(xmalloc, xrealloc): Add casts.

[bpt/emacs.git] / lisp / replace.el

;;; replace.el --- replace commands for Emacs.

;; Copyright (C) 1985, 1986, 1987, 1992, 1994 Free Software Foundation, Inc.

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:

;; This package supplies the string and regular-expression replace functions
;; documented in the Emacs user's manual.

;;; Code:

(defconst case-replace t "\
*Non-nil means query-replace should preserve case in replacements.")

(defvar query-replace-history nil)

(defvar query-replace-interactive nil
  "Non-nil means `query-replace' uses the last search string.
That becomes the \"string to replace\".")

(defun query-replace-read-args (string regexp-flag)
  (let (from to)
    (if query-replace-interactive
	(setq from (car (if regexp-flag regexp-search-ring search-ring)))
      (setq from (read-from-minibuffer (format "%s: " string)
				       nil nil nil
				       'query-replace-history)))
    (setq to (read-from-minibuffer (format "%s %s with: " string from)
				   nil nil nil
				   'query-replace-history))
    (list from to current-prefix-arg)))

(defun query-replace (from-string to-string &optional arg)
  "Replace some occurrences of FROM-STRING with TO-STRING.
As each match is found, the user must type a character saying
what to do with it.  For directions, type \\[help-command] at that time.

If `query-replace-interactive' is non-nil, the last incremental search
string is used as FROM-STRING--you don't have to specify it with the
minibuffer.

Preserves case in each replacement if `case-replace' and `case-fold-search'
are non-nil and FROM-STRING has no uppercase letters.
\(Preserving case means that if the string matched is all caps, or capitalized,
then its replacement is upcased or capitalized.)

Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.

To customize possible responses, change the \"bindings\" in `query-replace-map'."
  (interactive (query-replace-read-args "Query replace" nil))
  (perform-replace from-string to-string t nil arg))
(define-key esc-map "%" 'query-replace)

(defun query-replace-regexp (regexp to-string &optional arg)
  "Replace some things after point matching REGEXP with TO-STRING.
As each match is found, the user must type a character saying
what to do with it.  For directions, type \\[help-command] at that time.

If `query-replace-interactive' is non-nil, the last incremental search
regexp is used as REGEXP--you don't have to specify it with the
minibuffer.

Preserves case in each replacement if `case-replace' and `case-fold-search'
are non-nil and REGEXP has no uppercase letters.
Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.
In TO-STRING, `\\&' stands for whatever matched the whole of REGEXP,
and `\\=\\N' (where N is a digit) stands for
 whatever what matched the Nth `\\(...\\)' in REGEXP."
  (interactive (query-replace-read-args "Query replace regexp" t))
  (perform-replace regexp to-string t t arg))

(defun map-query-replace-regexp (regexp to-strings &optional arg)
  "Replace some matches for REGEXP with various strings, in rotation.
The second argument TO-STRINGS contains the replacement strings, separated
by spaces.  This command works like `query-replace-regexp' except
that each successive replacement uses the next successive replacement string,
wrapping around from the last such string to the first.

Non-interactively, TO-STRINGS may be a list of replacement strings.

If `query-replace-interactive' is non-nil, the last incremental search
regexp is used as REGEXP--you don't have to specify it with the minibuffer.

A prefix argument N says to use each replacement string N times
before rotating to the next."
  (interactive
   (let (from to)
     (setq from (if query-replace-interactive
		    (car regexp-search-ring)
		  (read-from-minibuffer "Map query replace (regexp): "
					nil nil nil
					'query-replace-history)))
     (setq to (read-from-minibuffer
	       (format "Query replace %s with (space-separated strings): "
		       from)
	       nil nil nil
	       'query-replace-history))
     (list from to current-prefix-arg)))
  (let (replacements)
    (if (listp to-strings)
	(setq replacements to-strings)
      (while (/= (length to-strings) 0)
	(if (string-match " " to-strings)
	    (setq replacements
		  (append replacements
			  (list (substring to-strings 0
					   (string-match " " to-strings))))
		  to-strings (substring to-strings
				       (1+ (string-match " " to-strings))))
	  (setq replacements (append replacements (list to-strings))
		to-strings ""))))
    (perform-replace regexp replacements t t nil arg)))

(defun replace-string (from-string to-string &optional delimited)
  "Replace occurrences of FROM-STRING with TO-STRING.
Preserve case in each match if `case-replace' and `case-fold-search'
are non-nil and FROM-STRING has no uppercase letters.
\(Preserving case means that if the string matched is all caps, or capitalized,
then its replacement is upcased or capitalized.)

Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.

If `query-replace-interactive' is non-nil, the last incremental search
string is used as FROM-STRING--you don't have to specify it with the
minibuffer.

This function is usually the wrong thing to use in a Lisp program.
What you probably want is a loop like this:
  (while (search-forward FROM-STRING nil t)
    (replace-match TO-STRING nil t))
which will run faster and will not set the mark or print anything."
  (interactive (query-replace-read-args "Replace string" nil))
  (perform-replace from-string to-string nil nil delimited))

(defun replace-regexp (regexp to-string &optional delimited)
  "Replace things after point matching REGEXP with TO-STRING.
Preserve case in each match if `case-replace' and `case-fold-search'
are non-nil and REGEXP has no uppercase letters.
Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.
In TO-STRING, `\\&' stands for whatever matched the whole of REGEXP,
and `\\=\\N' (where N is a digit) stands for
 whatever what matched the Nth `\\(...\\)' in REGEXP.

If `query-replace-interactive' is non-nil, the last incremental search
regexp is used as REGEXP--you don't have to specify it with the minibuffer.

This function is usually the wrong thing to use in a Lisp program.
What you probably want is a loop like this:
  (while (re-search-forward REGEXP nil t)
    (replace-match TO-STRING nil nil))
which will run faster and will not set the mark or print anything."
  (interactive (query-replace-read-args "Replace regexp" t))
  (perform-replace regexp to-string nil t delimited))
\f
(defvar regexp-history nil
  "History list for some commands that read regular expressions.")

(defalias 'delete-non-matching-lines 'keep-lines)
(defun keep-lines (regexp)
  "Delete all lines except those containing matches for REGEXP.
A match split across lines preserves all the lines it lies in.
Applies to all lines after point."
  (interactive (list (read-from-minibuffer
		      "Keep lines (containing match for regexp): "
		      nil nil nil 'regexp-history)))
  (save-excursion
    (or (bolp) (forward-line 1))
    (let ((start (point)))
      (while (not (eobp))
	;; Start is first char not preserved by previous match.
	(if (not (re-search-forward regexp nil 'move))
	    (delete-region start (point-max))
	  (let ((end (save-excursion (goto-char (match-beginning 0))
				     (beginning-of-line)
				     (point))))
	    ;; Now end is first char preserved by the new match.
	    (if (< start end)
		(delete-region start end))))
	(setq start (save-excursion (forward-line 1)
				    (point)))
	;; If the match was empty, avoid matching again at same place.
	(and (not (eobp)) (= (match-beginning 0) (match-end 0))
	     (forward-char 1))))))

(defalias 'delete-matching-lines 'flush-lines)
(defun flush-lines (regexp)
  "Delete lines containing matches for REGEXP.
If a match is split across lines, all the lines it lies in are deleted.
Applies to lines after point."
  (interactive (list (read-from-minibuffer
		      "Flush lines (containing match for regexp): "
		      nil nil nil 'regexp-history)))
  (save-excursion
    (while (and (not (eobp))
		(re-search-forward regexp nil t))
      (delete-region (save-excursion (goto-char (match-beginning 0))
				     (beginning-of-line)
				     (point))
		     (progn (forward-line 1) (point))))))

(defalias 'count-matches 'how-many)
(defun how-many (regexp)
  "Print number of matches for REGEXP following point."
  (interactive (list (read-from-minibuffer
		      "How many matches for (regexp): "
		      nil nil nil 'regexp-history)))
  (let ((count 0) opoint)
    (save-excursion
     (while (and (not (eobp))
		 (progn (setq opoint (point))
			(re-search-forward regexp nil t)))
       (if (= opoint (point))
	   (forward-char 1)
	 (setq count (1+ count))))
     (message "%d occurrences" count))))
\f
(defvar occur-mode-map ())
(if occur-mode-map
    ()
  (setq occur-mode-map (make-sparse-keymap))
  (define-key occur-mode-map [mouse-2] 'occur-mode-mouse-goto)
  (define-key occur-mode-map "\C-c\C-c" 'occur-mode-goto-occurrence))

