scsh-0.6/scsh/rx/re-high.scm

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;;; Regular expression matching for scsh
;;; Copyright (c) 1998 by Olin Shivers.
;;; Translates the re to a Posix string, and returns a CRE record,
;;; but doesn't actually compile the Posix string into a C regex_t struct.
;;; Uses the :POSIX field to cache the CRE record.
(define (compile-regexp re)
(let* ((compile (lambda () (receive (s lev pcount tvec)
(regexp->posix-string re)
(new-cre s tvec))))
(check-cache (lambda (fetch set)
(or (fetch re) ; Already cached.
(let ((cre (compile))) ; Compile it,
(set re cre) ; cache it,
cre))))) ; and return it.
(? ((re-seq? re)
(check-cache re-seq:posix set-re-seq:posix))
((re-choice? re)
(check-cache re-choice:posix set-re-choice:posix))
((re-repeat? re)
(check-cache re-repeat:posix set-re-repeat:posix))
((re-char-set? re)
(check-cache re-char-set:posix set-re-char-set:posix))
((re-string? re)
(check-cache re-string:posix set-re-string:posix))
((re-submatch? re)
(check-cache re-submatch:posix set-re-submatch:posix))
((re-dsm? re)
(check-cache re-dsm:posix set-re-dsm:posix))
((re-bos? re) (or bos-cre (set! bos-cre (compile))))
((re-eos? re) (or eos-cre (set! eos-cre (compile))))
((re-bol? re) (error "BOL regexp not supported in this implementation."))
((re-eol? re) (error "EOL regexp not supported in this implementation."))
(else (error "compile-regexp -- not a regexp" re)))))
(define bos-cre #f)
(define eos-cre #f)
(define (regexp-search re str . maybe-start)
(let* ((tsm (re-tsm re))
(mvec (make-vector (+ 1 tsm) #f))
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(cre (compile-regexp re)))
(cre-search cre mvec str (:optional maybe-start 0))))
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(define (regexp-search? re str . maybe-start)
(cre-search? (compile-regexp re) str (:optional maybe-start 0)))