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Add dict-set*

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This commit is contained in:
Jay McCarthy 2010-08-12 08:33:45 -06:00
parent a8fc09b49a
commit 2d1787a309
3 changed files with 88 additions and 0 deletions
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20
collects/racket/dict.rkt
View File

@ -11,7 +11,9 @@
dict-ref
dict-set!
dict-set*!
dict-set
dict-set*
dict-update!
dict-update
dict-remove!
@ -242,6 +244,14 @@
[else
(raise-type-error 'dict-set! "dict" 0 d key val)]))
(define (dict-set*! d . pairs)
(unless (even? (length pairs))
(error 'dict-set*! "expected an even number of association elements, but received an odd number: ~e" pairs))
(let loop ([pairs pairs])
(unless (null? pairs)
(dict-set! d (car pairs) (cadr pairs))
(loop (cddr pairs)))))
(define (dict-set d key val)
(cond
[(hash? d) (hash-set d key val)]
@ -264,6 +274,16 @@
[else
(raise-type-error 'dict-set "dict" 0 d key val)]))
(define (dict-set* d . pairs)
(unless (even? (length pairs))
(error 'dict-set* "expected an even number of association elements, but received an odd number: ~e" pairs))
(let loop ([d d]
[pairs pairs])
(if (null? pairs)
d
(loop (dict-set d (car pairs) (cadr pairs))
(cddr pairs)))))
(define dict-update!
(case-lambda
[(d key xform)

51
collects/scribblings/reference/dicts.scrbl
View File

@ -110,6 +110,33 @@ h
v
]}
@defproc[(dict-set*! [dict (and/c dict? (not/c immutable?))]
[key any/c]
[v any/c]
...
...) void?]{
Maps each @scheme[key] to each @scheme[v] in @scheme[dict], overwriting any
existing mapping for each @scheme[key]. The update can fail with a
@scheme[exn:fail:contract] exception if @scheme[dict] is not mutable
or if any @scheme[key] is not an allowed key for the dictionary (e.g., not
an exact integer in the appropriate range when @scheme[dict] is a
@tech{vector}). The update takes place from the left, so later mappings overwrite
earlier mappings.
@examples[
#:eval dict-eval
(define h (make-hash))
(dict-set*! h 'a "apple" 'b "banana")
h
(define v1 (vector #f #f #f))
(dict-set*! v1 0 "apple" 1 "banana")
v1
(define v2 (vector #f #f #f))
(dict-set*! v2 0 "apple" 0 "banana")
v2
]}
@defproc[(dict-set [dict (and/c dict? immutable?)]
[key any/c]
@ -131,6 +158,30 @@ dictionary.
(dict-set '((a . "apple") (b . "beer")) 'b "banana")
]}
@defproc[(dict-set* [dict (and/c dict? immutable?)]
[key any/c]
[v any/c]
...
...)
(and/c dict? immutable?)]{
Functionally extends @scheme[dict] by mapping each @scheme[key] to
each @scheme[v], overwriting any existing mapping for each @scheme[key], and
returning an extended dictionary. The update can fail with a
@scheme[exn:fail:contract] exception if @scheme[dict] does not support
functional extension or if any @scheme[key] is not an allowed key for the
dictionary. The update takes place from the left, so later mappings overwrite
earlier mappings.
@examples[
#:eval dict-eval
(dict-set* #hash() 'a "apple" 'b "beer")
(dict-set* #hash((a . "apple") (b . "beer")) 'b "banana" 'a "anchor")
(dict-set* '() 'a "apple" 'b "beer")
(dict-set* '((a . "apple") (b . "beer")) 'b "banana" 'a "anchor")
(dict-set* '((a . "apple") (b . "beer")) 'b "banana" 'b "balistic")
]}
@defproc[(dict-ref [dict dict?]
[key any/c]

17
collects/tests/racket/dict.rktl
View File

@ -77,6 +77,23 @@
(test #t equal? d bigger)))))])
(try-add smaller "ONE")
(try-add d "ONE")
(try-add d 'one))
(let ([try-add
(lambda (d val)
(let ([bigger (if mutable?
(begin
(err/rt-test (dict-set* smaller 1 val))
(dict-set*! smaller 1 (gensym) 1 val)
d)
(begin
(err/rt-test (dict-set*! smaller 1 val))
(dict-set* smaller 1 (gensym) 1 val)))])
(test cnt dict-count bigger)
(when (eq? val 'one)
(unless (pair? d)
(test #t equal? d bigger)))))])
(try-add smaller "ONE")
(try-add d "ONE")
(try-add d 'one)))))
(try-simple (vector 'zero 'one 'two) #t #f #f)