replace.el

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

;; Copyright (C) 1985, 1986, 1987, 1992, 1994, 1996, 1997, 2000, 2001, 2002,
;;   2003, 2004  Free Software Foundation, Inc.

;; Maintainer: FSF

;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

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

;;; Code:

(defcustom case-replace t
  "*Non-nil means `query-replace' should preserve case in replacements."
  :type 'boolean
  :group 'matching)

(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\".")

(defcustom query-replace-from-history-variable 'query-replace-history
  "History list to use for the FROM argument of `query-replace' commands.
The value of this variable should be a symbol; that symbol
is used as a variable to hold a history list for the strings
or patterns to be replaced."
  :group 'matching
  :type 'symbol
  :version "20.3")

(defcustom query-replace-to-history-variable 'query-replace-history
  "History list to use for the TO argument of `query-replace' commands.
The value of this variable should be a symbol; that symbol
is used as a variable to hold a history list for replacement
strings or patterns."
  :group 'matching
  :type 'symbol
  :version "20.3")

(defcustom query-replace-skip-read-only nil
  "*Non-nil means `query-replace' and friends ignore read-only matches."
  :type 'boolean
  :group 'matching
  :version "21.4")

(defun query-replace-descr (string)
  (mapconcat 'isearch-text-char-description string ""))

(defun query-replace-read-from (string regexp-flag)
  "Query and return the `from' argument of a query-replace operation.
The return value can also be a pair (FROM . TO) indicating that the user
wants to replace FROM with TO."
  (if query-replace-interactive
      (car (if regexp-flag regexp-search-ring search-ring))
    (let* ((lastfrom (car (symbol-value query-replace-from-history-variable)))
	   (lastto (car (symbol-value query-replace-to-history-variable)))
	   (from
	    ;; The save-excursion here is in case the user marks and copies
	    ;; a region in order to specify the minibuffer input.
	    ;; That should not clobber the region for the query-replace itself.
	    (save-excursion
	      (when (equal lastfrom lastto)
		;; Typically, this is because the two histlists are shared.
		(setq lastfrom (cadr (symbol-value
				      query-replace-from-history-variable))))
	      (read-from-minibuffer
	       (if (and lastto lastfrom)
		   (format "%s (default %s -> %s): " string
			   (query-replace-descr lastfrom)
			   (query-replace-descr lastto))
		 (format "%s: " string))
	       nil nil nil
	       query-replace-from-history-variable
	       nil t))))
      (if (and (zerop (length from)) lastto lastfrom)
	  (cons lastfrom lastto)
	;; Warn if user types \n or \t, but don't reject the input.
	(and regexp-flag
	     (string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\(\\\\[nt]\\)" from)
	     (let ((match (match-string 3 from)))
	       (cond
		((string= match "\\n")
		 (message "Note: `\\n' here doesn't match a newline; to do that, type C-q C-j instead"))
		((string= match "\\t")
		 (message "Note: `\\t' here doesn't match a tab; to do that, just type TAB")))
	       (sit-for 2)))
	from))))

(defun query-replace-read-to (from string regexp-flag)
  "Query and return the `from' argument of a query-replace operation."
  (let ((to (save-excursion
	      (read-from-minibuffer
	       (format "%s %s with: " string (query-replace-descr from))
	       nil nil nil
	       query-replace-to-history-variable from t))))
    (when (and regexp-flag
	       (string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\\\[,#]" to))
      (let (pos list char)
	(while
	    (progn
	      (setq pos (match-end 0))
	      (push (substring to 0 (- pos 2)) list)
	      (setq char (aref to (1- pos))
		    to (substring to pos))
	      (cond ((eq char ?\#)
		     (push '(number-to-string replace-count) list))
		    ((eq char ?\,)
		     (setq pos (read-from-string to))
		     (push `(replace-quote ,(car pos)) list)
		     (let ((end
			    ;; Swallow a space after a symbol
			    ;; if there is a space.
			    (if (and (or (symbolp (car pos))
					 ;; Swallow a space after 'foo
					 ;; but not after (quote foo).
					 (and (eq (car-safe (car pos)) 'quote)
					      (not (= ?\( (aref to 0)))))
				     (eq (string-match " " to (cdr pos))
					 (cdr pos)))
				(1+ (cdr pos))
			      (cdr pos))))
		       (setq to (substring to end)))))
	      (string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\\\[,#]" to)))
	(setq to (nreverse (delete "" (cons to list)))))
      (replace-match-string-symbols to)
      (setq to (cons 'replace-eval-replacement
		     (if (> (length to) 1)
			 (cons 'concat to)
		       (car to)))))
    to))

