section 10 - lisp to scheme - vrije universiteit tjdhondt/esl/lisp_to_scheme_files/section 10 -...

Evolution of Software Languages 1

Evolution of

Software Languages

Theo D'Hondt

Bachelor of Computer Science Faculty of Sciences and Bio-Engineering Sciences

Vrije Universiteit Brussel Academic Year 2015-2016

Section 10: LISP to Scheme

10: LISP to Scheme

Evolution of Software Languages 2

John McCarthy

10: LISP to Scheme

http://www.independent.co.uk/news/obituaries/john-mccarthy-computer-scientist-known-as-the-

father-of-ai-6255307.html

Father of LISP Credited with term "AI" Built on the IBM 604/9 Originated at MIT and at Stanford

Survives in Common Lisp Gave rise to Scheme First "functional" language

http://www.independent.co.uk/news/obituaries/john-mccarthy-computer-scientist-known-as-the-father-of-ai-6255307.html

Evolution of Software Languages 3

John McCarthy

10: LISP to Scheme

http://www.independent.co.uk/news/obituaries/john-mccarthy-computer-scientist-known-as-the-

father-of-ai-6255307.html

Father of LISP Credited with term "AI" Built on the IBM 604/9 Originated at MIT and at Stanford

Survives in Common Lisp Gave rise to Scheme First "functional" language

Lispers say these are LISP...

Arc, AutoLISP, Clojure, Common Lisp, Emacs Lisp, EuLisp, Franz

Lisp, Hy, Interlisp, ISLISP, LeLisp, LFE, Maclisp, MDL, Newlisp, NIL, Picolisp, Portable Standard Lisp,

Racket, RPL, Scheme, SKILL, Spice Lisp, T, Zetalisp

http://www.independent.co.uk/news/obituaries/john-mccarthy-computer-scientist-known-as-the-father-of-ai-6255307.html

Evolution of Software Languages 4

LISP I Programmer's Manual (March 1960)

10: LISP to Scheme

Define a function collapse:

given some implementation for a function append:

Evolution of Software Languages 5

LISP I Programmer's Manual (March 1960)

10: LISP to Scheme

Define a function collapse:

given some implementation for a function append:

resulting in the input card deck

Evolution of Software Languages 6

(pre-) Common Lisp

10: LISP to Scheme

S-expressions Functions as values Meta-circularity Quoting and eval Automatic garbage collection Full syntactic macros (later) CLOS and MOP Encourages imperative style Ambivalent view on functions/function values Ambivalent view on scoping No tail call optimisation No full continuations

Evolution of Software Languages 7

(pre-) Common Lisp

10: LISP to Scheme

S-expressions Functions as values Meta-circularity Quoting and eval Automatic garbage collection Full syntactic macros (later) CLOS and MOP Encourages imperative style Ambivalent view on functions/function values Ambivalent view on scoping No tail call optimisation No full continuations

https://en.wikipedia.org/wiki/Symbolics

Evolution of Software Languages 8

(pre-) Common Lisp

10: LISP to Scheme

S-expressions Functions as values Meta-circularity Quoting and eval Automatic garbage collection Full syntactic macros (later) CLOS and MOP Encourages imperative style Ambivalent view on functions/function values Ambivalent view on scoping No tail call optimisation No full continuations

https://en.wikipedia.org/wiki/Symbolics

http://www.computerhistory.org/revolution/artificial-

intelligence-robotics/13/290/1254

Evolution of Software Languages 9

LISP example1

10: LISP to Scheme

(defparameter *width* 100) (defparameter *height* 30) (defparameter *jungle* '(45 10 10 10)) (defparameter *plant-energy* 80)

(defparameter *plants* (make-hash-table :test #'equal))

(defun random-plant (left top width height) (let ((pos (cons (+ left (random width)) (+ top (random height))))) (setf (gethash pos *plants*) t)))

(defun add-plants () (apply #'random-plant *jungle*) (random-plant 0 0 *width* *height*))

(defstruct animal x y energy dir genes)

