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

;;; mouse.el --- window system-independent mouse support

;; Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: hardware

;; 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 provides various useful commands (including help
;; system access) through the mouse.  All this code assumes that mouse
;; interpretation has been abstracted into Emacs input events.
;;
;; The code is rather X-dependent.

;;; Code:

;;; Utility functions.

;;; Indent track-mouse like progn.
(put 'track-mouse 'lisp-indent-function 0)

(defcustom mouse-yank-at-point nil
  "*If non-nil, mouse yank commands yank at point instead of at click."
  :type 'boolean
  :group 'mouse)
\f
;; Provide a mode-specific menu on a mouse button.

(defun mouse-major-mode-menu (event prefix)
  "Pop up a mode-specific menu of mouse commands."
  ;; Switch to the window clicked on, because otherwise
  ;; the mode's commands may not make sense.
  (interactive "@e\nP")
  ;; Let the mode update its menus first.
  (run-hooks 'activate-menubar-hook)
  (let (;; This is where mouse-major-mode-menu-prefix
	;; returns the prefix we should use (after menu-bar).
	;; It is either nil or (SOME-SYMBOL).
	(mouse-major-mode-menu-prefix nil)
	;; Make a keymap in which our last command leads to a menu
	(newmap (make-sparse-keymap (concat mode-name " Mode")))
	result)
    ;; Make our menu inherit from the desired keymap
    ;; which we want to display as the menu now.
    (set-keymap-parent newmap
		       (mouse-major-mode-menu-1
			(and (current-local-map)
			     (lookup-key (current-local-map) [menu-bar]))))
    (setq result (x-popup-menu t (list newmap)))
    (if result
	(let ((command (key-binding
			(apply 'vector (append '(menu-bar)
					       mouse-major-mode-menu-prefix
					       result)))))
	  ;; Clear out echoing, which perhaps shows a prefix arg.
	  (message "")
	  (if command
	      (progn
		(setq prefix-arg prefix)
		(command-execute command)))))))

;; Compute and cache the equivalent keys in MENU and all its submenus.
;;;(defun mouse-major-mode-menu-compute-equiv-keys (menu)
;;;  (and (eq (car menu) 'keymap)
;;;       (x-popup-menu nil menu))
;;;  (while menu
;;;    (and (consp (car menu))
;;;	 (consp (cdr (car menu)))
;;;	 (let ((tail (cdr (car menu))))
;;;	   (while (and (consp tail)
;;;		       (not (eq (car tail) 'keymap)))
;;;	     (setq tail (cdr tail)))
;;;	   (if (consp tail)
;;;	       (mouse-major-mode-menu-compute-equiv-keys tail))))
;;;    (setq menu (cdr menu))))

;; Given a mode's menu bar keymap,
;; if it defines exactly one menu bar menu,
;; return just that menu.
;; Otherwise return a menu for all of them.
(defun mouse-major-mode-menu-1 (menubar)
  (if menubar
      (let ((tail menubar)
	    submap)
	(while tail
	  (if (consp (car tail))
	      (if submap
		  (setq submap t)
		(setq submap (car tail))))
	  (setq tail (cdr tail)))
	(if (eq submap t)
	    menubar
	  (setq mouse-major-mode-menu-prefix (list (car submap)))
	  (cdr (cdr submap))))))
\f
;; Commands that operate on windows.

(defun mouse-minibuffer-check (event)
  (let ((w (posn-window (event-start event))))
    (and (window-minibuffer-p w)
	 (not (minibuffer-window-active-p w))
	 (error "Minibuffer window is not active")))
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook))

(defun mouse-delete-window (click)
  "Delete the window you click on.
This must be bound to a mouse click."
  (interactive "e")
  (mouse-minibuffer-check click)
  (delete-window (posn-window (event-start click))))

(defun mouse-select-window (click)
  "Select the window clicked on; don't move point."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let ((oframe (selected-frame))
	(frame (window-frame (posn-window (event-start click)))))
    (select-window (posn-window (event-start click)))
    (raise-frame frame)
    (select-frame frame)
    (or (eq frame oframe)
	(set-mouse-position (selected-frame) (1- (frame-width)) 0))))

(defun mouse-tear-off-window (click)
  "Delete the window clicked on, and create a new frame displaying its buffer."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let* ((window (posn-window (event-start click)))
	 (buf (window-buffer window))
	 (frame (make-frame)))
    (select-frame frame)
    (switch-to-buffer buf)
    (delete-window window)))

(defun mouse-delete-other-windows ()
  "Delete all window except the one you click on."
  (interactive "@")
  (delete-other-windows))

(defun mouse-split-window-vertically (click)
  "Select Emacs window mouse is on, then split it vertically in half.
The window is split at the line clicked on.
This command must be bound to a mouse click."
  (interactive "@e")
  (mouse-minibuffer-check click)
  (let ((start (event-start click)))
    (select-window (posn-window start))
    (let ((new-height (1+ (cdr (posn-col-row (event-end click)))))
	  (first-line window-min-height)
	  (last-line (- (window-height) window-min-height)))
      (if (< last-line first-line)
	  (error "Window too short to split")
	(split-window-vertically
	 (min (max new-height first-line) last-line))))))

(defun mouse-split-window-horizontally (click)
  "Select Emacs window mouse is on, then split it horizontally in half.
The window is split at the column clicked on.
This command must be bound to a mouse click."
  (interactive "@e")
  (mouse-minibuffer-check click)
  (let ((start (event-start click)))
    (select-window (posn-window start))
    (let ((new-width (1+ (car (posn-col-row (event-end click)))))
	  (first-col window-min-width)
	  (last-col (- (window-width) window-min-width)))
      (if (< last-col first-col)
	  (error "Window too narrow to split")
	(split-window-horizontally
	 (min (max new-width first-col) last-col))))))

