33 lines
1.2 KiB
Racket
33 lines
1.2 KiB
Racket
#lang scribble/manual
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@require[@for-label[phc-toolkit/stx
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racket/base]]
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@title{for*/list*}
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@author{@author+email["Georges Dupéron" "georges.duperon@gmail.com"]}
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@defmodule[phc-toolkit/untyped/for-star-list-star]
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@defform[(for*/list* [sequences …] . body)
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#:grammar ([sequences
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(* [id seq-expr] …)
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([id seq-expr] …)])]{
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This form allows iteration over sequences, collecting
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nested lists as the final result. Each @racket[sequences]
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group of @racket[[id seq-expr]] starts a new level of
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nesting. When the @racket[*] is present at the beginning of
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a group, its bindings are evaluated in sequence (like
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@racket[let*] and @racket[for*/list]), otherwise they are
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evaluated in parallel (like @racket[let] and
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@racket[for/list]).
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This form is equivalent to:
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@racketblock[
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(for/list ([id seq-expr …])
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(for/list ([id seq-expr …])
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(for/list ([id seq-expr …])
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…
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(for/list ([id seq-expr …])
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body))))]
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except when a group of @racket[[id seq-expr]] starts with
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a @racket[*], then @racket[for*/list] is used for that
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group instead of @racket[for/list].} |