diff lisp/packages/dabbrev.el @ 0:376386a54a3c r19-14

Import from CVS: tag r19-14
author cvs
date Mon, 13 Aug 2007 08:45:50 +0200
parents
children ac2d302a0011
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/packages/dabbrev.el	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,870 @@
+;;; dabbrev.el --- dynamic abbreviation package
+;; Copyright (C) 1985, 1986, 1992, 1994 Free Software Foundation, Inc.
+
+;; Author: Don Morrison
+;; Maintainer: Lars Lindberg <Lars.Lindberg@sypro.cap.se>
+;; Created: 16 Mars 1992
+;; Lindberg's last update version: 5.7
+;; Keywords: abbrev expand completion
+
+;; 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 of the License, 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 program; if not, write to the Free Software
+;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+;;; Synched up with: FSF 19.30.
+
+;;; Commentary:
+
+;; The purpose with this package is to let you write just a few
+;; characters of words you've written earlier to be able to expand
+;; them.
+;;
+;; To expand a word, just put the point right after the word and press
+;; M-/ (dabbrev-expand) or M-C-/ (dabbrev-completion).
+;;
+;; Check out the customizable variables below to learn about all the
+;; features of this package.
+
+;;; Hints and tips for major modes writers:
+
+;; Recommended values		C/Lisp etc	text
+;; dabbrev-case-fold-search	nil		t
+;; dabbrev-case-replace		nil		t
+;;
+;; Set the variables you want special for your mode like this:
+;; (set (make-local-variable 'dabbrev-case-replace) nil)
+;; Then you don't interfer with other modes.
+;;
+;; If your mode handles buffers that refers to other buffers
+;; (i.e. compilation-mode, gud-mode), then try to set
+;; `dabbrev-select-buffers-function' or `dabbrev-friend-buffer-function'
+;; to a function that point out those buffers.
+
+;; Same goes for major-modes that are connected to other modes.  There
+;; are for instance a number of mail-modes.  One for reading, one for
+;; creating a new mail etc.  Maybe those should be connected.
+
+;; Example for GNUS (when we write a reply, we want dabbrev to look in
+;; the article for expansion):
+;; (set (make-local-variable 'dabbrev-friend-buffer-function)
+;;      (lambda (buffer)
+;;         (save-excursion
+;;           (set-buffer buffer)
+;;           (memq major-mode '(news-reply-mode gnus-article-mode)))))
+
+
+;; Known bugs and limitations.
+;; - Possible to do several levels of `dabbrev-completion' in the
+;;   minibuffer.
+;; - dabbrev-completion doesn't handle resetting the globals variables
+;;   right.  It resets them after finding the abbrev.
+
+;; Future enhancements
+;;  - Check the tags-files? Like tags-complete?
+;;  - Add the possibility of searching both forward and backward to
+;;    the nearest expansion.
+;;  - Check the kill-ring when everything else fails.  (Maybe something
+;;  for hippie-expand?).  [Bng] <boris@cs.rochester.edu>
+
+;;; These people gave suggestions:
+;;  [hymie]	Hyman Rosen <marks!hymie@jyacc.jyacc.com>
+;;  [burgett]	Steve Burgett <burgett@bizet.eecs.berkeley.edu>
+;;  [jules]	Julian Gosnell <jules@x.co.uk>
+;;  [kifer]	Michael Kifer <kifer@sbcs.sunysb.edu>
+;;  [ake]	Ake Stenhoff <extaksf@aom.ericsson.se>
+;;  [alon]	Alon Albert <al%imercury@uunet.uu.net>
+;;  [tromey]	Tom Tromey <tromey@busco.lanl.gov>
+;;  [Rolf]	Rolf Schreiber <rolf@mathematik.uni-stuttgart.de>
+;;  [Petri]	Petri Raitio <per@tekla.fi>
+;;  [ejb]	Jay Berkenbilt <ejb@ERA.COM>
+;;  [hawley]	Bob Hawley <rth1@quartet.mt.att.com>
+;;  ... and to all the people who have participated in the beta tests.
+
+;;; Code:
+
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+;;; Customization variables
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+(defvar dabbrev-backward-only nil
+  "*If non-nil, `dabbrev-expand' only looks backwards.")
+
+(defvar dabbrev-limit nil
+  "*Limits region searched by `dabbrev-expand' to this many chars away.")
+
+(defvar dabbrev-abbrev-skip-leading-regexp nil
+  "*Regexp for skipping leading characters of an abbreviation.
+
+Example: Set this to \"\\\\$\" for programming languages
+in which variable names may appear with or without a leading `$'.
