47 lines
1.4 KiB
Racket
47 lines
1.4 KiB
Racket
#lang scribble/manual
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@(require scribble/eval "utils.rkt"
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(for-label racket/base unstable/sequence racket/contract))
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@(define the-eval (make-base-eval))
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@(the-eval '(require unstable/sequence))
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@(define-syntax speed
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(syntax-rules ()
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[(_ id what)
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(t "An " (racket id) " application can provide better performance for "
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(elem what)
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" iteration when it appears directly in a " (racket for)
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" clause.")]))
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@title[#:tag "sequence"]{Sequences}
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@defmodule[unstable/sequence]
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@unstable[@author+email["Sam Tobin-Hochstadt" "samth@ccs.neu.edu"]]
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@defproc[(in-syntax [stx syntax?]) sequence?]{
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Produces a sequence equivalent to @racket[(syntax->list lst)].
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@speed[in-syntax "syntax"]
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@examples[#:eval the-eval
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(for/list ([x (in-syntax #'(1 2 3))])
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x)]}
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@defproc[(in-pairs [seq sequence?]) sequence?]{
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Produces a sequence equivalent to
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@racket[(in-parallel (sequence-lift car seq) (sequence-lift cdr seq))].
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}
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@defproc[(in-sequence-forever [seq sequence?] [val any/c]) sequence?]{
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Produces a sequence whose values are the elements of @racket[seq], followed by @racket[val] repeated.
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}
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@defproc[(sequence-lift [f procedure?] [seq sequence?]) sequence?]{
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Produces the sequence of @racket[f] applied to each element of @racket[seq].
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@examples[#:eval the-eval
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(for/list ([x (sequence-lift add1 (in-range 10))])
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x)]
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}
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@close-eval[the-eval]
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