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

;;; dabbrev.el --- dynamic abbreviation package

;; Copyright (C) 1985, 86, 92, 94, 96, 1997, 2000, 2001
;;   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 convenience

;; 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:

;; 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 interfere 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@ql.org>
;;  [hawley]	Bob Hawley <rth1@quartet.mt.att.com>
;;  ... and to all the people who have participated in the beta tests.

;;; Code:

;;----------------------------------------------------------------
;; Customization variables
;;----------------------------------------------------------------

(defgroup dabbrev nil
  "Dynamic Abbreviations"
  :tag "Dynamic Abbreviations"
  :group 'abbrev
  :group 'convenience)

(defcustom dabbrev-backward-only nil
  "*If non-nil, `dabbrev-expand' only looks backwards."
  :type 'boolean
  :group 'dabbrev)

(defcustom dabbrev-limit nil
  "*Limits region searched by `dabbrev-expand' to this many chars away."
  :type '(choice (const :tag "off" nil)
		 integer)
  :group 'dabbrev)

(defcustom 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."
  :type '(choice regexp
		 (const :tag "off" nil))
  :group 'dabbrev)

(defcustom dabbrev-case-fold-search 'case-fold-search
  "*Control whether dabbrev searches should ignore case.
A value of nil means case is significant.
A value of `case-fold-search' means case is significant
 if `case-fold-search' is nil.
Any other non-nil version means case is not significant."
  :type '(choice (const :tag "off" nil)
		 (const :tag "like search" case-fold-search)
		 (other :tag "on" t))
  :group 'dabbrev)

(defcustom 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' says to ignore case."
  :type 'boolean
  :group 'dabbrev)

(defcustom dabbrev-case-replace 'case-replace
  "*Controls whether dabbrev preserves case when expanding the abbreviation.
A value of nil means preserve case.
A value of `case-replace' means preserve case if `case-replace' is nil.
Any other non-nil version means do not preserve case.

This variable has an effect only when the value of
`dabbrev-case-fold-search' specifies to ignore case."
  :type '(choice (const :tag "off" nil)
		 (const :tag "like M-x query-replace" case-replace)
		 (other :tag "on" t))
  :group 'dabbrev)

(defcustom 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_\"."
  :type '(choice (const nil)
		 regexp)
  :group 'dabbrev)

(defcustom 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, except those named in `dabbrev-ignored-buffer-names',
or matched by `dabbrev-ignored-regexps'."
  :type 'boolean
  :group 'dabbrev)

(defcustom dabbrev-ignored-buffer-names '("*Messages*" "*Buffer List*")
  "*List of buffer names that dabbrev should not check.
See also `dabbrev-ignored-buffer-regexps'."
  :type '(repeat (string :tag "Buffer name"))
  :group 'dabbrev
  :version "20.3")

(defcustom dabbrev-ignored-buffer-regexps nil
  "*List of regexps matching names of buffers that dabbrev should not check.
See also `dabbrev-ignored-buffer-names'."
  :type '(repeat regexp)
  :group 'dabbrev
  :version "21.1")

(defcustom 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."
  :type '(choice (const :tag "off" nil)
		 (const :tag "on" t)
		 (other :tag "ask" other))
  :group 'dabbrev)

;; 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.")

(defcustom 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."
  :type 'function
  :group 'dabbrev)

(defcustom 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)

;; If non-nil, a function to use when copying successive words.
;; It should be `upcase' or `downcase'.
(defvar dabbrev--last-case-pattern 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)))

;;----------------------------------------------------------------
;; Exported functions
;;----------------------------------------------------------------

;;;###autoload
(define-key esc-map "/" 'dabbrev-expand)
;;;??? Do we want this?
;;;###autoload
(define-key esc-map [?\C-/] '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 (if (eq dabbrev-case-fold-search 'case-fold-search)
				 case-fold-search
			       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))
	      (completion-ignore-case 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))
	    (mapc (function (lambda (string)
			      (intern string my-obarray)))
		    completion-list))
	   ((string= abbrev (upcase abbrev))
	    (mapc (function (lambda (string)
			      (intern (upcase string) my-obarray)))
		    completion-list))
	   ((string= (substring abbrev 0 1)
		     (upcase (substring abbrev 0 1)))
	    (mapc (function (lambda (string)
			      (intern (capitalize string) my-obarray)))
		    completion-list))
	   (t
	    (mapc (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 nil))
     (t
      ;; * String is a common substring completion already.  Make list.
      (message "Making completion list...")
      (with-output-to-temp-buffer " *Completions*"
	(display-completion-list (all-completions init my-obarray)))
      (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 record-case-pattern
	       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-no-properties
				 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 record-case-pattern t)
	  (setq old nil)))

      ;;--------------------------------
      ;; Find the expansion
      ;;--------------------------------
      (or expansion
	  (setq expansion
		(dabbrev--find-expansion abbrev direction
					 (and (if (eq dabbrev-case-fold-search 'case-fold-search)
						  case-fold-search
						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 (or (eq dabbrev--last-buffer dabbrev--last-buffer-found)
		   (minibuffer-window-active-p (selected-window))))
	  (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
				     record-case-pattern)

      ;; 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-no-properties
     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 ()
  "Return a list of all buffers that should be searched for a possible abbrev.

