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fix PR 11123: 0-ary generator yield

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This commit is contained in:
Jon Rafkind 2010-08-24 00:11:22 -06:00
parent 65c245cdc7
commit e077b87d50
3 changed files with 36 additions and 0 deletions
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3
collects/racket/generator.rkt
View File

@ -112,6 +112,9 @@
(in-producer (generator () body0 body ... stop-value) stop-value)])
(lambda (stx)
(syntax-case stx ()
[(() (_ body0 body ...))
#'[()
(in-producer (generator () body0 body ... stop-value) stop-value)]]
[((id ...) (_ body0 body ...))
(with-syntax ([(stops ...) (syntax-case #'((id stop-value) ...) ()
[((x v) ...) #'(v ...)])])

26
collects/racket/private/for.rkt
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@ -1281,6 +1281,32 @@
#t
;; loop args
())])]
[[() (_ producer stop more ...)]
(with-syntax ([(more* ...) (generate-temporaries #'(more ...))])
#'[()
(:do-in
([(producer*) producer] [(more*) more] ...
[(stop?) (let ([s stop])
(if (procedure? s)
s
(lambda (args)
(and (not (null? args))
(eq? (car args) s)))))])
;; outer check
#t
;; loop bindings
()
;; pos check
#t
;; inner bindings
([(check) (call-with-values (lambda () (producer* more* ...))
(lambda vs vs))])
;; pre guard
(not (stop? check))
;; post guard
#t
;; loop args
())])]
;; multiple-values version
[[(id ...) (_ producer stop more ...)]
(with-syntax ([(more* ...) (generate-temporaries #'(more ...))])

7
collects/tests/racket/for.rktl
View File

@ -242,6 +242,7 @@
(for/list ([(x i) (in-indexed (in-generator (yield 1) (yield 2) (yield 3)))])
(list x i)))
;; test multiple values for in-generator
(test '[(1 2) (3 4)] 'for*-generator
(for*/list ([(n after)
(in-generator
@ -249,6 +250,12 @@
(yield 3 4))])
(list n after)))
;; test 0-ary yields
(test '(0 1 2) 'no-bind-in-generator
(for/list ([() (in-generator (yield) (yield) (yield))]
[i (in-naturals)])
i))
(let ([helper (lambda (i)
(yield (add1 i)))])
(test '(1 2 3) 'parameterized-yield