(defun mouse-drag-mode-line (start-event)
  "Change the height of a window by dragging on the mode line."
  (interactive "e")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (let ((done nil)
	(echo-keystrokes 0)
	(start-event-frame (window-frame (car (car (cdr start-event)))))
	(start-event-window (car (car (cdr start-event))))
	(start-nwindows (count-windows t))
	(old-selected-window (selected-window))
	should-enlarge-minibuffer
	event mouse minibuffer y top bot edges wconfig params growth)
    (setq params (frame-parameters))
    (setq minibuffer (cdr (assq 'minibuffer params)))
    (track-mouse
      (progn
	;; enlarge-window only works on the selected window, so
	;; we must select the window where the start event originated.
	;; unwind-protect will restore the old selected window later.
	(select-window start-event-window)
	;; if this is the bottommost ordinary window, then to
	;; move its modeline the minibuffer must be enlarged.
	(setq should-enlarge-minibuffer
	      (and minibuffer
		   (not (one-window-p t))
		   (= (nth 1 (window-edges minibuffer))
		      (nth 3 (window-edges)))))
	;; loop reading events and sampling the position of
	;; the mouse.
	(while (not done)
	  (setq event (read-event)
		mouse (mouse-position))
	  ;; do nothing if
	  ;;   - there is a switch-frame event.
	  ;;   - the mouse isn't in the frame that we started in
	  ;;   - the mouse isn't in any Emacs frame
	  ;; drag if
	  ;;   - there is a mouse-movement event
	  ;;   - there is a scroll-bar-movement event
	  ;;     (same as mouse movement for our purposes)
	  ;; quit if
	  ;;   - there is a keyboard event or some other unknown event
	  ;;     unknown event.
	  (cond ((integerp event)
		 (setq done t))
		((eq (car event) 'switch-frame)
		 nil)
		((not (memq (car event)
			    '(mouse-movement scroll-bar-movement)))
		 (if (consp event)
		     (setq unread-command-events
			   (cons event unread-command-events)))
		 (setq done t))
		((not (eq (car mouse) start-event-frame))
		 nil)
		((null (car (cdr mouse)))
		 nil)
		(t
		 (setq y (cdr (cdr mouse))
		       edges (window-edges)
		       top (nth 1 edges)
		       bot (nth 3 edges))
		 ;; scale back a move that would make the
		 ;; window too short.
		 (cond ((< (- y top -1) window-min-height)
			(setq y (+ top window-min-height -1))))
		 ;; compute size change needed
		 (setq growth (- y bot -1)
		       wconfig (current-window-configuration))
		 ;; Check for an error case.
		 (if (and (/= growth 0)
			  (not minibuffer)
			  (one-window-p t))
		     (error "Attempt to resize sole window"))
		 ;; grow/shrink minibuffer?
		 (if should-enlarge-minibuffer
		     (progn
		       ;; yes.  briefly select minibuffer so
		       ;; enlarge-window will affect the
		       ;; correct window.
		       (select-window minibuffer)
		       ;; scale back shrinkage if it would
		       ;; make the minibuffer less than 1
		       ;; line tall.
		       (if (and (> growth 0)
				(< (- (window-height minibuffer)
				      growth)
				   1))
			   (setq growth (1- (window-height minibuffer))))
		       (enlarge-window (- growth))
		       (select-window start-event-window))
		   ;; no.  grow/shrink the selected window
		   (enlarge-window growth))
		 ;; if this window's growth caused another
		 ;; window to be deleted because it was too
		 ;; short, rescind the change.
		 ;;
		 ;; if size change caused space to be stolen
		 ;; from a window above this one, rescind the
		 ;; change, but only if we didn't grow/srhink
		 ;; the minibuffer.  minibuffer size changes
		 ;; can cause all windows to shrink... no way
		 ;; around it.
		 (if (or (/= start-nwindows (count-windows t))
			 (and (not should-enlarge-minibuffer)
			      (/= top (nth 1 (window-edges)))))
		     (set-window-configuration wconfig)))))))))
\f
(defun mouse-drag-vertical-line (start-event)
  "Change the width of a window by dragging on the vertical line."
  (interactive "e")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (let* ((done nil)
	 (echo-keystrokes 0)
	 (start-event-frame (window-frame (car (car (cdr start-event)))))
	 (start-event-window (car (car (cdr start-event))))
	 (start-nwindows (count-windows t))
	 (old-selected-window (selected-window))
	 event mouse x left right edges wconfig growth
	 (which-side
	  (or (cdr (assq 'vertical-scroll-bars (frame-parameters start-event-frame)))
	      'right)))
    (if (one-window-p t)
	(error "Attempt to resize sole ordinary window"))
    (if (eq which-side 'left)
	(if (= (nth 0 (window-edges start-event-window)) 0)
	    (error "Attempt to drag leftmost scrollbar"))
      (if (= (nth 2 (window-edges start-event-window))
	     (frame-width start-event-frame))
	  (error "Attempt to drag rightmost scrollbar")))
    (track-mouse
      (progn
	;; enlarge-window only works on the selected window, so
	;; we must select the window where the start event originated.
	;; unwind-protect will restore the old selected window later.
	(select-window start-event-window)
	;; loop reading events and sampling the position of
	;; the mouse.
	(while (not done)
	  (setq event (read-event)
		mouse (mouse-position))
	  ;; do nothing if
	  ;;   - there is a switch-frame event.
	  ;;   - the mouse isn't in the frame that we started in
	  ;;   - the mouse isn't in any Emacs frame
	  ;; drag if
	  ;;   - there is a mouse-movement event
	  ;;   - there is a scroll-bar-movement event
	  ;;     (same as mouse movement for our purposes)
	  ;; quit if
	  ;;   - there is a keyboard event or some other unknown event
	  ;;     unknown event.
	  (cond ((integerp event)
		 (setq done t))
		((eq (car event) 'switch-frame)
		 nil)
		((not (memq (car event)
			    '(mouse-movement scroll-bar-movement)))
		 (if (consp event)
		     (setq unread-command-events
			   (cons event unread-command-events)))
		 (setq done t))
		((not (eq (car mouse) start-event-frame))
		 nil)
		((null (car (cdr mouse)))
		 nil)
		(t
		 (save-selected-window
		   ;; If the scroll bar is on the window's left,
		   ;; adjust the window on the left.
		   (if (eq which-side 'left)
		       (select-window (previous-window)))
		   (setq x (- (car (cdr mouse))
			      (if (eq which-side 'left) 2 0))
			 edges (window-edges)
			 left (nth 0 edges)
			 right (nth 2 edges))
		   ;; scale back a move that would make the
		   ;; window too thin.
		   (if (< (- x left -1) window-min-width)
		       (setq x (+ left window-min-width -1)))
		   ;; compute size change needed
		   (setq growth (- x right -1)
			 wconfig (current-window-configuration))
		   (enlarge-window growth t)
		   ;; if this window's growth caused another
		   ;; window to be deleted because it was too
		   ;; thin, rescind the change.
		   ;;
		   ;; if size change caused space to be stolen
		   ;; from a window to the left of this one,
		   ;; rescind the change.
		   (if (or (/= start-nwindows (count-windows t))
			   (/= left (nth 0 (window-edges))))
		       (set-window-configuration wconfig))))))))))
\f
(defun mouse-set-point (event)
  "Move point to the position clicked on with the mouse.
This should be bound to a mouse click event type."
  (interactive "e")
  (mouse-minibuffer-check event)
  ;; Use event-end in case called from mouse-drag-region.
  ;; If EVENT is a click, event-end and event-start give same value.
  (let ((posn (event-end event)))
    (if (not (windowp (posn-window posn)))
	(error "Cursor not in text area of window"))
    (select-window (posn-window posn))
    (if (numberp (posn-point posn))
	(goto-char (posn-point posn)))))

