Category : Miscellaneous Language Source Code
Archive   : XSCHMDOC.ZIP
Filename : XSCHEME.INI

; xscheme.ini - initialization code for XScheme version 0.16

(load "macros.s")
(load "qquote.s")

; this version of EVAL knows about the optional enviroment parameter
(define (eval x #!optional env)
((if (default-object? env)
(compile x)
(compile x env))))

(define (autoload-from-file file syms #!optional env)
(map (lambda (sym) (put sym '%autoload file)) syms)
'())

(define (*unbound-handler* sym cont)
(let ((file (get sym '%autoload)))
(if file (load file))
(if (not (bound? sym))
(error "unbound variable" sym))
(cont '())))

(define head car)
(define (tail x) (force (cdr x)))
(define empty-stream? null?)
(define the-empty-stream '())

(macro cons-stream
(lambda (x)
(list 'cons (cadr x) (list 'delay (caddr x)))))

(macro make-environment
(lambda (x)
(append '(let ()) (cdr x) '((the-environment)))))

(define initial-user-environment (the-environment))

(macro case
(lambda (form)
(let ((test (cadr form))
(sym (gensym)))
`(let ((,sym ,test))
(cond ,@(map (lambda (x)
(if (eq? (car x) 'else)
x
`((memv ,sym ',(car x)) ,@(cdr x))))
(cddr form)))))))