mes/mes.mes

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;;; -*-scheme-*-
;;; Mes --- Maxwell Equations of Software
;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
;;;
;;; mes.mes: This file is part of Mes.
;;;
;;; Mes is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Mes is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Mes. If not, see <http://www.gnu.org/licenses/>.
;; The Maxwell Equations of Software -- John McCarthy page 13
;; http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf
;; (define (caar x) (car (car x)))
;; (define (cadr x) (car (cdr x)))
;; (define (cdar x) (cdr (car x)))
;; (define (cddr x) (cdr (cdr x)))
;; (define (caadr x) (car (car (cdr x))))
;; (define (caddr x) (car (cdr (cdr x))))
;; (define (cddar x) (cdr (cdr (car x))))
;; (define (cdadr x) (cdr (car (cdr x))))
;; (define (cadar x) (car (cdr (car x))))
;; (define (cdddr x) (cdr (cdr (cdr x))))
;; ;; Page 12
;; (define (pairlis x y a)
;; ;;(debug "pairlis x=~a y=~a a=~a\n" x y a)
;; (cond
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;; ((null? x) a)
;; ((atom? x) (cons (cons x y) a))
;; (#t (cons (cons (car x) (car y))
;; (pairlis (cdr x) (cdr y) a)))))
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;; (define (assq x a)
;; ;;(stderr "assq x=~a\n" x)
;; ;;(debug "assq x=~a a=~a\n" x a)
;; (cond
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;; ((null? a) #f)
;; ((eq? (caar a) x) (car a))
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;; (#t (assq x (cdr a)))))
;; ;; Page 13
;; (define (eval-quote fn x)
;; ;(debug "eval-quote fn=~a x=~a" fn x)
;; (apply fn x '()))
(define (evcon c a)
;;(debug "evcon c=~a a=~a\n" c a)
(cond
;; single-statement cond
;; ((eval (caar c) a) (eval (cadar c) a))
((eval (caar c) a)
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(cond ((null? (cddar c)) (eval (cadar c) a))
(#t (eval (cadar c) a)
(evcon
(cons (cons #t (cddar c)) '())
a))))
(#t (evcon (cdr c) a))))
(define (evlis m a)
;;(debug "evlis m=~a a=~a\n" m a)
;; (display 'mes-evlis:)
;; (display m)
;; (newline)
(cond
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((null? m) '())
(#t (cons (eval (car m) a) (evlis (cdr m) a)))))
(define (apply fn x a)
;; (display 'mes-apply:)
;; (newline)
;; (display 'fn:)
;; (display fn)
;; (newline)
;; (display 'builtin:)
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;; (display (builtin? fn))
;; (newline)
;; (display 'x:)
;; (display x)
;; (newline)
(cond
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((atom? fn)
(cond
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((eq? fn 'current-module) ;; FIXME
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(c:apply current-module '() a))
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((builtin? fn)
(call fn x))
(#t (apply (eval fn a) x a))))
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((eq? (car fn) 'lambda)
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(begin-env (cddr fn) (pairlis (cadr fn) x a)))
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((eq? (car fn) 'label) (apply (caddr fn) x (cons (cons (cadr fn)
(caddr fn)) a)))))
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(define (begin-env body a)
(cond ((null? body) *unspecified*)
((null? (cdr body)) (eval (car body) a))
(#t (eval (car body) a)
(begin-env (cdr body) a))))
(define (set-env! x e a)
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(set-cdr! (assq x a) e))
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(define (eval e a)
;;(debug "eval e=~a a=~a\n" e a)
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;;(debug "eval (atom? ~a)=~a\n" e (atom? e))
;; (display 'mes-eval:)
;; (display e)
;; (newline)
;; (display 'a:)
;; (display a)
;; (newline)
(cond
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((eq? e #t) #t)
((eq? e #f) #f)
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((char? e) e)
((number? e) e)
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((string? e) e)