(defvar mouse-last-region-beg nil)
(defvar mouse-last-region-end nil)
(defvar mouse-last-region-tick nil)

(defun mouse-region-match ()
  "Return non-nil if there's an active region that was set with the mouse."
  (and (mark t) mark-active
       (eq mouse-last-region-beg (region-beginning))
       (eq mouse-last-region-end (region-end))
       (eq mouse-last-region-tick (buffer-modified-tick))))

(defun mouse-set-region (click)
  "Set the region to the text dragged over, and copy to kill ring.
This should be bound to a mouse drag event."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let ((posn (event-start click))
	(end (event-end click)))
    (select-window (posn-window posn))
    (if (numberp (posn-point posn))
	(goto-char (posn-point posn)))
    ;; If mark is highlighted, no need to bounce the cursor.
    ;; On X, we highlight while dragging, thus once again no need to bounce.
    (or transient-mark-mode
	(memq (framep (selected-frame)) '(x pc w32))
	(sit-for 1))
    (push-mark)
    (set-mark (point))
    (if (numberp (posn-point end))
	(goto-char (posn-point end)))
    ;; Don't set this-command to kill-region, so that a following
    ;; C-w will not double the text in the kill ring.
    ;; Ignore last-command so we don't append to a preceding kill.
    (let (this-command last-command deactivate-mark)
      (copy-region-as-kill (mark) (point)))
    (mouse-set-region-1)))

(defun mouse-set-region-1 ()
  (setq mouse-last-region-beg (region-beginning))
  (setq mouse-last-region-end (region-end))
  (setq mouse-last-region-tick (buffer-modified-tick)))

(defcustom mouse-scroll-delay 0.25
  "*The pause between scroll steps caused by mouse drags, in seconds.
If you drag the mouse beyond the edge of a window, Emacs scrolls the
window to bring the text beyond that edge into view, with a delay of
this many seconds between scroll steps.  Scrolling stops when you move
the mouse back into the window, or release the button.
This variable's value may be non-integral.
Setting this to zero causes Emacs to scroll as fast as it can."
  :type 'number
  :group 'mouse)

(defcustom mouse-scroll-min-lines 1
  "*The minimum number of lines scrolled by dragging mouse out of window.
Moving the mouse out the top or bottom edge of the window begins
scrolling repeatedly.  The number of lines scrolled per repetition
is normally equal to the number of lines beyond the window edge that
the mouse has moved.  However, it always scrolls at least the number
of lines specified by this variable."
  :type 'integer
  :group 'mouse)

(defun mouse-scroll-subr (window jump &optional overlay start)
  "Scroll the window WINDOW, JUMP lines at a time, until new input arrives.
If OVERLAY is an overlay, let it stretch from START to the far edge of
the newly visible text.
Upon exit, point is at the far edge of the newly visible text."
  (cond
   ((and (> jump 0) (< jump mouse-scroll-min-lines))
    (setq jump mouse-scroll-min-lines))
   ((and (< jump 0) (< (- jump) mouse-scroll-min-lines))
    (setq jump (- mouse-scroll-min-lines))))
  (let ((opoint (point)))
    (while (progn
	     (goto-char (window-start window))
	     (if (not (zerop (vertical-motion jump window)))
		 (progn
		   (set-window-start window (point))
		   (if (natnump jump)
		       (if (window-end window)
			   (progn
			     (goto-char (window-end window))
			     ;; window-end doesn't reflect the window's new
			     ;; start position until the next redisplay.
			     (vertical-motion (1- jump) window))
			 (vertical-motion (- (window-height window) 2)))
		     (goto-char (window-start window)))
		   (if overlay
		       (move-overlay overlay start (point)))
		   ;; Now that we have scrolled WINDOW properly,
		   ;; put point back where it was for the redisplay
		   ;; so that we don't mess up the selected window.
		   (or (eq window (selected-window))
		       (goto-char opoint))
		   (sit-for mouse-scroll-delay)))))
    (or (eq window (selected-window))
	(goto-char opoint))))

;; Create an overlay and immediately delete it, to get "overlay in no buffer".
(defvar mouse-drag-overlay (make-overlay 1 1))
(delete-overlay mouse-drag-overlay)
(overlay-put mouse-drag-overlay 'face 'region)

(defvar mouse-selection-click-count 0)

(defvar mouse-selection-click-count-buffer nil)

