-;
-; 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
-(def (quote list) (lambda l l))
-
-(def (quote def!)
- (macro (a b)
- (list
- def
- (list quote a)
- b)
- )
- )
-
-(begin
- (def! append
- (lambda args
- (def! a-l
- (lambda (a b)
- (cond ((null? a) b)
- (else (cons (car a) (a-l (cdr a) b)))
- )
- )
- )
-
- (def! a-ls
- (lambda (l)
- (cond ((null? l) l)
- ((null? (cdr l)) (car l))
- (else (a-l (car l) (a-ls (cdr l))))
- )
- )
- )
- (a-ls args)
- )
- )
- 'append)
-
-(append '(a b c) '(d e f) '(g h i))
-
- ;
- ; Define a variable without returning the value
- ; Useful when defining functions to avoid
- ; having lots of output generated.
- ;
- ; Also accepts the alternate
- ; form for defining lambdas of
- ; (define (name a y z) sexprs ...)
- ;
-
-(begin
- (def (quote define)
- (macro (a . b)
- ; check for alternate lambda definition form
-
- (cond ((list? a)
- (set! b
- (cons lambda (cons (cdr a) b)))
- (set! a (car a))
- )
- (else
- (set! b (car b))
- )
- )
- (cons begin
- (cons
- (cons def
- (cons (cons quote (cons a '()))
- (cons b '())
- )
- )
- (cons
- (cons quote (cons a '()))
- '())
- )
- )
- )
- )
- 'define
- )
-
- ; basic list accessors
-
-(define (caar l) (car (car l)))
-
-(define (cadr l) (car (cdr l)))
-
-(define (cdar l) (cdr (car l)))
-
-(define (caddr l) (car (cdr (cdr l))))
-
- ; (if <condition> <if-true>)
- ; (if <condition> <if-true> <if-false)
-
-(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)
-
- ; simple math operators
-
-(define zero? (macro (value) (list eqv? value 0)))
-
-(zero? 1)
-(zero? 0)
-(zero? "hello")
-
-(define positive? (macro (value) (list > value 0)))
-
-(positive? 12)
-(positive? -12)
-
-(define negative? (macro (value) (list < value 0)))
-
-(negative? 12)
-(negative? -12)
-
-(define (abs a) (if (>= a 0) a (- a)))
-
-(abs 12)
-(abs -12)
-
-(define max (lambda (a . b)
- (while (not (null? b))
- (cond ((< a (car b))
- (set! a (car b)))
- )
- (set! b (cdr b))
- )
- a)
- )
-
-(max 1 2 3)
-(max 3 2 1)
-
-(define min (lambda (a . b)
- (while (not (null? b))
- (cond ((> a (car b))
- (set! a (car b)))
- )
- (set! b (cdr b))
- )
- a)
- )
-
-(min 1 2 3)
-(min 3 2 1)
-
-(define (even? a) (zero? (% a 2)))
-
-(even? 2)
-(even? -2)
-(even? 3)
-(even? -1)
-
-(define (odd? a) (not (even? a)))
-
-(odd? 2)
-(odd? -2)
-(odd? 3)
-(odd? -1)
-
-
-(define (list-tail a b)
- (if (zero? b)
- a
- (list-tail (cdr a (- b 1)))
- )
- )
-
-(define (list-ref a b)
- (car (list-tail a b))
- )
-
-(define (list-tail a b)
- (if (zero? b)
- a
- (list-tail (cdr a) (- b 1))))
-
-(list-tail '(1 2 3) 2)
-
-(define (list-ref a b) (car (list-tail a b)))
-
-(list-ref '(1 2 3) 2)
-
-
- ; define a set of local
- ; variables one at a time 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 (a . b)
-
- ;
- ; make the list of names in the let
- ;
-
- (define (_n a)
- (cond ((not (null? a))
- (cons (car (car a))
- (_n (cdr a))))
- (else ())
- )
- )
-
- ; the set of expressions is
- ; the list of set expressions
- ; pre-pended to the
- ; expressions to evaluate
-
- (define (_v a b)
- (cond ((null? a) b) (else
- (cons
- (list set
- (list quote
- (car (car a))
- )
- (cond ((null? (cdr (car a))) ())
- (else (cadr (car a))))
- )
- (_v (cdr a) b)
- )
- )
- )
- )
-
- ; the parameters to the lambda is a list
- ; of nils of the right length
-
- (define (_z a)
- (cond ((null? a) ())
- (else (cons () (_z (cdr a))))
- )
- )
- ; build the lambda.
-
- (cons (cons lambda (cons (_n a) (_v a b))) (_z a))
- )
- )
-
-(let* ((a 1) (y a)) (+ a y))
-
-(define let let*)
- ; recursive equality
-
-(define (equal? a b)
- (cond ((eq? a b) #t)
- ((pair? a)
- (cond ((pair? b)
- (cond ((equal? (car a) (car b))
- (equal? (cdr a) (cdr b)))
- )
- )
- )
- )
- )
- )
-
-(equal? '(a b c) '(a b c))
-(equal? '(a b c) '(a b b))
-
-(define member (lambda (obj a . test?)
- (cond ((null? a)
- #f
- )
- (else
- (if (null? test?) (set! test? equal?) (set! test? (car test?)))
- (if (test? obj (car a))
- a
- (member obj (cdr a) test?))
- )
- )
- )
- )
-
-(member '(2) '((1) (2) (3)))
-
-(member '(4) '((1) (2) (3)))
-
-(define (memq obj a) (member obj a eq?))
-
-(memq 2 '(1 2 3))
-
-(memq 4 '(1 2 3))
-
-(memq '(2) '((1) (2) (3)))
-
-(define (_assoc a b t?)
- (if (null? b)
- #f
- (if (t? a (caar b))
- (car b)
- (_assoc a (cdr b) t?)
- )
- )
- )
-
-(define (assq a b) (_assoc a b eq?))
-(define (assoc a b) (_assoc a b equal?))
-
-(assq 'a '((a 1) (b 2) (c 3)))
-(assoc '(c) '((a 1) (b 2) ((c) 3)))
-
-(define string (lambda a (list->string a)))
-
-(display "apply\n")
-(apply cons '(a b))
-
-(define map
- (lambda (a . b)
- (define (args b)
- (cond ((null? b) ())
- (else
- (cons (caar b) (args (cdr b)))
- )
- )
- )
- (define (next b)
- (cond ((null? b) ())
- (else
- (cons (cdr (car b)) (next (cdr b)))
- )
- )
- )
- (define (domap b)
- (cond ((null? (car b)) ())
- (else
- (cons (apply a (args b)) (domap (next b)))
- )
- )
- )
- (domap b)
- )
- )
-
-(map cadr '((a b) (d e) (g h)))
-
-(define for-each (lambda (a . b)
- (apply map a b)
- #t))
-
-(for-each display '("hello" " " "world" "\n"))
-
-(define (newline) (write-char #\newline))
-
-(newline)