57 lines
1.8 KiB
Racket
57 lines
1.8 KiB
Racket
#lang scribble/manual
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@(require scribble/eval "utils.rkt"
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(for-label racket/base unstable/struct racket/contract))
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@(define the-eval (make-base-eval))
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@(the-eval '(require unstable/struct))
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@title[#:tag "struct"]{Structs}
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@unstable[@author+email["Ryan Culpepper" "ryanc@racket-lang.org"]]
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@defmodule[unstable/struct]
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@defform[(make struct-id expr ...)]{
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Creates an instance of @racket[struct-id], which must be bound as a
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struct name. The number of @racket[expr]s is statically checked
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against the number of fields associated with @racket[struct-id]. If
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they are different, or if the number of fields is not known, an error
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is raised at compile time.
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@examples[#:eval the-eval
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(define-struct triple (a b c))
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(make triple 3 4 5)
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(make triple 2 4)
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]
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}
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@defproc[(struct->list [v any/c]
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[#:on-opaque on-opaque (or/c 'error 'return-false 'skip) 'error])
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(or/c list? #f)]{
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Returns a list containing the struct instance @racket[v]'s
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fields. Unlike @racket[struct->vector], the struct name itself is not
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included.
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If any fields of @racket[v] are inaccessible via the current inspector
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the behavior of @racket[struct->list] is determined by
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@racket[on-opaque]. If @racket[on-opaque] is @racket['error] (the
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default), an error is raised. If it is @racket['return-false],
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@racket[struct->list] returns @racket[#f]. If it is @racket['skip],
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the inaccessible fields are omitted from the list.
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@examples[#:eval the-eval
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(define-struct open (u v) #:transparent)
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(struct->list (make-open 'a 'b))
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(struct->list #s(pre 1 2 3))
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(define-struct (secret open) (x y))
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(struct->list (make-secret 0 1 17 22))
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(struct->list (make-secret 0 1 17 22) #:on-opaque 'return-false)
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(struct->list (make-secret 0 1 17 22) #:on-opaque 'skip)
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(struct->list 'not-a-struct #:on-opaque 'return-false)
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(struct->list 'not-a-struct #:on-opaque 'skip)
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]
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}
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@close-eval[the-eval]
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