[fw/altos] / src / lisp / ao_lisp_const.lisp

                                        ; basic list accessors


(setq cadr (lambda (l) (car (cdr l))))
(setq caddr (lambda (l) (car (cdr (cdr l)))))
(setq list (lexpr (l) l))

                                        ; evaluate a list of sexprs

(setq progn (lexpr (l) (last l)))

                                        ; simple math operators

(setq 1+ (lambda (x) (+ x 1)))
(setq 1- (lambda (x) (- x 1)))

                                        ; define a variable without returning the value

(set 'def (macro (def-param)
                 (list
                  'progn
                  (list
                   'set
                   (list
                    'quote
                    (car def-param))
                   (cadr def-param)
                   )
                  (list
                   'quote
                   (car def-param)
                   )
                  )
                 )
     )

                                        ; 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 (let-param)
                ((lambda (vars exprs make-names make-exprs make-nils)
                   (progn

                                        ;
                                        ; make the list of names in the let
                                        ;

                     (set '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
                                        ;
                     (set '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)
                                               )
                                         )
                                       )
                          )
                     (set 'exprs (make-exprs vars exprs))

                                        ;
                                        ; the parameters to the lambda is a list
                                        ; of nils of the right length
                                        ;
                     (set 'make-nils (lambda (vars)
                                      (cond (vars (cons nil (make-nils (cdr vars))))
                                            )
                                      )
                          )
                                        ;
                                        ; build the lambda.
                                        ;
                     (set 'last-let-value 
                     (cons
                      (list
                       'lambda
                       (make-names vars)
                       (cond ((cdr exprs) (cons 'progn exprs))
                             ((car exprs))
                             )
                       )
                      (make-nils vars)
                      )
                     )
                     )
                     
                   )
                 (car let-param)
                 (cdr let-param)
                 ()
                 ()
                 ()
                 )
                )
     )