(defvar occur-buffer nil)
(defvar occur-nlines nil)
(defvar occur-pos-list nil)

(defun occur-mode ()
  "Major mode for output from \\[occur].
Move point to one of the occurrences in this buffer,
then use \\[occur-mode-goto-occurrence] to go to the same occurrence
in the buffer that the occurrences were found in.
Or click \\<occur-mode-map>\\[occur-mode-mouse-goto] on an occurrence line.
\\{occur-mode-map}"
  (kill-all-local-variables)
  (use-local-map occur-mode-map)
  (setq major-mode 'occur-mode)
  (setq mode-name "Occur")
  (make-local-variable 'occur-buffer)
  (make-local-variable 'occur-nlines)
  (make-local-variable 'occur-pos-list)
  (run-hooks 'occur-mode-hook))

(defun occur-mode-mouse-goto (event)
  "In Occur mode, go to the occurrence whose line you click on."
  (interactive "e")
  (let (buffer pos)
    (save-excursion
      (set-buffer (window-buffer (posn-window (event-end event))))
      (save-excursion
	(goto-char (posn-point (event-end event)))
	(setq pos (occur-mode-find-occurrence))
	(setq buffer occur-buffer)))
    (pop-to-buffer buffer)
    (goto-char (marker-position pos))))

(defun occur-mode-find-occurrence ()
  (if (or (null occur-buffer)
	  (null (buffer-name occur-buffer)))
      (progn
	(setq occur-buffer nil
	      occur-pos-list nil)
	(error "Buffer in which occurrences were found is deleted")))
  (let* ((line-count
	  (count-lines (point-min)
		       (save-excursion
			 (beginning-of-line)
			 (point))))
	 (occur-number (save-excursion
			 (beginning-of-line)
			 (/ (1- line-count)
			    (cond ((< occur-nlines 0)
				   (- 2 occur-nlines))
				  ((> occur-nlines 0)
				   (+ 2 (* 2 occur-nlines)))
				  (t 1)))))
	 (pos (nth occur-number occur-pos-list)))
    (if (< line-count 1)
	(error "No occurrence on this line"))
    (or pos
	(error "No occurrence on this line"))
    pos))

(defun occur-mode-goto-occurrence ()
  "Go to the occurrence the current line describes."
  (interactive)
  (let ((pos (occur-mode-find-occurrence)))
    (pop-to-buffer occur-buffer)
    (goto-char (marker-position pos))))
\f
(defvar list-matching-lines-default-context-lines 0
  "*Default number of context lines to include around a `list-matching-lines'
match.  A negative number means to include that many lines before the match.
A positive number means to include that many lines both before and after.")

(defalias 'list-matching-lines 'occur)

(defun occur (regexp &optional nlines)
  "Show all lines in the current buffer containing a match for REGEXP.

If a match spreads across multiple lines, all those lines are shown.

Each line is displayed with NLINES lines before and after, or -NLINES
before if NLINES is negative.
NLINES defaults to `list-matching-lines-default-context-lines'.
Interactively it is the prefix arg.

