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Documented forms for generic instance chaperones, impersonators, and contracts.

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This commit is contained in:
Carl Eastlund 2013-07-25 01:24:07 -04:00
parent 2f473c2403
commit 08ae925408
1 changed files with 41 additions and 0 deletions
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pkgs/racket-pkgs/racket-doc/scribblings/reference/generic.scrbl
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@ -194,4 +194,45 @@ syntax error.}
(gen-print* z #:width "not a number" #:height 5)
]
@defform[(generic-instance/c gen-id [method-id method-ctc] ...)
#:contracts ([method-ctc contract?])]{
Creates a contract that recognizes structures that implement the @tech{generic
interface} @racket[gen-id], and constrains their implementations of the
specified @racket[method-id]s with the corresponding @racket[method-ctc]s.
}
@defform[(impersonate-generics gen-id val-expr [method-id method-proc] ...)
#:contracts ([method-proc (any/c . -> . any/c)])]{
Creates an @tech{impersonator} of @racket[val-expr], which must be a structure
that implements the @tech{generic interface} @racket[gen-id]. The impersonator
applies the specified @racket[method-proc]s to the structure's implementation
of the corresponding @racket[method-id]s, and replaces the method
implementation with the result.
}
@defform[(chaperone-generics gen-id val-expr [method-id method-proc] ...)
#:contracts ([method-proc (any/c . -> . any/c)])]{
Creates a @tech{chaperone} of @racket[val-expr], which must be a structure
that implements the @tech{generic interface} @racket[gen-id]. The chaperone
applies the specified @racket[method-proc]s to the structure's implementation
of the corresponding @racket[method-id]s, and replaces the method
implementation with the result, which must be a chaperone of the original.
}
@defform[(redirect-generics mode gen-id val-expr [method-id method-proc] ...)
#:contracts ([method-proc (any/c . -> . any/c)])]{
Creates an @tech{impersonator} of @racket[val-expr], like
@racket[impersonate-generics], if @racket[mode] evaluates to @racket[#f].
Creates a @tech{chaperone} of @racket[val-expr], like
@racket[chaperone-generics], otherwise.
}
@close-eval[evaluator]