-cadr (lambda (l) (car (cdr l)))
+;
+; 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
+ ;
+
+(setq def (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)
+ ;
+
+(def defun (macro (name args exprs)
+ (list
+ def
+ name
+ (list
+ 'lambda
+ args
+ (cond ((cdr exprs)
+ (cons progn exprs))
+ ((car 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 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)) (setq y (+ x 1)) y)
+
+(def let (macro (vars exprs)
+ ((lambda (make-names make-exprs make-nils)
+ (progn
+
+ ;
+ ; make the list of names in the let
+ ;
+
+ (setq make-names (lambda (vars)
+ (cond (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
+
+ (setq make-exprs (lambda (vars exprs)
+ (progn
+ (cond (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
+
+ (setq make-nils (lambda (vars)
+ (cond (vars (cons nil (make-nils (cdr vars))))
+ )
+ )
+ )
+ ; prepend the set operations
+ ; to the expressions
+
+ (setq exprs (make-exprs vars exprs))
+
+ ; build the lambda.
+
+ (cons
+ (list
+ 'lambda
+ (make-names vars)
+ (cond ((cdr exprs) (cons 'progn exprs))
+ ((car exprs))
+ )
+ )
+ (make-nils vars)
+ )
+ )
+ )
+ ()
+ ()
+ ()
+ )
+ )
+ )
+
+ ; boolean operators
+
+(def or (lexpr (l)
+ (let ((ret nil))
+ (while l
+ (cond ((setq ret (car l))
+ (setq l nil))
+ ((setq l (cdr l)))))
+ ret
+ )
+ )
+ )
+
+ ; execute to resolve macros
+
+(or nil t)
+
+(def and (lexpr (l)
+ (let ((ret t))
+ (while l
+ (cond ((setq ret (car l))
+ (setq l (cdr l)))
+ ((setq ret (setq l nil)))
+ )
+ )
+ ret
+ )
+ )
+ )
+
+ ; execute to resolve macros
+
+(and t nil)
+
projects / fw / altos / blobdiff