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add docs example for in-generator, where arity > 1

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Stephen Chang 2013-08-29 16:38:12 -04:00
parent ac21f854a2
commit d5c2443c05
1 changed files with 12 additions and 0 deletions
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pkgs/racket-pkgs/racket-doc/scribblings/reference/sequences.scrbl
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@ -1049,6 +1049,18 @@ values from the generator.
values for each element, its arity should be declared with an
@racket[#:arity arity-k] clause; the @racket[arity-k] must be a
literal, exact, non-negative integer.
@examples[#:eval generator-eval
(let ([g (in-generator
(let loop ([n 3])
(unless (zero? n) (yield n (add1 n)) (loop (sub1 n)))))])
(let-values ([(not-empty? next) (sequence-generate g)])
(let loop () (when (not-empty?) (next) (loop))) 'done))
(let ([g (in-generator #:arity 2
(let loop ([n 3])
(unless (zero? n) (yield n (add1 n)) (loop (sub1 n)))))])
(let-values ([(not-empty? next) (sequence-generate g)])
(let loop () (when (not-empty?) (next) (loop))) 'done))]
To use an existing generator as a sequence, use @racket[in-producer]
with a stop-value known for the generator: