx,maxy,

Notethatifalabel'spositionorsizeischangedwithGUI.SetPosition,GUI.SetSizeorGUI.SetPositionAndSize,itstillretainsitsalignmentwithrespecttoitsnewx,y,width,andheightvalues.

Canvases

Thecanvasisaratheruniquewidget.Itisessentiallyadrawingsurfacethatyouplaceinthewindow.TherearecallsusingacanvaswidgetthatessentiallyduplicateallthestandardDrawmodulecalls,alongwithcallscorrespondingtoFont.DrawandvariousPicmodulecalls.

ThedifferenceisthatthecallsusingtheCanvaswidgetuse(0,0)tomeanthebottomleftcornerofthecanvas(notthewindow)andalldrawingisclippedtothecanvas(meaningthatifyouaccidentallydrawoffthecanvas,thepartofthepictureoutsidetheboundsofthecanvaswillnotappear).OneofthemostcommonbugsistoaccidentallyusetheactualDrawmoduleroutinesinsteadoftheGUI.Drawroutineswhendrawinginacanvas.IfthedrawingisgoesoutsidetheboundsoftheCanvas,youhavemadethismistake.

AnotherfeatureoftheCanvaswidgetisthatyoucanspecifyaprocedurestobecalledwheneverauserclicksintheCanvaswidget,dragsthemousewiththemousebuttondownandthenletsgoofthemousebutton.Theseproceduresallowyourprogramtorespondtomouseactivitytakingplaceinthecanvaswidget.

HereisaprogramthatusesaCanvastoallowtheusertodrawandabuttontoallowtheusertoerasethedrawing.

%The"Draw"program

importGUI

varoldx,oldy:int

varcanvas:int%Thedrawingcanvas.

varclear:int%Theclearbutton.

%Calledwhentheuserpressesthemousebuttoninthecanvas.

%Setstheinitialmouseposition.

procedureMouseDown(mx,my:int)

oldx:=mx

oldy:=my

endMouseDown

%Calledastheuserdragsthemousewiththebuttondowninthecanvas.

%Drawsalinefromthepreviousmousepositiontothecurrentposition.

procedureMouseDrag(mx,my:int)

GUI.DrawLine(canvas,oldx,oldy,mx,my,colorfg)

oldx:=mx

oldy:=my

endMouseDrag

%Calledwhenthemousebuttonisreleased.

procedureDoNothing(mx,my:int)

endDoNothing

%Calledwhentheclearbuttonispressed.

procedureClear

GUI.DrawCls(canvas)

endClear

%Createthecanvas

canvas:=GUI.CreateCanvasFull(10,30,maxx-20,maxy-40,0,

MouseDown,MouseDrag,DoNothing)

%Createtheclearbutton

clear:=GUI.CreateButton(maxxdiv2-20,0,40,"Clear",Clear)

endloop

Hereistheoutputwindowaftertheuserhasdrawnsomelines.

OutputofDraw.dem

MultipleWindows

Turingallowsformultiplerunwindows.Thiscanbeusedtoaddextrafunctionalitytoprograms,howeverthereareafewissuesthatmustbeunderstoodbeforemultiplewindowscanbesuccessfullyused.

Turingusestheconceptofselectedwindowsandactivewindows.AselectedwindowisdeterminedbytheprogramandischangedbyWindow.Select.Theselectedwindowisthewindowinwhichalloutputappears.Whenawidgetiscreated,itisautomaticallycreatedintheselectedwindow.

Anactivewindowislastwindowonwhichtheuserclicked.Theactivewindowisshownbyhavingitstitlebarhighlighted.Whenausertypes,allkeystrokesaresenttotheactivewindow.

Itisentirelypossibletohavetheselectedwindowandtheactivewindowbetodifferentwindows.

Whenyoucallgetch,Mouse.ButtonWait,oranyotherinputroutine,Turingchecksonlytheselectedwindow.TheGUILibraryworksaroundthisbyselectingallthewindowsthathavewidgetsinthem(oneatatime,startingwiththeactivewindow)andcheckingeachforevents.

Ifyouareprocessinganeventfromoneofseveralwindows,makecertainthatthecorrectwindowisselectedbeforeyououtputyourresults.Notethatthewidgetsautomaticallyselectthecorrectwindow,sothereisnoneedtochangetheselectedwindowbeforemakinganycallstotheGUImodule.

Ifyoucloseawindowwithwidgetsinit,useGUI.CloseWindowtoclosethewindow.Thisremovesallthewidgetsinthewindowbeforeclosingit.Ifyouhaveseveralwindowswithwidgetsandwantsomewindowstobehiddenandthenshownlater,usetheGUI.ShowWindowandGUI.HideWindowtoshowandhidethewindowswithwidgetsinthem.

TheGUILibraryInternals

WhileitisnotnecessarytoknowtheinternalsoftheGUILibrarytouseit,weprovidethisbriefoverviewforthosewhowishtounderstandtheinnerworkingsofthelibrary.

TheGUILibraryconsistsoffourparts.TheonlypartvisibletotheuseristheGUImodule.Thisislocatedin"%oot/lib/GUI",where%ootisthedirectoryinwhichtheOOTexecutableislocated.TheGUImoduleisessentiallyaseriesofproceduresthatprovideafrontendtotheWidgetModuleandtheWidgetClassLibrary.

TheWidgetModuleisamodulecalledWidgetModulethatconsistsofaseriesofsubprogramsthatcoveralltheaspectsofGUI'sthatdonotpertaintoaparticularwidget.Forexample,theproceduretochangethebackgroundcolorishere,aswellastheproceduretoprocessanevent.Itislocatedin"%oot/lib/GuiClass/wdgtmod.tu"

TheGUIClassLibraryconsistsofaseriesofclassesarrangedinahierarchyillustratedinthefollowingfigure.MostoftheactualTuringcodefortheGUILibraryislocatedintheWidgetClassLibrary.Eachdifferenttypeofwidgethasitsownclass.Widgetsthatsharecommonbehaviorhavethesameparent.Forexample,boththeverticalandhorizontalsliderhaveasliderclassasaparent.ThoseclasseswhosenamesstartwithGenericareabstractclasses.Theyshouldnotbeinstantiatedthemselves.Theyareusedtodefinecommonbehavioramongtheirsubclasses.TheTuringsourcefortheclassescanbefoundinthedirectory"%oot/lib/GuiClass"

ThefourthpartistheWidgetGlobalsmodule.ThismodulethatconsistsmostlyofglobalvariablesusedbytheGUIClassLibraryandtheWidgetmodule.Itislocatedin"%oot/lib/GuiClass/wdgtglob.tu"

HereisanexampleofhowtheGUImoduleworks:whenyoucreateabuttonusingGUI.CreateButton,theCreateButtonfunctionintheGUImodulecreatesanobjectoftypeButtonClass.(ButtonClassisfoundintheWidgetClassLibrarydiscussedfurtherdown).ItthencallstheInitializeprocedureoftheButtonClasstoinitializethebuttonwiththespecifiedparameters.FinallyitassignsanIDnumbertothewidgetandarrangesitinatableforfuturereference.Hereis

anotherexample:whenyoucallaprocedurelikeGUI.Show,theShowproceduretakesthewidgetID,looksuptheobjectthatitrepresents,andthencallstheShowprocedureoftheobject.

StudentswhowishtoaddnewwidgetstotheGUIlibrarywillhavetounderstandtheprinciplesofobjectorientedprogramming,astheywillbeaddinganewclasstotheGUIClassLibraryandthenaddingnewsubprogramsintheGUImodulethatwillcalltheirnewclasses.(Attheveryleast,aCreatesubprogramwillberequiredforthenewwidget.)

AsuggestedprojectwouldbetocreatenewversionsoftheButtonClass,CheckBoxClassandRadioButtonClassclassesthatarebuttons,checkboxesandradiobuttonswiththenewWindows95/NTappearance.TheycouldbecalledtheButton95Class,CheckBox95ClassandRadioButton95Class.Properlywritten,thesenewclassesshouldinheritfromButtonClass,etc.andcontainonlythoseproceduresthatdifferfromthebaseclass(presumablytheproceduresthatdisplaythewidget).

TheGUIClassLibraryHierarchy

GUIModuleRoutinesSummary

TheroutinesintheGUImodulearedividedintoseveraldifferenttypes.Therearetheroutinestocreatevariouswidgets,theroutinestocreatemenusandmenuitems,theroutinestodogeneralactivities(suchasprocessinganevent,changingthebackgroundcolor,etc.)andtheroutinesthatactonvarioustypesofwidgets.

Hereisthelistoftheroutinesthatcreatewidgets:

GUI.CreateButton,GUI.CreateButtonFull Createabutton.GUI.CreateCheckBox,GUI.CreateCheckBoxFull Createacheckbox.GUI.CreateRadioButton,GUI.CreateRadioButtonFull Createaradiobutton.GUI.CreatePictureButton,GUI.CreatePictureButtonFull Createapicturebutton.

GUI.CreatePictureRadioButton,GUI.CreatePictureRadioButtonFull

Createapictureradiobutton.

GUI.CreateHorizontalSlider Createahorizontalslider.

GUI.CreateVerticalSlider Createaverticalslider.GUI.CreateHorizontalScrollBar,GUI.CreateHorizontalScrollBarFull

Createahorizontalscrollbar.

GUI.CreateVerticalScrollBar,GUI.CreateVerticalScrollBarFull

Createaverticalscrollbar.

GUI.CreateCanvas,GUI.CreateCanvasFull Createacanvas.GUI.CreateTextField,GUI.CreateTextFieldFull Createatextfield.GUI.CreateTextBoxFull,GUI.CreateTextBoxFull Createatextbox.

GUI.CreateTextBoxChoice Createamulti-lineselector.

GUI.CreateLine Createaline.GUI.CreateFrame Createaframe.GUI.CreateLabelledFrame Createalabelledframe.GUI.CreateLabel,GUI.CreateLabelFull Createalabel.GUI.CreatePicture Createapicture.

Hereisthelistofroutinesthatcreatemenusandmenuitems:

GUI.CreateMenu Createamenu.GUI.CreateMenuItem,GUI.CreateMenuItemFull Createamenuitem.

Hereisthelistofgeneralroutines:

GUI.ProcessEvent Processasinglekeyboardormousedownevent.GUI.Quit Telltheprogramtoexittheeventloop.

GUI.ResetQuit Resetthe"quit"flagsoaprogramcanreentertheeventloop.

GUI.Refresh Redrawallthewidgetsonthescreen.GUI.SetBackgroundColor Changethewindow'sbackgroundcolour.GUI.SetNullEventHandler Setthenulleventhandler.GUI.SetKeyEventHandler Setthekeystrokeeventhandler.GUI.SetMouseEventHandler Setthemouseeventhandler.GUI.HideMenuBar Hidethemenubarinthewindow.GUI.ShowMenuBar Showthemenubarinthewindow.

GUI.GetEventWidgetID Gettheselectedwidget'sID(usedinawidget'sactionprocedure).

GUI.GetEventWindow Getthewindowthattheeventtookplacein(usedinawidget'sactionprocedure).

GUI.GetEventTime Getthetime(inmilliseconds)thattheeventtookplace(usedinawidget'sactionprocedure).

GUI.GetScrollBarWidth Returnthewidthofascrollbar.GUI.GetMenuBarHeight Returntheheightofamenubar.

GUI.GetVersion ReturnthecurrentversionnumberoftheGUImodule.

Hereisalistofroutinesthatactonthewidgetsandthesortofwidgetstheyacton.

GUI.Show Displaythewidget. All

GUI.Hide Hidethewidget. All

GUI.GetXReturnthexcoordinateofthewidget'sleftedge.

GUI.GetY

Returntheycoordinateofthewidget'sbottomedge.

GUI.GetWidthReturnthewidget'sactualwidth.

GUI.GetHeightReturnthewidget'sactualheight.

GUI.Dispose Disposeofthewidget. All

GUI.SetPosition Setthewidget'sposition. All

GUI.SetSize Setthewidget'ssize. All

GUI.SetPositionAndSize Setthewidget'spositionandsize. All

GUI.EnableEnablethewidgettorespondtoevents.

ActiveWidgets

GUI.Disable

Disablethewidgetfromrespondingtoevents.

ActiveWidgets

GUI.SetLabel Setthewidget'stextlabel.

Button,CheckBox,RadioButton,Label,LabelledFrame

Setthebutton's

GUI.SetColor color. Button

GUI.SetDefault Makethebuttonthedefaultbutton. Button

GUI.GetCheckBoxGetwhetheracheckboxisfilled.

CheckBox

GUI.SetCheckBox Setacheckboxtobefilledornot. CheckBox

GUI.SelectRadio Selectaradiobutton.

RadioButton,PictureRadioButton

GUI.GetSliderValue Returnthecurrentvalueoftheslider.

Slider,ScrollBar

GUI.SetSliderValue Setthevalueoftheslider.

Slider,ScrollBar

GUI.SetSliderMinMaxSettheslider'sminimumandmaximum.

Slider,ScrollBar

GUI.SetSliderSize Settheslider'slength(orheight).

Slider,ScrollBar

GUI.SetSliderReverseReversethedirectionoftheslider.

Slider,ScrollBar

GUI.SetScrollAmount

Setthescrollbar'sthumbsizeandthescrollamountforarrows/pageupanddown.

ScrollBar

DrawArc,DrawBox,DrawCls,DrawDot,DrawFill,DrawFillArc,DrawFillBox,DrawFillMapleLeaf,DrawFillOval,DrawFillPolygon,DrawFillStar,DrawLine,DrawMapleLeaf,DrawOval,DrawPolygon,

RoutinesthatperformthesamefunctionastheDrawmodulefortheCanvas

Canvas

DrawStar,DrawText widget.

GUI.FontDraw"Font.Draw"fortheCanvaswidget.

Canvas

PicDraw,PicNew,PicScreenLoad,PicScreenSave

RoutinesthatperformthesamefunctionasthePicmodulefortheCanvaswidget.

Canvas

GUI.SetXOR

PerformsView.Set("xor")fortheCanvasWidget.

Canvas

GUI.SetText Setthetextofatextfield. TextField

GUI.SetEchoChar

Setthecharacterthatappearswhenuserentersakeystroke.

TextField

GUI.SetSelection Settheselectioninthetextfield. TextField

GUI.SetActive

Makethetextfieldtheactiveone(wherekeystrokeswillgoandwherethecursorblinks).

TextField

GUI.ClearText Clearatextbox. TextBox

GUI.AddText Addtexttoatextbox. TextBox

GUI.AddLine Addalineoftexttoatextbox. TextBox

GUI.SetTopLineScrollstextboxtomakelineappearattop.

TextBox

GUI.SetScrollOnAdd Setswhethertextboxscrollswhentextadded.

TextBox

Widgets-CommonRoutines

Alloftheproceduresinthissectioncanbeusedwithanywidget,althoughsomemayhavenoeffect(forexampleGUI.GetXonamenuitemismeaningless).

GUI.ShowDisplaysawidget.UsedinconjunctionwithHidetohideandshowwidgets.Hiddenwidgetscannotgetevents(i.e.respondtokeystrokesormouseclicks).

GUI.Hide

Hidesawidget.UsedinconjunctionwithShowtohideandshowwidgets.Hiddenwidgetscannotgetevents(i.e.respondtokeystrokesormouseclicks).Ifanactivetextfield(seetextfield)ishidden,thenanykeystrokesinthewindowwillbeignored.

GUI.GetXGUI.GetY

Returnsthex(y)coordinateoftheleftedgeofawidget.Notethatthismaybedifferentfromthexcoordinatespecifiedinthewidget'sCreatecall.Forexample,ifaradiobuttoniscreatedwithrightjustification,thexcoordinateintheCreatemethodspecifiestherightedge.

Hereisasmallsubprogramthatshoulddrawarectangleentirelyaroundawidget(i.e.nopartofthewidgetshouldstickout).

procedureWidgetRect(widgetID:int)

constx:int:=GUI.GetX(widgetID)

consty:int:=GUI.GetY(widgetID)

constwidth:int:=GUI.GetWidth(widgetID)

constheight:int:=GUI.GetHeight(widgetID)

Draw.Box(x,y,x+width-1,y+height-1,black)

endWidgetRect

GUI.GetWidthGUI.GetHeight

Returnstheactualwidth(height)ofawidget.NotethatthismaybedifferentfromthewidthspecifiedintheCreatecall(especiallysincemanywidgetsallowyoutospecify0forthewidthandlettheGUImoduledeterminethenecessarywidth).

GUI.Dispose

Eliminatesawidget.Itshouldbecalledinordertofreeupanymemorythatthewidgetmighthaveallocated.Notethatyoucannotusethewidgetafterithasbeendisposedof.Ifyouwishtotemporarilygetridofawidget,considerusingtheHidemethodandthentheShowmethodwhenyouwanttouseitagain.

GUI.SetPosition

Movesawidgettothespecifiedlocation.Ifthewidgetisvisible,itismovedimmediatelytothenewlocation.Ifthewidgetishidden,itwillappearatthenewlocationwhentheShowprocedureiscalled.NotethatthelocationspecifiedinGUI.SetPositionarethesameasintheCreatemethod.Forexample,ifyouhadspecifiedacheckboxtoberightjustifiedintheCreateCheckBoxFullfunction,thenthelocationinacalltoSetPositionwouldspecifythelower-rightcornerasopposedtothelower-leftcorner.

GUI.SetSize

Changesthesizeofawidget.Ifthewidgetisvisible,itssizeischangedimmediately,otherwisethewidgetwillappearinitsnewsizewhenthewidgetisnextmadevisible.Notethatthewidthandheightparametersarenotnecessarilytheactualwidthandheightofthewidget.Forexample,theTextFieldwidgetignorestheheightparameter,calculatingthewidget'sactualheightfromtheheightofthetextintheTextField.

GUI.SetPositionAndSize Changesthepositionandsizeofthewidgetsimultaneously.ItworksthesamewayastheSetPositionandSetSizeprocedures.

Widgets-Buttons

OutputofButtons.dem

Thebuttonwidgetisusedtoimplementatextualbutton.Whenyouclickonabutton,thebutton'sactionprocedureiscalled.Ifabuttonisgivenashortcut,thenenteringthekeystrokewillcausetheactionproceduretobecalled.Itwillnotvisiblycausethebuttontodepress.

Ifabutton'swidthorheightissettozero(ornotspecifiedatall),thenthebuttonisshapedtofitthetext.

Abuttoncanbethedefaultbuttonforawindow.Ifthatisthecase,thenthebuttonwillbedrawnwithatickerborderarounditandiftheuserpressesENTER,thenthebutton'sactionprocedurewillbecalled.

Whenabuttonisnotenabled,thetextinthebuttonisgrayedoutandthebuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

GUI.CreateButtonCreatesanddisplaysabutton.GUI.CreateButtonspecifiesthelocation,width,textandactionprocedureofthebutton.

GUI.CreateButtonFullCreatesanddisplaysabutton.GUI.CreateButtonFullalsospecifiestheheight,keyboardshortcutanddefaultstatusofthebutton.

GUI.EnableGUI.Disable

Enables(disables)abutton.Disabledbuttonshavetheirtextgrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

GUI.SetLabel Changesthetextofabutton.

GUI.SetDefault

Setsthe"defaultstatus"ofabutton.Ifabuttonisthedefaultbutton,thenitisdrawnwithaheavyoutlineanditisactivatedwhentheuserpressesENTER(RETURNonaMacintosh).

Widgets-CheckBoxes

OutputofCheckBoxes.dem

Thecheckboxwidgetisusedtoimplementacheckboxthatcanbesetorunset.Whenyouclickonacheckbox,thestatusofthecheckboxflipsfromsettounsetandbackagainandthecheckbox'sactionprocedureiscalledwiththenewstatusasaparameter.Ifacheckboxisgivenashortcut,thenenteringthekeystrokewillcausethecheckboxtochangestatusandtheactionproceduretobecalled.Thenewstatuswillbedisplayedimmediately.

Acheckbox'ssizeisnotspecifiedduringcreation.Itisdeterminedbasedonthesizeofthetext.Insteadtheuserspecifiesthelower-leftcornerofthecheckbox(orthelower-rightifthecheckboxisrightjustified).

Whenacheckboxisnotenabled,thelabelbesidethecheckboxisgrayedout

andthecheckboxnolongerrespondstoanymouseclicksorkeystrokesuntilthecheckboxisenabledagain.

GUI.CreateCheckBox

Createsanddisplaysaleftaligned(checkboxtotheleftofthelabel)checkbox.GUI.CreateCheckBoxspecifiesthelocation,textandactionprocedureofthecheckbox.

GUI.CreateCheckBoxFull

Createsanddisplaysacheckbox.GUI.CreateCheckBoxFullalsospecifiesthealignmentofthecheckbox(whetherthecheckboxistherightorleftofthetext)andthecheckbox'skeyboardshortcut.

Enables(disables)acheckbox.Disabledcheckboxeshavetheirtextgrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

GUI.SetLabel Changesthetextofacheckbox.

GUI.GetCheckBoxReturnsacheckbox'sstatus.Ifthecheckboxisset(hasanXinit),GUI.GetCheckBoxreturnstrue,otherwiseitreturnsfalse.

GUI.SetCheckBoxSetsthestatusofacheckbox.Itcallsthecheckbox'sactionprocedurewiththenewstatusandredrawsthewidgetwiththenewstatus.

Widgets-RadioButtons

OutputofRadioButtons.dem

Theradiobuttonwidgetisusedtoimplementasetofbuttonsofwhichoneandonlyonebuttonmustbeselectedatalltimes.(Thinkold-styleradiostationbutton.Selectingone"deselects"thepreviously-selectedstation.)Whenyouclickonaradiobutton,anyotherradiobuttonthatispartofthesetisdeselectedandtheradiobutton'sactionprocedureiscalled.Ifaradiobuttonisgivenashortcut,thenenteringthekeystrokewillcausetheradiobuttontobeselected(andanyotherradiobuttoninthegrouptobede-selected)andtheactionproceduretobecalled.Thenewly-selectedordeselectedradiobuttonswillbedisplayedimmediately.

Whenaradiobuttoniscreated,thewidgetIDofanotherradiobuttonmustbesupplied.AvalueofzeroforthewidgetIDindicatesthatthisradiobuttonispart

ofanewgroup.ThewidgetIDmustbetheIDofthelastradiobuttonaddedtothegroup.Becauseradiobuttonsarealmostalwaysplacedingroupsyoucanspecify-1forthexandycoordinatesandtheradiobuttonwillbeplacedjustbelowthepreviousradiobuttonandretainthesamealignment.Whenagroupofradiobuttonsisselected,thefirstradiobuttoncreatedinthegroupwillbetheselectedone.YoucanchangethisbyusingtheGUI.SelectRadioproceduretoselectadifferentone.

Aradiobutton'ssizeisnotspecifiedduringcreation.Itisdeterminedbasedonthesizeofthetext.Theuserspecifiesthelower-leftcorneroftheradiobutton(orthelower-rightiftheradiobuttonisrightjustified).

Whenaradiobuttonisnotenabled,thelabelbesidetheradiobuttonisgrayedoutandtheradiobuttonnolongerrespondstoanymouseclicksorkeystrokesuntiltheradiobuttonisenabledagain.

GUI.CreateRadioButton

Createsanddisplaysaleftaligned(circletotheleftofthelabel)radiobutton.GUI.CreateRadioButtonspecifiesthelocation,text,theradiobuttontobejoinedtoandtheactionprocedureoftheradiobutton.

GUI.CreateRadioButtonFull

Createsanddisplaysaradiobutton.GUI.CreateRadioButtonFullalsospecifiesthealignmentoftheradiobutton(whetherthecircleistherightorleftofthetext)andtheradiobutton'skeyboardshortcut.

Enables(disables)aradiobutton.Disabledradiobuttonshavetheirtextgrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

GUI.SetLabel Changesthetextofaradiobutton.

GUI.SelectRadioSelectsaradiobutton.Thepreviously-selectedradiobuttonis"de-selected".Theactionprocedureoftheradiobuttoniscalled.

Widgets-PictureButtons

OutputofPictureButtons.dem

Thepicturebuttonwidget(hereaftersimplycalledabutton)issimplyabuttonwithapictureonitinsteadoftext.ThepicturemustbecreatedbytheprogrambeforehandusingPic.NeworPic.FileNew.TheresultingpicturecanthenbeusedasaparametertoGUI.CreatePictureButton.Ingeneral,picturesshouldbeamaximumofabout30pixelshighandwide,althoughthereisnobuiltinlimitintheGUIlibrary.

Whenyouclickonapicturebutton,thepicturebutton'sactionprocedureiscalled.Ifapicturebuttonisgivenashortcut,thenenteringthekeystrokewillcausetheactionproceduretobecalled.Itwillnotvisiblycausethebuttontodepress.

Ifabutton'swidthorheightissettozero(ornotspecifiedatall),thenthebutton

isshapedtofitthepicture.

Whenapicturebuttonisnotenabled,thepicturebuttonisgrayedoutandthepicturebuttonnolongerrespondstoanymouseclicksorkeystrokesuntilthebuttonisenabledagain.

GUI.CreatePictureButton

Createsanddisplaysapicturebutton.Thebuttonisautomaticallysizedtofitthepicture.Ifyouneedtoknowtheprecisesizeofthebutton,usetheGUI.GetWidthandGUI.GetHeightfunctions.GUI.CreatePictureButtonspecifiesthelocation,pictureidandactionprocedureofthebutton.

GUI.CreatePictureButtonFull

Createsanddisplaysapicturebutton.GUI.CreatePictureButtonFullalsospecifiesthewidth,heightandkeyboardshortcutofthebutton.Italsospecifieswhetherthebuttonpictureshouldbemergedwiththebackgroundcolorornot.

Enables(disables)apicturebutton.Disabledpicturebuttonsaregrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

Widgets-PictureRadioButtons

OutputofPictureRadioButtons.dem

Thepictureradiobuttonwidget(hereaftersimplycalledabutton)issimplyapicturebutton(seeWidget-PictureButton)thathasthebehaviorofaradiobutton.Thismeansthatoneandonlyonepictureradiobuttonofagroupisselectedatanytime.Aselectedpictureradiobuttonisdisplayedasbeingpressed.

Whenyouclickonapicturebutton,thepreviously-selectedpictureradiobuttonwillbede-selectedandthenewpicturebutton'sactionprocedureiscalled.Ifapicturebuttonisgivenashortcut,thenenteringthekeystrokewillcausetheactionproceduretobecalledandthepictureradiobuttonwillbedrawnselected.

Createsanddisplaysapictureradiobutton.Thebuttonisautomaticallysizedtofitthe

GUI.CreatePictureRadioButton

picture.Ifyouneedtoknowtheprecisesizeofthebutton,usetheGUI.GetWidthandGUI.GetHeightfunctions.GUI.CreatePictureRadioButtonspecifiesthelocation,pictureidandactionprocedureofthebuttonaswellastheradiopicturebuttontobejoinedto.

GUI.CreatePictureRadioButtonFull

Createsanddisplaysapictureradiobutton.GUI.CreatePictureRadioButtonFullalsospecifiesthewidth,heightandkeyboardshortcutofthebutton.Italsospecifieswhetherthebuttonpictureshouldbemergedwiththebackgroundcolorornot.

Enables(disables)apictureradiobutton.Disabledpicturebuttonsaregrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

Widgets-Sliders

OutputofSliders.dem

Slidersaretheequivalentofavolumecontrolonastereo.Tocontrolaslider,theusersimplyclicksonthecontrolknobandslidesthecontrolleftandright(upanddownforaverticalslider).Whenevertheuserslidesthecontrolknob,theactionprocedureofthewidgetiscalledwiththecurrentvalueasaparameter.

TherangeofvaluesthatthesliderwillgiveisdeterminedbytheminandmaxparametersintheCreatecall.Theleftsideoftheslider(bottomforverticalsliders)representstheminimumvalue,whiletheright(top)representsthemaximumvalue.

