-cadr (lambda (l) (car (cdr l)))
-list (lexpr (l) l)
-1+ (lambda (x) (+ x 1))
-1- (lambda (x) (- x 1))
+;
+; Copyright © 2016 Keith Packard <keithp@keithp.com>
+;
+; This program 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 2 of the License, or
+; (at your option) any later version.
+;
+; This program 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.
+;
+; Lisp code placed in ROM
+
+ ; return a list containing all of the arguments
+
+(set (quote list) (lexpr (l) l))
+
+ ;
+ ; Define a variable without returning the value
+ ; Useful when defining functions to avoid
+ ; having lots of output generated
+ ;
+
+(set (quote define) (macro (name val rest)
+ (list
+ 'progn
+ (list
+ 'set
+ (list 'quote name)
+ val)
+ (list 'quote name)
+ )
+ )
+ )
+
+ ;
+ ; A slightly more convenient form
+ ; for defining lambdas.
+ ;
+ ; (defun <name> (<params>) s-exprs)
+ ;
+
+(define defun (macro (name args exprs)
+ (list
+ define
+ name
+ (cons 'lambda (cons args exprs))
+ )
+ )
+ )
+
+ ; basic list accessors
+
+
+(defun cadr (l) (car (cdr l)))
+
+(defun caddr (l) (car (cdr (cdr l))))
+
+(defun nth (list n)
+ (cond ((= n 0) (car list))
+ ((nth (cdr list) (1- n)))
+ )
+ )
+
+ ; simple math operators
+
+(defun 1+ (x) (+ x 1))
+(defun 1- (x) (- x 1))
+
+(define if (macro (test args)
+ (cond ((null? (cdr args))
+ (list
+ cond
+ (list test (car args)))
+ )
+ (else
+ (list
+ cond
+ (list test (car args))
+ (list 'else (cadr args))
+ )
+ )
+ )
+ )
+ )
+
+(if (> 3 2) 'yes)
+(if (> 3 2) 'yes 'no)
+(if (> 2 3) 'no 'yes)
+(if (> 2 3) 'no)
+
+ ; define a set of local
+ ; variables and then evaluate
+ ; a list of sexprs
+ ;
+ ; (let (var-defines) sexprs)
+ ;
+ ; where var-defines are either
+ ;
+ ; (name value)
+ ;
+ ; or
+ ;
+ ; (name)
+ ;
+ ; e.g.
+ ;
+ ; (let ((x 1) (y)) (set! y (+ x 1)) y)
+
+(define let (macro (vars exprs)
+ ((lambda (make-names make-exprs make-nils)
+
+ ;
+ ; make the list of names in the let
+ ;
+
+ (set! make-names (lambda (vars)
+ (cond ((not (null? vars))
+ (cons (car (car vars))
+ (make-names (cdr vars))))
+ )
+ )
+ )
+
+ ; the set of expressions is
+ ; the list of set expressions
+ ; pre-pended to the
+ ; expressions to evaluate
+
+ (set! make-exprs (lambda (vars exprs)
+ (cond ((not (null? vars)) (cons
+ (list set
+ (list quote
+ (car (car vars))
+ )
+ (cadr (car vars))
+ )
+ (make-exprs (cdr vars) exprs)
+ )
+ )
+ (exprs)
+ )
+ )
+ )
+
+ ; the parameters to the lambda is a list
+ ; of nils of the right length
+
+ (set! make-nils (lambda (vars)
+ (cond ((not (null? vars)) (cons () (make-nils (cdr vars))))
+ )
+ )
+ )
+ ; prepend the set operations
+ ; to the expressions
+
+ (set! exprs (make-exprs vars exprs))
+
+ ; build the lambda.
+
+ (cons (cons 'lambda (cons (make-names vars) exprs))
+ (make-nils vars)
+ )
+ )
+ ()
+ ()
+ ()
+ )
+ )
+ )
+
+(let ((x 1)) x)
+
+ ; boolean operators
+
+(define or (lexpr (l)
+ (let ((ret #f))
+ (while (not (null? l))
+ (cond ((car l) (set! ret #t) (set! l ()))
+ ((set! l (cdr l)))))
+ ret
+ )
+ )
+ )
+
+ ; execute to resolve macros
+
+(or #f #t)
+
+(define and (lexpr (l)
+ (let ((ret #t))
+ (while (not (null? l))
+ (cond ((car l)
+ (set! l (cdr l)))
+ (#t
+ (set! ret #f)
+ (set! l ()))
+ )
+ )
+ ret
+ )
+ )
+ )
+
+ ; execute to resolve macros
+
+(and #t #f)
+
+(defun equal? (a b)
+ (cond ((eq? a b) #t)
+ ((and (pair? a) (pair? b))
+ (and (equal? (car a) (car b))
+ (equal? (cdr a) (cdr b)))
+ )
+ (else #f)
+ )
+ )
+
+(equal? '(a b c) '(a b c))
+(equal? '(a b c) '(a b b))
projects / fw / altos / blobdiff