+(For example, in Makefiles.)
+
+Set this to nil if no characters should be skipped.")
+
+;; XEmacs change: The old defaults are just too obnoxious.  Rarely
+;; do you actually want the case-folding behavior here, even though
+;; it's useful to have case-fold-search set to t most of the time.
+(defvar dabbrev-case-fold-search nil ;;'case-fold-search
+  "*Non-nil if dabbrev searches should ignore case.
+A value of nil means case is significant.
+
+The value of this variable is an expression; it is evaluated
+and the resulting value determines the decision.
+For example: setting this to `case-fold-search' means evaluate that
+variable to see whether its value is nil.")
+
+(defvar dabbrev-upcase-means-case-search nil
+  "*The significance of an uppercase character in an abbreviation.
+nil means case fold search, non-nil means case sensitive search.
+
+This variable has an effect only when the value of
+`dabbrev-case-fold-search' evaluates to t.")
+
+;; XEmacs change: likewise here.
+;; I recommend that you set this to nil.
+(defvar dabbrev-case-replace nil ;;'case-replace
+  "*Non-nil means dabbrev should preserve case when expanding the abbreviation.
+More precisely, it preserves the case pattern of the abbreviation as you
+typed it--as opposed to the case pattern of the expansion that is copied.
+The value of this variable is an expression; it is evaluated
+and the resulting value determines the decision.
+For example, setting this to `case-replace' means evaluate that
+variable to see if its value is t or nil.
+
+This variable has an effect only when the value of
+`dabbrev-case-fold-search' evaluates to t.")
+
+(defvar dabbrev-abbrev-char-regexp nil
+  "*Regexp to recognize a character in an abbreviation or expansion.
+This regexp will be surrounded with \\\\( ... \\\\) when actually used.
+
+Set this variable to \"\\\\sw\" if you want ordinary words or
+\"\\\\sw\\\\|\\\\s_\" if you want symbols (including characters whose
+syntax is \"symbol\" as well as those whose syntax is \"word\".
+
+The value nil has a special meaning: the abbreviation is from point to
+previous word-start, but the search is for symbols.
+
+For instance, if you are programming in Lisp, `yes-or-no-p' is a symbol,
+while `yes', `or', `no' and `p' are considered words.  If this
+variable is nil, then expanding `yes-or-no-' looks for a symbol
+starting with or containing `no-'.  If you set this variable to
+\"\\\\sw\\\\|\\\\s_\", that expansion looks for a symbol starting with
+`yes-or-no-'.  Finally, if you set this variable to \"\\\\sw\", then
+expanding `yes-or-no-' signals an error because `-' is not part of a word;
+but expanding `yes-or-no' looks for a word starting with `no'.
+
+The recommended value is \"\\\\sw\\\\|\\\\s_\".")
+
+(defvar dabbrev-check-all-buffers t
+  "*Non-nil means dabbrev package should search *all* buffers.
+
+Dabbrev always searches the current buffer first.  Then, if
+`dabbrev-check-other-buffers' says so, it searches the buffers
+designated by `dabbrev-select-buffers-function'.
+
+Then, if `dabbrev-check-all-buffers' is non-nil, dabbrev searches
+all the other buffers.")
+
+(defvar dabbrev-check-other-buffers t
+  "*Should \\[dabbrev-expand] look in other buffers?\
+
+nil: Don't look in other buffers.
+t: Also look for expansions in the buffers pointed out by
+   `dabbrev-select-buffers-function'.
+Anything else: When we can't find any more expansions in
+the current buffer, then ask the user whether to look in other
+buffers too.
+
+The default value is t.")
+
+;; I guess setting this to a function that selects all C- or C++-
+;; mode buffers would be a good choice for a debugging buffer,
+;; when debugging C- or C++-code.
+(defvar dabbrev-select-buffers-function 'dabbrev--select-buffers
+  "A function that selects buffers that should be searched by dabbrev.
+The function should take no arguments and return a list of buffers to
+search for expansions.  Have a look at `dabbrev--select-buffers' for
+an example.
+
+A mode setting this variable should make it buffer local.")
+
+(defvar dabbrev-friend-buffer-function 'dabbrev--same-major-mode-p
+  "*A function to decide whether dabbrev should search OTHER-BUFFER.
+The function should take one argument, OTHER-BUFFER, and return
+non-nil if that buffer should be searched.  Have a look at
+`dabbrev--same-major-mode-p' for an example.
+
+The value of `dabbrev-friend-buffer-function' has an effect only if
+the value of `dabbrev-select-buffers-function' uses it.  The function
+`dabbrev--select-buffers' is one function you can use here.
