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Fixing the docs for the new hash/c combinator.

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Stevie Strickland 2010-05-12 15:25:27 -04:00
parent 4a48da022b
commit a838fa0606
1 changed files with 17 additions and 9 deletions
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26
collects/scribblings/reference/contracts.scrbl
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@ -319,21 +319,29 @@ type named by @racket[struct-id], and whose field values match the
Produces a contract on parameters whose values must match
@racket[contract].}
@defproc[(hash/c [key contract?]
@defproc[(hash/c [key chaperone-contract?]
[val contract?]
[#:immutable immutable (or/c #t #f 'dont-care) 'dont-care])
[#:immutable immutable (or/c #t #f 'dont-care) 'dont-care]
[#:flat? flat? boolean? #f])
contract?]{
Produces a contract that recognizes @racket[hash] tables with keys and values
as specified by the @racket[key] and @racket[val] arguments.
If the @racket[immutable] argument is @racket[#f] or
@racket['dont-care], then the resulting contract is a flat contract,
and the @racket[key] and @racket[val] arguments must also be flat
contracts.
If the @racket[flat?] argument is @racket[#t], then the resulting contract is
a flat contract, and the @racket[key] and @racket[val] arguments must also be flat
contracts. Such flat contracts will be unsound if applied to mutable hash tables,
as they will not check future operations on the hash table.
If @racket[immutable] is @racket[#t], then the other arguments do not
have to be flat contracts, the result is not a flat contract, and
checking this contract involves making a copy of the hash-table.
If the @racket[immutable] argument is @racket[#t] and the @racket[key] and
@racket[val] arguments are flat contracts, the result will be a flat contract.
If either the domain or the range is a chaperone contract, then the result will
be a chaperone contract.
If the @racket[key] argument is a chaperone contract, then the resulting contract
can only be applied to @racket[equal?]-based hash tables. When a higher-order
@racket[hash/c] contract is applied to a hash table, the result is not @racket[eq?]
to the input. The result will be a copy for immutable hash tables, and either a
@tech{chaperone} or @tech{proxy} of the input for mutable hash tables.
}