Insomeinstances,youwillwantthereversetobetrue(right/topisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesoftheslider.

Slidersalwayshaveafixedheight(forhorizontalsliders)orwidth(forverticalsliders).ThelengthparameterintheCreatecallspecifieshowlongtheslidershouldbe.

GUI.CreateHorizontalSlider

Createsanddisplaysahorizontal(left-right)slider.GUI.CreateHorizontalSliderspecifiesthelocation,length,minimumandmaximumvaluesfortheslider,theinitialvalueoftheslider,andtheactionprocedureoftheslider.

GUI.CreateVerticalSlider

Createsanddisplaysavertical(up-down)slider.GUI.CreateVerticalSliderspecifiesthelocation,length,minimumandmaximumvaluesfortheslider,theinitialvalueoftheslider,andtheactionprocedureoftheslider.

Enables(disables)aslider.Disabledsliderscannotgetevents(i.e.respondtomouseclicks).

GUI.GetSliderValue Returnsthecurrentvalueofaslider.

GUI.SetSliderValueSetsthevalueofaslider.Itmovesthecontrolknobontheslidertotheappropriatelocationandcallstheslider'sactionprocedurewiththenewvalue.

GUI.SetSliderMinMax

Setstheminimumandmaximumvaluesofaslider.Itredrawsthecontrolknobtotakeintoaccountthenewminimumandmaximum.Ifthecurrentvalueofthesliderisoutsidethenewmin/max,thenthevalueisadjustedappropriately.

GUI.SetSliderSizeChangesthelengthofaslider.Redrawsthesliderandchangesthepositionofthecontrolknobtotakeintoaccountthenewsizeoftheslider.

GUI.SetSliderReverse

Setsasliderinto(oroutof,ifalreadyinto)"reversemode".Normally,asliderisatitsminimumvaluewhenthecontrolknobisontheleftside(bottomforaverticalslider).Thisreversesit,sotheminimumvalueiswhenthesliderisattherightside(topforverticalsliders)ofthetrack.Callingthisroutineasecondtimereversesitbacktonormal.Thisprocedureredrawstheslidertomovethecontrolknobtoitsnewlocation.

Widgets-ScrollBars

OutputofScrollBars.dem

Scrollbarsareusuallyusedtoallowausertoseeapieceofadocumentthatcannotbedisplayedonthescreeninitsentirety.Thepictureaboveshowsthescrollbarsappearance.Tocontrolascrollbar,thereareafewchoices:theusercanclickonthethumb(theboxinthescrollbar)andslideitupanddown,ortheusercanclickinthescrollbaritselfaboveorbelowthethumb(inwhichcasethethumbismovedupordownone"page"),ortheusercanclickontheupordownarrowsattheendsofthescrollbar(inwhichcasethethumbismovedupone"line").Theprogrammerdefinesapageoraline.Whenthevalueofthescrollbarchanges,theactionprocedureofthescrollbariscalledwiththenewvalueasaparameter.

Therangeofvaluesthatthescrollbarwillgiveisdeterminedbytheminand

maxparametersintheCreatecall.Theleftsideofthescrollbar(bottomforverticalscrollbars)representstheminimumvalue,whiletheright(top)representsthemaximumvalue.Thereisalsothe"thumbsize".Thisrepresentstherangeofvaluesthatcanbeseenatonceonthescreen.

Forexample,ifyouhaveawindowthatcandisplay20linesoftextatonceandthereare100linesoftext,youwouldsetminto1,maxto100,andthumbSizeto20.Thevaluereturnedbythescrollbarwouldthenbethelinenumberofthefirstlineonthescreentobedisplayed.Whenthescrollbarwasatitsmaximumvalue,itwouldreturn81,sincebydoingso,lines81-100wouldbedisplayed.

Whenascrollbarisdisabledorthescrollbar'sthumbsizeisgreaterthanthedifferencebetweentheminimumandmaximumvalues(i.e.theitembeingscrolledfitsinthewindow),thescrollbarisdeactivated.Thebarisdrawninwhiteratherthangrayandthearrowsaregrayedout.Thescrollbardoesnotrespondtomouseclicks.

Insomeinstances,youwillwanttheminimumandmaximumvaluesofthescrollbartobereversed(right/topisminimum).Inthatcase,calltheGUI.SetSliderReverseproceduretoflipthevaluesofthescrollbar.

Scrollbarsalwayshaveafixedheight(forhorizontalscrollbars)orwidth(forverticalscrollbars).Togetthescrollbar'swidth,usetheGUI.GetScrollBarWidthfunction.ThelengthparameterintheCreatecallspecifieshowlongthescrollbarshouldbe.

GUI.CreateHorizontalScrollBar

Createsanddisplaysahorizontal(left-right)scrollbar.GUI.CreateHorizontalScrollBarspecifiesthelocation,length,minimumandmaximumvaluesforthescrollbar,theinitialvalueofthescrollbar,andthescrollbar'sactionprocedure.

Bydefault,thearrowincrement(theamountthevalueischangedwhenthescrollingarrowsarepressed)issettoone.Thepageup/downincrement(theamountthevalueischangedwhentheuserclicksin

thebartotherightorleftofthethumb)issettoonequarterthedifferencebetweentheminimumandthemaximum.The"thumbsize"issettozero(seethedescriptionofscrollbarsforanexplanationofthethumbsize).

GUI.CreateVerticalScrollBar

Createsanddisplaysavertical(up-down)scrollbar.GUI.CreateVerticalScrollBarspecifiesthelocation,length,minimumandmaximumvaluesforthescrollbar,theinitialvalueofthescrollbar,andthescrollbar'sactionprocedure.

Bydefault,thearrowincrement(theamountthevalueischangedwhenthescrollingarrowsarepressed)issettoone.Thepageup/downincrement(theamountthevalueischangedwhentheuserclicksinthebartotherightorleftofthethumb)issettoonequarterthedifferencebetweentheminimumandthemaximum.The"thumbsize"issettozero(seethedescriptionofscrollbarsforanexplanationofthethumbsize).

GUI.CreateHorizontalScrollBarFull

Createsanddisplaysahorizontal(left-right)scrollbar.GUI.CreateHorizontalScrollBarFullalsospecifiesthearrowincrement,pageincrement,andthumbsizeforthescrollbar.

GUI.CreateVerticalScrollBarFull

Createsanddisplaysahorizontal(left-right)scrollbar.GUI.CreateVerticalScrollBarFullalsospecifiesthearrowincrement,pageincrementandthumbsizeforthescrollbar.

Enables(disables)ascrollbar.Disabledscrollbarscannotgetevents(i.e.respondto

mouseclicks).GUI.GetSliderValue Returnsthecurrentvalueofascrollbar.

GUI.SetSliderValue

Setsthevalueofascrollbar.Itmovesthecontrolknobonthescrollbartotheappropriatelocationandcallsthescrollbar'sactionprocedurewiththenewvalue.

GUI.SetSliderMinMax

Setstheminimumandmaximumvaluesofascrollbar.Itredrawsthecontrolknobtotakeintoaccountthenewminimumandmaximum.Ifthecurrentvalueofthescrollbarisoutsidethenewmin/max,thenthevalueisadjustedappropriately.

GUI.SetSliderSize

Changesthelengthofascrollbar.Redrawsthescrollbarandchangesthepositionofthecontrolknobtotakeintoaccountthenewsizeofthescrollbar.

GUI.SetSliderReverse

Setsascrollbarinto(oroutof,ifalreadyinto)"reversemode".Normally,ascrollbarisatitsminimumvaluewhenthecontrolknobisontheleftside(bottomforaverticalscrollbar).Thisreversesit,sotheminimumvalueiswhenthescrollbarisattherightside(topforverticalscrollbars)ofthetrack.Callingthisroutineasecondtimereversesitbacktonormal.Thisprocedureredrawsthescrollbartomovethecontrolknobtoitsnewlocation.

GUI.SetScrollAmount

Setsascrollbar'sarrowincrement,pageincrement,andthumbsize.Redrawsthescrollbartotakeintoaccountthenewthumbsize.

Widgets-Canvases

OutputofCanvases.dem

Acanvasisadrawingsurfaceforusebytheprogram.Itdiffersfromjustusingthewindowsurfacetodrawoninthat(0,0)representsthelower-leftcornerofthecanvasandalldrawingisclippedtothecanvas.(Thismeansthatifyouaccidentallyattempttodrawoutsideofthecanvas,itwillnotactuallydrawbeyondtheborderofthecanvas.)

CanvaseshaveproceduresthatemulatealltheproceduresintheDrawmoduleaswellasaproceduretoemulateFont.Draw,Pic.Draw,Pic.New,Pic.ScreenLoad,andPic.ScreenSave.

Youcangetmousefeedbackfromacanvas.UsingtheGUI.CreateCanvasFullmethod,youcanspecifythreeroutinesthatarecalledwhenthemousebuttonisdepressedwhilepointinginacanvas.Oneroutinewillbecalledwhentheuserpressesthemousebuttondowninacanvas.Anotherroutinewillbecalledwhiletheuserdragsthemousewiththemousebuttondown.Thisroutineisrepeatedlycalledwheneverthemousechangespositionwhilethemousebuttonisdown.Thelastroutineiscalledwhenthemousebuttonisreleased.Allthreeroutines

takeanxandyparameter,whichisthelocationofthemousewithrespecttothecanvas(i.e.(0,0)isthelower-leftcornerofthecanvas).

GUI.CreateCanvasCreatesanddisplaysacanvas.GUI.CreateCanvasspecifiesthelocationandsizeofthecanvas.Thecanvaswillhavealineborderaroundit.

GUI.CreateCanvasFull

Createsanddisplaysacanvas.GUI.CreateCanvasFullalsospecifiesthetypeofborderandthreeprocedurestobecalledwhenamouseispressed,draggedorreleasedonthecanvas.

Enables(disables)acanvas.Disabledcanvasescannotgetevents(i.e.respondtomouseclicks).Ifnomouseroutineswerespecified(i.e.thecanvaswascreatedwithGUI.CreateCanvasandnotGUI.CreateCanvasFull)thisroutineessentiallydoesnothing.

GUI.DrawArcGUI.DrawBoxGUI.DrawClsGUI.DrawDotGUI.DrawFillGUI.DrawFillArcGUI.DrawFillBoxGUI.DrawFillMapleLeafGUI.DrawFillOvalGUI.DrawFillPolygonGUI.DrawFillStarGUI.DrawLineGUI.DrawBoxGUI.DrawMapleLeafGUI.DrawOvalGUI.DrawPolygonGUI.DrawStarGUI.DrawTextGUI.FontDrawGUI.PicDrawGUI.PicNewGUI.PicScreenLoad

AlltheseroutinesdrawtoacanvasinthesamemannerasthesimilarlynamedDraw�,Pic�andFont.Drawsubprograms.Allcoordinatesarebasedonthecanvasandalldrawingisclippedtothecanvasdrawingsurface.Ifthecanvasisin"xormode",allthedrawingwillbedonewith"xor"set.(SeeView.Setformoreinformationabout"xor".)

GUI.PicScreenSave

GUI.SetXOR

Setsthe"xormode"ofacanvas.Whenin"xormode",alltheDraw...proceduresofacanvasaretreatedasiftheView.Set("xor")statementhadbeenexecutedbeforetheDrawprocedure.

Widgets-TextFields

OutputofTextFields.dem

Atextfieldisaboxforenteringonelineoftext.WhentheuserpressesENTER,thetextfield'sactionprocedureiscalled.

Onlyonetextfieldisactiveatatime.Theactivetextfieldhasablinkingcursor(oritsselectionhighlighted).Ifakeystrokeoccurswhenawindowhasanactivetextfieldinit,thekeystrokewillbedirectedtotheactivetextfield.YoucanchangewhichtextfieldisactivewiththeGUI.SetActiveprocedureorbysimplyclickingonanothertextfieldwiththemouse.

Whenmultipletextfieldsarecreatedinawindow,thefirsttextfieldcreatedisactivewhentheprogrambegins.

Thecurrentversionofthetextfielddoesnotsupportcutandpasteorkeyboardcommandstoextendtheselection.

Becausestringsareamaximumof255characters,thisisthemaximumnumberofcharactersinatextfield.

TheTABcharactercyclesbetweendifferenttextfieldsinawindow.Itcyclesthroughthetextfieldsintheorderinwhichtheywerecreated.BACKTAB(shift+TAB)cyclesthroughthefieldsinreverseorder.

GUI.CreateTextField

Createsanddisplaysatextfield.GUI.CreateTextFieldspecifiesthelocation,width,initialtextstring,andactionprocedureofthetextfield.Theheightofthetextfieldisdeterminedbytheheightofthefontusedbythetextfield.Thetextfieldwillhavealineborderaroundit.

GUI.CreateTextFieldFull

Createsanddisplaysatextfield.GUI.CreateTextFieldFullalsospecifiesthetypeofborder,fontforenteredtext,andkindofinputrestriction(integeronly,etc.)

Enables(disables)atextfield.Disabledpicturebuttonsaregrayedoutandcannotgetevents(i.e.respondtokeystrokesormouseclicks).

GUI.SetText Setsthetextofatextfield.Thecursorissetthebeginningofthetext.

GUI.GetText Returnsthecurrenttextofatextfield.GUI.SetSelection Setstheselection(theselectedtext)inatextfield.GUI.SetActive Makesatextfieldactive.

Widgets-TextBoxes

OutputofTextBoxes.dem

Atextboxisaboxusedfordisplayinglargerquantitiesoftext.Ithasbothverticalandhorizontalscrollbarstoallowtheusertoscrollthroughallthetextinthebox.

GUI.CreateTextBoxCreatesanddisplaysatextbox.GUI.CreateTextBoxspecifiesthelocationandsizeofthetextbox.Thetextboxwillhavealineborderaroundit.

GUI.CreateTextBoxFullCreatesanddisplaysatextbox.GUI.CreateTextBoxFullalsospecifiesthetypeofborderandthefontfordisplayedtext.