The lines are shown in a buffer named `*Occur*'.
It serves as a menu to find any of the occurrences in this buffer.
\\[describe-mode] in that buffer will explain how."
  (interactive (list (let* ((default (car regexp-history))
			    (input 
			     (read-from-minibuffer
			      (if default
				  (format "List lines matching regexp (default `%s'): " default)
				"List lines matching regexp: ")
			      nil nil nil
			      'regexp-history)))
		       (if (> (length input) 0) input
			 (setcar regexp-history default)))
		     current-prefix-arg))
  (setq nlines (if nlines (prefix-numeric-value nlines)
		 list-matching-lines-default-context-lines))
  (let ((first t)
	(buffer (current-buffer))
	(linenum 1)
	(prevpos (point-min))
	(final-context-start (make-marker)))
;;;	(save-excursion
;;;	  (beginning-of-line)
;;;	  (setq linenum (1+ (count-lines (point-min) (point))))
;;;	  (setq prevpos (point)))
    (with-output-to-temp-buffer "*Occur*"
      (save-excursion
	(set-buffer standard-output)
	;; We will insert the number of lines, and "lines", later.
	(insert " matching ")
	(let ((print-escape-newlines t))
	  (prin1 regexp))
	(insert " in buffer " (buffer-name buffer) ?. ?\n)
	(occur-mode)
	(setq occur-buffer buffer)
	(setq occur-nlines nlines)
	(setq occur-pos-list ()))
      (if (eq buffer standard-output)
	  (goto-char (point-max)))
      (save-excursion
	(beginning-of-buffer)
	;; Find next match, but give up if prev match was at end of buffer.
	(while (and (not (= prevpos (point-max)))
		    (re-search-forward regexp nil t))
	  (goto-char (match-beginning 0))
	  (beginning-of-line)
	  (save-match-data
	    (setq linenum (+ linenum (count-lines prevpos (point)))))
	  (setq prevpos (point))
	  (goto-char (match-end 0))
	  (let* ((start (save-excursion
			  (goto-char (match-beginning 0))
			  (forward-line (if (< nlines 0) nlines (- nlines)))
			  (point)))
		 (end (save-excursion
			(goto-char (match-end 0))
			(if (> nlines 0)
			    (forward-line (1+ nlines))
			    (forward-line 1))
			(point)))
		 (tag (format "%3d" linenum))
		 (empty (make-string (length tag) ?\ ))
		 tem)
	    (save-excursion
	      (setq tem (make-marker))
	      (set-marker tem (point))
	      (set-buffer standard-output)
	      (setq occur-pos-list (cons tem occur-pos-list))
	      (or first (zerop nlines)
		  (insert "--------\n"))
	      (setq first nil)
	      (insert-buffer-substring buffer start end)
	      (backward-char (- end start))
	      (setq tem nlines)
	      (while (> tem 0)
		(insert empty ?:)
		(forward-line 1)
		(setq tem (1- tem)))
	      (let ((this-linenum linenum))
		(set-marker final-context-start
			    (+ (point) (- (match-end 0) (match-beginning 0))))
		(while (< (point) final-context-start)
		  (if (null tag)
		      (setq tag (format "%3d" this-linenum)))
		  (insert tag ?:)
		  (put-text-property (save-excursion
				       (beginning-of-line)
				       (point))
				     (save-excursion
				       (end-of-line)
				       (point))
				     'mouse-face 'highlight)
		  (setq tag nil)
		  (forward-line 1)
		  (setq this-linenum (1+ this-linenum))))
	      (while (< tem nlines)
		(insert empty ?:)
		(forward-line 1)
		(setq tem (1+ tem))))				
	    (forward-line 1)))
	(set-buffer standard-output)
	;; Put positions in increasing order to go with buffer.
	(setq occur-pos-list (nreverse occur-pos-list))
	(goto-char (point-min))
	(if (= (length occur-pos-list) 1)
	    (insert "1 line")
	  (insert (format "%d lines" (length occur-pos-list))))
	(if (interactive-p)
	    (message "%d matching lines." (length occur-pos-list)))))))
\f
;; It would be nice to use \\[...], but there is no reasonable way
;; to make that display both SPC and Y.
(defconst query-replace-help
  "Type Space or `y' to replace one match, Delete or `n' to skip to next,
RET or `q' to exit, Period to replace one match and exit,
Comma to replace but not move point immediately,
C-r to enter recursive edit (\\[exit-recursive-edit] to get out again),
C-w to delete match and recursive edit,
C-l to clear the screen, redisplay, and offer same replacement again,
! to replace all remaining matches with no more questions,
^ to move point back to previous match."
  "Help message while in query-replace")

(defvar query-replace-map (make-sparse-keymap)
  "Keymap that defines the responses to questions in `query-replace'.
The \"bindings\" in this map are not commands; they are answers.
The valid answers include `act', `skip', `act-and-show',
`exit', `act-and-exit', `edit', `delete-and-edit', `recenter',
`automatic', `backup', `exit-prefix', and `help'.")