(defun query-replace-read-args (string regexp-flag &optional noerror)
  (unless noerror
    (barf-if-buffer-read-only))
  (let* ((from (query-replace-read-from string regexp-flag))
	 (to (if (consp from) (prog1 (cdr from) (setq from (car from)))
	       (query-replace-read-to from string regexp-flag))))
    (list from to current-prefix-arg)))

(defun query-replace (from-string to-string &optional delimited start end)
  "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.

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

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.

Matching is independent of case if `case-fold-search' is non-nil and
FROM-STRING has no uppercase letters.  Replacement transfers the case
pattern of the old text to the new text, if `case-replace' and
`case-fold-search' are non-nil and FROM-STRING has no uppercase
letters.  \(Transferring the case pattern means that if the old text
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.
Fourth and fifth arg START and END specify the region to operate on.

To customize possible responses, change the \"bindings\" in `query-replace-map'."
  (interactive (let ((common
		      (query-replace-read-args "Query replace" nil)))
		 (list (nth 0 common) (nth 1 common) (nth 2 common)
		       ;; These are done separately here
		       ;; so that command-history will record these expressions
		       ;; rather than the values they had this time.
		       (if (and transient-mark-mode mark-active)
			   (region-beginning))
		       (if (and transient-mark-mode mark-active)
			   (region-end)))))
  (perform-replace from-string to-string t nil delimited nil nil start end))

(define-key esc-map "%" 'query-replace)

(defun query-replace-regexp (regexp to-string &optional delimited start end)
  "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.

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

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.

Matching is independent of case if `case-fold-search' is non-nil and
REGEXP has no uppercase letters.  Replacement transfers the case
pattern of the old text to the new text, if `case-replace' and
`case-fold-search' are non-nil and REGEXP has no uppercase letters.
\(Transferring the case pattern means that if the old text 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.
Fourth and fifth arg START and END specify the region to operate on.

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.
`\\?' lets you edit the replacement text in the minibuffer
at the given position for each replacement.

In interactive calls, the replacement text can contain `\\,'
followed by a Lisp expression.  Each
replacement evaluates that expression to compute the replacement
string.  Inside of that expression, `\\&' is a string denoting the
whole match as a string, `\\N' for a partial match, `\\#&' and `\\#N'
for the whole or a partial match converted to a number with
`string-to-number', and `\\#' itself for the number of replacements
done so far (starting with zero).

If the replacement expression is a symbol, write a space after it
to terminate it.  One space there, if any, will be discarded.

When using those Lisp features interactively in the replacement
text, TO-STRING is actually made a list instead of a string.
Use \\[repeat-complex-command] after this command for details."
  (interactive
   (let ((common
	  (query-replace-read-args "Query replace regexp" t)))
     (list (nth 0 common) (nth 1 common) (nth 2 common)
	   ;; These are done separately here
	   ;; so that command-history will record these expressions
	   ;; rather than the values they had this time.
	   (if (and transient-mark-mode mark-active)
	       (region-beginning))
	   (if (and transient-mark-mode mark-active)
	       (region-end)))))
  (perform-replace regexp to-string t t delimited nil nil start end))

(define-key esc-map [?\C-%] 'query-replace-regexp)

(defun query-replace-regexp-eval (regexp to-expr &optional delimited start end)
  "Replace some things after point matching REGEXP with the result of TO-EXPR.
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.

TO-EXPR is a Lisp expression evaluated to compute each replacement.  It may
reference `replace-count' to get the number of replacements already made.
If the result of TO-EXPR is not a string, it is converted to one using
`prin1-to-string' with the NOESCAPE argument (which see).

For convenience, when entering TO-EXPR interactively, you can use `\\&' or
`\\0' to stand for whatever matched the whole of REGEXP, and `\\N' (where
N is a digit) to stand for whatever matched the Nth `\\(...\\)' in REGEXP.
Use `\\#&' or `\\#N' if you want a number instead of a string.
In interactive use, `\\#' in itself stands for `replace-count'.

