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adding gvector-remove-last!

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This commit is contained in:
Danny Yoo 2012-01-30 11:21:30 -05:00 committed by Ryan Culpepper
parent ef846caaa1
commit bbab60545e
3 changed files with 42 additions and 0 deletions
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17
collects/data/gvector.rkt
View File

@ -28,6 +28,11 @@
"")
index)))
(define (check-nonempty who n)
(unless (> n 0)
(error who "empty")))
(define ((bad-index-error who index))
(raise-mismatch-error who "index out of range" index))
@ -67,6 +72,16 @@
(vector-copy! v index v (add1 index) n)
(vector-set! v (sub1 n) #f)])))
(define (gvector-remove-last! gv)
(let ([n (gvector-n gv)]
[v (gvector-vec gv)])
(check-nonempty 'gvector-remove-last! n)
(define last-val (vector-ref v (sub1 n)))
(set-gvector-n! gv (sub1 n))
(vector-set! v (sub1 n) #f)
last-val))
(define (gvector-count gv)
(gvector-n gv))
@ -213,6 +228,8 @@
(->* (gvector?) () #:rest any/c any)]
[gvector-remove!
(-> gvector? exact-nonnegative-integer? any)]
[gvector-remove-last!
(-> gvector? any)]
[gvector-count
(-> gvector? any)]
[gvector->vector

6
collects/data/scribblings/gvector.scrbl
View File

@ -83,6 +83,12 @@ down. Takes time proportional to @racket[(- (gvector-count gv)
index)].
}
@defproc[(gvector-remove-last! [gv gvector?])
any/c]{
Removes the element at the end and returns it. Takes constant time.
}
@defproc[(gvector-count [gv gvector?])
exact-nonnegative-integer?]{

19
collects/tests/data/gvector.rkt
View File

@ -53,6 +53,25 @@
(gvector->vector gv))
'#(2 3))
(test-equal? "gvector-remove-last!"
(let ([gv (gvector 1 2 3)])
(check-equal? (gvector-remove-last! gv) 3)
(check-equal? (gvector-remove-last! gv) 2)
(check-equal? (gvector-remove-last! gv) 1)
(gvector->vector gv))
'#())
(test-equal? "gvector-add and gvector-remove-last!"
(let ([gv (gvector)])
(gvector-add! gv 'rock)
(gvector-add! gv 'paper)
(check-equal? (gvector-remove-last! gv) 'paper)
(gvector-add! gv 'scissor)
(check-equal? (gvector-remove-last! gv) 'scissor)
(check-equal? (gvector-remove-last! gv) 'rock)
(gvector->vector gv))
'#())
(test-equal? "gvector-count"
(gvector-count (gvector 1 2 3))
3)