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((vector? e) e)
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((atom? e) (cdr (assq e a)))
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((builtin? e) e)
((atom? (car e))
(cond
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((eq? (car e) 'quote) (cadr e))
((eq? (car e) 'lambda) e)
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((eq? (car e) 'set!) (set-env! (cadr e) (caddr e) a))
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((eq? (car e) 'unquote) (eval (cadr e) a))
((eq? (car e) 'quasiquote) (eval-quasiquote (cadr e) a))
((eq? (car e) 'cond) (evcon (cdr e) a))
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((pair? (assq (car e) (cdr (assq '*macro* a))))
(c:eval
(c:apply
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(cdr (assq (car e) (cdr (assq '*macro* a))))
(cdr e)
a)
a))
(#t (apply (car e) (evlis (cdr e) a) a))))
(#t (apply (car e) (evlis (cdr e) a) a))))
(define (eval-quasiquote e a)
;; (display 'mes-eval-quasiquote:)
;; (display e)
;; (newline)
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(cond ((null? e) e)
((atom? e) e)
((atom? (car e)) (cons (car e) (eval-quasiquote (cdr e) a)))
((eq? (caar e) 'unquote) (cons (eval (cadar e) a) '()))
((eq? (caar e) 'quote) (cons (cadar e) '()))
((eq? (caar e) 'quasiquote) (cons (cadar e) '()))
(#t (cons (car e) (eval-quasiquote (cdr e) a)))))
;; readenv et al works, but slows down dramatically
(define (DISABLED-readenv a)
(readword (getchar) '() a))
(define (readword c w a)
;; (display 'mes-readword:)
;; (display c)
;; (newline)
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(cond ((eq? c -1) ;; eof
(cond ((eq? w '()) '())
(#t (lookup w a))))
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((eq? c 10) ;; \n
(cond ((eq? w '()) (readword (getchar) w a))
;; DOT ((eq? w '(*dot*)) (car (readword (getchar) '() a)))
(#t (lookup w a))))
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((eq? c 32) ;; \space
(readword 10 w a))
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((eq? c 40) ;; (
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(cond ((eq? w '()) (readlist a))
(#t (ungetchar c) (lookup w a))))
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((eq? c 41) ;; )
(cond ((eq? w '()) (ungetchar c) w)
(#t (ungetchar c) (lookup w a))))
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((eq? c 39) ;; '
(cond ((eq? w '())
(cons (lookup (cons c '()) a)
(cons (readword (getchar) w a) '())))
(#t (ungetchar c) (lookup w a))))
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((eq? c 59) ;; ;
(readcomment c)
(readword 10 w a))
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((eq? c 35) ;; #
(cond ((eq? (peekchar) 33) ;; !
(getchar)
(readblock (getchar))
(readword 10 w a))
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;; TODO: char, vector
(#t (readword (getchar) (append w (cons c '())) a))))
(#t (readword (getchar) (append w (cons c '())) a))))
(define (readblock c)
;; (display 'mes-readblock:)
;; (display c)
;; (newline)
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(cond ((eq? c 33) (cond ((eq? (peekchar) 35) (getchar))
(#t (readblock (getchar)))))
(#t (readblock (getchar)))))
(define (eat-whitespace)
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(cond ((eq? (peekchar) 10) (getchar) (eat-whitespace))
((eq? (peekchar) 32) (getchar) (eat-whitespace))
((eq? (peekchar) 35) (getchar) (eat-whitespace))
(#t #t)))
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(define (readlist a)
;; (display 'mes-readlist:)
;; (newline)
(eat-whitespace)
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(cond ((eq? (peekchar) 41) ;; )
(getchar)
'())
;; TODO *dot*
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(#t (cons (readword (getchar) '() a) (readlist a)))))
(define (readcomment c)
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(cond ((eq? c 10) ;; \n
c)
(#t (readcomment (getchar)))))