GUI.ClearText Clearsallthetextinatextbox.Addstexttothecurrentlineofthetextbox.Doesnot

GUI.AddTextaddanewlineafterthetext.Equivalenttoputtext...Thisscrollsthetextbox(ifnecessary)sothattheaddedtextisnowvisible.Tomovethecursortotheendofthetextwithoutaddinganyextratext,callGUI.AddTextwith""forthetextparameter.

GUI.AddLineAddstexttothecurrentlineofthetextboxfollowedbyanewline.Equivalenttoputtext.Thisscrollsthetextbox(ifnecessary)sothattheaddedtextisnowvisible.

Widgets-Lines

OutputofLines.dem

LinesareorganizationalelementsthatmakethewindowlookbetterandhelporganizetheGUIelements.

GUI.CreateLineCreatesanddisplaysaline.GUI.CreateLinespecifiestheendpointsoftheline(whichmustbeeitherverticalorhorizontal)andthetypeofline.

Widgets-Frames

OutputofFrames.dem

FramesareorganizationalelementsthatmakethewindowlookbetterandhelporganizetheGUIelements.Framesandlabelledframesaretheonlywidgetsinwhichotherwidgetscanbeplaced.

GUI.CreateFrameCreatesanddisplaysaframe.GUI.CreateFramespecifiesthecoordinatesofthelower-leftandupper-rightcorneroftheframeandthetypeofborderoftheframe.

Widgets-LabelledFrames

OutputofLabelledFrames.dem

LabelledframesareorganizationalelementsthatmakethewindowlookbetterandhelporganizetheGUIelements.Framesandlabelledframesaretheonlywidgetsinwhichotherwidgetscanbeplaced.

GUI.CreateLabelledFrame

Createsanddisplaysalabelledframe.GUI.CreateLabelledFramespecifiesthecoordinatesofthelower-leftandupper-rightcorneroftheframe,thetypeofborderoftheframe,andthetextoftheframe'slabel.

GUI.SetLabel Changesthetextofalabelledframe.

Widgets-Labels

OutputofLabels.dem

LabelsareorganizationalelementsthatmakethewindowlookbetterandhelporganizetheGUIelements.Theyaresimplytextplacedinawindow.Toaidinaligningtextwithvariouswidgets,itispossibletoaligntextinalargerregion(asshowninthefigure).

GUI.CreateLabelCreatesanddisplaysalabel.GUI.CreateLabelspecifiesthelower-leftcornerofthetextandthetextitself.Thesystemfontisusedtodisplaythelabel.

GUI.CreateLabelFull

Createsanddisplaysalabel.GUI.CreateLabelFullalsospecifiesthewidth,height,alignment,andfontforthelabel.Thewidthandheightarespecifiedforalignment

purposes.GUI.SetLabel Changesthetextofalabel.

Widgets-Pictures

OutputofPictures.dem

PicturesareorganizationalelementsthatmakethewindowlookbetterandhelporganizetheGUIelements.Theyaresimplyapictureplacedinawindow.ThepicturesarespecifiedusingapictureIDfromanyofthePic�subprograms.

GUI.CreatePictureCreatesanddisplaysapicture.GUI.CreatePicturespecifiesthelocation,pictureID,andwhetherthepictureshouldbemergedwiththebackground.

Widgets-Menus

OutputofMenus.dem

Menusareusedinmostmoderninterfaces.Inordertocreateafullsetofmenus,youmustcreatethemenuandthencreatethemenuitemsinthatmenu.Themenusareautomaticallyaddedtothemenubaroftheselectedmenu.

Menuitemsaretheindividualentriesofamenu.Tocreatemenusforawindow,youmustcreateamenu,thencreatethemenuitemsforthatmenu,thencreatethenextmenu,thentheitemsforthatmenu,etc.Allmenuitemsareautomaticallyaddedtothelastmenuandafterthelastmenuitemofthecurrentlyselected(notactive!)window.

Whenyouselectaniteminamenu,theactionprocedureoftheitemiscalled.Theactionprocedurehasnoparameters.

Asofthev1.0releaseoftheGUILibrary,itisanerrortocreateamenuitemwithouthavingcreatedamenufirst.Infuturereleasesitwillbepossibletocreatemenusandattachandremovethemfrommenubarswhendesired.

Menusandmenuitemscanbeenabledanddisabled.Adisabledmenuitemisgrayedout.Whentheuserselectsthemenu,allitemsinthemenuappeardisabledandcannotbeselected.Adisabledmenuitemisgrayedoutwhenthemenuisdisplayed.Theusercannotselectthemenuitem.

Separatorsinamenuappearasasolidlineacrossthemenu.Thesearecreatedbycreatingamenuitemwhosetextisthreedashes"---".

GUI.CreateMenu

Createsanddisplaysamenu.Themenuwillbeaddedaftertheothermenusinthemenubar.Iftherearenopreviousmenus,thenamenubarisautomaticallycreatedandthemenuadded.GUI.CreateMenuspecifiesthetextthatwillappearinthemenubar.Itissuggestedthatthetextnothaveanyspacesinit.

Enables(disables)amenu.Disabledmenusaregrayedoutinthemenubar.Ifselected,allthemenuitemsinthemenubarappeardisabledandcannotbeselected.

GUI.CreateMenuItem

Createsamenuitem.GUI.CreateMenuItemspecifiesthetextofthemenuitemandtheactionproceduretobecalledwhenthemenuitemisselected.Themenuitemwillbeaddedtothelastmenuaftertheothermenuitemsinthemenu.Iftherearenomenusdefined,anerrorresults.

GUI.CreateMenuItemFull Createsamenuitem.GUI.CreateMenuItemFullalsospecifiesashortcutkeystroke.

Enables(disables)amenuitem.Disabledmenuitemsaregrayedoutwhenthemenuisdisplayedandcannotbeselectedbytheuser.

Widgets-GeneralRoutines

ThefollowingproceduresareincludedintheGUImodulebutdonotrelatetoaspecificwidget.

GUI.ProcessEvent

Thisfunctionprocessesasingleevent(amousebuttonpressorakeystroke).Iftheeventactivatesawidget,thentheactionprocedureofthewidgetiscalled.Tofindoutwhichwidgetwasactivatedandcalledtheactionprocedure(necessaryifseveralwidgetshavethesameactionprocedure),youcancallGUI.GetEventWidgetID.Togettheexacttimethattheeventoccurred,youcancallGUI.GetEventTime.Togetthewindowinwhichtheeventtookplace,youcancallGUI.GetEventWindow.Ifamouseclickoccurred,butdidnotactivateanywidget,thenthedefaultmouseeventhandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtorespondtomouseeventsthatdonotaffectawidget,callGUI.SetMouseEventHandlertospecifyyourowndefaultmouseeventhandler.Ifakeystrokeoccurred,butdidnotactivateanywidget(i.e.itwasn'tashortcutforawidgetandtherearenotextfieldsinthewindow)thenthedefaultkeystrokehandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtorespondtokeystrokeeventsthatdonotaffectawidget,callGUI.SetKeyEventHandlertospecifyyourowndefaultkeyeventhandler.Ifnoeventoccurred,thenthenulleventhandleriscalled.Bydefault,thisdoesnothing.However,ifyouwantyourprogramtoperformsomeactionrepetitivelywhenitisnotdoinganythingelse,thencallGUI.SetNullEventHandlertospecifyyourownnulleventhandler.Thenullevent

handlerisoftenusedforsuchthingsasupdatingaclockandmakingcertainthatmusicisplayinginthebackground.

GUI.Quit

ThisprocedurecausesGUI.ProcessEventtoreturntrue.Iftheprogramisstructuredproperlywitha

endloop

attheendoftheprogram,thentheprogramwillexittheloopafterfinishingthecurrentactionprocedure.ThisprocedureisusuallycalledfromtheactionprocedureofaQuitbuttonorExitmenuitem.

GUI.Refresh

Thisroutineredrawsallthewidgetsinthecurrently-selectedwindow.Thisisusedwhensomeformofdrawingmayhaveoverwrittenthewidgetsinawindow.ItisusedbytheGUILibrarytoredrawallthewidgetswhenthebackgroundcolorofawindowhaschanged.

GUI.SetBackgroundColorGUI.SetBackgroundColour

Changesthebackgroundcolorofthecurrently-selectedwindow.(Bothspellingsofcolorareacceptable.)Thisdoesnotchangethevalueofcolor0inthewindow.Insteaditfillstheentirewindowwiththenewbackgroundcolorandthenredrawsallthewidgets.Theusualbackgroundcoloroutsideofwhiteisgray.

GUI.SetNullEventHandler

Setsthenewnulleventhandler.ThespecifiedprocedurewillbecalledeverytimeGUI.ProcessEventiscalledandthereisnokeystrokeormousebuttonpressed.

GUI.SetMouseEventHandler

Setsthenewdefaultmouseeventhandler.ThespecifiedprocedurewillbecalledeverytimeGUI.ProcessEventiscalledandthereisamousebuttonpressedwhichisnothandledbyanywidget.

GUI.SetKeyEventHandler

Setsthenewdefaultkeystrokeeventhandler.ThespecifiedprocedurewillbecalledeverytimeGUI.ProcessEventiscalledandthereisakeystrokewhichisnothandledbyanywidget.

GUI.HideMenuBar

Hidesthemenubarintheselectedwindow.Nomenuitemscanbeselectedwhenthemenubarishidden.(Menuitemshortcutswillbeignoredwhenthemenubarishidden.)

GUI.ShowMenuBar Showsthemenubarintheselectedwindow.

GUI.GetEventWidgetID

ReturnsthewidgetIDofthewidgetthatwasactivatedbythemousebuttonpressorthekeystroke.Thisfunctionshouldonlybecalledinanactionprocedure,asitwillreturn-1whenthereisnoeventthatactivatedawidgetbeingprocessed.

GUI.GetEventWindow

ReturnsthewindowIDofthewindowinwhichtheevent(mousebuttonorkeystroke)tookplace.Thisfunctionshouldonlybecalledinanactionprocedureorinadefaultmouseorkeystrokeeventhandler,asitwillreturn-1whenthereisnoeventbeingprocessed.

GUI.GetEventTime

Returnsthetimeinmillisecondswhentheevent(mousebuttonorkeystroke)tookplace.ThisvalueisthesamevaluethatTime.Elapsedreturnsifcalledwhentheeventwasprocessed.Thisfunctionshouldonlybecalledinanactionprocedureorinadefaultmouseorkeystrokeornulleventhandler,asitwillreturn-1whenthereisnoeventbeingprocessed.

GUI.SetDisplayWhenCreated

Setswhetherwidgetsareautomaticallydisplayedwhencreated,orwhetherGUI.Showmustbecalledfirst.Bydefault,thisissettotrue(widgetsaredisplayedwhencreated).However,theremaybetimeswhenyouwanttocreateawidgetandthenmakeseveraladditionalcallsbeforedisplayingthewidget.Closesawindowwithwidgetsinit.This

GUI.CloseWindow

procedureautomaticallydisposesofanywidgetsinthewindowandmakescertainthattheGUILibraryrecognizesthatthewindownolongerexists.ThisprocedurewillcallWindow.Close,sothereisnoneedfortheusertodoso.

GUI.ShowWindow

Showsahiddenwindowwithwidgetsinit.ThisproceduremakescertainthattheGUILibraryrecognizesthatthewindowisvisible.ThisprocedurewillcallWindow.Show,sothereisnoneedfortheusertodoso.

GUI.HideWindow

Hidesavisiblewindowwithwidgetsinit.ThisproceduremakescertainthattheGUILibraryrecognizesthatthewindowisnolongervisible.ThisprocedurewillcallWindow.Hide,sothereisnoneedfortheusertodoso.

GUI.GetScrollBarWidthReturnsthewidthofascrollbar.Usefulwhenplacingascrollbarwidgetbeneathanotherobject.

GUI.GetMenuBarHeightReturnstheheightofthemenubar.Usefulwhenplacingwidgetstomakecertainthattheydonotoverlapthemenu.

GUI.GetVersion

ReturnsthecurrentversionoftheGUImodule.BecausetheGUImoduleisexpectedtogrow,newversionswillprobablybemadeavailableatHoltSoftware'swebsitelocatedathttp://www.holtsoft.com/turing.Ifyouwishtousefeaturesthatdonotappearinearlierversionsofthelibrary,youcanhaveyourprogramcheckthatthecurrentavailableversionmeetstheprogramsneeds.GUI.GetVersionreturnsanintegerfrom100-999andisreadas1.00to9.99.

