mes/mes.mes
2016-07-09 18:56:59 +02:00

224 lines
6.6 KiB
Scheme

;;; -*-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
;; ((null x) a)
;; ((atom x) (cons (cons x y) a))
;; (#t (cons (cons (car x) (car y))
;; (pairlis (cdr x) (cdr y) a)))))
;; (define (assoc x a)
;; ;;(stderr "assoc x=~a\n" x)
;; ;;(debug "assoc x=~a a=~a\n" x a)
;; (cond
;; ((null a) #f)
;; ((eq (caar a) x) (car a))
;; (#t (assoc 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)
(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
((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:)
;; (display (builtin fn))
;; (newline)
;; (display 'x:)
;; (display x)
;; (newline)
(cond
((atom fn)
(cond
((eq fn 'current-module) ;; FIXME
(c:apply current-module '() a))
((builtin fn)
(call fn x))
(#t (apply (eval fn a) x a))))
((eq (car fn) 'lambda)
(cond ((null (cdr (cddr fn)))
(eval (caddr fn) (pairlis (cadr fn) x a)))
(#t
(eval (caddr fn) (pairlis (cadr fn) x a))
(apply (cons (car fn) (cons (cadr fn) (cdddr fn)))
x
(pairlis (cadr fn) x a)))))
((eq (car fn) 'label) (apply (caddr fn) x (cons (cons (cadr fn)
(caddr fn)) a)))))
(define (eval e a)
;;(debug "eval e=~a a=~a\n" e a)
;;(debug "eval (atom ~a)=~a\n" e (atom e))
;; (display 'mes-eval:)
;; (display e)
;; (newline)
;; (display 'a:)
;; (display a)
;; (newline)
(cond
((number e) e)
((eq e #t) #t)
((eq e #f) #f)
((atom e) (cdr (assoc e a)))
((builtin e) e)
((atom (car e))
(cond
((eq (car e) 'quote) (cadr e))
((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))
((pair (assoc (car e) (cdr (assoc '*macro* a))))
(c:eval
(c:apply
(cdr (assoc (car e) (cdr (assoc '*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)
(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)
(cond ((eq c -1) ;; eof
(cond ((eq w '()) '())
(#t (lookup w a))))
((eq c 10) ;; \n
(cond ((eq w '()) (readword (getchar) w a))
;; DOT ((eq w '(*dot*)) (car (readword (getchar) '() a)))
(#t (lookup w a))))
((eq c 32) ;; \space
(readword 10 w a))
((eq c 40) ;; (
(cond ((eq w '()) (readlis a))
(#t (ungetchar c) (lookup w a))))
((eq c 41) ;; )
(cond ((eq w '()) (ungetchar c) w)
(#t (ungetchar c) (lookup w a))))
((eq c 39) ;; '
(cond ((eq w '())
(cons (lookup (cons c '()) a)
(cons (readword (getchar) w a) '())))
(#t (ungetchar c) (lookup w a))))
((eq c 59) ;; ;
(readcomment c)
(readword 10 w a))
((eq c 35) ;; #
(cond ((eq (peekchar) 33) ;; !
(getchar)
(readblock (getchar))
(readword 10 w a))
(#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)
(cond ((eq c 33) (cond ((eq (peekchar) 35) (getchar))
(#t (readblock (getchar)))))
(#t (readblock (getchar)))))
(define (eat-whitespace)
(cond ((eq (peekchar) 10) (getchar) (eat-whitespace))
((eq (peekchar) 32) (getchar) (eat-whitespace))
((eq (peekchar) 35) (getchar) (eat-whitespace))
(#t #t)))
(define (readlis a)
;; (display 'mes-readlis:)
;; (newline)
(eat-whitespace)
(cond ((eq (peekchar) 41) ;; )
(getchar)
'())
;; TODO *dot*
(#t (xcons (readlis a) (readword (getchar) '() a)))))
(define (xcons a b)
(cons b a))
(define (readcomment c)
(cond ((eq c 10) ;; \n
c)
(#t (readcomment (getchar)))))