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

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 that are surrounded by word boundaries.
Fourth and fifth arg START and END specify the region to operate on."
  (interactive
   (progn
   (barf-if-buffer-read-only)
   (let* ((from
	   ;; Let-bind the history var to disable the "foo -> bar" default.
	   ;; Maybe we shouldn't disable this default, but for now I'll
	   ;; leave it off.  --Stef
	   (let ((query-replace-to-history-variable nil))
	     (query-replace-read-from "Query replace regexp" t)))
	  (to (list (read-from-minibuffer
		     (format "Query replace regexp %s with eval: "
			     (query-replace-descr from))
		     nil nil t query-replace-to-history-variable from t))))
     ;; We make TO a list because replace-match-string-symbols requires one,
     ;; and the user might enter a single token.
     (replace-match-string-symbols to)
     (list from (car to) current-prefix-arg
	   (if (and transient-mark-mode mark-active)
	       (region-beginning))
	   (if (and transient-mark-mode mark-active)
	       (region-end))))))
  (perform-replace regexp (cons 'replace-eval-replacement to-expr)
		   t 'literal delimited nil nil start end))

(defun map-query-replace-regexp (regexp to-strings &optional n start end)
  "Replace some matches for REGEXP with various strings, in rotation.
The second argument TO-STRINGS contains the replacement strings,
separated by spaces.  Third arg DELIMITED (prefix arg if interactive),
if non-nil, means replace only matches surrounded by word boundaries.
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.

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

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.
Fourth and fifth arg START and END specify the region to operate on."
  (interactive
   (let* ((from (if query-replace-interactive
		    (car regexp-search-ring)
		  (read-from-minibuffer "Map query replace (regexp): "
					nil nil nil
					'query-replace-history nil t)))
	  (to (read-from-minibuffer
	       (format "Query replace %s with (space-separated strings): "
		       (query-replace-descr from))
	       nil nil nil
	       'query-replace-history from t)))
     (list from to
	   (and current-prefix-arg
		(prefix-numeric-value current-prefix-arg))
	   (if (and transient-mark-mode mark-active)
	       (region-beginning))
	   (if (and transient-mark-mode mark-active)
	       (region-end)))))
  (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 n nil start end)))

(defun replace-string (from-string to-string &optional delimited start end)
  "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.)

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.
Fourth and fifth arg START and END specify the region to operate on.

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.
\(You may need a more complex loop if FROM-STRING can match the null string
and TO-STRING is also null.)"
  (interactive
   (let ((common
	  (query-replace-read-args "Replace string" nil)))
     (list (nth 0 common) (nth 1 common) (nth 2 common)
	   (if (and transient-mark-mode mark-active)
	       (region-beginning))
	   (if (and transient-mark-mode mark-active)
	       (region-end)))))
  (perform-replace from-string to-string nil nil delimited nil nil start end))

(defun replace-regexp (regexp to-string &optional delimited start end)
  "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.

In Transient Mark mode, if the mark is active, operate on the contents
of the region.  Otherwise, operate from point to the end of the buffer.

Third arg DELIMITED (prefix arg if interactive), if non-nil, means replace
only matches surrounded by word boundaries.
Fourth and fifth arg START and END specify the region to operate on.

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.
`\\?' lets you edit the replacement text in the minibuffer
at the given position for each replacement.

In interactive calls, the replacement text may contain `\\,'
followed by a Lisp expression used as part of the replacement
text.  Inside of that expression, `\\&' is a string denoting the
whole match, `\\N' a partial matches, `\\#&' and `\\#N' the
respective numeric values from `string-to-number', and `\\#'
itself for `replace-count', the number of replacements occured so
far.

If your Lisp expression is an identifier and the next letter in
the replacement string would be interpreted as part of it, you
can wrap it with an expression like `\\,(or \\#)'.  Incidentally,
for this particular case you may also enter `\\#' in the
replacement text directly.

When using those Lisp features interactively in the replacement
text, TO-STRING is actually made a list instead of a string.
Use \\[repeat-complex-command] after this command for details.

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
   (let ((common
	  (query-replace-read-args "Replace regexp" t)))
     (list (nth 0 common) (nth 1 common) (nth 2 common)
	   (if (and transient-mark-mode mark-active)
	       (region-beginning))
	   (if (and transient-mark-mode mark-active)
	       (region-end)))))
  (perform-replace regexp to-string nil t delimited nil nil start end))


(defvar regexp-history nil
  "History list for some commands that read regular expressions.")


