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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 Produces a contract on parameters whose values must match
@racket[contract].} @racket[contract].}
@defproc[(hash/c [key contract?] @defproc[(hash/c [key chaperone-contract?]
[val 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?]{ contract?]{
Produces a contract that recognizes @racket[hash] tables with keys and values Produces a contract that recognizes @racket[hash] tables with keys and values
as specified by the @racket[key] and @racket[val] arguments. as specified by the @racket[key] and @racket[val] arguments.
If the @racket[immutable] argument is @racket[#f] or If the @racket[flat?] argument is @racket[#t], then the resulting contract is
@racket['dont-care], then the resulting contract is a flat contract, a flat contract, and the @racket[key] and @racket[val] arguments must also be flat
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,
contracts. as they will not check future operations on the hash table.
If @racket[immutable] is @racket[#t], then the other arguments do not If the @racket[immutable] argument is @racket[#t] and the @racket[key] and
have to be flat contracts, the result is not a flat contract, and @racket[val] arguments are flat contracts, the result will be a flat contract.
checking this contract involves making a copy of the hash-table. 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.
} }