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strict check whether given expression is multiple value or not

This commit is contained in:
Yuichi Nishiwaki 2013-12-10 08:14:14 -08:00
parent 7fe6a5007c
commit 45fb1be04f
1 changed files with 4 additions and 2 deletions
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6
piclib/built-in.scm
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@ -261,16 +261,18 @@
(picrin macro) (picrin macro)
(picrin core-syntax)) (picrin core-syntax))
(define *values-tag* (cons #f '()))
(define (values . args) (define (values . args)
(if (and (pair? args) (if (and (pair? args)
(null? (cdr args))) (null? (cdr args)))
(car args) (car args)
(cons '*values-tag* args))) (cons *values-tag* args)))
(define (call-with-values producer consumer) (define (call-with-values producer consumer)
(let ((res (producer))) (let ((res (producer)))
(if (and (pair? res) (if (and (pair? res)
(eq? '*values-tag* (car res))) (eq? *values-tag* (car res)))
(apply consumer (cdr res)) (apply consumer (cdr res))
(consumer res)))) (consumer res))))