(defalias 'delete-non-matching-lines 'keep-lines)
(defalias 'delete-matching-lines 'flush-lines)
(defalias 'count-matches 'how-many)


(defun keep-lines-read-args (prompt)
  "Read arguments for `keep-lines' and friends.
Prompt for a regexp with PROMPT.
Value is a list, (REGEXP)."
  (list (read-from-minibuffer prompt nil nil nil
			      'regexp-history nil t)))

(defun keep-lines (regexp &optional rstart rend)
  "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.

If REGEXP contains upper case characters (excluding those preceded by `\\'),
the matching is case-sensitive.

Second and third arg RSTART and REND specify the region to operate on.

Interactively, in Transient Mark mode when the mark is active, operate
on the contents of the region.  Otherwise, operate from point to the
end of the buffer."

  (interactive
   (progn
     (barf-if-buffer-read-only)
     (keep-lines-read-args "Keep lines (containing match for regexp): ")))
  (if rstart
      (progn
	(goto-char (min rstart rend))
	(setq rend (copy-marker (max rstart rend))))
    (if (and transient-mark-mode mark-active)
	(setq rstart (region-beginning)
	      rend (copy-marker (region-end)))
      (setq rstart (point)
	    rend (point-max-marker)))
    (goto-char rstart))
  (save-excursion
    (or (bolp) (forward-line 1))
    (let ((start (point))
	  (case-fold-search  (and case-fold-search
				  (isearch-no-upper-case-p regexp t))))
      (while (< (point) rend)
	;; Start is first char not preserved by previous match.
	(if (not (re-search-forward regexp rend 'move))
	    (delete-region start rend)
	  (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 (< (point) rend)
	     (= (match-beginning 0) (match-end 0))
	     (forward-char 1))))))


(defun flush-lines (regexp &optional rstart rend)
  "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.

If REGEXP contains upper case characters (excluding those preceded by `\\'),
the matching is case-sensitive.

Second and third arg RSTART and REND specify the region to operate on.

Interactively, in Transient Mark mode when the mark is active, operate
on the contents of the region.  Otherwise, operate from point to the
end of the buffer."

  (interactive
   (progn
     (barf-if-buffer-read-only)
     (keep-lines-read-args "Flush lines (containing match for regexp): ")))
  (if rstart
      (progn
	(goto-char (min rstart rend))
	(setq rend (copy-marker (max rstart rend))))
    (if (and transient-mark-mode mark-active)
	(setq rstart (region-beginning)
	      rend (copy-marker (region-end)))
      (setq rstart (point)
	    rend (point-max-marker)))
    (goto-char rstart))
  (let ((case-fold-search (and case-fold-search
			       (isearch-no-upper-case-p regexp t))))
    (save-excursion
      (while (and (< (point) rend)
		  (re-search-forward regexp rend t))
	(delete-region (save-excursion (goto-char (match-beginning 0))
				       (beginning-of-line)
				       (point))
		       (progn (forward-line 1) (point)))))))


(defun how-many (regexp &optional rstart rend)
  "Print number of matches for REGEXP following point.

If REGEXP contains upper case characters (excluding those preceded by `\\'),
the matching is case-sensitive.

Second and third arg RSTART and REND specify the region to operate on.

Interactively, in Transient Mark mode when the mark is active, operate
on the contents of the region.  Otherwise, operate from point to the
end of the buffer."

  (interactive
   (keep-lines-read-args "How many matches for (regexp): "))
  (save-excursion
    (if rstart
	(goto-char (min rstart rend))
      (if (and transient-mark-mode mark-active)
	  (setq rstart (region-beginning)
		rend (copy-marker (region-end)))
	(setq rstart (point)
	      rend (point-max-marker)))
      (goto-char rstart))
    (let ((count 0)
	  opoint
	  (case-fold-search (and case-fold-search
				 (isearch-no-upper-case-p regexp t))))
      (while (and (< (point) rend)
		  (progn (setq opoint (point))
			 (re-search-forward regexp rend t)))
	(if (= opoint (point))
	    (forward-char 1)
	  (setq count (1+ count))))
      (message "%d occurrences" count))))