(define-key query-replace-map " " 'act)
(define-key query-replace-map "\d" 'skip)
(define-key query-replace-map [delete] 'skip)
(define-key query-replace-map [backspace] 'skip)
(define-key query-replace-map "y" 'act)
(define-key query-replace-map "n" 'skip)
(define-key query-replace-map "Y" 'act)
(define-key query-replace-map "N" 'skip)
(define-key query-replace-map "," 'act-and-show)
(define-key query-replace-map "q" 'exit)
(define-key query-replace-map "\r" 'exit)
(define-key query-replace-map [return] 'exit)
(define-key query-replace-map "." 'act-and-exit)
(define-key query-replace-map "\C-r" 'edit)
(define-key query-replace-map "\C-w" 'delete-and-edit)
(define-key query-replace-map "\C-l" 'recenter)
(define-key query-replace-map "!" 'automatic)
(define-key query-replace-map "^" 'backup)
(define-key query-replace-map "\C-h" 'help)
(define-key query-replace-map "?" 'help)
(define-key query-replace-map "\C-g" 'quit)
(define-key query-replace-map "\C-]" 'quit)
(define-key query-replace-map "\e" 'exit-prefix)
(define-key query-replace-map [escape] 'exit-prefix)

(defun perform-replace (from-string replacements
		        query-flag regexp-flag delimited-flag
			&optional repeat-count map)
  "Subroutine of `query-replace'.  Its complexity handles interactive queries.
Don't use this in your own program unless you want to query and set the mark
just as `query-replace' does.  Instead, write a simple loop like this:
  (while (re-search-forward \"foo[ \t]+bar\" nil t)
    (replace-match \"foobar\" nil nil))
which will run faster and probably do exactly what you want."
  (or map (setq map query-replace-map))
  (let ((nocasify (not (and case-fold-search case-replace
			    (string-equal from-string
					  (downcase from-string)))))
	(literal (not regexp-flag))
	(search-function (if regexp-flag 're-search-forward 'search-forward))
	(search-string from-string)
	(real-match-data nil)		; the match data for the current match
	(next-replacement nil)
	(replacement-index 0)
	(keep-going t)
	(stack nil)
	(next-rotate-count 0)
	(replace-count 0)
	(lastrepl nil)			;Position after last match considered.
	(match-again t)
	(message
	 (if query-flag
	     (substitute-command-keys
	      "Query replacing %s with %s: (\\<query-replace-map>\\[help] for help) "))))
    (if (stringp replacements)
	(setq next-replacement replacements)
      (or repeat-count (setq repeat-count 1)))
    (if delimited-flag
	(setq search-function 're-search-forward
	      search-string (concat "\\b"
				    (if regexp-flag from-string
				      (regexp-quote from-string))
				    "\\b")))
    (push-mark)
    (undo-boundary)
    (unwind-protect
	;; Loop finding occurrences that perhaps should be replaced.
	(while (and keep-going
		    (not (eobp))
		    (funcall search-function search-string nil t)
		    ;; If the search string matches immediately after
		    ;; the previous match, but it did not match there
		    ;; before the replacement was done, ignore the match.
		    (if (or (eq lastrepl (point))
			    (and regexp-flag
				 (eq lastrepl (match-beginning 0))
				 (not match-again)))
			(if (eobp)
			    nil
			  ;; Don't replace the null string 
			  ;; right after end of previous replacement.
			  (forward-char 1)
			  (funcall search-function search-string nil t))
		      t))

	  ;; Save the data associated with the real match.
	  (setq real-match-data (match-data))

