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[regexp] linear-time group unpacking, hooray for mutability

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ben 2015-12-08 03:23:29 -05:00
parent 2b1ab27825
commit c5ea8c032c
1 changed files with 9 additions and 9 deletions
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18
regexp.rkt
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@ -45,15 +45,15 @@
(syntax-parser
[(f pat-stx arg* ...)
#:with num-groups (count-groups #'pat-stx #:src #'f)
#:with ((index* . group-id*) ...)
#`#,(for/list ([i (in-range (syntax-e #'num-groups))])
(cons i (format-id #'f "group-~a" i)))
;; Chaining list-ref?
#'(let ([m (regexp-match pat-stx arg* ...)])
(if m
(let ([group-id* (or (list-ref m index*) (error 'regexp-match! "Internal error, try Racket's `regexp-match`"))] ...)
(list (car m) group-id* ...))
m))]
#:with (index* ...) #`#,(for/list ([i (in-range (syntax-e #'num-groups))]) i)
#'(let ([maybe-match (regexp-match pat-stx arg* ...)])
(if maybe-match
(let ([m : (Listof (Option String)) maybe-match])
(list (car maybe-match)
(begin (set! m (cdr m))
(or (car m) (error 'regexp-match! (format "Internal error at result index ~a, try Racket's regexp-match" index*))))
...))
#f))]
[(f arg* ...)
(syntax/loc #'f (regexp-match arg* ...))]))