(defun mouse-drag-region (start-event)
  "Set the region to the text that the mouse is dragged over.
Highlight the drag area as you move the mouse.
This must be bound to a button-down mouse event.
In Transient Mark mode, the highlighting remains as long as the mark
remains active.  Otherwise, it remains until the next input event."
  (interactive "e")
  (mouse-minibuffer-check start-event)
  (let* ((echo-keystrokes 0)
	 (start-posn (event-start start-event))
	 (start-point (posn-point start-posn))
	 (start-window (posn-window start-posn))
	 (start-frame (window-frame start-window))
	 (bounds (window-edges start-window))
	 (top (nth 1 bounds))
	 (bottom (if (window-minibuffer-p start-window)
		     (nth 3 bounds)
		   ;; Don't count the mode line.
		   (1- (nth 3 bounds))))
	 (click-count (1- (event-click-count start-event))))
    (setq mouse-selection-click-count click-count)
    (setq mouse-selection-click-count-buffer (current-buffer))
    (mouse-set-point start-event)
    ;; In case the down click is in the middle of some intangible text,
    ;; use the end of that text, and put it in START-POINT.
    (if (< (point) start-point)
	(goto-char start-point))
    (setq start-point (point))
    (let ((range (mouse-start-end start-point start-point click-count)))
      (move-overlay mouse-drag-overlay (car range) (nth 1 range)
		    (window-buffer start-window)))
    (deactivate-mark)
    ;; end-of-range is used only in the single-click case.
    ;; It is the place where the drag has reached so far
    ;; (but not outside the window where the drag started).
    (let (event end end-point last-end-point (end-of-range (point)))
      (track-mouse
	(while (progn
		 (setq event (read-event))
		 (or (mouse-movement-p event)
		     (eq (car-safe event) 'switch-frame)))
	  (if (eq (car-safe event) 'switch-frame)
	      nil
	    (setq end (event-end event)
		  end-point (posn-point end))
	    (if (numberp end-point)
		(setq last-end-point end-point))

	    (cond
	     ;; Are we moving within the original window?
	     ((and (eq (posn-window end) start-window)
		   (integer-or-marker-p end-point))
	      ;; Go to START-POINT first, so that when we move to END-POINT,
	      ;; if it's in the middle of intangible text,
	      ;; point jumps in the direction away from START-POINT.
	      (goto-char start-point)
	      (goto-char end-point)
	      (if (zerop (% click-count 3))
		  (setq end-of-range (point)))
	      (let ((range (mouse-start-end start-point (point) click-count)))
		(move-overlay mouse-drag-overlay (car range) (nth 1 range))))

	     (t
	      (let ((mouse-row (cdr (cdr (mouse-position)))))
		(cond
		 ((null mouse-row))
		 ((< mouse-row top)
		  (mouse-scroll-subr start-window (- mouse-row top)
				     mouse-drag-overlay start-point)
		  ;; Without this, point tends to jump back to the starting
		  ;; position where the mouse button was pressed down.
		  (setq end-of-range (overlay-start mouse-drag-overlay)))
		 ((>= mouse-row bottom)
		  (mouse-scroll-subr start-window (1+ (- mouse-row bottom))
				     mouse-drag-overlay start-point)
		  (setq end-of-range (overlay-end mouse-drag-overlay))))))))))
      (if (consp event)
	  (let ((fun (key-binding (vector (car event)))))
	    ;; Run the binding of the terminating up-event, if possible.
	    ;; In the case of a multiple click, it gives the wrong results,
	    ;; because it would fail to set up a region.
	    (if (not (= (overlay-start mouse-drag-overlay)
			(overlay-end mouse-drag-overlay)))
		(let* ((stop-point
			(if (numberp (posn-point (event-end event)))
			    (posn-point (event-end event))
			  last-end-point))
		       ;; The end that comes from where we ended the drag.
		       ;; Point goes here.
		       (region-termination
			(if (and stop-point (< stop-point start-point))
			    (overlay-start mouse-drag-overlay)
			  (overlay-end mouse-drag-overlay)))
		       ;; The end that comes from where we started the drag.
		       ;; Mark goes there.
		       (region-commencement
			(- (+ (overlay-end mouse-drag-overlay)
			      (overlay-start mouse-drag-overlay))
			   region-termination))
		       last-command this-command)
		  (push-mark region-commencement t t)
		  (goto-char region-termination)
		  ;; Don't let copy-region-as-kill set deactivate-mark.
		  (let (deactivate-mark)
		    (copy-region-as-kill (point) (mark t)))
		  (let ((buffer (current-buffer)))
		    (mouse-show-mark)
		    ;; mouse-show-mark can call read-event,
		    ;; and that means the Emacs server could switch buffers
		    ;; under us.  If that happened, 
		    ;; avoid trying to use the region.
		    (and (mark t) mark-active
			 (eq buffer (current-buffer))
			 (mouse-set-region-1))))
	      (delete-overlay mouse-drag-overlay)
	      ;; Run the binding of the terminating up-event.
	      (if (fboundp fun)
		  (setq unread-command-events
			(cons event unread-command-events)))))
	(delete-overlay mouse-drag-overlay)))))
\f
;; Commands to handle xterm-style multiple clicks.

(defun mouse-skip-word (dir)
  "Skip over word, over whitespace, or over identical punctuation.
If DIR is positive skip forward; if negative, skip backward."
  (let* ((char (following-char))
	 (syntax (char-to-string (char-syntax char))))
    (cond ((or (string= syntax "w") (string= syntax " "))
	   (if (< dir 0)
	       (skip-syntax-backward syntax)
	     (skip-syntax-forward syntax)))
	  ((string= syntax "_")
	   (if (< dir 0)
	       (skip-syntax-backward "w_")
	     (skip-syntax-forward "w_")))
	  ((< dir 0)
	   (while (and (not (bobp)) (= (preceding-char) char))
	     (forward-char -1)))
	  (t
	   (while (and (not (eobp)) (= (following-char) char))
	     (forward-char 1))))))

