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;;;; Copyright (C) 1997 Free Software Foundation, Inc.
;;;;
;;;; This program is free software; you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation; either version 2, or (at your option)
;;;; any later version.
;;;;
;;;; This program is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with this software; see the file COPYING. If not, write to
;;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;;;;
;;;; POSIX regex support functions.
(define-module (ice-9 regex))
;;; FIXME:
;;; It is not clear what should happen if a `match' function
;;; is passed a `match number' which is out of bounds for the
;;; regexp match: return #f, or throw an error? These routines
;;; throw an out-of-range error.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;; These procedures are not defined in SCSH, but I found them useful.
(define-public (match:count match)
(- (vector-length match) 1))
(define-public (match:string match)
(vector-ref match 0))
(define-public (match:prefix match)
(make-shared-substring (match:string match)
0
(match:start match 0)))
(define-public (match:suffix match)
(make-shared-substring (match:string match)
(match:end match 0)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;; SCSH compatibility routines.
(define-public (regexp-match? match)
(and (vector? match)
(string? (vector-ref match 0))
(let loop ((i 1))
(cond ((>= i (vector-length match)) #t)
((and (pair? (vector-ref match i))
(integer? (car (vector-ref match i)))
(integer? (cdr (vector-ref match i))))
(loop (+ 1 i)))
(else #f)))))
(define-public (regexp-quote regexp)
(call-with-output-string
(lambda (p)
(let loop ((i 0))
(and (< i (string-length regexp))
(begin
(case (string-ref regexp i)
((#\* #\. #\( #\) #\+ #\? #\\ #\^ #\$ #\{ #\})
(write-char #\\ p)))
(write-char (string-ref regexp i) p)
(loop (1+ i))))))))
(define-public (match:start match . args)
(let* ((matchnum (if (pair? args)
(+ 1 (car args))
1))
(start (car (vector-ref match matchnum))))
(if (= start -1) #f start)))
(define-public (match:end match . args)
(let* ((matchnum (if (pair? args)
(+ 1 (car args))
1))
(end (cdr (vector-ref match matchnum))))
(if (= end -1) #f end)))
(define-public (match:substring match . args)
(let* ((matchnum (if (pair? args)
(car args)
0))
(start (match:start match matchnum))
(end (match:end match matchnum)))
(and start end (make-shared-substring (match:string match)
start
end))))
(define-public (string-match pattern str . args)
(let ((rx (make-regexp pattern))
(start (if (pair? args) (car args) 0)))
(regexp-exec rx str start)))
(define-public (regexp-substitute port match . items)
;; If `port' is #f, send output to a string.
(if (not port)
(call-with-output-string
(lambda (p)
(apply regexp-substitute p match items)))
;; Otherwise, process each substitution argument in `items'.
(for-each (lambda (obj)
(cond ((string? obj) (display obj port))
((integer? obj) (display (match:substring match obj) port))
((eq? 'pre obj) (display (match:prefix match) port))
((eq? 'post obj) (display (match:suffix match) port))
(else (error 'wrong-type-arg obj))))
items)))
(define-public (regexp-substitute/global port regexp string . items)
;; If `port' is #f, send output to a string.
(if (not port)
(call-with-output-string
(lambda (p)
(apply regexp-substitute/global p regexp string items)))
;; Otherwise, compile the regexp and match it against the
;; string, looping if 'post is encountered in `items'.
(let ((rx (make-regexp regexp)))
(let next-match ((str string))
(let ((match (regexp-exec rx str)))
(if (not match)
(display str port)
;; Process all of the items for this match.
(for-each
(lambda (obj)
(cond
((string? obj) (display obj port))
((integer? obj) (display (match:substring match obj) port))
((procedure? obj) (display (obj match) port))
((eq? 'pre obj) (display (match:prefix match) port))
((eq? 'post obj) (next-match (match:suffix match)))
(else (error 'wrong-type-arg obj))))
items)))))))
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