is groovy static or dynamic

Copyright © 2013 Russel Winder 1

Is Groovy Static or Dynamic?

Russel Winder

email: [email protected]: [email protected]

twitter: @russel_winderweb: http://www.russel.org.uk

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Prelude


Debate [d be t]ɪˈ ɪn 1. (Government, Politics & Diplomacy) a formal discussion, as in a legislative body, in which opposing arguments are put forward 2. discussion or dispute 3. (Philosophy) the formal presentation and opposition of a specific motion, followed by a votevb 1. to discuss (a motion), esp in a formal assembly 2. to deliberate upon (something) he debated with himself whether to go

[from Old French debatre to discuss, argue, from Latin battuere]

debater n

Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003.


foment [f m nt]əˈ ɛvb (tr) 1. to encourage or instigate (trouble, discord, etc.); stir up 2. (Medicine) Med to apply heat and moisture to (a part of the body) to relieve pain and inflammation

[from Late Latin f ment re, from Latin f mentum a poultice, ultimately from ō ā ōfov re to foster]ē

fomentation [ f m n te n]ˌ əʊ ɛ ˈ ɪʃə nfomenter n

Usage: Both foment and ferment can be used to talk about stirring up trouble: he was accused of fomenting/fermenting unrest. Only ferment can be used intransitively or as a noun: his anger continued to ferment (not foment); rural areas were unaffected by the ferment in the cities

Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003


fermentn [ f m nt]ˈ ɜː ɛ 1. (Life Sciences & Allied Applications / Biochemistry) any agent or substance, such as a bacterium, mould, yeast, or enzyme, that causes fermentation 2. (Life Sciences & Allied Applications / Biochemistry) another word for fermentation 3. commotion; unrestvb [f m nt]əˈ ɛ 1. (Life Sciences & Allied Applications / Biochemistry) to undergo or cause to undergo fermentation 2. to stir up or seethe with excitement

[from Latin fermentum yeast, from ferv re to seethe]ēfermentable adjfermentability nfermenter n

Usage: See at foment



The intention of this session is to

foment debate.


Let the fomentation begin.


No not the fermentation.


Starting Point


2003

Groovy is created as thedynamic symbiote to Java.


Dynamic languages have no typed variables.


static totallyDynamic(x, y) { x * y}


Duck typing:

The receiver of the message decides the meaning of the message.


Operators are not messages to areceiving object in Java…


…Java isn't really an object-oriented language.


Fortunately, Groovy decided to follow Smalltalk,and have a meta-object protocol.


Groovy is truly object-oriented,message passing is the operational semantic,

and all variables are references to objects.


x * y

transforms to

x.plus(y)

to realize message passing with method call.


Interesting Issue


Objects clearly have static types.


Java allows for despatch by signature,

i.e. methods can be overloaded.


Adding types to parameters is requiredfor despatch by signature.


static runtimeTyping(Number x, Number y) { x * y}


Groovy is an optionally typed language:

variables, not just function and method parameters, may or may not be given a type.


Adding types works in harmony withmethod overloading.


All type checking is at run time.

This is harmonious with duck typing.


Being up to date


2013

Groovy is the dynamic symbiote to Java,and

Groovy can now be the static language replacement for Java.


@TypeChecked

@CompileStatic


@TypeCheckedstatic staticTyping(x, y) { x * y}


Compile time interface conformance,

no duck typing.


✘✘


Groovy now has C++-style message passing.


@TypeCheckedstatic staticTyping(Number x, Number y) { x * y}


Enforce don't ask.


A totally different view of how computation proceeds: a different computational model.


class ExpandoDynamic { static void main(args) { def x = new Expando() x.multiply = { y -> x.data * y } x.data = 'XX' def y = 2 assert x * 2 == 'XXXX' }}


@TypeCheckedclass ExpandoStatic { static void main(args) { def x = new Expando() x.multiply = { y -> x.data * y } x.data = 'XX' def y = 2 assert x * 2 == 'XXXX' }}


Should a language support two disparate computational models?


final class Thing { final x Thing(x) { this.x = x } Thing multiply(Thing y) { new Thing(x * y.x) } boolean equals(Thing y) { x == y.x } boolean equals (Object y) { x == y } String toString() { x.toString() }}

x = new Thing('XX')y = new Thing(2)z = new Thing(2.0)

assert x * y == 'XXXX'assert x * y == new Thing('XXXX')assert x * z == 'XXXX'assert x * z == new Thing('XXXX')

assert y * z == 4.0assert y * z == new Thing(4.0)

assert z * y == 4.0assert z * y == new Thing(4.0)


@TypeCheckedfinal class Thing { final Integer x_i final String x_s Thing(Integer x) { this.x_i = x ; assert this.x_s == null } Thing(String x) { this.x_s = x ; assert this.x_i == null } Thing multiply(Thing y) { if (x_i == null) { new Thing(StringGroovyMethods.multiply(x_s, (Number)y.x)) } else { new Thing(x_i * y.x_i) } } Object getX() { x_i == null ? x_s : x_i } boolean equals(Thing y) { x_i == null ? x_s == y.x_s : x_i == y.x_i } boolean equals (Object y) { x == y } String toString() { x.toString() }}

x = new Thing('XX')y = new Thing(2)

assert x * y == 'XXXX'assert x * y == new Thing('XXXX')


Should a language do one thing well?


class Duck { static main(args) { def total = 1 def data = [2, 3] try { total += data.sum() } catch (MissingMethodException mme) { total = 0 } assert total == 6 }}


@TypeCheckedclass NotDuck { static void main(String[] args) { Integer total = 1 List data = [2, 3] total += (Integer)data.sum() assert total == 6 }}


Should a language be all things…


…or should we embrace polyglot programming?


Groovy + { JavaScalaCeylonKotlin


Tooling and IDE support is a big issue.


Endnote


This is philosophizing.


Personal experience useful.

We are allowed to debate and (dis)agree.

Create a personal view.


What is really needed is some objective research.


Psychology of programming.

PPIG.


foment [f m nt]əˈ ɛvb (tr) 1. to encourage or instigate (trouble, discord, etc.); stir up 2. (Medicine) Med to apply heat and moisture to (a part of the body) to relieve pain and inflammation

[from Late Latin f ment re, from Latin f mentum a poultice, ultimately from ō ā ōfov re to foster]ē

fomentation [ f m n te n] nˌ əʊ ɛ ˈ ɪʃəfomenter n

Usage: Both foment and ferment can be used to talk about stirring up trouble: he was accused of fomenting/fermenting unrest. Only ferment can be used intransitively or as a noun: his anger continued to ferment (not foment); rural areas were unaffected by the ferment in the cities



fermentn [ f m nt]ˈ ɜː ɛ 1. (Life Sciences & Allied Applications / Biochemistry) any agent or substance, such as a bacterium, mould, yeast, or enzyme, that causes fermentation 2. (Life Sciences & Allied Applications / Biochemistry) another word for fermentation 3. commotion; unrestvb [f m nt]əˈ ɛ 1. (Life Sciences & Allied Applications / Biochemistry) to undergo or cause to undergo fermentation 2. to stir up or seethe with excitement

[from Latin fermentum yeast, from ferv re to seethe]ēfermentable adjfermentability nfermenter n

Usage: See at foment



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Is Groovy Static or Dynamic?

Russel Winder





Groovy is Static or Dynamic

Russel Winder




is groovy static or dynamic

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