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add 'infinite' generator

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svn: r17552
This commit is contained in:
Jon Rafkind 2010-01-07 21:53:37 +00:00
parent eaad64d612
commit db6a9de7ed
1 changed files with 6 additions and 1 deletions
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7
collects/scheme/generator.ss
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@ -4,7 +4,7 @@
scheme/control scheme/control
scheme/stxparam scheme/splicing) scheme/stxparam scheme/splicing)
(provide yield generator in-generator) (provide yield generator in-generator infinite)
;; (define-syntax-parameter yield ;; (define-syntax-parameter yield
;; (lambda (stx) ;; (lambda (stx)
@ -74,6 +74,11 @@
#'[(id ...) #'[(id ...)
(in-producer (generator body0 body ... stop-value) stop-value)]]))) (in-producer (generator body0 body ... stop-value) stop-value)]])))
(define (infinite sequence)
(generator
(for ([i (in-cycle sequence)])
(yield i))))
#| #|
;; examples ;; examples
(for/list ([i (in-generator (for-each yield '(1 2 3)) (yield 'four))]) i) (for/list ([i (in-generator (for-each yield '(1 2 3)) (yield 'four))]) i)