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Remove hash-intersect.

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This function was merged into Racket.
This commit is contained in:
Sergiu Ivanov 2021-04-29 20:50:26 +02:00
parent c7912705ca
commit 096f21a47f
1 changed files with 1 additions and 39 deletions
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40
utils.rkt
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@ -50,12 +50,7 @@
[boolean-power (-> number? (listof (listof boolean?)))]
[boolean-power/stream (-> number? (stream/c (listof boolean?)))]
[any->01 (-> any/c (or/c 0 1))]
[01->boolean (-> (or/c 0 1) boolean?)]
[hash-intersect (->* [(and/c hash? immutable?)]
[#:combine (-> any/c any/c any/c)
#:combine/key (-> any/c any/c any/c any/c)]
#:rest (listof hash?)
(and/c hash? immutable?))])
[01->boolean (-> (or/c 0 1) boolean?)])
;; Contracts
(contract-out [variable-mapping? contract?]
[string-variable-mapping? contract?]
@ -591,39 +586,6 @@
(test-case "lists-transpose"
(check-equal? (lists-transpose '((1 2) (a b))) '((1 a) (2 b)))))
;;; Like hash-union, but computes the intersection of hash
;;; tables.
;;;
;;; The intersections are computed by functional update, intersecting
;;; the first hash table with every other one supplied, one by one.
;;; The new mappings are computed either using combine or combine/key.
;;;
;;; TODO: I submitted this function to the Racket repository. Remove
;;; this function from this module when the update gets applied.
(define (hash-intersect
#:combine [combine #f]
#:combine/key [combine/key
(if combine
(λ (_ x y) (combine x y))
(error 'hash-intersect))]
one . rest)
(define common-keys (apply set-intersect (map hash-keys (cons one rest))))
(define res (for/hash ([k (in-list common-keys)])
(values k (hash-ref one k))))
(for*/fold ([res res]) ([hm (in-list rest)]
[(k v) (in-hash res)])
(hash-set res k (combine/key k v (hash-ref hm k)))))
(module+ test
(test-case "hash-intersect"
(define h1 #hash((a . 1) (b . 2) (c . 3)))
(define h2 #hash((a . 4) (b . 5)))
(define h3 #hash((a . 7) (c . 8)))
(check-equal? (hash-intersect h1 h2 h3 #:combine +)
'#hash((a . 12)))
(check-equal? (hash-intersect h1 h3 #:combine -)
'#hash((a . -6) (c . -5)))))
;;; =========
;;; Functions
;;; =========