PredefinedFunctionsandProceduresabs addr arctan arctand anyclassbreak buttonchoose buttonmoved buttonwait ceilchr clock cls color colorbackcolour colourback cos cosd datedelay drawarc drawbox drawdot drawfilldrawfillarc drawfillbox drawfillmapleleaf drawfilloval drawfillpolygondrawfillstar drawline drawmapleleaf drawoval drawpicdrawpolygon drawstar empty eof erealstrexp fetcharg floor frealstr getchgetchar getenv getpid getpriority haschindex intreal intstr length lnlocate locatexy lower max maxcolmaxcolor maxcolour maxint maxnat maxrowmaxx maxy min minint minnatmousehide mouseshow mousewhere nargs natrealnatstr nil ord palette playplaydone pred rand randint randnextrandomize randseed realstr repeat roundsetpriority setscreen sign simutime sinsind sizeof sizepic sound sqrtstrint strintok strnat strnatok strrealstrrealok succ sysclock sysexit systemtakepic time upper wallclock whatcolwhatcolor whatcolorback whatcolour whatcolourback whatdotcolorwhatdotcolour whatpalette whatrow whattextchar whattextcolorwhattextcolorback whattextcolour whattextcolourback

PredefinedModulesBrush Button CheckBox Comm ConcurrencyConfig Dir Draw DropBox EditBoxError ErrorNum Event File FontGUI Input Joytick Keyboard LimitsListBox Math Menu Mouse MusicNet Obsolete PC Pen PicPrint RadioButton Rand RGB SoundSprite Str Stream Student SysText Time TypeConv Video ViewWindow

PredefinedOOTConstants(...meansseveralconstantswiththeprefix,seethemoduleforacompletelist)

black blue brightblue brightcyanbrightmagenta brightpurple brightred brightwhitebrushErrorBase cdMaxNumColors cdMaxNumColours cdMaxNumPagescdScreenWidth clLanguageVersion clMaxNumDirStreams clMaxNumRunTimeArgsclRelease cmFPU cmOS cmProcessorcolourbg colorfg colourfg configErrorBasedarkgray darkgrey defFontID defWinIDe...(ErrorNum) errWinID excp...(Exceptions) fileErrorBasefontErrorBase fsysErrorBase generalErrorBase graygrey guiErrorBase joystick1 joystick2magenta mouseErrorBase musicErrorBase ootAttr...(File)penErrorBase pic...(Pic) picXorplaceCenterDisplay placeCentreWindow printerErrorBase purplered rgbErrorBase spriteErrorBase streamErrorBasetimeErrorBase unixSignalToException viewErrorBase whiteyellow

Keywordsaddressint all and array asmassert begin bind bits bodyboolean break by case charcheat checked class close collectioncondition const decreasing def deferreddiv else elseif elsif endendfor endif endloop enum exitexport external false fcn flexiblefor fork forward free functionget handler if implement importin include inherit init intint1 int2 int4 invariant labelloop mod module monitor natnat1 nat2 nat4 new notobjectclass of opaque open orpacked pause pervasive pointer postpre priority proc procedure processput quit read real real4real8 record register rem resultreturn seek self set shlshr signal skip string tagtell then timeout to truetype unchecked union unqualified varwait when write xor

OperatorsMathematicalOperators

Operator Operation ResultTypePrefix+ Identity AsOperandsPrefix- Negative AsOperands+ Addition AsOperands- Subtraction AsOperands* Multiplication AsOperands/ Division AsOperandsdiv IntegerDivision intmod Modulo intrem Remainder int** Exponentiation AsOperands< LessThan boolean> GreaterThan boolean= Equals boolean<= LessThanorEqual boolean>= GreaterThanorEqual booleannot= NotEqual boolean

BooleanOperators

Operator Operation ResultTypePrefixnot Negation booleanand And booleanor Or booleanxor ExclusiveOr boolean=> Implication boolean

SetOperators

Operator Operation ResultType+ Union set- SetSubtraction set* Intersection set= Equality booleannot= Inequality boolean<= Subset boolean< Strict(Proper)Subset boolean>= Superset boolean> Strict(Proper)Superset boolean

OperatorsonMembersandSets

Operator Operation ResultTypein MemberofSet booleannotin NotMemberofSet booleanxor ExclusiveOr set

BitManipulationOperators

Operator Operation ResultTypeshl Shiftleft natshr Shiftright natand Bit-wiseAnd nator Bit-wiseOr natxor Bit-wiseExclusiveOr nat

PointerOperators

Operator Operation ResultType^ Followpointer Targettype

TypeCheats

Operator Operation ResultType# Typecheat nat

OperatorShortForms

Thesecanbeusedinplaceoftheabovenotation.not ~not= ~=notin ~inand &or |

OperatorPrecedence

Highestprecedenceoperatorsfirst.

1. **,^,#2. prefix+and-3. *,/,div,mod,rem,shl,shr4. +,-,xor5. <,>,=,<=,>=,not=,in,notin6. not7. and8. or9. =>

FileStatementsFileCommands

open openafile close closeafile put writealphanumerictexttoafile get readalphanumerictextfromafile write binarywritetoafile read binaryreadfromafile seek movetoaspecifiedpositioninafile tell reportthecurrentfileposition eof checkforendoffile

FileCommandSyntaxopen:streamNo,fileName,ioCapability{,ioCapability}

ioCapabilityisoneofget,put,read,write,seek,mod

putorwritecapabilitywillcauseanyexistingfiletobetruncatedtozerolengthunlessthemodcapabilityisalsospecified.

seekcapabilityisneededtouseseekortellcommands.

close:streamNo

get:streamNo,getItem{,getItem}

put:streamNo,putItem{,putItem}

read:streamNo[:fileStatus],readItem{,readItem}

write:streamNo[:fileStatus],writeItem{,writeItem}

seek:streamNo,filePositionorseek:streamNo,*

tell:streamNo,filePositionVar

eof(streamNo):boolean(Thisisafunction)

AppendingtoaTextFile%Openthefileforput,butdonoteraseit

open:streamNo,fileName,put{,get},mod

%Movethefilepointertotheendofthefile

seek:streamNo,*

ControlConstructs

for[decreasing]variable:startValue..endValue...statements...exitwhenexpn...statements...

endfor

loop...statements...exitwhenexpn...statements...

endloop

ifconditionthen...statements...{elsifconditionthen...statements...}[else...statements...]

caseexpnof...statements...{labelexpn{,expn...statements...}[label:...statements...]

endcase

Anynumberofexitandexitwhenstatementscanappearatanyplaceinsidefor..endforconstructsandloop..endloopconstructs.

KeyCodesOrdinalvaluesofkeystrokesreturnedbygetchandgetchar.

(space) 32

` 96Ctrl-A 1 ! 33 A 65 a 97Ctrl-B 2 " 34 B 66 b 98Ctrl-C 3 # 35 C 67 c 99Ctrl-D 4 $ 36 D 68 d 100Ctrl-E 5 % 37 E 69 e 101Ctrl-F 6 & 38 F 70 f 102Ctrl-G 7 ' 39 G 71 g 103

Ctrl-H/BS 8 ( 40 H 72 h 104Ctrl-I/Tab 9 ) 41 I 73 i 105Ctrl-J/Enter 10 * 42 J 74 j 106

Ctrl-K 11 + 43 K 75 k 107Ctrl-L 12 , 44 L 76 l 108Ctrl-M 13 - 45 M 77 m 109Ctrl-N 14 . 46 N 78 n 110Ctrl-O 15 / 47 O 79 o 111Ctrl-P 16 0 48 P 80 p 112Ctrl-Q 17 1 49 Q 81 q 113Ctrl-R 18 2 50 R 82 r 114Ctrl-S 19 3 51 S 83 s 115Ctrl-T 20 4 52 T 84 t 116Ctrl-U 21 5 53 U 85 u 117Ctrl-V 22 6 54 V 86 v 118Ctrl-W 23 7 55 W 87 w 119

Ctrl-X 24 8 56 X 88 x 120Ctrl-Y 25 9 57 Y 89 y 121Ctrl-Z 26 : 58 Z 90 z 122

Ctrl-[/Esc 27 ; 59 [ 91 { 123Ctrl-\ 28 < 60 \ 92 | 124Ctrl-] 29 = 61 ] 93 } 125Ctrl-^ 30 > 62 ^ 94 ~ 126Ctrl-_ 31 ? 63 _ 95 Ctrl-BS 127

Alt-9 128

Alt-D 160

F6 192

Ctrl-F3 224Alt-0 129 Alt-F 161 F7 193 Ctrl-F4 225Alt-- 130 Alt-G 162 F8 194 Ctrl-F5 226Alt-= 131 Alt-H 163 F9 195 Ctrl-F6 227

Ctrl-PgUp 132 Alt-J 164 F10 196 Ctrl-F7 228F11 133 Alt-K 165 197 Ctrl-F8 229F12 134 Alt-L 166 198 Ctrl-F9 230

Shift-F11 135 167 Home 199 Ctrl-F10 231Shift-F12 136 168 UpArrow 200 Alt-F1 232Ctrl-F11 137 169 PgUp 201 Alt-F2 233Ctrl-F12 138 170 202 Alt-F3 234

Alt-F11 139 171 LeftArrow 203 Alt-F4 235

Alt-F12 140 Alt-Z 172 204 Alt-F5 236

Ctrl-UpArrow 141 Alt-X 173 RightArrow 205 Alt-F6 237

142 Alt-C 174 206 Alt-F7 238BackTab 143 Alt-V 175 End 207 Alt-F8 239

Alt-Q 144 Alt-B 176 DownArrow 208 Alt-F9 240

Ctrl-DownArrow 145 Alt-N 177 PgDn 209 Alt-F10 241

Ctrl-Insert 146 Alt-M 178 Insert 210 242

Ctrl-Delete 147 179 Delete 211 Ctrl-LeftArrow 243

Alt-T 148 180 Shift-F1 212 Ctrl-RightArrow 244

Alt-Y 149 181 Shift-F2 213 Ctrl-End 245Alt-U 150 182 Shift-F3 214 Ctrl-PgDn 246Alt-I 151 183 Shift-F4 215 Ctrl-Home 247Alt-O 152 184 Shift-F5 216 Alt-1 248Alt-P 153 185 Shift-F6 217 Alt-2 249 154 186 Shift-F7 218 Alt-3 250 155 F1 187 Shift-F8 219 Alt-4 251 156 F2 188 Shift-F9 220 Alt-5 252 157 F3 189 Shift-F10 221 Alt-6 253

Alt-A 158 F4 190 Ctrl-F1 222 Alt-7 254Alt-S 159 F5 191 Ctrl-F2 223 Alt-8 225

OrdinalvaluesofcharactersthataresetbyInput.KeyDown.

Backspace 8

(space) 32

` 96Tab 9 ! 33 A 65 a 97Enter 10 ! 34 B 66 b 98Escape 27 # 35 C 67 c 99

$ 36 D 68 d 100F11 133 % 37 E 69 e 101F12 134 & 38 F 70 f 102Shift 180 ' 39 G 71 g 103Control 181 ( 40 H 72 h 104Alt 182 ) 41 I 73 i 105

Keypad5 183 * 42 J 74 j 106F1 187 + 43 K 75 k 107F2 188 , 44 L 76 l 108F3 189 - 45 M 77 m 109F4 190 . 46 N 78 n 110F5 191 / 47 O 79 o 111F6 192 0 48 P 80 p 112F7 193 1 49 Q 81 q 113F8 194 2 50 R 82 r 114F9 195 3 51 S 83 s 115F10 196 4 52 T 84 t 116

5 53 U 85 u 117Home 199 6 54 V 86 v 118

UpArrow 200 7 55 W 87 w 119PgUp 201 8 56 X 88 x 120

LeftArrow 203 9 57 Y 89 y 121RightArrow 205 : 58 Z 90 z 122

End 207 ; 59 [ 91 { 123DownArrow 208 < 60 \ 92 | 124

PgDn 209 = 61 ] 93 } 125Insert 210 > 62 ^ 94 ~ 126Delete 211 ? 63 _ 95

RunWindowCharacterSetTheTuringcharactersetandtheirASCIIvalues

chr(8)=backspacechr(9)=tabchar(10)=newline

Youcanalsoget(onmostsystems),theMS-DOScharactersetbyusingthecommandsetscreen("msdos").Thisisthecharactersetafterthesetscreen("msdos")commandwasgiven.

ClickthebuttontolaunchtheprogramtodisplaythecharactersetinTuring.

TuringTeacher/AdministratorQuickStartGuideThisguideisdesignedtobetheminimalinformationthatyoushouldreadifyouareteachingcoursesusingTuring4.0orareinchargeofadministeringTuring4.0

ThisguideprovidesinformationontheTuringenvironment(theeditor,therunwindows,etc.)ItdoesnotprovideanyinformationontheTuringprogramminglanguageitself.

Note,ifyouhaveanyquestionsnotansweredhere,pleasecheckwiththeTuringTeacher/Administrator'sCompleteGuideformoreinformation.

TableofContents

1. MakingCertainYouHavetheLastestVersion2. MandatoryAdministrationIssues3. UsingtheParallelPortsinTuring44. StudentDistribution5. TechnicalSupport

1.MakingCertainYouHavetheLastestVersion

Turing4.0isupdatedregularly.Tofindoutwhatversionyouarecurrentlyrunning,clicktheAboutTuringmenuitemintheHelpmenu.TofindoutthecurrentversionofTuring,gotohttp://www.holtsoft.com/turing/support/#currentversion.Thisliststhecurrentversionofthesoftware.

Thispagealsolistswhichbugshavebeenfixedandwhennewfeatureshavebeenadded.Thepagealsocontainsasection(http://www.holtsoft.com/turing/support/#turing4patches)whereafilecanbedownloadedthatwillupdatemostversionsofTuringtothelatestversion.

Ifyouareateacheroranadministratorataschoolandrequireacompleteinstallationfile(asopposedtothepublicallyavailablepatch),contactTomWestat(416)978-8363.

2.MandatoryAdministrationIssues

Turing4.0hasbeendesignedtorunoneitheranetworkorinstalledonindividualstand-alonemachines.Runningonanetworkisoftenpreferredbecauseofeaseofadministration.However,Turing,likeanyotherapplicationwillloadsomewhatfasterwhenitislaunchedifitisstoredlocally.

ThereareonlytwoadministrationissuesthatmustbeaddressedtoconfigureTuringproperly.

1. Setthestart-in(oftencalledthe"working")directoryproperly.

Itisimportantthatthestart-indirectoryforTuringbesettothestudent'shomedirectory.Thisisdonebysettingthestart-in(orworking)directoryoftheshortcutormenuitemusedtolaunchTuringtothedrivemappedtothestudent'shomedirectory.

Theshortcut'sworkingdirectorycanbemodifiedbychangingit'sstart-inorworkingdirectoryproperty.(TodisplaythePropertiesdialogbox,rightclickontheshortcutormenuitemandselectPropertiesfromthepop-upmenu.)

PropertiesforaShortcutunderWindows2000

Thisrequiresthatyouhavewriteaccesstotheshortcut.Notethatcommercialmenufront-endshavetheirownwayofsettingthestart-indirectoryofapplications.

Ifthereisnodrivemappedtothestudent'shomedirectory,orthismethodisnotapplicabletoyoursystemsetup,pleasecheckwiththeTuringTeacher/Administrator'sCompleteGuideformoreinformation.