(defparameter *animals* (list (make-animal :x (ash *width* -1) :y (ash *height* -1) :energy 1000 :dir 0 :genes (loop repeat 8 collecting (1+ (random 10))))))

http://landoflisp.com/source.html

http://landoflisp.com/source.html

Evolution of Software Languages 10

LISP example2

10: LISP to Scheme

(defun move (animal) (let ((dir (animal-dir animal)) (x (animal-x animal)) (y (animal-y animal))) (setf (animal-x animal) (mod (+ x (cond ((and (>= dir 2) (< dir 5)) 1) ((or (= dir 1) (= dir 5)) 0) (t -1)) *width*) *width*)) (setf (animal-y animal) (mod (+ y (cond ((and (>= dir 0) (< dir 3)) -1) ((and (>= dir 4) (< dir 7)) 1) (t 0)) *height*) *height*)) (decf (animal-energy animal))))

(defun turn (animal) (let ((x (random (apply #'+ (animal-genes animal))))) (labels ((angle (genes x) (let ((xnu (- x (car genes)))) (if (< xnu 0) 0 (1+ (angle (cdr genes) xnu)))))) (setf (animal-dir animal) (mod (+ (animal-dir animal) (angle (animal-genes animal) x)) 8)))))

Evolution of Software Languages 11

LISP example3

10: LISP to Scheme

(defun eat (animal) (let ((pos (cons (animal-x animal) (animal-y animal)))) (when (gethash pos *plants*) (incf (animal-energy animal) *plant-energy*) (remhash pos *plants*))))

(defparameter *reproduction-energy* 200)

(defun reproduce (animal) (let ((e (animal-energy animal))) (when (>= e *reproduction-energy*) (setf (animal-energy animal) (ash e -1)) (let ((animal-nu (copy-structure animal)) (genes (copy-list (animal-genes animal))) (mutation (random 8))) (setf (nth mutation genes) (max 1 (+ (nth mutation genes) (random 3) -1))) (setf (animal-genes animal-nu) genes) (push animal-nu *animals*)))))

Evolution of Software Languages 12

LISP example4

10: LISP to Scheme

(defun update-world () (setf *animals* (remove-if (lambda (animal) (

Evolution of Software Languages 13

LISP example5

10: LISP to Scheme

(defun evolution () (draw-world) (fresh-line) (let ((str (read-line))) (cond ((equal str "quit") ()) (t (let ((x (parse-integer str :junk-allowed t))) (if x (loop for i below x do (update-world) if (zerop (mod i 1000)) do (princ #\.)) (update-world)) (evolution))))))

Evolution of Software Languages 14

Carl Hewitt

10: LISP to Scheme

http://www.erlang-factory.com/sfbay2015/carl-hewitt

Researcher at MIT Built "Planner" Defined "Actors" Hard to read papers Fathered ACT-1, ... (Henry Lieberman)

(PhD with Seymour Papert)

Evolution of Software Languages 15

The Actor Model1

10: LISP to Scheme

Evolution of Software Languages 16

The Actor Model2

10: LISP to Scheme

(define p (act->scheme '((define counter (BEHAVIOR (value) (METHOD (up n) (BECOME counter (+ value n))) (METHOD (down n) (BECOME counter (- value n))) (METHOD (display) (display "value=") (display value) (newline)))) (define c1 (NEW counter 0)) (define c2 (NEW counter 5)) (SEND c2 down 2) (SEND c1 up 1) (SEND c2 up 5) (SEND c1 display) (SEND c2 display)))) (define act-p (eval p (interaction-environment))) (act-p))

Evolution of Software Languages 17

The Actor Model2

10: LISP to Scheme

(define p (act->scheme '((define counter (BEHAVIOR (value) (METHOD (up n) (BECOME counter (+ value n))) (METHOD (down n) (BECOME counter (- value n))) (METHOD (display) (display "value=") (display value) (newline)))) (define c1 (NEW counter 0)) (define c2 (NEW counter 5)) (SEND c2 down 2) (SEND c1 up 1) (SEND c2 up 5) (SEND c1 display) (SEND c2 display)))) (define act-p (eval p (interaction-environment))) (act-p))

Evolution of Software Languages 18

The Actor Model2

10: LISP to Scheme

(define p (act->scheme '((define counter (BEHAVIOR (value) (METHOD (up n) (BECOME counter (+ value n))) (METHOD (down n) (BECOME counter (- value n))) (METHOD (display) (display "value=") (display value) (newline))))