;; Return a list of region bounds based on START and END according to MODE.
;; If MODE is 0 then set point to (min START END), mark to (max START END).
;; If MODE is 1 then set point to start of word at (min START END),
;; mark to end of word at (max START END).
;; If MODE is 2 then do the same for lines.
(defun mouse-start-end (start end mode)
  (if (> start end)
      (let ((temp start))
        (setq start end
              end temp)))
  (setq mode (mod mode 3))
  (cond ((= mode 0)
	 (list start end))
        ((and (= mode 1)
              (= start end)
	      (char-after start)
              (= (char-syntax (char-after start)) ?\())
	 (list start
	       (save-excursion
		 (goto-char start)
		 (forward-sexp 1)
		 (point))))
        ((and (= mode 1)
              (= start end)
	      (char-after start)
              (= (char-syntax (char-after start)) ?\)))
	 (list (save-excursion 
		 (goto-char (1+ start))
		 (backward-sexp 1)
		 (point))
	       (1+ start)))
	((and (= mode 1)
              (= start end)
	      (char-after start)
              (= (char-syntax (char-after start)) ?\"))
	 (let ((open (or (eq start (point-min))
			 (save-excursion
			   (goto-char (- start 1))
			   (looking-at "\\s(\\|\\s \\|\\s>")))))
	   (if open
	       (list start
		     (save-excursion
		       (condition-case nil
			   (progn 
			     (goto-char start)
			     (forward-sexp 1)
			     (point))
			 (error end))))
	     (list (save-excursion
		     (condition-case nil
			 (progn
			   (goto-char (1+ start))
			   (backward-sexp 1)
			   (point))
		       (error end)))
		   (1+ start)))))
        ((= mode 1)
	 (list (save-excursion
		 (goto-char start)
		 (mouse-skip-word -1)
		 (point))
	       (save-excursion
		 (goto-char end)
		 (mouse-skip-word 1)
		 (point))))
        ((= mode 2)
	 (list (save-excursion
		 (goto-char start)
		 (beginning-of-line 1)
		 (point))
	       (save-excursion
		 (goto-char end)
		 (forward-line 1)
		 (point))))))
\f
;; Subroutine: set the mark where CLICK happened,
;; but don't do anything else.
(defun mouse-set-mark-fast (click)
  (mouse-minibuffer-check click)
  (let ((posn (event-start click)))
    (select-window (posn-window posn))
    (if (numberp (posn-point posn))
	(push-mark (posn-point posn) t t))))

(defun mouse-undouble-last-event (events)
  (let* ((index (1- (length events)))
	 (last (nthcdr index events))
	 (event (car last))
	 (basic (event-basic-type event))
	 (old-modifiers (event-modifiers event))
	 (modifiers (delq 'double (delq 'triple (copy-sequence old-modifiers))))
	 (new
	  (if (consp event)
	      ;; Use reverse, not nreverse, since event-modifiers
	      ;; does not copy the list it returns.
	      (cons (event-convert-list (reverse (cons basic modifiers)))
		    (cdr event))
	    event)))
    (setcar last new)
    (if (and (not (equal modifiers old-modifiers))
	     (key-binding (apply 'vector events)))
	t
      (setcar last event)
      nil)))

;; Momentarily show where the mark is, if highlighting doesn't show it. 

(defvar mouse-region-delete-keys '([delete])
  "List of keys which shall cause the mouse region to be deleted.")

(defun mouse-show-mark ()
  (if transient-mark-mode
      (if window-system
	  (delete-overlay mouse-drag-overlay))
    (if window-system
	(let ((inhibit-quit t)
	      (echo-keystrokes 0)
	      event events key ignore
	      x-lost-selection-hooks)
	  (add-hook 'x-lost-selection-hooks
		    '(lambda (seltype)
		       (if (eq seltype 'PRIMARY)
			   (progn (setq ignore t)
				  (throw 'mouse-show-mark t)))))
	  (move-overlay mouse-drag-overlay (point) (mark t))
	  (catch 'mouse-show-mark
	    ;; In this loop, execute scroll bar and switch-frame events.
	    ;; Also ignore down-events that are undefined.
	    (while (progn (setq event (read-event))
			  (setq events (append events (list event)))
			  (setq key (apply 'vector events))
			  (or (and (consp event)
				   (eq (car event) 'switch-frame))
			      (and (consp event)
				   (eq (posn-point (event-end event))
				       'vertical-scroll-bar))
			      (and (memq 'down (event-modifiers event))
				   (not (key-binding key))
				   (not (mouse-undouble-last-event events))
				   (not (member key mouse-region-delete-keys)))))
	      (and (consp event)
		   (or (eq (car event) 'switch-frame)
		       (eq (posn-point (event-end event))
			   'vertical-scroll-bar))
		   (let ((keys (vector 'vertical-scroll-bar event)))
		     (and (key-binding keys)
			  (progn
			    (call-interactively (key-binding keys)
						nil keys)
			    (setq events nil)))))))
	  ;; If we lost the selection, just turn off the highlighting.
	  (if ignore
	      nil
	    ;; For certain special keys, delete the region.
	    (if (member key mouse-region-delete-keys)
		(delete-region (overlay-start mouse-drag-overlay)
			       (overlay-end mouse-drag-overlay))
	      ;; Otherwise, unread the key so it gets executed normally.
	      (setq unread-command-events
		    (nconc events unread-command-events))))
	  (setq quit-flag nil)
	  (delete-overlay mouse-drag-overlay))
      (save-excursion
       (goto-char (mark t))
       (sit-for 1)))))

(defun mouse-set-mark (click)
  "Set mark at the position clicked on with the mouse.
Display cursor at that position for a second.
This must be bound to a mouse click."
  (interactive "e")
  (mouse-minibuffer-check click)
  (select-window (posn-window (event-start click)))
  ;; We don't use save-excursion because that preserves the mark too.
  (let ((point-save (point)))
    (unwind-protect
	(progn (mouse-set-point click)
	       (push-mark nil t t)
	       (or transient-mark-mode
		   (sit-for 1)))
      (goto-char point-save))))

(defun mouse-kill (click)
  "Kill the region between point and the mouse click.
The text is saved in the kill ring, as with \\[kill-region]."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let* ((posn (event-start click))
	 (click-posn (posn-point posn)))
    (select-window (posn-window posn))
    (if (numberp click-posn)
	(kill-region (min (point) click-posn)
		     (max (point) click-posn)))))

(defun mouse-yank-at-click (click arg)
  "Insert the last stretch of killed text at the position clicked on.
Also move point to one end of the text thus inserted (normally the end).
Prefix arguments are interpreted as with \\[yank].
If `mouse-yank-at-point' is non-nil, insert at point
regardless of where you click."
  (interactive "e\nP")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (or mouse-yank-at-point (mouse-set-point click))
  (setq this-command 'yank)
  (setq mouse-selection-click-count 0)
  (yank arg))

(defun mouse-kill-ring-save (click)
  "Copy the region between point and the mouse click in the kill ring.
This does not delete the region; it acts like \\[kill-ring-save]."
  (interactive "e")
  (mouse-set-mark-fast click)
  (let (this-command last-command)
    (kill-ring-save (point) (mark t)))
  (mouse-show-mark))

;;; This function used to delete the text between point and the mouse
;;; whenever it was equal to the front of the kill ring, but some
;;; people found that confusing.