+
+A mode setting this variable should make it buffer local.")
+
+(defvar dabbrev-search-these-buffers-only nil
+  "If non-nil, a list of buffers which dabbrev should search.
+If this variable is non-nil, dabbrev will only look in these buffers.
+It will not even look in the current buffer if it is not a member of
+this list.")
+
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+;;; Internal variables
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+
+;; Last obarray of completions in `dabbrev-completion'
+(defvar dabbrev--last-obarray nil)
+
+;; Table of expansions seen so far
+(defvar dabbrev--last-table nil)
+
+;; Last string we tried to expand.
+(defvar dabbrev--last-abbreviation nil)
+
+;; Location last abbreviation began
+(defvar dabbrev--last-abbrev-location nil)
+
+;; Direction of last dabbrevs search
+(defvar dabbrev--last-direction 0)
+
+;; Last expansion of an abbreviation.
+(defvar dabbrev--last-expansion nil)
+
+;; Location the last expansion was found.
+(defvar dabbrev--last-expansion-location nil)
+
+;; The list of remaining buffers with the same mode as current buffer.
+(defvar dabbrev--friend-buffer-list nil)
+
+;; The buffer we looked in last.
+(defvar dabbrev--last-buffer nil)
+
+;; The buffer we found the expansion last time.
+(defvar dabbrev--last-buffer-found nil)
+
+;; The buffer we last did a completion in.
+(defvar dabbrev--last-completion-buffer nil)
+
+;; Same as dabbrev-check-other-buffers, but is set for every expand.
+(defvar dabbrev--check-other-buffers dabbrev-check-other-buffers)
+
+;; The regexp for recognizing a character in an abbreviation.
+(defvar dabbrev--abbrev-char-regexp nil)
+
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+;;; Macros
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+
+;;; Get the buffer that mini-buffer was activated from
+(defsubst dabbrev--minibuffer-origin ()
+  (car (cdr (buffer-list))))
+
+;; Make a list of some of the elements of LIST.
+;; Check each element of LIST, storing it temporarily in the
+;; variable ELEMENT, and include it in the result
+;; if CONDITION evaluates non-nil.
+(defmacro dabbrev-filter-elements (element list condition)
+  (` (let (dabbrev-result dabbrev-tail (, element))
+       (setq dabbrev-tail (, list))
+       (while dabbrev-tail
+	 (setq (, element) (car dabbrev-tail))
+	 (if (, condition)
+	     (setq dabbrev-result (cons (, element) dabbrev-result)))
+	 (setq dabbrev-tail (cdr dabbrev-tail)))
+       (nreverse dabbrev-result))))
+
+(defun dabbrev--extent-clicked-on (event extent user-data)
+  (let ((buffer (first user-data))
+	(point (second user-data))
+	(init (third user-data))
+	(wconfig (fourth user-data)))
+    (set-window-configuration wconfig)
+    (set-buffer buffer)
+    (goto-char point)
+    (dabbrev--substitute-expansion nil init (extent-string extent))))
+
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+;;; Exported functions
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+
+;; XEmacs changes:
+;;;###autoload
+(define-key global-map [(meta /)] 'dabbrev-expand)
+;;;??? Do we want this?
+;;;###autoload
+(define-key global-map [(meta control /)] 'dabbrev-completion)
+
+;;;###autoload
+(defun dabbrev-completion (&optional arg)
+  "Completion on current word.
+Like \\[dabbrev-expand] but finds all expansions in the current buffer
+and presents suggestions for completion.
+
+With a prefix argument, it searches all buffers accepted by the
+function pointed out by `dabbrev-friend-buffer-function' to find the
+completions.
+
+If the prefix argument is 16 (which comes from C-u C-u),
+then it searches *all* buffers.
+
+With no prefix argument, it reuses an old completion list
+if there is a suitable one already."
+
+  (interactive "*P")
+  (dabbrev--reset-global-variables)
+  (let* ((dabbrev-check-other-buffers (and arg t))
+	 (dabbrev-check-all-buffers
+	  (and arg (= (prefix-numeric-value arg) 16)))
+	 (abbrev (dabbrev--abbrev-at-point))
+	 (ignore-case-p  (and (eval dabbrev-case-fold-search)
+				(or (not dabbrev-upcase-means-case-search)
+				    (string= abbrev (downcase abbrev)))))
+	 (my-obarray dabbrev--last-obarray)
+	 init)
+    (save-excursion
+      (if (and (null arg)
+	       my-obarray
+	       (or (eq dabbrev--last-completion-buffer (current-buffer))
+		   (and (window-minibuffer-p (selected-window))
+			(eq dabbrev--last-completion-buffer
+			    (dabbrev--minibuffer-origin))))
+	       dabbrev--last-abbreviation
+	       (>= (length abbrev) (length dabbrev--last-abbreviation))
+	       (string= dabbrev--last-abbreviation
+			(substring abbrev 0
+				   (length dabbrev--last-abbreviation)))
+	       (setq init (try-completion abbrev my-obarray)))
+	  ;; We can reuse the existing completion list.