(defvar occur-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map [mouse-2] 'occur-mode-mouse-goto)
    (define-key map "\C-c\C-c" 'occur-mode-goto-occurrence)
    (define-key map "\C-m" 'occur-mode-goto-occurrence)
    (define-key map "o" 'occur-mode-goto-occurrence-other-window)
    (define-key map "\C-o" 'occur-mode-display-occurrence)
    (define-key map "\M-n" 'occur-next)
    (define-key map "\M-p" 'occur-prev)
    (define-key map "r" 'occur-rename-buffer)
    (define-key map "c" 'clone-buffer)
    (define-key map "g" 'revert-buffer)
    (define-key map "q" 'quit-window)
    (define-key map "z" 'kill-this-buffer)
    map)
  "Keymap for `occur-mode'.")

(defvar occur-revert-arguments nil
  "Arguments to pass to `occur-1' to revert an Occur mode buffer.
See `occur-revert-function'.")

(defcustom occur-mode-hook '(turn-on-font-lock)
  "Hook run when entering Occur mode."
  :type 'hook
  :group 'matching)

(defcustom occur-hook nil
  "Hook run when `occur' is called."
  :type 'hook
  :group 'matching)

(put 'occur-mode 'mode-class 'special)
(defun occur-mode ()
  "Major mode for output from \\[occur].
\\<occur-mode-map>Move point to one of the items in this buffer, then use
\\[occur-mode-goto-occurrence] to go to the occurrence that the item refers to.
Alternatively, click \\[occur-mode-mouse-goto] on an item to go to it.

\\{occur-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (use-local-map occur-mode-map)
  (setq major-mode 'occur-mode)
  (setq mode-name "Occur")
  (set (make-local-variable 'revert-buffer-function) 'occur-revert-function)
  (make-local-variable 'occur-revert-arguments)
  (add-hook 'change-major-mode-hook 'font-lock-defontify nil t)
  (setq next-error-function 'occur-next-error)
  (run-hooks 'occur-mode-hook))

(defun occur-revert-function (ignore1 ignore2)
  "Handle `revert-buffer' for Occur mode buffers."
  (apply 'occur-1 (append occur-revert-arguments (list (buffer-name)))))

(defun occur-mode-mouse-goto (event)
  "In Occur mode, go to the occurrence whose line you click on."
  (interactive "e")
  (let (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))))
    (pop-to-buffer (marker-buffer pos))
    (goto-char pos)))

(defun occur-mode-find-occurrence ()
  (let ((pos (get-text-property (point) 'occur-target)))
    (unless pos
      (error "No occurrence on this line"))
    (unless (buffer-live-p (marker-buffer pos))
      (error "Buffer for this occurrence was killed"))
    pos))

(defun occur-mode-goto-occurrence ()
  "Go to the occurrence the current line describes."
  (interactive)
  (let ((pos (occur-mode-find-occurrence)))
    (pop-to-buffer (marker-buffer pos))
    (goto-char pos)))

(defun occur-mode-goto-occurrence-other-window ()
  "Go to the occurrence the current line describes, in another window."
  (interactive)
  (let ((pos (occur-mode-find-occurrence)))
    (switch-to-buffer-other-window (marker-buffer pos))
    (goto-char pos)))

(defun occur-mode-display-occurrence ()
  "Display in another window the occurrence the current line describes."
  (interactive)
  (let ((pos (occur-mode-find-occurrence))
	window
	;; Bind these to ensure `display-buffer' puts it in another window.
	same-window-buffer-names
	same-window-regexps)
    (setq window (display-buffer (marker-buffer pos)))
    ;; This is the way to set point in the proper window.
    (save-selected-window
      (select-window window)
      (goto-char pos))))

(defun occur-find-match (n search message)
  (if (not n) (setq n 1))
  (let ((r))
    (while (> n 0)
      (setq r (funcall search (point) 'occur-match))
      (and r
           (get-text-property r 'occur-match)
           (setq r (funcall search r 'occur-match)))
      (if r
          (goto-char r)
        (error message))
      (setq n (1- n)))))

(defun occur-next (&optional n)
  "Move to the Nth (default 1) next match in an Occur mode buffer."
  (interactive "p")
  (occur-find-match n #'next-single-property-change "No more matches"))