2. SeteitherBeginnerorRegularModeforStudents.

TuringcanbesettoBeginnermode,inwhichcaseonlyonefileisopenatatime.Openingupanotherfileclosesthefirstone.Whentheprogramisrunning,theEditorwindowminimizes.Inthisway,onlyonewindowisusuallyvisibleatatime.Inthisfashion,BeginnermodeissimilartotheoldDOSTuring.

InRegularmode,anynumberoffilescanbeopenedandeachappearsinitsowneditorwindow.

Ingeneral,wesuggestBeginnermodeforgrade9and10andRegularmodeforallothers.IfyouareusingBeginnermode,wesuggestthatyoupointouttothestudentsthattheycanusethePrefencestochangetoRegularmodewhentheyfeelcomfortablewiththeenvironment.

Tochangethemode(ortomakeanyotherchangetothesystempreferences),youmustopenaDOSwindow,cdtothedirectoryinwhichtheTuringexecutable(turing.exe)islocatedandissuethecommand:

turing-admin

ThiswillcauseTuringtostartinAdministratormode,displayingthefollowingdialogbox:

AdministrationModeNotification

SelectingPreferencesfromtheFilemenuwilldisplayatabbeddialogboxofalltheTuringpreferences.

PreferencesinAdministratorMode

Set(orunset)theBeginnerModepreference,clicktheOKbuttonandquitTuring.Ofcourse,youcanchangeanyotherpreferencesthatyouwouldlike.AnychangesthatyoumakeherewillaffectallthoseusingTuring.

3.UsingtheParallelPortsinTuring4

Turing4.0supportstheparallelputandparallelgetcommandstoallowyoutosetthepinsontheparallelportlowandhigh.IfyouarerunningunderWindowsNT,2000orXP,youwillneedtoinstalladevicedriveroneachmachine.Instructionsfordoingsocanbefoundhere.Ifparallelputandparallelgetdonotseemtofunction,youmayneedtochangetheirBIOSsettings.Youcangetinformationonhowtodothathere.

4.StudentDistributionofTuring4.0

TheOntarioMinistrylicensedoesnotincludetherighttoredistributethesoftwaretostudents.Ifyouwishtogivethesoftwaretostudents,aseparatelicensemustbeobtaineddirectlyfromHoltSoftware.

Ifyourschooldoesnothavesuchalicense,studentscanpurchasethesoftwareforhomeusebyprintingandthenmailinganorderformfoundhttp://www.holtsoft.com/studentbuy.Thisorderformcanalsobeusedtoallowinterestedstudentstopurchasetextbooks.

Ifyourschoolhaspurchasedaredistributionlicense(almost200schoolshavedoneso),thenyoumayredistributetheTuringsoftwaretoyourstudents.YoucaneitherburncopiesoftheCDtodistributetostudentsorplacetheTuringinstallerfileontoyourschoolInternetserverandgiveyourstudentstheURL.

Ifyouplacethisfileonyourschoolinternetserver,youmustnotmakeanylinksfromyourwebpagestothesoftware.

Thiswillpreventotherusersofthewebfromdownloadingyoursoftware.Ifyouplacelinksfromyourschool'swebsite,thenatsomepointawebsearchenginewillfindthesoftwareandpostitslocationtotheinternetatlarge,allowingforlargescalepiracy(andaveryoverloadedschoolwebserver).Iftherearenolinkstothesoftware,thenonlythosewhohavebeentoldtheexactURLwillbeabletodownloadthesoftware.

NotethatifyouarecopyinganumberofdifferentprogramsontoasingleCDforredistribution,youmayrenametheTuringinstallerprogramtosomethingmoredescriptive.

Permanentstudentredistributionlicensescanbepurchasedfor$500-$750formostschools.Ifyouareinterestedinpurchasingastudentredistributionlicense,contactChrisStephensonat(416)978-6476orchris@hsa.on.ca

5.TechnicalSupport

Ifyouhaveproblems,questionsorsuggestionsabouttheTuringsoftware,contacttechnicalsupportat:Telephone: (416)978-8363Tollfree: 1-800-361-8324Fax: (416)978-1509E-mail: west@hsa.on.ca

TuringTeacher/AdministratorGuideThisistheTuringTeacher/Administratorguide.ItcontainsmostoftheinformationthatyouwillneedtoadministertheTuring4.0software.ItshouldbereadbythosewhoareteachingcoursesusingTuring4.0orareinchargeofadministeringTuring4.0

ThisguideprovidesinformationontheTuringenvironment(theeditor,therunwindows,etc.)ItdoesnotprovideanyinformationontheTuringprogramminglanguageitself.

NotethatthereissomeoverlapwiththeTuringTeacher/AdministratorQuickStartGuide.

TableofContents

1. MakingCertainYouHavetheLastestVersion2. MandatoryAdministrationIssues3. ChangingSystemPreferences4. TuringPreferences5. ParallelPortandTuring46. MissingFeaturesfromTuring47. TheTuringDebugger8. StudentDistribution9. TechnicalSupport

1.MakingCertainYouHavetheLastestVersion

Turing4.0isupdatedregularly.Tofindoutwhatversionyouarecurrentlyrunning,clicktheAboutTuringmenuitemintheHelpmenu.TofindoutthecurrentversionofTuring,gotohttp://www.holtsoft.com/turing/support/#currentversion.Thisliststhecurrentversionofthesoftware.

Thispagealsolistswhichbugshavebeenfixedandwhennewfeatureshavebeenadded.Thepagealsocontainsasection(http://www.holtsoft.com/turing/support/#turing4patches)whereafilecanbedownloadedthatwillupdatemostversionsofTuringtothelatestversion.

Ifyouareateacheroranadministratorataschoolandrequireacompleteinstallationfile(asopposedtothepublicallyavailablepatch),contactTomWestat(416)978-8363.

2.MandatoryAdministrationIssues

Turing4.0hasbeendesignedtorunoneitheranetworkorinstalledonindividualstand-alonemachines.Runningonanetworkisoftenpreferredbecauseofeachofinstallation,however,Turingwillloadsomewhatfasterwhenitislaunchedifitisstoredlocally.

Turing4.0hasbeendesignedtorunoneitheranetworkorinstalledonindividualstand-alonemachines.Runningonanetworkisoftenpreferredbecauseofeaseofadministration.However,Turing,likeanyotherapplicationwillloadsomewhatfasterwhenitislaunchedifitisstoredlocally.

ThereareafewadministrationissuesthatmustbeaddressedtoconfigureTuringproperly.

1. Setthestart-in(oftencalledthe"working")directoryproperly.

Itisimportantthatthestart-indirectoryforTuringbesettothestudent'shomedirectory.Thiscanbedoneinavarietyofways,fromleasttomostcomplicated.

1. Manyschoolshavethestudent'shomedirectorymappedtoadrive(oftenH:\).Ifthisisthecase,thensetthestart-in(orworking)directoryoftheshortcutormenuitemusedtolaunchTuringtothemappeddrive.

Theshortcut'sworkingdirectorycanbemodifiedbychangingit'sstart-inorworkingdirectoryproperty.(TodisplaythePropertiesdialogbox,rightclickontheshortcutormenuitemandselectPropertiesfromthepop-upmenu.)

PropertiesforaShortcutunderWindows2000

Thisrequireschangingtheshortcut'spropertiesrequireswriteaccesstotheshortcut.Notethatcommercialmenufront-endshavetheirownwayofsettingthestart-indirectoryofapplications.

2. Ifthe"MyDocuments"folderismappedtothestudentshomedirectory,youcansetthepreferencestomakeTuringusethe"MyDocuments"folderasthestart-infolder.Notethatthisoptionisthepreferredoptionforhomeusers,wherethe"MyDocuments"folderisthehomedirectory.

TheUse"MyDocuments"FolderintheAdminPane

Tochangethepreference,enterAdministratormode(seeChangingSystemPreferencesbelow)andsettheUse"MyDocuments"FoldercheckboxintheAdminpaneoftheTuringPreferences(seeTuringPreferencesbelow).

3. Ifeachstudent'shomedirectoryisspecifieddifferently(i.e.thereisnomappingofthehomedirectorytoadrive),thenyoumayneedtouseenvironmentvariablestocreateauseablepath.Forexample,ifstudentsfilesarestoreding:\class108\[StudentName]andthereisanenvironmentvariablesUSERNAMEthatcontainsthestudent'sname,thenthethestart-indirectoryfortheshortcutshouldbesettog:\class108\%USERNAME%.

4. Occasionallyusershavereportedsituationslikethepreviouscase,exceptthatWindowsseemsunabletosetthestart-indirectoryproperlyusingenvironmentvariables.

TheStartupDirectoryTextFieldintheAdminPane

Tosetthestart-indirectory,enterAdministratormode(seeChangingSystemPreferencesbelow)andsettheStartupDirectorytextfieldintheAdminpaneoftheTuringPreferencesappropriately(seeTuringPreferencesbelow)includingspecifyingthedirectoryusingtheenvironmentvariables.

2. SeteitherBeginnerorRegularModeforStudents.

TuringcanbesettoBeginnermode,inwhichcaseonlyonefileisopenatatime.Openingupanotherfileclosesthefirstone.Whentheprogramisrunning,theEditorwindowminimizes.Inthisway,onlyonewindowisusuallyvisibleatatime.Inthisfashion,BeginnermodeissimilartotheoldDOSTuring.

InRegularmode,anynumberoffilescanbeopenedandeachappearsinitsowneditorwindow.

Ingeneral,wesuggestBeginnermodeforgrade9and10andRegularmodeforallothers.IfyouareusingBeginnermode,wesuggestthatyoupointouttothestudentsthattheycanusethePrefencestochangetoRegularmodewhentheyfeelcomfortablewiththeenvironment.

Tochangethepreference,youwillneedtoenterAdministratormode(seeChangingSystemPreferencesbelow)andchangetheBeginnerModepreferenceintheGeneralpaneappropriately(seeTuringPreferencesbelow).

3. Windows95andtheTuringNetmodule

IfyouareusingWindows95(notWindows98/Me/NT/2000/XP)andyouwishtousetheTuringNetmoduleinordertowriteprogramsthatcommunicatewithothercomputers,thenyoumayneedupdatetheWindow95networkingcode.

Thiscanbedonebyrunningtheprogramlocatedat:

[Turingdirectory]\support\Microsoft\W95ws2setup.exe

ThisprogramfromMicrosoftpatchesWindows95networkingcode.ItmustberunoneverycomputerrunningWindows95unlessthemachinesbootfromaserver.

4. ParallelPortUsageIfyouareintendtouseTuringtocontroldevicesattachedtotheparallelport(usingtheparallelputandparallelget,andarerunningunderWindowsNT/XP/2000,youwillneedtoinstalladevicedriver.(WindowsNT/XP/2000donotallowdirectaccesstothesystemhardware.).Thedevicedrivercanbeinstalledbyrunningtheprogramlocatedat:

[Turingdirectory]\support\dlportio_install.exe

FurtherinformationcanbefoundinParallelPortandTuring4.

3.ChangingSystemPreferences

Turingusesatwolevelpreferencemodel.Thereisacentralsetofpreferencesthatarekeptin

[TuringDirectory]\Support\Ini\turing_admin.ini

ThesepreferencesarethesameforallusersandarecalledtheSystemPreferences.Asecondsetofpreferencesisstoredineachstudent'shomedirectoryinafilecalledturing.ini.ThesepreferencesoverridethecentralpreferencesandallowstudentstoindividuallymodifythebehaviourofTuring.

Whenastudentmodifiesthepreferences,theturing.inifileinthestudent'shomedirectoryischanged.TochangetheSystempreferences(i.e.thecontentsoftheturing_admin.inifile),Turingmustbestartedupwiththecommandline

turing-admin

ThiscanbedonebystartingupaDOSwindow,doingacdtothedirectoryinwhichturing.exeisstoredandthentypingturing-admin.Theusermusthavewriteaccesstothedirectoryinwhichtheturing_admin.inifileisstored.

WhenTuringislaunched,itwilldisplayamessageboxonstart-upindicatingthatitisinAdministratormodeandwherethepreferenceswillbestored.

AdministrationModeNotification

SelectingPreferencesfromtheFilemenuwilldisplayatabbeddialogboxofalltheTuringpreferences.IfyouareinAdministratormode,thenanextratablabeledAdminwillappearwithextrapreferencesthatcanonlybesetbytheAdministrator.NotethatindividualstudentscannotoverridethepreferencesthatappearontheAdminpane.

PreferencesinAdministratorMode

OncethePreferenceshavebeenset,theAdministratorcanexitTuring.