This function makes a list of all the buffers returned by `buffer-list', and
then filters out every buffer for which `dabbrev-friend-buffer-function',
if it is bound, returns nil.  The resulting partial list is returned."
  (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.
	(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
			(dabbrev-filter-elements
			 buffer (buffer-list)
			 (let ((bn (buffer-name buffer)))
			   (and (not (member bn dabbrev-ignored-buffer-names))
				(not (memq buffer dabbrev--friend-buffer-list))
				(not
				 (let ((tail dabbrev-ignored-buffer-regexps)
				       (match nil))
				   (while (and tail (not match))
				     (setq match (string-match (car tail) bn)
					   tail (cdr tail)))
				   match)))))
			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.  Remove the current buffer.
	(when dabbrev--friend-buffer-list
	  (walk-windows (lambda (w)
			  (unless (eq w (selected-window))
			    (setq dabbrev--friend-buffer-list
				  (cons (window-buffer w)
					(delq (window-buffer w)
					      dabbrev--friend-buffer-list))))))
	  (setq dabbrev--friend-buffer-list
		(delq (current-buffer) dabbrev--friend-buffer-list)))
	;; 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)))

;;;----------------------------------------------------------------
(defun dabbrev--substitute-expansion (old abbrev expansion record-case-pattern)
  "Replace OLD with EXPANSION in the buffer.
OLD is text currently in the buffer, perhaps the abbreviation
or perhaps another expansion that was tried previously.
ABBREV is the abbreviation we are expanding.
It is \" \" if we are copying subsequent words.
EXPANSION is the expansion substring to be used this time.
RECORD-CASE-PATTERN, if non-nil, means set `dabbrev--last-case-pattern'
to record whether we upcased the expansion, downcased it, or did neither."
  ;;(undo-boundary)
  (let ((use-case-replace (and (if (eq dabbrev-case-fold-search 'case-fold-search)
				   case-fold-search
				 dabbrev-case-fold-search)
			       (or (not dabbrev-upcase-means-case-search)
				   (string= abbrev (downcase abbrev)))
			       (if (eq dabbrev-case-replace 'case-replace)
				   case-replace
				 dabbrev-case-replace))))

    ;; If we upcased or downcased the original expansion,
    ;; do likewise for the subsequent words when we copy them.
    (and (equal abbrev " ")
	 dabbrev--last-case-pattern
	 (setq expansion
	       (funcall dabbrev--last-case-pattern expansion)))

    ;; If the expansion has mixed case
    ;; and it is not simply a capitalized word,
    ;; or if the abbrev has mixed case,
    ;; and if the given abbrev's case pattern
    ;; matches the start of the expansion,
    ;; copy the expansion's case
    ;; instead of downcasing all the rest.
    ;; Treat a one-capital-letter abbrev as "not all upper case",
    ;; so as to force preservation of the expansion's pattern
    ;; if the expansion starts with a capital letter.
    (let ((expansion-rest (substring expansion 1)))
      (if (and (not (and (or (string= expansion-rest (downcase expansion-rest))
			     (string= expansion-rest (upcase expansion-rest)))
			 (or (string= abbrev (downcase abbrev))
			     (and (string= abbrev (upcase abbrev))
				  (> (length abbrev) 1)))))
	       (string= abbrev
			(substring expansion 0 (length abbrev))))
	  (setq use-case-replace nil)))
    (if (equal abbrev " ")
	(setq use-case-replace nil))
    (if use-case-replace
	(setq expansion (downcase expansion)))

    ;; In case we insert subsequent words,
    ;; record if we upcased or downcased the first word,
    ;; in order to do likewise for subsequent words.
    (and record-case-pattern
	 (setq dabbrev--last-case-pattern 
	       (and use-case-replace
		    (cond ((equal abbrev (upcase abbrev)) 'upcase)
			  ((equal abbrev (downcase abbrev)) 'downcase)))))

    (if old
	(save-excursion
	  (search-backward old))
      ;;(set-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 argument 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-no-properties
				(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-no-properties
			   (match-beginning 0) (match-end 0))))
	      (setq dabbrev--last-table
		    (cons found-string dabbrev--last-table))
	      (if (and ignore-case (eval dabbrev-case-replace))
		  result
		result)))))))

(dolist (mess '("^No dynamic expansion for .* found$"
		"^No further dynamic expansion for .* found$"
		"^No possible abbreviation preceding point$"))
  (add-to-list 'debug-ignored-errors mess))

(provide 'dabbrev)

;;; dabbrev.el ends here