(defun occur-prev (&optional n)
  "Move to the Nth (default 1) previous match in an Occur mode buffer."
  (interactive "p")
  (occur-find-match n #'previous-single-property-change "No earlier matches"))

(defun occur-next-error (&optional argp reset)
  "Move to the Nth (default 1) next match in an Occur mode buffer.
Compatibility function for \\[next-error] invocations."
  (interactive "p")
  (when reset
    (occur-find-match 0 #'next-single-property-change "No first match"))
  (occur-find-match
   (prefix-numeric-value argp)
   (if (> 0 (prefix-numeric-value argp))
       #'previous-single-property-change
     #'next-single-property-change)
   "No more matches")
  ;; In case the *Occur* buffer is visible in a nonselected window.
  (set-window-point (get-buffer-window (current-buffer)) (point))
  (occur-mode-goto-occurrence))


(defcustom list-matching-lines-default-context-lines 0
  "*Default number of context lines included around `list-matching-lines' matches.
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."
  :type 'integer
  :group 'matching)

(defalias 'list-matching-lines 'occur)

(defcustom list-matching-lines-face 'bold
  "*Face used by \\[list-matching-lines] to show the text that matches.
If the value is nil, don't highlight the matching portions specially."
  :type 'face
  :group 'matching)

(defcustom list-matching-lines-buffer-name-face 'underline
  "*Face used by \\[list-matching-lines] to show the names of buffers.
If the value is nil, don't highlight the buffer names specially."
  :type 'face
  :group 'matching)

(defun occur-accumulate-lines (count &optional no-props)
  (save-excursion
    (let ((forwardp (> count 0))
	  (result nil))
      (while (not (or (zerop count)
		      (if forwardp
			  (eobp)
			(bobp))))
	(setq count (+ count (if forwardp -1 1)))
	(push
	 (funcall (if no-props
		      #'buffer-substring-no-properties
		    #'buffer-substring)
	  (line-beginning-position)
	  (line-end-position))
	 result)
	(forward-line (if forwardp 1 -1)))
      (nreverse result))))

(defun occur-read-primary-args ()
  (list (let* ((default (car regexp-history))
	       (input
		(read-from-minibuffer
		 (if default
		     (format "List lines matching regexp (default `%s'): "
			     (query-replace-descr default))
		   "List lines matching regexp: ")
		 nil
		 nil
		 nil
		 'regexp-history
		 default)))
	  (if (equal input "")
	      default
	    input))
	(when current-prefix-arg
	  (prefix-numeric-value current-prefix-arg))))

(defun occur-rename-buffer (&optional unique-p)
  "Rename the current *Occur* buffer to *Occur: original-buffer-name*.
Here `original-buffer-name' is the buffer name were occur was originally run.
When given the prefix argument, the renaming will not clobber the existing
buffer(s) of that name, but use `generate-new-buffer-name' instead.
You can add this to `occur-hook' if you always want a separate *Occur*
buffer for each buffer where you invoke `occur'."
  (interactive "P")
  (with-current-buffer
      (if (eq major-mode 'occur-mode) (current-buffer) (get-buffer "*Occur*"))
    (rename-buffer (concat "*Occur: "
                           (mapconcat #'buffer-name
                                      (car (cddr occur-revert-arguments)) "/")
                           "*")
                   unique-p)))

(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.
\\<occur-mode-map>\\[describe-mode] in that buffer will explain how.

If REGEXP contains upper case characters (excluding those preceded by `\\'),
the matching is case-sensitive."
  (interactive (occur-read-primary-args))
  (occur-1 regexp nlines (list (current-buffer))))

(defun multi-occur (bufs regexp &optional nlines)
  "Show all lines in buffers BUFS containing a match for REGEXP.
This function acts on multiple buffers; otherwise, it is exactly like
`occur'."
  (interactive
   (cons
    (let* ((bufs (list (read-buffer "First buffer to search: "
				    (current-buffer) t)))
	   (buf nil)
	   (ido-ignore-item-temp-list bufs))
      (while (not (string-equal
		   (setq buf (read-buffer
			      (if (eq read-buffer-function 'ido-read-buffer)
				  "Next buffer to search (C-j to end): "
				"Next buffer to search (RET to end): ")
			      nil t))
		   ""))
	(add-to-list 'bufs buf)
	(setq ido-ignore-item-temp-list bufs))
      (nreverse (mapcar #'get-buffer bufs)))
    (occur-read-primary-args)))
  (occur-1 regexp nlines bufs))