	  ;; Before we make the replacement, decide whether the search string
	  ;; can match again just after this match.
	  (if regexp-flag
	      (setq match-again (looking-at search-string)))
	  ;; If time for a change, advance to next replacement string.
	  (if (and (listp replacements)
		   (= next-rotate-count replace-count))
	      (progn
		(setq next-rotate-count
		      (+ next-rotate-count repeat-count))
		(setq next-replacement (nth replacement-index replacements))
		(setq replacement-index (% (1+ replacement-index) (length replacements)))))
	  (if (not query-flag)
	      (progn
		(store-match-data real-match-data)
		(replace-match next-replacement nocasify literal)
		(setq replace-count (1+ replace-count)))
	    (undo-boundary)
	    (let (done replaced key def)
	      ;; Loop reading commands until one of them sets done,
	      ;; which means it has finished handling this occurrence.
	      (while (not done)
		(store-match-data real-match-data)
		(replace-highlight (match-beginning 0) (match-end 0))
		(message message from-string next-replacement)
		(setq key (read-event))
		(setq key (vector key))
		(setq def (lookup-key map key))
		;; Restore the match data while we process the command.
		(cond ((eq def 'help)
		       (with-output-to-temp-buffer "*Help*"
			 (princ
			  (concat "Query replacing "
				  (if regexp-flag "regexp " "")
				  from-string " with "
				  next-replacement ".\n\n"
				  (substitute-command-keys
				   query-replace-help)))
			 (save-excursion
			   (set-buffer standard-output)
			   (help-mode))))
		      ((eq def 'exit)
		       (setq keep-going nil)
		       (setq done t))
		      ((eq def 'backup)
		       (if stack
			   (let ((elt (car stack)))
			     (goto-char (car elt))
			     (setq replaced (eq t (cdr elt)))
			     (or replaced
				 (store-match-data (cdr elt)))
			     (setq stack (cdr stack)))
			 (message "No previous match")
			 (ding 'no-terminate)
			 (sit-for 1)))
		      ((eq def 'act)
		       (or replaced
			   (replace-match next-replacement nocasify literal))
		       (setq done t replaced t))
		      ((eq def 'act-and-exit)
		       (or replaced
			   (replace-match next-replacement nocasify literal))
		       (setq keep-going nil)
		       (setq done t replaced t))
		      ((eq def 'act-and-show)
		       (if (not replaced)
			   (progn
			     (replace-match next-replacement nocasify literal)
			     (setq replaced t))))
		      ((eq def 'automatic)
		       (or replaced
			   (replace-match next-replacement nocasify literal))
		       (setq done t query-flag nil replaced t))
		      ((eq def 'skip)
		       (setq done t))
		      ((eq def 'recenter)
		       (recenter nil))
		      ((eq def 'edit)
		       (store-match-data
			(prog1 (match-data)
			  (save-excursion (recursive-edit))))
		       ;; Before we make the replacement,
		       ;; decide whether the search string
		       ;; can match again just after this match.
		       (if regexp-flag
			   (setq match-again (looking-at search-string))))
		      ((eq def 'delete-and-edit)
		       (delete-region (match-beginning 0) (match-end 0))
		       (store-match-data
			(prog1 (match-data)
			  (save-excursion (recursive-edit))))
		       (setq replaced t))
		      ;; Note: we do not need to treat `exit-prefix'
		      ;; specially here, since we reread
		      ;; any unrecognized character.
		      (t
		       (setq this-command 'mode-exited)
		       (setq keep-going nil)
		       (setq unread-command-events
			     (append (listify-key-sequence key)
				     unread-command-events))
		       (setq done t))))
	      ;; Record previous position for ^ when we move on.
	      ;; Change markers to numbers in the match data
	      ;; since lots of markers slow down editing.
	      (setq stack
		    (cons (cons (point)
				(or replaced
				    (mapcar (lambda (elt)
					      (and elt
						   (prog1 (marker-position elt)
						     (set-marker elt nil))))
				     (match-data))))
			  stack))
	      (if replaced (setq replace-count (1+ replace-count)))))
	  (setq lastrepl (point)))
      (replace-dehighlight))
    (or unread-command-events
	(message "Replaced %d occurrence%s"
		 replace-count
		 (if (= replace-count 1) "" "s")))
    (and keep-going stack)))

(defvar query-replace-highlight nil
  "*Non-nil means to highlight words during query replacement.")

(defvar replace-overlay nil)

(defun replace-dehighlight ()
  (and replace-overlay
       (progn
	 (delete-overlay replace-overlay)
	 (setq replace-overlay nil))))

(defun replace-highlight (start end)
  (and query-replace-highlight
       (progn
	 (or replace-overlay
	     (progn
	       (setq replace-overlay (make-overlay start end))
	       (overlay-put replace-overlay 'face
			    (if (internal-find-face 'query-replace)
				'query-replace 'region))))
	 (move-overlay replace-overlay start end (current-buffer)))))

;;; replace.el ends here