;;; A list (TEXT START END), describing the text and position of the last
;;; invocation of mouse-save-then-kill.
(defvar mouse-save-then-kill-posn nil)

(defun mouse-save-then-kill-delete-region (beg end)
  ;; We must make our own undo boundaries
  ;; because they happen automatically only for the current buffer.
  (undo-boundary)
  (if (or (= beg end) (eq buffer-undo-list t))
      ;; If we have no undo list in this buffer,
      ;; just delete.
      (delete-region beg end)
    ;; Delete, but make the undo-list entry share with the kill ring.
    ;; First, delete just one char, so in case buffer is being modified
    ;; for the first time, the undo list records that fact.
    (let (before-change-function after-change-function
	  before-change-functions after-change-functions)
      (delete-region beg
		     (+ beg (if (> end beg) 1 -1))))
    (let ((buffer-undo-list buffer-undo-list))
      ;; Undo that deletion--but don't change the undo list!
      (let (before-change-function after-change-function
	    before-change-functions after-change-functions)
	(primitive-undo 1 buffer-undo-list))
      ;; Now delete the rest of the specified region,
      ;; but don't record it.
      (setq buffer-undo-list t)
      (if (/= (length (car kill-ring)) (- (max end beg) (min end beg)))
	  (error "Lossage in mouse-save-then-kill-delete-region"))
      (delete-region beg end))
    (let ((tail buffer-undo-list))
      ;; Search back in buffer-undo-list for the string
      ;; that came from deleting one character.
      (while (and tail (not (stringp (car (car tail)))))
	(setq tail (cdr tail)))
      ;; Replace it with an entry for the entire deleted text.
      (and tail
	   (setcar tail (cons (car kill-ring) (min beg end))))))
  (undo-boundary))

(defun mouse-save-then-kill (click)
  "Save text to point in kill ring; the second time, kill the text.
If the text between point and the mouse is the same as what's
at the front of the kill ring, this deletes the text.
Otherwise, it adds the text to the kill ring, like \\[kill-ring-save],
which prepares for a second click to delete the text.

If you have selected words or lines, this command extends the
selection through the word or line clicked on.  If you do this
again in a different position, it extends the selection again.
If you do this twice in the same position, the selection is killed." 
  (interactive "e")
  (let ((before-scroll
	 (with-current-buffer (window-buffer (posn-window (event-start click)))
	   point-before-scroll)))
    (mouse-minibuffer-check click)
    (let ((click-posn (posn-point (event-start click)))
	  ;; Don't let a subsequent kill command append to this one:
	  ;; prevent setting this-command to kill-region.
	  (this-command this-command))
      (if (and (save-excursion
		 (set-buffer (window-buffer (posn-window (event-start click))))
		 (and (mark t) (> (mod mouse-selection-click-count 3) 0)
		      ;; Don't be fooled by a recent click in some other buffer.
		      (eq mouse-selection-click-count-buffer 
			  (current-buffer)))))
	  (if (not (and (eq last-command 'mouse-save-then-kill)
			(equal click-posn
			       (car (cdr-safe (cdr-safe mouse-save-then-kill-posn))))))
	      ;; Find both ends of the object selected by this click.
	      (let* ((range
		      (mouse-start-end click-posn click-posn
				       mouse-selection-click-count)))
		;; Move whichever end is closer to the click.
		;; That's what xterm does, and it seems reasonable.
		(if (< (abs (- click-posn (mark t)))
		       (abs (- click-posn (point))))
		    (set-mark (car range))
		  (goto-char (nth 1 range)))
		;; We have already put the old region in the kill ring.
		;; Replace it with the extended region.
		;; (It would be annoying to make a separate entry.)
		(kill-new (buffer-substring (point) (mark t)) t)
		(mouse-set-region-1)
		;; Arrange for a repeated mouse-3 to kill this region.
		(setq mouse-save-then-kill-posn
		      (list (car kill-ring) (point) click-posn))
		(mouse-show-mark))
	    ;; If we click this button again without moving it,
	    ;; that time kill.
	    (mouse-save-then-kill-delete-region (mark) (point))
	    (setq mouse-selection-click-count 0)
	    (setq mouse-save-then-kill-posn nil))
	(if (and (eq last-command 'mouse-save-then-kill)
		 mouse-save-then-kill-posn
		 (eq (car mouse-save-then-kill-posn) (car kill-ring))
		 (equal (cdr mouse-save-then-kill-posn) (list (point) click-posn)))
	    ;; If this is the second time we've called
	    ;; mouse-save-then-kill, delete the text from the buffer.
	    (progn
	      (mouse-save-then-kill-delete-region (point) (mark))
	      ;; After we kill, another click counts as "the first time".
	      (setq mouse-save-then-kill-posn nil))
	  ;; This is not a repetition.
	  ;; We are adjusting an old selection or creating a new one.
	  (if (or (and (eq last-command 'mouse-save-then-kill)
		       mouse-save-then-kill-posn)
		  (and mark-active transient-mark-mode)
		  (and (memq last-command
			     '(mouse-drag-region mouse-set-region))
		       (or mark-even-if-inactive
			   (not transient-mark-mode))))
	      ;; We have a selection or suitable region, so adjust it.
	      (let* ((posn (event-start click))
		     (new (posn-point posn)))
		(select-window (posn-window posn))
		(if (numberp new)
		    (progn
		      ;; Move whichever end of the region is closer to the click.
		      ;; That is what xterm does, and it seems reasonable.
		      (if (< (abs (- new (point))) (abs (- new (mark t))))
			  (goto-char new)
			(set-mark new))
		      (setq deactivate-mark nil)))
		(kill-new (buffer-substring (point) (mark t)) t)
		(mouse-show-mark))
	    ;; Set the mark where point is, then move where clicked.
	    (mouse-set-mark-fast click)
	    (if before-scroll
		(goto-char before-scroll))
	    (exchange-point-and-mark)
	    (kill-new (buffer-substring (point) (mark t)))
	    (if window-system
		(mouse-show-mark)))
	  (mouse-set-region-1)
	  (setq mouse-save-then-kill-posn
		(list (car kill-ring) (point) click-posn)))))))
\f
(global-set-key [M-mouse-1] 'mouse-start-secondary)
(global-set-key [M-drag-mouse-1] 'mouse-set-secondary)
(global-set-key [M-down-mouse-1] 'mouse-drag-secondary)
(global-set-key [M-mouse-3] 'mouse-secondary-save-then-kill)
(global-set-key [M-mouse-2] 'mouse-yank-secondary)