+	  nil
+	;;--------------------------------
+	;; New abbreviation to expand.
+	;;--------------------------------
+	(setq dabbrev--last-abbreviation abbrev)
+	;; Find all expansion
+	(let ((completion-list
+	       (dabbrev--find-all-expansions abbrev ignore-case-p)))
+	  ;; Make an obarray with all expansions
+	  (setq my-obarray (make-vector (length completion-list) 0))
+	  (or (> (length my-obarray) 0)
+	      (error "No dynamic expansion for \"%s\" found%s"
+		     abbrev
+		     (if dabbrev--check-other-buffers "" " in this-buffer")))
+	  (cond
+	   ((or (not ignore-case-p)
+		(not dabbrev-case-replace))
+	    (mapcar (function (lambda (string)
+				(intern string my-obarray)))
+		    completion-list))
+	   ((string= abbrev (upcase abbrev))
+	    (mapcar (function (lambda (string)
+				(intern (upcase string) my-obarray)))
+		    completion-list))
+	   ((string= (substring abbrev 0 1)
+		     (upcase (substring abbrev 0 1)))
+	    (mapcar (function (lambda (string)
+				(intern (capitalize string) my-obarray)))
+		    completion-list))
+	   (t
+	    (mapcar (function (lambda (string)
+				(intern (downcase string) my-obarray)))
+		    completion-list)))
+	  (setq dabbrev--last-obarray my-obarray)
+	  (setq dabbrev--last-completion-buffer (current-buffer))
+	  ;; Find the longest common string.
+	  (setq init (try-completion abbrev my-obarray)))))
+    ;;--------------------------------
+    ;; Let the user choose between the expansions
+    ;;--------------------------------
+    (or (stringp init)
+	(setq init abbrev))
+    (cond
+     ;; * Replace string fragment with matched common substring completion.
+     ((and (not (string-equal init ""))
+	   (not (string-equal (downcase init) (downcase abbrev))))
+      (if (> (length (all-completions init my-obarray)) 1)
+	  (message "Repeat `%s' to see all completions"
+		   (key-description (this-command-keys)))
+	(message "The only possible completion"))
+      (dabbrev--substitute-expansion nil abbrev init))
+     (t
+      ;; * String is a common substring completion already.  Make list.
+      (message "Making completion list...")
+      ;; construct the arg before calling `with-output-to-temp-buffer'
+      ;; because that changes the window config
+      (let ((arg (list (current-buffer)
+		       (set-marker (make-marker) (point))
+		       init
+		       (current-window-configuration))))
+	(with-output-to-temp-buffer " *Completions*"
+	  (display-completion-list (all-completions init my-obarray)
+				   'dabbrev--extent-clicked-on
+				   arg)))
+      (message "Making completion list...done")))
+    (and (window-minibuffer-p (selected-window))
+	 (message nil))))
+
+;;;###autoload
+(defun dabbrev-expand (arg)
+  "Expand previous word \"dynamically\".
+
+Expands to the most recent, preceding word for which this is a prefix.
+If no suitable preceding word is found, words following point are
+considered.  If still no suitable word is found, then look in the
+buffers accepted by the function pointed out by variable
+`dabbrev-friend-buffer-function'.
+
+A positive prefix argument, N, says to take the Nth backward *distinct*
+possibility.  A negative argument says search forward.
+
+If the cursor has not moved from the end of the previous expansion and
+no argument is given, replace the previously-made expansion
+with the next possible expansion not yet tried.
+
+The variable `dabbrev-backward-only' may be used to limit the
+direction of search to backward if set non-nil.
+
+See also `dabbrev-abbrev-char-regexp' and \\[dabbrev-completion]."
