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Add Whalesong specific versions of letrec and letrec-values to avoid the undefined value

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This commit is contained in:
Jens Axel Søgaard 2014-08-12 19:35:15 +02:00
parent 60a70798a8
commit daa767998a
1 changed files with 369 additions and 348 deletions
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21
whalesong/lang/kernel.rkt
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@ -37,6 +37,27 @@
(provide current-print-mode)
;; Custom letrec and letrec-values in order to avoid running
;; into the (in Racket) newly introduced undefined value.
(provide letrec letrec-values)
(define-syntax (letrec stx)
(syntax-case stx ()
[(_ ([id expr] ...) body ...)
(syntax/loc stx
(let ([id '**undefined**] ...)
(set! id expr) ...
(let () body ...)))]))
(define-syntax (letrec-values stx)
(syntax-case stx ()
[(_ ([(id ...) expr] ...) body ...)
(syntax/loc stx
(let ([id '**undefined**] ... ...)
(set!-values (id ...) expr) ...
(let () body ...)))]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Primitive function stubs