;; An overlay which records the current secondary selection
;; or else is deleted when there is no secondary selection.
;; May be nil.
(defvar mouse-secondary-overlay nil)

(defvar mouse-secondary-click-count 0)

;; A marker which records the specified first end for a secondary selection.
;; May be nil.
(defvar mouse-secondary-start nil)

(defun mouse-start-secondary (click)
  "Set one end of the secondary selection to the position clicked on.
Use \\[mouse-secondary-save-then-kill] to set the other end
and complete the secondary selection."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let ((posn (event-start click)))
    (save-excursion
      (set-buffer (window-buffer (posn-window posn)))
      ;; Cancel any preexisting secondary selection.
      (if mouse-secondary-overlay
	  (delete-overlay mouse-secondary-overlay))
      (if (numberp (posn-point posn))
	  (progn
	    (or mouse-secondary-start
		(setq mouse-secondary-start (make-marker)))
	    (move-marker mouse-secondary-start (posn-point posn)))))))

(defun mouse-set-secondary (click)
  "Set the secondary selection to the text that the mouse is dragged over.
This must be bound to a mouse drag event."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let ((posn (event-start click))
	beg
	(end (event-end click)))
    (save-excursion
      (set-buffer (window-buffer (posn-window posn)))
      (if (numberp (posn-point posn))
	  (setq beg (posn-point posn)))
      (if mouse-secondary-overlay
	  (move-overlay mouse-secondary-overlay beg (posn-point end))
	(setq mouse-secondary-overlay (make-overlay beg (posn-point end))))
      (overlay-put mouse-secondary-overlay 'face 'secondary-selection))))

(defun mouse-drag-secondary (start-event)
  "Set the secondary selection to the text that the mouse is dragged over.
Highlight the drag area as you move the mouse.
This must be bound to a button-down mouse event.
The function returns a non-nil value if it creates a secondary selection."
  (interactive "e")
  (mouse-minibuffer-check start-event)
  (let* ((echo-keystrokes 0)
	 (start-posn (event-start start-event))
	 (start-point (posn-point start-posn))
	 (start-window (posn-window start-posn))
	 (start-frame (window-frame start-window))
	 (bounds (window-edges start-window))
	 (top (nth 1 bounds))
	 (bottom (if (window-minibuffer-p start-window)
		     (nth 3 bounds)
		   ;; Don't count the mode line.
		   (1- (nth 3 bounds))))
	 (click-count (1- (event-click-count start-event))))
    (save-excursion
      (set-buffer (window-buffer start-window))
      (setq mouse-secondary-click-count click-count)
      (or mouse-secondary-overlay
	  (setq mouse-secondary-overlay
		(make-overlay (point) (point))))
      (overlay-put mouse-secondary-overlay 'face 'secondary-selection)
      (if (> (mod click-count 3) 0)
	  ;; Double or triple press: make an initial selection
	  ;; of one word or line.
	  (let ((range (mouse-start-end start-point start-point click-count)))
	    (set-marker mouse-secondary-start nil)
	    (move-overlay mouse-secondary-overlay 1 1
			  (window-buffer start-window))
	    (move-overlay mouse-secondary-overlay (car range) (nth 1 range)
			  (window-buffer start-window)))
	;; Single-press: cancel any preexisting secondary selection.
	(or mouse-secondary-start
	    (setq mouse-secondary-start (make-marker)))
	(set-marker mouse-secondary-start start-point)
	(delete-overlay mouse-secondary-overlay))
      (let (event end end-point)
	(track-mouse
	  (while (progn
		   (setq event (read-event))
		   (or (mouse-movement-p event)
		       (eq (car-safe event) 'switch-frame)))

	    (if (eq (car-safe event) 'switch-frame)
		nil
	      (setq end (event-end event)
		    end-point (posn-point end))
	      (cond
	       ;; Are we moving within the original window?
	       ((and (eq (posn-window end) start-window)
		     (integer-or-marker-p end-point))
		(let ((range (mouse-start-end start-point end-point
					      click-count)))
		  (if (or (/= start-point end-point)
			  (null (marker-position mouse-secondary-start)))
		      (progn
			(set-marker mouse-secondary-start nil)
			(move-overlay mouse-secondary-overlay
				      (car range) (nth 1 range))))))
               (t
                (let ((mouse-row (cdr (cdr (mouse-position)))))
                  (cond
                   ((null mouse-row))
                   ((< mouse-row top)
                    (mouse-scroll-subr start-window (- mouse-row top)
				       mouse-secondary-overlay start-point))
                   ((>= mouse-row bottom)
                    (mouse-scroll-subr start-window (1+ (- mouse-row bottom))
                                       mouse-secondary-overlay start-point)))))))))

	(if (consp event)
	    (if (marker-position mouse-secondary-start)
		(save-window-excursion
		  (delete-overlay mouse-secondary-overlay)
		  (x-set-selection 'SECONDARY nil)
		  (select-window start-window)
		  (save-excursion
		    (goto-char mouse-secondary-start)
		    (sit-for 1)
		    nil))
	      (x-set-selection
	       'SECONDARY
	       (buffer-substring (overlay-start mouse-secondary-overlay)
				 (overlay-end mouse-secondary-overlay)))))))))

(defun mouse-yank-secondary (click)
  "Insert the secondary selection at the position clicked on.
Move point to the end of the inserted text.
If `mouse-yank-at-point' is non-nil, insert at point
regardless of where you click."
  (interactive "e")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (or mouse-yank-at-point (mouse-set-point click))
  (insert (x-get-selection 'SECONDARY)))

(defun mouse-kill-secondary ()
  "Kill the text in the secondary selection.
This is intended more as a keyboard command than as a mouse command
but it can work as either one.