+  (interactive "*P")
+  (let (abbrev expansion old direction (orig-point (point)))
+    ;; abbrev -- the abbrev to expand
+    ;; expansion -- the expansion found (eventually) or nil until then
+    ;; old -- the text currently in the buffer
+    ;;    (the abbrev, or the previously-made expansion)
+    (save-excursion
+      (if (and (null arg)
+	       (markerp dabbrev--last-abbrev-location)
+	       (marker-position dabbrev--last-abbrev-location)
+	       (or (eq last-command this-command)
+		   (and (window-minibuffer-p (selected-window))
+			(= dabbrev--last-abbrev-location
+			   (point)))))
+	  ;; Find a different expansion for the same abbrev as last time.
+	  (progn
+	    (setq abbrev dabbrev--last-abbreviation)
+	    (setq old dabbrev--last-expansion)
+	    (setq direction dabbrev--last-direction))
+	;; If the user inserts a space after expanding
+	;; and then asks to expand again, always fetch the next word.
+	(if (and (eq (preceding-char) ?\ )
+		 (markerp dabbrev--last-abbrev-location)
+		 (marker-position dabbrev--last-abbrev-location)
+		 (= (point) (1+ dabbrev--last-abbrev-location)))
+	    (progn
+	      ;; The "abbrev" to expand is just the space.
+	      (setq abbrev " ")
+	      (save-excursion
+		(if dabbrev--last-buffer
+		    (set-buffer dabbrev--last-buffer))
+		;; Find the end of the last "expansion" word.
+		(if (or (eq dabbrev--last-direction 1)
+			(and (eq dabbrev--last-direction 0)
+			     (< dabbrev--last-expansion-location (point))))
+		    (setq dabbrev--last-expansion-location
+			  (+ dabbrev--last-expansion-location
+			     (length dabbrev--last-expansion))))
+		(goto-char dabbrev--last-expansion-location)
+		;; Take the following word, with intermediate separators,
+		;; as our expansion this time.
+		(re-search-forward
+		 (concat "\\(\\(" dabbrev--abbrev-char-regexp "\\)+\\)"))
+		(setq expansion
+		      (buffer-substring dabbrev--last-expansion-location
+					(point)))
+
+		;; Record the end of this expansion, in case we repeat this.
+		(setq dabbrev--last-expansion-location (point)))
+	      ;; Indicate that dabbrev--last-expansion-location is
+	      ;; at the end of the expansion.
+	      (setq dabbrev--last-direction -1))
+
+	  ;; We have a different abbrev to expand.
+	  (dabbrev--reset-global-variables)
+	  (setq direction (if (null arg)
+			      (if dabbrev-backward-only 1 0)
+			    (prefix-numeric-value arg)))
+	  (setq abbrev (dabbrev--abbrev-at-point))
+	  (setq old nil)))
+
+      ;;--------------------------------
+      ;; Find the expansion
+      ;;--------------------------------
+      (or expansion
+	  (setq expansion
+		(dabbrev--find-expansion abbrev direction
+					 (and (eval dabbrev-case-fold-search)
+					      (or (not dabbrev-upcase-means-case-search)
+						  (string= abbrev (downcase abbrev))))))))
+    (cond
+     ((not expansion)
+      (dabbrev--reset-global-variables)
+      (if old
+	  (save-excursion
+	    (setq buffer-undo-list (cons orig-point buffer-undo-list))
+	    ;; Put back the original abbrev with its original case pattern.
+	    (search-backward old)
+	    (insert abbrev)
+	    (delete-region (point) (+ (point) (length old)))))
+      (error "No%s dynamic expansion for `%s' found"
+	     (if old " further" "") abbrev))
+     (t
+      (if (not (eq dabbrev--last-buffer dabbrev--last-buffer-found))
+	  (progn
+	    (message "Expansion found in '%s'"
+		     (buffer-name dabbrev--last-buffer))
+	    (setq dabbrev--last-buffer-found dabbrev--last-buffer))
+	(message nil))
+      (if (and (or (eq (current-buffer) dabbrev--last-buffer)
+		   (null dabbrev--last-buffer))
+	       (numberp dabbrev--last-expansion-location)
+	       (and (> dabbrev--last-expansion-location (point))))
+	  (setq dabbrev--last-expansion-location
+		(copy-marker dabbrev--last-expansion-location)))
+      ;; Success: stick it in and return.
+      (setq buffer-undo-list (cons orig-point buffer-undo-list))
+      (dabbrev--substitute-expansion old abbrev expansion)
+      ;; Save state for re-expand.
+      (setq dabbrev--last-expansion expansion)	
+      (setq dabbrev--last-abbreviation abbrev)
+      (setq dabbrev--last-abbrev-location (point-marker))))))
+
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+;;; Local functions
+;;;----------------------------------------------------------------
+;;;----------------------------------------------------------------
+
+;;; Checks if OTHER-BUFFER has the same major mode as current buffer.
