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match: stop searching for unused tmps when all have been found

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Bogdan Popa 2020-11-07 12:14:55 +02:00 committed by Sam Tobin-Hochstadt
parent 684a1f1039
commit 21cd97f2b2
1 changed files with 7 additions and 1 deletions
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8
racket/collects/racket/match/compiler.rkt
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@ -138,10 +138,16 @@
;; present in `body'. ;; present in `body'.
(define (remove-unused-tmps tmps accs body) (define (remove-unused-tmps tmps accs body)
(define seen (make-hasheq)) (define seen (make-hasheq))
(define todo (make-hasheq
(for/list ([tmp (in-list (syntax-e tmps))])
(cons tmp #t))))
(let loop ([stx body]) (let loop ([stx body])
(cond (cond
;; stop the search early if all the tmps have already been found
[(hash-empty? todo)]
[(identifier? stx) [(identifier? stx)
(for/first ([tmp (in-list (syntax-e tmps))] #:when (free-identifier=? tmp stx)) (for/first ([tmp (in-list (hash-keys todo))] #:when (free-identifier=? tmp stx))
(hash-remove! todo tmp)
(hash-set! seen tmp #t))] (hash-set! seen tmp #t))]
[(list? (syntax-e stx)) [(list? (syntax-e stx))
(for-each loop (syntax-e stx))])) (for-each loop (syntax-e stx))]))