255 lines
8.0 KiB
Scheme
255 lines
8.0 KiB
Scheme
#| -*-Scheme-*-
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Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
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1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
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2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
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2017, 2018, 2019, 2020 Massachusetts Institute of Technology
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This file is part of MIT/GNU Scheme.
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MIT/GNU Scheme is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at
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your option) any later version.
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MIT/GNU Scheme is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with MIT/GNU Scheme; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
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USA.
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|#
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;;;; Regular Expressions
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(define hash-of-false (hash-object #f))
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(define match-group hash-of-false)
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(define (re-match-start i)
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(let ((index (re-match-start-index i)))
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(and index
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(make-mark (re-match-group) index))))
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(define (re-match-end i)
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(let ((index (re-match-end-index i)))
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(and index
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(make-mark (re-match-group) index))))
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(define (re-match-extract-string i)
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(group-extract-string (re-match-group)
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(or (re-match-start-index i)
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(error "No such register:" i))
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(re-match-end-index i)))
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(define (re-match-group)
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(let ((group (unhash-object match-group)))
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(if (not group)
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(error "No match group"))
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group))
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(define (re-match-data)
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(let ((group (unhash-object match-group)))
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(cons group
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(if group
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(let ((v (make-vector 20)))
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(do ((i 0 (fix:+ i 1)))
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((fix:= i 20))
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(vector-set!
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v i
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(let ((index (vector-ref registers i)))
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(and index
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;; Start marks are right-inserting,
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;; end marks are left-inserting.
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(make-permanent-mark group index (fix:>= i 10))))))
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v)
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(vector-copy registers)))))
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(define (set-re-match-data! data)
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(let ((group (car data))
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(marks (cdr data)))
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(if group
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(begin
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(set! match-group (group-hash-number group))
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(do ((i 0 (fix:+ i 1)))
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((fix:= i 20))
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(vector-set! registers i
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(let ((mark (vector-ref marks i)))
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(and mark
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(let ((index (mark-index mark)))
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(mark-temporary! mark)
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index))))))
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(begin
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(set! match-group hash-of-false)
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(do ((i 0 (fix:+ i 1)))
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((fix:= i 20))
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(vector-set! registers i (vector-ref marks i)))))))
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(define (preserving-match-data thunk)
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(let ((data unspecific))
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(dynamic-wind (lambda () (set! data (re-match-data)) unspecific)
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thunk
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(lambda () (set-re-match-data! data)))))
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(define (replace-match replacement #!optional preserve-case? literal?)
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(let ((start (re-match-start 0))
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(end (mark-left-inserting-copy (re-match-end 0))))
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(let ((replacement
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(let ((replacement
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(if (and (not (default-object? literal?)) literal?)
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replacement
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(re-substitute-registers replacement))))
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(if (and (not (default-object? preserve-case?)) preserve-case?)
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;; Emacs uses a more complicated algorithm here,
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;; which breaks the replaced string into words,
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;; makes the decision based on examining all the
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;; words, and then changes each word in the
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;; replacement to match the pattern.
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(let ((replaced (extract-string start end)))
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(cond ((string-capitalized? replaced)
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(string-capitalize replacement))
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((string-upper-case? replaced)
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(string-upcase replacement))
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(else replacement)))
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replacement))))
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(delete-string start end)
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(insert-string replacement start))
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(mark-temporary! end)
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end))
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(define (re-substitute-registers pattern)
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(let ((end (string-length pattern)))
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(if (substring-find-next-char pattern 0 end #\\)
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(apply
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string-append
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(let loop ((start 0))
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(let ((slash (substring-find-next-char pattern start end #\\)))
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(if slash
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(cons (substring pattern start slash)
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(let ((next (+ slash 1)))
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(cons (let ((char
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(if (< next end)
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(string-ref pattern next)
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#\\)))
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(let ((n
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(if (char=? #\& char)
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0
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(char->digit char))))
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(cond ((not n)
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(string char))
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((not (re-match-start-index n))
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(error "No match for register" n))
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(else
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(extract-string
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(re-match-start n)
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(re-match-end n))))))
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(if (< next end)
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(loop (+ next 1))
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'()))))
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(list (substring pattern start end))))))
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pattern)))
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(define (delete-match)
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(let ((group (re-match-group))
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(start (re-match-start-index 0)))
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(group-delete! group start (re-match-end-index 0))
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(make-mark group start)))
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(define (search-forward string start #!optional end case-fold-search)
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(%re-search string start (default-end-mark start end)
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(default-case-fold-search case-fold-search start)
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re-compile-string
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re-search-buffer-forward))
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(define (search-backward string end #!optional start case-fold-search)
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(%re-search string (default-start-mark start end) end
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(default-case-fold-search case-fold-search end)
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re-compile-string
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re-search-buffer-backward))
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(define (re-search-forward regexp start #!optional end case-fold-search)
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(%re-search regexp start (default-end-mark start end)
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(default-case-fold-search case-fold-search start)
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re-compile-pattern
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re-search-buffer-forward))
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(define (re-search-backward regexp end #!optional start case-fold-search)
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(%re-search regexp (default-start-mark start end) end
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(default-case-fold-search case-fold-search end)
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re-compile-pattern
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re-search-buffer-backward))
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(define (%re-search string start end case-fold-search compile-string search)
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(let ((group (mark-group start)))
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(let ((index
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(search (if (compiled-regexp? string)
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string
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(compile-string string case-fold-search))
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(group-syntax-table group)
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group
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(mark-index start)
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(mark-index end))))
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(and index
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(make-mark group index)))))
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(define (re-match-forward regexp start #!optional end case-fold-search)
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(let ((end (default-end-mark start end))
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(case-fold-search (default-case-fold-search case-fold-search start))
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(group (mark-group start)))
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(let ((index
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(re-match-buffer-forward (if (compiled-regexp? regexp)
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regexp
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(re-compile-pattern regexp
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case-fold-search))
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(group-syntax-table group)
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group
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(mark-index start)
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(mark-index end))))
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(and index
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(make-mark group index)))))
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(define (re-search-buffer-forward regexp syntax-table group start end)
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(and (fix:< start end)
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(let ((index
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((ucode-primitive re-search-buffer-forward)
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(compiled-regexp/byte-stream regexp)
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(compiled-regexp/translation-table regexp)
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(syntax-table-argument syntax-table)
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registers group start end)))
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(set! match-group (compute-match-group group index))
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index)))
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(define (re-search-buffer-backward regexp syntax-table group start end)
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(and (fix:< start end)
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(let ((index
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((ucode-primitive re-search-buffer-backward)
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(compiled-regexp/byte-stream regexp)
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(compiled-regexp/translation-table regexp)
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(syntax-table-argument syntax-table)
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registers group start end)))
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(set! match-group (compute-match-group group index))
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index)))
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(define (re-match-buffer-forward regexp syntax-table group start end)
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(let ((index
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((ucode-primitive re-match-buffer)
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(compiled-regexp/byte-stream regexp)
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(compiled-regexp/translation-table regexp)
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(syntax-table-argument syntax-table)
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registers group start end)))
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(set! match-group (compute-match-group group index))
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index))
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(define-integrable (syntax-table-argument syntax-table)
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(char-syntax-table/entries (or syntax-table standard-char-syntax-table)))
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(define (compute-match-group group index)
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(if index
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(group-hash-number group)
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hash-of-false))
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