+(defun dabbrev--same-major-mode-p (other-buffer)
+  (eq major-mode
+      (save-excursion
+	(set-buffer other-buffer)
+	major-mode)))
+
+;;; Back over all abbrev type characters and then moves forward over
+;;; all skip characters.
+(defun dabbrev--goto-start-of-abbrev ()
+  ;; Move backwards over abbrev chars
+  (save-match-data
+    (if (not (bobp))
+	(progn
+	  (forward-char -1)
+	  (while (and (looking-at dabbrev--abbrev-char-regexp)
+		      (not (bobp)))
+	    (forward-char -1))
+	  (or (looking-at dabbrev--abbrev-char-regexp)
+	      (forward-char 1))))
+    (and dabbrev-abbrev-skip-leading-regexp
+	 (while (looking-at dabbrev-abbrev-skip-leading-regexp)
+	   (forward-char 1)))))
+
+;;; Extract the symbol at point to serve as abbreviation.
+(defun dabbrev--abbrev-at-point ()
+  ;; Check for error
+  (if (bobp)
+      (error "No possible abbreviation preceding point"))
+  ;; Return abbrev at point
+  (save-excursion
+    ;; Record the end of the abbreviation.
+    (setq dabbrev--last-abbrev-location (point))
+    ;; If we aren't right after an abbreviation,
+    ;; move point back to just after one.
+    ;; This is so the user can get successive words
+    ;; by typing the punctuation followed by M-/.
+    (save-match-data
+      (if (save-excursion
+	    (forward-char -1)
+	    (not (looking-at (concat "\\("
+				     (or dabbrev-abbrev-char-regexp
+					 "\\sw\\|\\s_")
+				     "\\)+"))))
+	  (if (re-search-backward (or dabbrev-abbrev-char-regexp
+				      "\\sw\\|\\s_")
+				  nil t)
+	      (forward-char 1)
+	    (error "No possible abbreviation preceding point"))))
+    ;; Now find the beginning of that one.
+    (dabbrev--goto-start-of-abbrev)
+    (buffer-substring dabbrev--last-abbrev-location
+		      (point))))
+	
+;;; Initializes all global variables
+(defun dabbrev--reset-global-variables ()
+  ;; dabbrev--last-obarray and dabbrev--last-completion-buffer
+  ;; must not be reset here.
+  (setq dabbrev--last-table nil
+	dabbrev--last-abbreviation nil
+	dabbrev--last-abbrev-location nil
+	dabbrev--last-direction nil
+	dabbrev--last-expansion nil
+	dabbrev--last-expansion-location nil
+	dabbrev--friend-buffer-list nil
+	dabbrev--last-buffer nil
+	dabbrev--last-buffer-found nil
+	dabbrev--abbrev-char-regexp (or dabbrev-abbrev-char-regexp
+					"\\sw\\|\\s_")
+	dabbrev--check-other-buffers dabbrev-check-other-buffers))
+
+;;; Find all buffers that are considered "friends" according to the
+;;; function pointed out by dabbrev-friend-buffer-function.
+(defun dabbrev--select-buffers ()
+  (save-excursion
+    (and (window-minibuffer-p (selected-window))
+	 (set-buffer (dabbrev--minibuffer-origin)))
+    (let ((orig-buffer (current-buffer)))
+      (dabbrev-filter-elements
+       buffer (buffer-list)
+       (and (not (eq orig-buffer buffer))
+	    (boundp 'dabbrev-friend-buffer-function)
+	    (funcall dabbrev-friend-buffer-function buffer))))))
+
+;;; Search for ABBREV, N times, normally looking forward,
+;;; but looking in reverse instead if REVERSE is non-nil.
+(defun dabbrev--try-find (abbrev reverse n ignore-case)
+  (save-excursion
+    (save-restriction
+      (widen)
+      (let ((expansion nil))
+	(and dabbrev--last-expansion-location
+	     (goto-char dabbrev--last-expansion-location))
+	(let ((case-fold-search ignore-case)
+	      (count n))
+	  (while (and (> count 0)
+		      (setq expansion (dabbrev--search abbrev
+						       reverse
+						       ignore-case)))
+	    (setq count (1- count))))
+	(and expansion
+	     (setq dabbrev--last-expansion-location (point)))
+	expansion))))
+
+;;; Find all expansions of ABBREV
+(defun dabbrev--find-all-expansions (abbrev ignore-case)
+  (let ((all-expansions nil)
+	expansion)
+    (save-excursion
+      (goto-char (point-min))
+      (while (setq expansion (dabbrev--find-expansion abbrev -1 ignore-case))
+	(setq all-expansions (cons expansion all-expansions))))
+    all-expansions))
+
+(defun dabbrev--scanning-message ()
+  (message "Scanning `%s'" (buffer-name (current-buffer))))
+
+;;; Find one occasion of ABBREV.