4.TuringPreferences

ThissectionlistsallthepreferencesavailableinTuringsortedbythepane

"General"Pane

The"General"Pane

BeginnerModeWhenBeginnermodeisset,onlyonefilecanbecanbeloadedintotheTuringenvironmentatatime.TheEditorwindowisminimizedeverytimetheRunwindowisactiveandvice-versa.Thedebuggercannotbedisplayedorused.Ifthisboxisnotset,thenTuringisinRegularmodeandmultiplefilescanbeopensimultaneously.BeginnermodeisrecommendedforstudentswhoareoverwhelmedorconfusedbytoomanyTuringwindows(especiallystudentsingrades9and10).OneWindowModeThisoptionisnotavailableinTuring4.0.ItwillbeusedtoswitchbetweenMDIandSDImodesinafutureversionofthesoftware.DisplayFullPathnames

ThefullpathnameandnotjustthefilenamearedisplayedintheEditorwindow'stitlebarandrecentfilessubmenu.SavePreviousFileas".BAK"Whenafileissavedovertopofanolderfile,theolderfileisrenamedwitha.BAKsuffix(i.e.test.ttotest.bak)ConfirmonQuitWhentheuserclosesthelasteditorwindow,TuringdisplaysadialogboxaskingwhethertheuserwishestoQuit.Onsystemswhereloadingisslow(usuallyoveranetwork),thiscanstoptheusersfromaccidentallyquittingTuring.SkipSplashScreenWhenTuringstartsup,itnormallydisplaysa"Splash"screenwiththeversionnumber.TheSplashscreendisappearswhentheuserclicksabuttonorafter3seconds.TurningthisoptionoffcausestheSplashscreennottobedisplayed.Add".t"toFileNamesWhenaSaveFiledialogboxappearsandtheuserspecifiesafilenamewithoutafilesuffix,Turingadds".t".Thiscanberemovedbytheuser.ConvertLeadingSpacesintoTabsWhenTuringsavesafile,itnormallyconvertsgroupsofleadingspacesintoTABcharacters,savingdiskspace.ThenumberofspacespertabisspecifiedbytheSpacesperTabtextfield.Ifthischeckboxisnotselected,thenthespacesarenotconverted.Don'tSaveRecentFilesMenuNormallyTuringliststhelastseveralfilesopened.However,ifstudentsdonothaveindividualaccounts,thenthisfeaturemaynotbeusefulandcanbeturnedoff.FindUsesSelectedTextBydefault,TuringusestheWindowsbehaviourthatwhenaFindcommandisgivenandthereisselectedtext,theselectedtextiscopiedtotheFinddialogbox.Ifyoudon'tlikethisbehaviour,thenunsettingthisoptionwillstopthisbehaviour.Ifitisnotset,thenanadditionalmenuitemisplacedintheSearchmenuthatfindsthenextoccuranceofthecurrentlyselectedtext.StartinLastActiveDirectoryIfstudentsarewritinglargeprojectsinmanysubdirectories,thenthisoptioncanbeenabledtoautomaticallystartTuringinthelastdirectoryinwhichafilewasloadedorsaved.TheTuringpreferencesfileisstillstoredinthestudent'shomedirectory.SpacesperTab

ThisspecifiesthenumberofspacesthataTabisconvertedtoandfrom.WhenTuringreadsatextfileintotheeditor,alltabsareconvertedontospaces.IfyoucreatedtheTuringfileonaneditorwhereTabsareadifferentnumberofspaces,thenchangethisvalueappropriately.IndentSizeWhenTabispressedintheTuringeditor,itisconvertedintospaces.ThenumberintheIndentSizetextfielddetermineshowmanyspacestheTabkeyisconvertedto.NotetheSpacesperTabisusedwhenTuringreads/writesfiles.TheIndentSizefieldisusedwhenTuringrespondstotheTabkey.FileAssociationMicrosoftWindowshastheabilitytoassociatefileswithaparticularsuffixwithspecificprograms.TheTuringenvironmentcanbeassociatedwiththefollowingfilesuffixes:.t,.tur,.dem,.tiand.tu.ToassociatethesefilesuffixeswithTuring,clicktheAssociate".t"fileswithTuringbutton.Toresetthefileassociationsbacktowhattheywerebefore,clicktheReset".t"FileAssociation.

"EditorWindow"Pane

The"EditorWindow"Pane

EditorFontYoucanchangethefontsizeandtypefaceusedintheeditorwindow.Ifyouchangethetypeface,youmustchooseamonospacedfontwhereboldandnon-boldlettersarethesamesize.Manymonospacedfontshavedifferentsizesforboldandnon-boldletters.FullScreenforBeginnerModeIfinbeginnermode,editorwindowsareautomaticallyinfullscreenmode.Youcanchangethisbehaviourbuyunsettingthischeckbox.FullScreenforRegularModeEditorwindowsarenormally25x80columns(orthesizespecifiedbytheEditorWindowRows/Columnstextfields).Ifthischeckboxisset,editorwindowsareautomaticallymaximizedtofillthescreen.Thisoptionissuggestedforsystemswith640x480screenresolution.Userscanchangethewindowsizebyclickingthefullscreen/normalwindowbuttoninthewindow'stitlebar.EditorWindowRows/ColumnsThesetextfieldscontrolthesizeofeditorwindowswhenfirstcreated.SyntaxColoringWhenselected,partsofTuringprogramsappearindifferentcolors:commentsappearingreen,stringsinred,keywordsinboldface,predefinedidentifiersinblack,anduseridentifiersinblue.AlwaysShow'Debugger'MenuIntheinterestofkeepingtheinterfaceassimpleaspossible,andbecausemoststudentsdonotusethedebuggingfeatures,TuringdoesnotdisplaytheDebuggermenubydefault.Instead,theuserselectsShowDebuggerMenufromtheRunmenu.SettingthischeckboxcausestheDebuggermenutoalwaysbedisplayed.TextCursorWidthBydefault,thecursor(correctlycalledthecaret)is2pixelswide,allowingittobeseeneasilyintheEditorwindow.However,someuserspreferthecarettobe1pixelwideandsomepreferthecarettooverlayanentirecharacter(inasimilarmannertoDOSeditors).Legalvaluesare1(whichrepresenta1pixelthickcaret),2(whichrepresenta2pixelthickcaret),and3(whichrepresentsatextcursorthatcoverstheentirecharacter.

"RunWindow"Pane

The"RunWindow"Pane

DefaultRunWindowFontYoucanchangethefontsizeandtypefaceusedintheTuringrunwindow.Ifyouchangethetypeface,youmustchooseamonospacedfont.NotethatchangingthesizeoftherunwindowfontmaycauseoddoutputinTuringprogramsthatwerewrittenassumingaparticularcharactersize.StartinGraphicsModeThismakestheinitialrunwindowagraphicswindow.Theusercanusegraphicswithoutthesetscreen("graphics")commandintheprogram.Outputthatscrollsoffthetopofthescreenislost.Intextmode,graphicsarenotallowed,butalltextoutputiskeptandcanbescrolled,saved,andprintedatanytime.FullScreenRunWindowThiscausesthedefaultrunwindowtooccupytheentirescreen.RunWindowRows/ColumnsThissetsthesizeofthedefaultrunwindow.Changingthesizemaycauseprogramsthatassumea25x80windowtomalfunction.UseSmallFontson640x480ScreenAstandard25x80windowdoesnotquitefitona640x480screenwithastandardsizetaskbar.Asaresult,withoutthisoption,thedefaultgraphicsmoderunwindowappearswithscrollbars.ThisoptioncausesTuringtouse

aslightlysmallerfontfor640x480runwindowssotheentirewindowfitsonthescreen.ThisoptionmaycauseoddoutputinTuringprogramsthatwerewrittenassumingaparticularcharactersize.

"Printing"Pane

The"Printing"Pane

Notethattheoptionsmarkedwithanasterisk(*)canbesetintheprintingdialog.

PrintingFont/PrintingHeaderFontYoucanchangethefontsizeandtypefaceusedinprinting.Ifyouchangethetypeface,youmustchooseamonospacedfontwhereboldandnon-boldlettersarethesamesize.Manymonospacedfontshavedifferentsizesforboldandnon-boldletters.BoldKeywords/ItalicizeIdentifiers*Thisallowsfor"syntaxcoloring"ofprintouts.Keywordscanbeplacedinboldandidentifiersitalicized.PrintPageHeaderOnsomesystems,aheaderpageisautomaticallyprintedoutandthereislittlereasonforapageheader.Unsettingthischeckboxwillcauseprintouts

nottohaveanyheaderontheprintedprograms.UserNameinHeaderNormallytheusernameisdisplayedintheheader.However,onsomesystemstheusernameisnon-descriptiveornon-existent.Thisallowsyoutodisabletheprintingoftheusernameonsuchsystems.Two-UpPrinting*Thisisapapersavingmeasure.Textisprintedinlandscapemodewithtwo"pages"perpieceofpaper.Thismeansthatlistingsusehalftheamountofpaper.Ofcourse,thefontismuchsmaller.LineNumbers*Thisprintsoutlinenumbersinfrontofeachlineoftheprogram.Thisisusefulifyouareprintingoutalistingtohandouttotheclass.BorderAroundTextSomeusersliketohaveathinborderprintedaroundthetextforeaseofdeterminingthemargins,etc.SettingthischeckboxcausesTuringtodisplayahairlineborderaroundprogramprintouts.MarginsIfyouneedtochangethemarginsonprintouts(forexample,tofacilitatetheinsertionofprogramlistingsinto3-ringbinders),thenyoucandobychangingthevaluesinthetextfields.Marginsareexpressedininches.UserNameOnsystemswheretheusernameisnon-descriptiveornon-existent,theusercanenteranamethatwillappearontheprintoutallowingittobeidentified.Ifstudentsarechoosinginappropriateusernames,thispreferencecanbedisabledintheAdmintabpreferencedialog.

"Admin"Pane

The"Admin"Pane

Note,theAdminpaneisonlyavailableinadministratormode.StudentsstartingTuringwillnothaveaccesstothisdialogbox.

StartupDirectoryUserswillstartinthedirectorylistedinthistextfield.Ifleftblank,TuringwillusetheworkingdirectoryoftheshortcutusedtostartTuring.Ifnoworkingdirectoryfortheshortcutisspecified,thedirectorywhereTuringisinstalledisused.Environmentvariablesprefixedandsuffixedwith%signscanbeusedhere(example:g:\students\%username%).Notethatinmostcases,thistextfieldshouldbeblank.Use"MyDocuments"folderThe"MyDocuments"foldercanbeusedasthestartupdirectoryinsteadofthecontentsoftheStartupDirectorytextfield.Thisismostcommonlyusedinsingleusersystems.CanSetUserNameAllowstheusertospecifytheusernametoappearontopofprintouts.Thischeckboxcanbeunsetifstudentsarechoosinginappropriateusernames.CanEnterRegularModeAllowstheusertoturnoffthebeginnermodepreference.Thischeckboxcanbeunsetifitisdesirabletohaveallstudentsworkinginbeginnermode.

DebuggerAvailableThischeckboxcanbeunsetinordertostopstudentsgettingaccesstothedebugger.CannotAlterPreferencesWhenset,thisstopsstudentsfromaccessingthePreferencesdialog.ItalsostopsTuringfromreadingthestudent'sturing.inifile.Thiscanbesetwhenitisimportanttohaveauniformsetofpreferencesonallstudentmachines,orwhenthereisnolog-onprocedureandstudentsaresharingmachines.Prohibituseof'Sys.Exec'Whenset,theSys.Execandsystemproceduresdonothing.Thiscanbesetifthereisasystemsecurityconcernaboutstudentsstartingarbitraryprograms.NoSoundorMusicWhenset,theTuringsoundandmusiccommandsdonothing.UseonlyStartupDirectoryandBelowCAUTION!Thisoptiononlyprovidesrudimentarysecurityandistobeusedonlyonsystemswheretheoperatingsystemcannotprovidepropersecurity.Thisoptionwillnotallowstudentstosaveorloadtoanydirectoryotherthattheirstartupdirectoryordirectoriescreatedinthestartupdirectory.Thisoptiondoesnotstopstudentsfrombrowsingthenamesoffilesinotherdirectories,onlyfromloadingorsavingfilesinthem.UseOnlyAllowedDrivesCAUTION!Thisoptiononlyprovidesrudimentarysecurityandistobeusedonlyonsystemswheretheoperatingsystemcannotprovidepropersecurity.Thisoptionallowsstudentstoloadfilesonlyfromthesetofdrivesspecifiedinthetextfield.The'*'representsnetworkdrives.ForbidUseofCertainDrivesCAUTION!Thisoptiononlyprovidesrudimentarysecurityandistobeusedonlyonsystemswheretheoperatingsystemcannotprovidepropersecurity.Thisoptionpreventsstudentsfromloadingfilesfromthesetofdrivesspecifiedinthetextfield.The'*'representsnetworkdrives.

5.UsingtheParallelPortsinTuring4

UnderTuring4.0and,itispossibletoaccesstheIBMPC'sparallelportforreadingandwriting.Thisisnormallydoneusingtheparallelputandparallelgetcommands.(InTuring4.0,youcanusePC.ParallelPutandPC.ParallelGettoaccessportsotherthanLPT1.)

UnderWindows95/98andMe,theoperatingsystemallowsdirectaccesstotheparallelport.UnderWindowsNT,2000andXP,accesstotheparallelportisrestrictedbytheoperatingsystem.Inordertoaccesstheport,underWindowsNT,2000andXP,itisnecessarytoinstalladevicedriveroneachmachinethatwillbeaccessingtheparallelport.Theneededdevicedriverinstallerislocatedat:

[Turingdirectory]\support\dlportio_install.exe

where[Turingdirectory]isthedirectoryinwhichTuringwasinstalled.ExecutingthisprogramwillinstallthedevicedriverintheWindowsSystemdirectoryofthemachineuponwhichitisexecuted.

Lastly,beforeaccessingtheparallelport,checkthattheparallelportisinnormalmodeandnotinbi-directional,PS/2,EPPorECPmode.YoucandeterminewhichmodetheparallelportisinusingtheDeviceManager.InthelistofdevicesintheDeviceManagerwindow,doubleclickPorts(COMandLPT),andthentheLPT(orPRN)port.Thisdisplaysapropertysheetabouttheparallelport.Takealookatwhatitsaysaboutit.Ifitisinanon-originalmode(i.e.mentionsbi-directional,PS/2,EPPorECPmode),thenyouwillprobablyneedtoadjustthesystemsBIOSsettings.

(UnderWindows2000theDeviceManagercanbedisplayedbyselectingtheSystemControlPanelfromSettingsintheStartmenu.SelecttheHardwaretabandthenclicktheDeviceManagerbutton.)

Ifthesettingfortheparallelportneedstobechanged,restartthemachine,andpresstheappropriatekeytoentertheBIOSSetUpProgram(thekeyvariesbetweenmachines,butisusuallynotedonthescreen).OftentheparallelportsettingsarefoundinAdvancedSettingsoftheprogram.TheparallelportshouldbesettoNormal,Standard,ATorUnidirectionalmode.(Allfour

namesaredifferentdescriptionsofthesamemode.)Oncethisisdoneandthenewsettingsaresaved,thenstartthemachineintoWindows.OnceinWindows,selectShutDownandturnthemachinecompletelyoff.Oncethemachineisoff,waitatleast10secondsinthepowered-offstate.Thenrestartthemachine.(Whileshuttingdownthemachineshouldnotbenecessary,wehavehadseveralcaseswherethechangeonlytookwhenthemachinehadbeenpowered-downandrestarted.)

