mes/scm.mes
Jan Nieuwenhuizen 00687ba91a add set!.
2016-07-10 10:43:26 +02:00

98 lines
3.1 KiB
Scheme
Executable file

;;; -*-scheme-*-
;;; Mes --- Maxwell Equations of Software
;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
;;;
;;; scm.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 (list . rest) rest)
(define (scm-define x a)
(cond ((atom? (cadr x)) (cons (cadr x) (eval (caddr x) a)))
(#t (cons (caadr x) (cons 'lambda (cons (cdadr x) (cddr x)))))))
(define (scm-define-macro x a)
(cons '*macro*
(cons (cons (caadr e) (cons 'lambda (cons (cdadr e) (cddr e))))
(cdr (assoc '*macro* a)))))
(define (loop2 r e a)
;; (display '____loop2)
;; (newline)
;; (display 'e:)
;; (display e)
;; (newline)
(cond ((null? e) r)
((eq? e 'EOF2)
(display 'loop2-exiting...)
(newline))
((atom? e)
(loop2 (eval e a) (readenv a) a))
((eq? (car e) 'define)
(loop2 *unspecified* (readenv a) (cons (scm-define e a) a)))
((eq? (car e) 'define-macro)
(loop2 *unspecified* (readenv a) (cons (scm-define-macro e a) a)))
((eq? (car e) 'set!)
(loop2 (set-cdr! (assoc (cadr e) a) (eval (caddr e) a)) (readenv a) a))
(#t (loop2 (eval e a) (readenv a) a))))
EOF
(define (+ x y) (- x (- 0 y)))
(define-macro (and x y)
(cond (x y)
(#t #f)))
(define-macro (or x y)
(cond (x x)
(#t y)))
(define (split-params bindings params)
(cond ((null? bindings) params)
(#t (split-params (cdr bindings)
(append params (cons (caar bindings) '()))))))
(define (split-values bindings values)
(cond ((null? bindings) values)
(#t (split-values (cdr bindings)
(append values (cdar bindings) '())))))
(define-macro (let bindings . body)
(cons (cons 'lambda (cons (split-params bindings '()) body))
(split-values bindings '())))
(define (expand-let* bindings body)
(cond ((null? bindings)
(cons (cons 'lambda (cons '() body)) '()))
(#t
(cons
(cons 'lambda (cons (cons (caar bindings) '())
(cons (expand-let* (cdr bindings) body) '())))
(cdar bindings)))))
(define-macro (let* bindings . body)
(expand-let* bindings body))
(define (map f l . r)
(cond ((null? l) '())
((null? r) (cons (f (car l)) (map f (cdr l))))
((null? (cdr r))
(cons (f (car l) (caar r)) (map f (cdr l) (cdar r))))))