+;;; DIRECTION > 0 means look that many times backwards.
+;;; DIRECTION < 0 means look that many times forward.
+;;; DIRECTION = 0 means try both backward and forward.
+;;; IGNORE-CASE non-nil means ignore case when searching.
+(defun dabbrev--find-expansion (abbrev direction ignore-case)
+  (let (expansion)
+    (save-excursion
+      (cond
+       (dabbrev--last-buffer
+	(set-buffer dabbrev--last-buffer)
+	(dabbrev--scanning-message))
+       ((and (not dabbrev-search-these-buffers-only)
+	     (window-minibuffer-p (selected-window)))
+	(set-buffer (dabbrev--minibuffer-origin))
+	;; In the minibuffer-origin buffer we will only search from
+	;; the top and down.
+	;; XEmacs: This is absolutely the stupidest thing I've ever
+	;; heard of.
+	;;(goto-char (point-min))
+	;;(setq direction -1)
+	(dabbrev--scanning-message)))
+      (cond
+       ;; ------------------------------------------
+       ;; Look backwards
+       ;; ------------------------------------------
+       ((and (not dabbrev-search-these-buffers-only)
+	     (>= direction 0)
+	     (setq dabbrev--last-direction (min 1 direction))
+	     (setq expansion (dabbrev--try-find abbrev t
+						(max 1 direction)
+						ignore-case)))
+	expansion)
+       ;; ------------------------------------------
+       ;; Look forward
+       ;; ------------------------------------------
+       ((and (or (not dabbrev-search-these-buffers-only)
+		 dabbrev--last-buffer)
+	     (<= direction 0)
+	     (setq dabbrev--last-direction -1)
+	     (setq expansion (dabbrev--try-find abbrev nil
+						(max 1 (- direction))
+						ignore-case)))
+	expansion)
+       ;; ------------------------------------------
+       ;; Look in other buffers.
+       ;; Start at (point-min) and look forward.
+       ;; ------------------------------------------
+       (t
+	(setq dabbrev--last-direction -1)
+	;; Make sure that we should check other buffers
+	(or dabbrev--friend-buffer-list
+	    dabbrev--last-buffer
+	    (setq dabbrev--friend-buffer-list
+		  (mapcar (function get-buffer)
+			  dabbrev-search-these-buffers-only))
+	    (not dabbrev--check-other-buffers)
+	    (not (or (eq dabbrev--check-other-buffers t)
+		     (progn
+		       (setq dabbrev--check-other-buffers
+			     (y-or-n-p "Scan other buffers also? ")))))
+	    (let* (friend-buffer-list non-friend-buffer-list)
+	      (setq dabbrev--friend-buffer-list
+		    (funcall dabbrev-select-buffers-function))
+	      (if dabbrev-check-all-buffers
+		  (setq non-friend-buffer-list
+			(nreverse
+			 (dabbrev-filter-elements
+			  buffer (buffer-list)
+			  (not (memq buffer dabbrev--friend-buffer-list))))
+			dabbrev--friend-buffer-list
+			(append dabbrev--friend-buffer-list
+				non-friend-buffer-list)))))
+	;; Move buffers that are visible on the screen
+	;; to the front of the list.
+	(if dabbrev--friend-buffer-list
+	    (let ((w (next-window (selected-window))))
+	      (while (not (eq w (selected-window)))
+		(setq dabbrev--friend-buffer-list
+		      (cons (window-buffer w)
+			    (delq (window-buffer w) dabbrev--friend-buffer-list)))
+		(setq w (next-window w)))))
+	;; Walk through the buffers
+	(while (and (not expansion) dabbrev--friend-buffer-list)
+	  (setq dabbrev--last-buffer
+		(car dabbrev--friend-buffer-list))
+	  (setq dabbrev--friend-buffer-list
+		(cdr dabbrev--friend-buffer-list))
+	  (set-buffer dabbrev--last-buffer)
+	  (dabbrev--scanning-message)
+	  (setq dabbrev--last-expansion-location (point-min))
+	  (setq expansion (dabbrev--try-find abbrev nil 1 ignore-case)))
+	expansion)))))
+
+(defun dabbrev--safe-replace-match (string &optional fixedcase literal)
+  (if (eq major-mode 'picture-mode)
+      (picture-replace-match string fixedcase literal)
+    (replace-match string fixedcase literal)))
+
+;;;----------------------------------------------------------------
+;;; Substitute the current string in buffer with the expansion
+;;; OLD is nil or the last expansion substring.