6.MissingFeaturesfromTuring4

Turing4.0doesnotyetincorporateallthefeaturesthatcurrentlyexistinObjectOrientedTuring3.1.1andareintendedforfutureTuringreleases.Overthenextfewmonths,newfeatureswillbeaddedandupdatestoTuringwillbemadeavailableonourwebsite.Thefeaturestobeaddedare:

ViewVariablesTheSpritemodule

Ifyouhaveimmediateneedofanyofthesefeatures,pleasecontinuetousetheObjectOrientedTuring3.1.1software.OntariouserscanobtainthesoftwarethroughtheirOESSsoftwarerepresentative.

TodeterminethecurrentreleaseofTuring,checktheTuringwebsiteat

http://www.holtsoft.com/turing/support

7.TheTuringDebugger

ThecurrentversionofTuringhasaDebuggerfacilitiesthatallowstudentstofollowexecutionofaprogrameitherpausingaftereachlineofexecutionorexecutingslowlywhilehighlightingeachlineofexecution.Becauseoftheconfusingnatureofthedebuggerformanystudents,thedefaultconfigurationofTuringdoesnotdisplaythedebuggermenuuntilthestudentrequestsitbyselectingtheShowDebuggerMenufromtheRunmenu.

AlwaysShow'Debugger'MenuintheEditorWindowPane

IfyouwishstudentstohaveamoreregularexposuretotheDebugger,youcansetaSystempreferencetocauseTuringtoalwaysdisplaytheDebuggermenu.Tosetthethispreference,enterAdministratormode(seeChangingSystemPreferencesbelow)andsettheAlwaysShow'Debugger'MenucheckboxintheEditorWindowpaneoftheTuringPreferences.

8.StudentDistributionofTuring4.0

TheOntarioMinistrylicensedoesnotincludetherighttoredistributethesoftwaretostudents.Ifyouwishtogivethesoftwaretostudents,aseparatelicensemustbeobtaineddirectlyfromHoltSoftware.

Ifyourschooldoesnothavesuchalicense,studentscanpurchasethesoftwareforhomeusebyprintingandthenmailinganorderformfoundhttp://www.holtsoft.com/studentbuy.Thisorderformcanalsobeusedtoallowinterestedstudentstopurchasetextbooks.

Ifyourschoolhaspurchasedaredistributionlicense(almost200schoolshavedoneso),thenyoumayredistributetheTuringsoftwaretoyourstudents.YoucaneitherburncopiesoftheCDtodistributetostudentsorplacetheTuringinstallerfileontoyourschoolInternetserverandgiveyourstudentstheURL.

Ifyouplacethisfileonyourschoolinternetserver,youmustnotmakeanylinksfromyourwebpagestothesoftware.

Thiswillpreventotherusersofthewebfromdownloadingyoursoftware.Ifyouplacelinksfromyourschool'swebsite,thenatsomepointawebsearchenginewillfindthesoftwareandpostitslocationtotheinternetatlarge,allowingforlargescalepiracy(andaveryoverloadedschoolwebserver).Iftherearenolinkstothesoftware,thenonlythosewhohavebeentoldtheexactURLwillbeabletodownloadthesoftware.

NotethatifyouarecopyinganumberofdifferentprogramsontoasingleCDforredistribution,youmayrenametheTuringinstallerprogramtosomethingmoredescriptive.

Permanentstudentredistributionlicensescanbepurchasedfor$500-$750formostschools.Ifyouareinterestedinpurchasingastudentredistributionlicense,contactChrisStephensonat(416)978-6476orchris@hsa.on.ca

9.TechnicalSupport

Ifyouhaveproblems,questionsorsuggestionsabouttheTuringsoftware,contacttechnicalsupportat:Telephone: (416)978-8363Tollfree: 1-800-361-8324Fax: (416)978-1509E-mail: west@hsa.on.ca

TuringDebuggerGuideIntroduction

Turingsupportsanumberoftoolstoenableuserstodebugtheirprogramsandexamineprogramexecution.Someoftheavailabletoolsare:

Steppingexecutionalineatatime.TracingexecutionwithasetpausebetweenlinesofexecutionSettingbreakpointstopauseexecutionatspecifiedpointsintheprogram.Viewingallopenresourcesofaprogramincludingfiles,fonts,pictures,etc.

AsofMay2002,theTuring4.1softwaredoesnotcontainthefollowingfeature:

Viewvariables.

Thisfeaturewillbeimplementedastimeanddeveloperresourcespermit.

DisplayingTheDebuggerMenu

Inordertouseanyofthedebuggercommands,youneedtohavetheDebuggermenushowingintheEditorwindow.Bydefault,theDebuggermenuishiddeninordertosimplifytheTuringenvironmentforthemajorityofstudentsnotusingthedebugger.

TherearetwowaysthattheDebuggermenucanbedisplayed.YoucanselecttheShowDebuggerMenucommandintheRunmenu.

ShowDebuggerMenucommandintheRunmenu

Ifyouareconsistenlyusingthedebugger,thenyoushouldchangethePreferencessothattheDebuggermenuisalwaysdisplayed.ThiscanbedonebybringinguptheEditorWindowpaneofthePreferencesdialogboxandsettingtheAlwaysShow'Debugger'Menucheckbox.

AlwaysShow'Debugger'MenuintheEditorWindowPane

UsingTheDebuggerMenu

ShowDebuggerMenucommandintheRunmenu

TheDebuggermenugivesyouaccesstoallthedebuggingfeaturesinTuring4.0.Thefollowingmenuoptionsareavailable:

ShowDebuggerControlsThiscommandcauseseachEditorwindowtodisplayasecondrowofcontrolsatthetopofthewindow(calledtheDebuggercontrols)thatallowtheusertostepthroughaprogramandtraceexecutionoftheprogram.WhentheDebuggercontrolsarevisible,thenthismenuitemchangestoHideDebuggerControls.

WindowwithDebuggerControlsVisible

ShowBreakpointsThiscommandcauseseachEditorwindowtodislayanareaontheleftwherebreakpointscanbeplaced.Abreakpointisamarkerthatcausestheprogramtopausewhenexecutionreachesthemarkedline.

WindowwithBreakpointVisible

ClearBreakpointsThiscommandquicklyeliminatesallbreakpointsthathavebeensetinanyEditorwindow.ShowAllocatedObjectsThiscommandshowsallthefiles,fonts,pictures,etcthathavebeenopenedorcreatedbytheprogrambuthavenotbeenclosed.Astheprogramexecutes,thiswindowupdateseverytimearesourceisallocatedorfreed.

AllocatedObjectsWindow

TuringExecution

Therestofthisdocumentwillusesometermsthatmustbeunderstoodproperly.

Running-ATuringprogramisrunningwhenstatementsarebeingcontinuouslyexecutedwithouthumanintervention.However,runningmaybestalledwhiletheprogramiswaitingforkeyboardinput,executingadelaystatement,etc.Paused-ATuringprogramispausedwhenexecutionistemporarilyhalted.Noinputisacceptedbytheprogramwhileitispaused.Aprogramcanbecomepausedinavarietyofwaysincluding:

TheuserpressingthePausebutton.TheuserpressingaStep,StepOverorStepReturnbutton.Executionreachingabreakpoint.Executionreachingthebreakstatementinaprogram.

WhenaTuringprogramispaused,thelineinthesourcecodeonwhichtheTuringprogramwasabouttoexecuteishighlighted.Ineachcase,theprogramcanresumerunningbyclickingtheResumebutton.TheprogramcanalsotemporarilyresumerunningbytheuserpressingtheStep,StepOverorStepReturnbutton.Oncethestatementorstatementsarefinishedrunning,theprogramispausedagain.Executing-AprogramisexecutingwhenitiseitherRunningorPaused.Halted-ATuringprogramishaltedwhenitcannolongerexecuting.Itcannotberesumedandmustbestartedfromthebeginninginordertorunitagain.Aprogramcanbehaltedby:

TheuserpressingtheStopbutton.Arun-timeerror.TheuserclosingaRunwindow.

SteppingaProgram

SteppingaprogramconsistsofexecutingaTuringprogramalineatatime.Aftereachstepcommand,executionpauses,highlightingthenextlinetobeexecuted.Tostepaprogram,theprogrammustnotberunning.TheDebuggercontrolsintheEditorwindowmustbevisible.Tosteptheprogram,theuserclicksoneofthethreebuttonsintheDebuggerControls:

Step-Iftheprogramishalted,thisexecutestheveryfirstlineofcodeandthenpauses.Iftheprogramispaused,itexecutesthehighlightedlineofcodeandthenpauses.Ifitlineofcodetobeexecutedisasubprogramcall,thenitentersthesubprogramandpausesatthefirstlineofcodeinthesubprogram.Ifitisattheendofthesubprogram,thenitleavesthesubprogramandpausesatthesubprogramcall.ThiscommandissometimescalledStepInto.StepOver-Thisexecutesasinglelineofcode.However,iftheprogramispausedatasubprogramcall,thentheentiresubprogramisexecutedandexecutionispausedatthenextlineafterthesubprogramcall.StepReturn-Thisresumesexecutionuntiltheexecutionreturnsfromasubprogram.Thenextlineafterthesubprogramcall.Notethatifthiscommandisgiveninthemainprogram,thenexecutionwillcontinueuntiltheprogramterminates.

TracingaProgram

Tracingaprogramissimplyexecutingaprogramslowlywitheachlineofcodeintheprogrambeinghighlightedasitisexecuted.Tracingallowsuserstoseehowcontrolconstructsoperate.Unlikestepping,withtracing,executioncontinuesuntilitispausedorhaltedinsomeotherfashion.

Tostartaprogramtracing,theDebuggerControlsmustbevisible.TheuserthenclickstheTraceExecutioncheckbox.Whentheprogramisnextrunning,eachtimeastatementisexecuted,thelineinthesourcecodewillbehighlighted.ThespeedatwhichthetracingoccursiscontrolledbytheTraceSpeedsliderfoundintheDebuggerControls.Whenthesliderisontheleft,thereisessentiallynodelaybetweenexecutionofstatements.(Notethatexecutionwillstillbemuchslowerthannottracingduetothetimetakentohighlighteachexecutingstatement.)Whenthesliderisontheright,eachstatementwillwaitforabout5secondsafterexecutingbeforethenextstatementisexecuted.

SettingBreakpoints

Oftenonlyaparticularsectionofcodeisofinteresttotheuser.Breakpointsprovideamechanismforpausingaprogramonlywhenexecutionreachesaspecifiedstatement.Tosetbreakpoints,theyneedtobedisplayedintheEditorwindow.ThisisdonewiththeShowBreakpointscommandintheDebuggermenu.Oncebreakpointsarevisible,theycanbeset(andremoved)bysimplyclickingthemouseinthebreakpointarea.Whenthemouseisoverthebreakpointarea,itturnsintoadiamond.Whenthebreakpointisset,areddiamondappearsinthebreakpointarea.Toremovethebreakpoint,simplyclickthereddiamondandthebreakpointdisappears.

WindowwithTwoBreakpointsSet

Whenexecutionreachesalinewithabreakpointonit,theprogrampausesand

thelineishighlighted.Theprogramcanthenberesumedorsteppedasdesired.Notethatitispossibletosetabreakpointonalinethatisnotexecuted.Ifyouplaceabreakpointonablankline,itisquitelikelythatexecutionwillnotstop.Likewise,inlinesbrokenovermultiplelines,itisbesttoputthebreakpointonthelastlineinthestatement.

Toclearallthebreakpoints,selectClearBreakpointsfromtheDebuggermenu.

ViewingOpenFiles/Pictures/Fonts,etc.

AcommonerrorinTuringprogramsistoneglecttocloseopenfiles(usingtheClosestatement)orfreepicturesorfonts(usingthePic.FreeorFont.Freeprocedures).TheAllocatedObjectswindowdisplaysallallocatedresourcesuntiltheyarefreed.ThiswindowisdisplayedbyselectingtheShowAllocatedObjectscommandfromtheDebuggermenu.Thecommandcanbegivenevenafteraprogramhashalted.Itisausefulcommandtousewhenamopen,Pic.NeworFont.Newhasfailedbecauseoftoomanyopenfiles,picturesorfonts.

Thewindowwillalsodisplayjusthowmuchmemoryeachpicturetakesup.

AllocatedObjectsWindow

Clickingonthelinecontainingtheallocatedobjectwillhighlightthelineinthecodewheretheobjectwasallocated.TheheadingsoneachofthecolumnscanbeclickedallowingtheobjectstobesortedeitherbytheirID,orbywhereintheprogramtheywereallocated.

Error.TripMsg PartofErrormodule

Syntax Error.TripMsg(errorCode:int,errorMessage:string)

Description

Error.TripMsgisaprocedurethatsetstheerrornumberanderrormessagethatisreturnedbyError.LastandError.LastMsg.Itdoesnothalttheprogram.

YoucanfindalistofconstantsforthelegalerrorcodesinthemoduleErrorNum.AnycalltoError.TripMsgshoulduseaconstantfoundintheErrorNummoduleorzero,iftheerrorcodeisnotrelevant(i.e.onlytheerrormessageisrelevant).

Example

Thisprogramsetsanerrorcode.Theprogramoutputs201fortheerrorand"File*really*notfound"forthemessage.

Error.TripMsg(eFsysFileNotFound,"File*really*notfound")

put"Errorcode=",Error.Last

put"Errormessage=",Error.LastMsg

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.TripMsgcallingTripMsg.

Error.Halt PartofErrormodule

Syntax Error.Halt(errorMessage:string)

Description

Error.HaltisaprocedurethatimmediatelyhaltsexecutionoftheprogramandshowsthespecifiederrormessageonthelineintheprogramthatcallsError.Halt.

Thisprocedureisusefulforallowingaquickhalttoaprogramwhileindicatinganerrorcondition.

Example

Thisprogramhaltsonthefirstlinewithanerrormessagestating"Executionterminatedbytheprogram."

Error.Halt("Executionterminatedbytheprogram.")

Execute

Status

Exportedqualified.

ThismeansthatyoucanonlycallthefunctionbycallingError.HaltnotbycallingHalt.

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