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attempt to document when flat contracts are predicates

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Robby Findler 2013-07-29 12:39:06 -05:00
parent 895b8d2760
commit 71ec424c70
1 changed files with 10 additions and 2 deletions
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pkgs/racket-pkgs/racket-doc/scribblings/reference/contracts.scrbl
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@ -76,8 +76,16 @@ Contracts in Racket are subdivided into three different categories:
@itemlist[@item{@deftech{Flat contract}s can be fully checked immediately for
a given value. These kinds of contracts are essentially
predicate functions. Using @racket[flat-contract-predicate],
you can extract the predicate from a flat contract, and
@racket[flat-contract?] recognizes a flat contract.}
you can extract the predicate from an arbitrary flat contract; some
flat contracts can be applied like functions, in which case
they accept a single argument and return @racket[#t] or
@racket[#f] to indicate if the given value would be accepted
by the contract. All of the flat contracts returned by functions
in this library can be used directly as predicates, but ordinary
Racket values that double as flat contracts (e.g., numbers or symbols)
cannot.
The function @racket[flat-contract?] recognizes a flat contract.}
@item{@deftech{Chaperone contracts} are not always immediately
checkable, but are guaranteed to not change any properties
of any values that they check. That is, they may wrap