+;;; ABBREV is the abbreviation we are working with.
+;;; EXPANSION is the expansion substring.
+(defun dabbrev--substitute-expansion (old abbrev expansion)
+  ;;(undo-boundary)
+  (let ((use-case-replace (and (eval dabbrev-case-fold-search)
+			       (or (not dabbrev-upcase-means-case-search)
+				   (string= abbrev (downcase abbrev)))
+			       (eval dabbrev-case-replace))))
+    (and nil use-case-replace
+	 (setq old (concat abbrev (or old "")))
+	 (setq expansion (concat abbrev expansion)))
+    (if old
+	(save-excursion
+	  (search-backward old))
+      ;;(store-match-data (list (point-marker) (point-marker)))
+      (search-backward abbrev))
+    ;; Make case of replacement conform to case of abbreviation
+    ;; provided (1) that kind of thing is enabled in this buffer
+    ;; and (2) the replacement itself is all lower case.
+    (dabbrev--safe-replace-match expansion
+				 (not use-case-replace)
+				 t)))
+
+
+;;;----------------------------------------------------------------
+;;; Search function used by dabbrevs library.
+
+;;; ABBREV is string to find as prefix of word.  Second arg, REVERSE,
+;;; is t for reverse search, nil for forward.  Variable dabbrev-limit
+;;; controls the maximum search region size.  Third argment IGNORE-CASE
+;;; non-nil means treat case as insignificant while looking for a match
+;;; and when comparing with previous matches.  Also if that's non-nil
+;;; and the match is found at the beginning of a sentence and is in
+;;; lower case except for the initial then it is converted to all lower
+;;; case for return.
+
+;;; Table of expansions already seen is examined in buffer
+;;; `dabbrev--last-table' so that only distinct possibilities are found
+;;; by dabbrev-re-expand.
+
+;;; Value is the expansion, or nil if not found.
+
+(defun dabbrev--search (abbrev reverse ignore-case)
+  (save-match-data
+    (let ((pattern1 (concat (regexp-quote abbrev)
+			    "\\(" dabbrev--abbrev-char-regexp "\\)"))
+	  (pattern2 (concat (regexp-quote abbrev)
+			   "\\(\\(" dabbrev--abbrev-char-regexp "\\)+\\)"))
+	  (found-string nil))
+      ;; Limited search.
+      (save-restriction
+	(and dabbrev-limit
+	     (narrow-to-region dabbrev--last-expansion-location
+			       (+ (point)
+				  (if reverse (- dabbrev-limit) dabbrev-limit))))
+	;;--------------------------------
+	;; Look for a distinct expansion, using dabbrev--last-table.
+	;;--------------------------------
+	(while (and (not found-string)
+		    (if reverse
+			(re-search-backward pattern1 nil t)
+		      (re-search-forward pattern1 nil t)))
+	  (goto-char (match-beginning 0))
+	  ;; In case we matched in the middle of a word,
+	  ;; back up to start of word and verify we still match.
+	  (dabbrev--goto-start-of-abbrev)
+
+	  (if (not (looking-at pattern1))
+	      nil
+	    ;; We have a truly valid match.  Find the end.
+	    (re-search-forward pattern2)
+	    (setq found-string
+		  (buffer-substring (match-beginning 1) (match-end 1)))
+	    (and ignore-case (setq found-string (downcase found-string)))
+	    ;; Ignore this match if it's already in the table.
+	    (if (dabbrev-filter-elements
+		 table-string dabbrev--last-table
+		 (string= found-string table-string))
+		(setq found-string nil)))
+	  ;; Prepare to continue searching.
+	  (if reverse
+	      (goto-char (match-beginning 0))
+	    (goto-char (match-end 0))))
+	;; If we found something, use it.
+	(if found-string
+	    ;; Put it into `dabbrev--last-table'
+	    ;; and return it (either downcased, or as is).
+	    (let ((result
+		   (buffer-substring (match-beginning 0) (match-end 0))))
+	      (setq dabbrev--last-table
+		    (cons found-string dabbrev--last-table))
+	      (if (and ignore-case (eval dabbrev-case-replace))
+		  (downcase result)
+		result)))))))
+
+(provide 'dabbrev)
+
+;; dabbrev.el ends here
+
+