(defun multi-occur-by-filename-regexp (bufregexp regexp &optional nlines)
  "Show all lines matching REGEXP in buffers named by BUFREGEXP.
See also `multi-occur'."
  (interactive
   (cons
    (let* ((default (car regexp-history))
	   (input
	    (read-from-minibuffer
	     "List lines in buffers whose filename matches regexp: "
	     nil
	     nil
	     nil
	     'regexp-history)))
      (if (equal input "")
	  default
	input))
    (occur-read-primary-args)))
  (when bufregexp
    (occur-1 regexp nlines
	     (delq nil
		   (mapcar (lambda (buf)
			     (when (and (buffer-file-name buf)
					(string-match bufregexp
						      (buffer-file-name buf)))
			       buf))
			   (buffer-list))))))

(defun occur-1 (regexp nlines bufs &optional buf-name)
  (unless buf-name
    (setq buf-name "*Occur*"))
  (let ((occur-buf (get-buffer-create buf-name))
	(made-temp-buf nil)
	(active-bufs (delq nil (mapcar #'(lambda (buf)
					   (when (buffer-live-p buf) buf))
				       bufs))))
    ;; Handle the case where one of the buffers we're searching is the
    ;; *Occur* buffer itself.
    (when (memq occur-buf bufs)
      (setq occur-buf (with-current-buffer occur-buf
			(clone-buffer "*Occur-temp*"))
	    made-temp-buf t))
    (with-current-buffer occur-buf
      (setq buffer-read-only nil)
      (occur-mode)
      (erase-buffer)
      (let ((count (occur-engine
		    regexp active-bufs occur-buf
		    (or nlines list-matching-lines-default-context-lines)
		    (and case-fold-search
			 (isearch-no-upper-case-p regexp t))
		    list-matching-lines-buffer-name-face
		    nil list-matching-lines-face nil)))
	(let* ((bufcount (length active-bufs))
	       (diff (- (length bufs) bufcount)))
	  (message "Searched %d buffer%s%s; %s match%s for `%s'"
		   bufcount (if (= bufcount 1) "" "s")
		   (if (zerop diff) "" (format " (%d killed)" diff))
		   (if (zerop count) "no" (format "%d" count))
		   (if (= count 1) "" "es")
		   regexp))
	;; If we had to make a temporary buffer, make it the *Occur*
	;; buffer now.
	(when made-temp-buf
	  (with-current-buffer (get-buffer buf-name)
	    (kill-buffer (current-buffer)))
	  (rename-buffer buf-name))
	(setq occur-revert-arguments (list regexp nlines bufs)
	      buffer-read-only t)
	(if (> count 0)
	    (progn
	      (display-buffer occur-buf)
	      (setq next-error-last-buffer occur-buf))
	  (kill-buffer occur-buf)))
      (run-hooks 'occur-hook))))

(defun occur-engine-add-prefix (lines)
  (mapcar
   #'(lambda (line)
       (concat "       :" line "\n"))
   lines))

(defun occur-engine (regexp buffers out-buf nlines case-fold-search
			    title-face prefix-face match-face keep-props)
  (with-current-buffer out-buf
    (setq buffer-read-only nil)
    (let ((globalcount 0)
	  (coding nil))
      ;; Map over all the buffers
      (dolist (buf buffers)
	(when (buffer-live-p buf)
	  (let ((matches 0)	;; count of matched lines
		(lines 1)	;; line count
		(matchbeg 0)
		(origpt nil)
		(begpt nil)
		(endpt nil)
		(marker nil)
		(curstring "")
		(headerpt (with-current-buffer out-buf (point))))
	    (save-excursion
	      (set-buffer buf)
	      (or coding
		  ;; Set CODING only if the current buffer locally
		  ;; binds buffer-file-coding-system.
		  (not (local-variable-p 'buffer-file-coding-system))
		  (setq coding buffer-file-coding-system))
	      (save-excursion
		(goto-char (point-min)) ;; begin searching in the buffer
		(while (not (eobp))
		  (setq origpt (point))
		  (when (setq endpt (re-search-forward regexp nil t))
		    (setq matches (1+ matches)) ;; increment match count
		    (setq matchbeg (match-beginning 0))