The current buffer (in case of keyboard use), or the buffer clicked on,
must be the one that the secondary selection is in.  This requirement
is to prevent accidents."
  (interactive)
  (let* ((keys (this-command-keys))
	 (click (elt keys (1- (length keys)))))
    (or (eq (overlay-buffer mouse-secondary-overlay)
	    (if (listp click)
		(window-buffer (posn-window (event-start click)))
	      (current-buffer)))
	(error "Select or click on the buffer where the secondary selection is")))
  (let (this-command)
    (save-excursion
      (set-buffer (overlay-buffer mouse-secondary-overlay))
      (kill-region (overlay-start mouse-secondary-overlay)
		   (overlay-end mouse-secondary-overlay))))
  (delete-overlay mouse-secondary-overlay)
;;;  (x-set-selection 'SECONDARY nil)
  (setq mouse-secondary-overlay nil))

(defun mouse-secondary-save-then-kill (click)
  "Save text to point in kill ring; the second time, kill the text.
You must use this in a buffer where you have recently done \\[mouse-start-secondary].
If the text between where you did \\[mouse-start-secondary] and where
you use this command matches the text at the front of the kill ring,
this command deletes the text.
Otherwise, it adds the text to the kill ring, like \\[kill-ring-save],
which prepares for a second click with this command to delete the text.

If you have already made a secondary selection in that buffer,
this command extends or retracts the selection to where you click.
If you do this again in a different position, it extends or retracts
again.  If you do this twice in the same position, it kills the selection."
  (interactive "e")
  (mouse-minibuffer-check click)
  (let ((posn (event-start click))
	(click-posn (posn-point (event-start click)))
	;; Don't let a subsequent kill command append to this one:
	;; prevent setting this-command to kill-region.
	(this-command this-command))
    (or (eq (window-buffer (posn-window posn))
	    (or (and mouse-secondary-overlay
		     (overlay-buffer mouse-secondary-overlay))
		(if mouse-secondary-start
		    (marker-buffer mouse-secondary-start))))
	(error "Wrong buffer"))
    (save-excursion
      (set-buffer (window-buffer (posn-window posn)))
      (if (> (mod mouse-secondary-click-count 3) 0)
	  (if (not (and (eq last-command 'mouse-secondary-save-then-kill)
			(equal click-posn
			       (car (cdr-safe (cdr-safe mouse-save-then-kill-posn))))))
	      ;; Find both ends of the object selected by this click.
	      (let* ((range
		      (mouse-start-end click-posn click-posn
				       mouse-secondary-click-count)))
		;; Move whichever end is closer to the click.
		;; That's what xterm does, and it seems reasonable.
		(if (< (abs (- click-posn (overlay-start mouse-secondary-overlay)))
		       (abs (- click-posn (overlay-end mouse-secondary-overlay))))
		    (move-overlay mouse-secondary-overlay (car range)
				  (overlay-end mouse-secondary-overlay))
		  (move-overlay mouse-secondary-overlay
				(overlay-start mouse-secondary-overlay)
				(nth 1 range)))
		;; We have already put the old region in the kill ring.
		;; Replace it with the extended region.
		;; (It would be annoying to make a separate entry.)
		(kill-new (buffer-substring
			   (overlay-start mouse-secondary-overlay)
			   (overlay-end mouse-secondary-overlay)) t)
		;; Arrange for a repeated mouse-3 to kill this region.
		(setq mouse-save-then-kill-posn
		      (list (car kill-ring) (point) click-posn)))
	    ;; If we click this button again without moving it,
	    ;; that time kill.
	    (progn
	      (mouse-save-then-kill-delete-region
	       (overlay-start mouse-secondary-overlay)
	       (overlay-end mouse-secondary-overlay))
	      (setq mouse-save-then-kill-posn nil)
	      (setq mouse-secondary-click-count 0)
	      (delete-overlay mouse-secondary-overlay)))
	(if (and (eq last-command 'mouse-secondary-save-then-kill)
		 mouse-save-then-kill-posn
		 (eq (car mouse-save-then-kill-posn) (car kill-ring))
		 (equal (cdr mouse-save-then-kill-posn) (list (point) click-posn)))
	    ;; If this is the second time we've called
	    ;; mouse-secondary-save-then-kill, delete the text from the buffer.
	    (progn
	      (mouse-save-then-kill-delete-region
	       (overlay-start mouse-secondary-overlay)
	       (overlay-end mouse-secondary-overlay))
	      (setq mouse-save-then-kill-posn nil)
	      (delete-overlay mouse-secondary-overlay))
	  (if (overlay-start mouse-secondary-overlay)
	      ;; We have a selection, so adjust it.
	      (progn
		(if (numberp click-posn)
		    (progn
		      ;; Move whichever end of the region is closer to the click.
		      ;; That is what xterm does, and it seems reasonable.
		      (if (< (abs (- click-posn (overlay-start mouse-secondary-overlay)))
			     (abs (- click-posn (overlay-end mouse-secondary-overlay))))
			  (move-overlay mouse-secondary-overlay click-posn
					(overlay-end mouse-secondary-overlay))
			(move-overlay mouse-secondary-overlay
				      (overlay-start mouse-secondary-overlay)
				      click-posn))
		      (setq deactivate-mark nil)))
		(if (eq last-command 'mouse-secondary-save-then-kill)
		    ;; If the front of the kill ring comes from 
		    ;; an immediately previous use of this command,
		    ;; replace it with the extended region.
		    ;; (It would be annoying to make a separate entry.)
		    (kill-new (buffer-substring
			       (overlay-start mouse-secondary-overlay)
			       (overlay-end mouse-secondary-overlay)) t)
		  (let (deactivate-mark)
		    (copy-region-as-kill (overlay-start mouse-secondary-overlay)
					 (overlay-end mouse-secondary-overlay)))))
	    (if mouse-secondary-start
		;; All we have is one end of a selection,
		;; so put the other end here.
		(let ((start (+ 0 mouse-secondary-start)))
		  (kill-ring-save start click-posn)
		  (if mouse-secondary-overlay
		      (move-overlay mouse-secondary-overlay start click-posn)
		    (setq mouse-secondary-overlay (make-overlay start click-posn)))
		  (overlay-put mouse-secondary-overlay 'face 'secondary-selection))))
	  (setq mouse-save-then-kill-posn
		(list (car kill-ring) (point) click-posn))))
      (if (overlay-buffer mouse-secondary-overlay)
	  (x-set-selection 'SECONDARY
			   (buffer-substring
			    (overlay-start mouse-secondary-overlay)
			    (overlay-end mouse-secondary-overlay)))))))
\f
(defcustom mouse-buffer-menu-maxlen 20
  "*Number of buffers in one pane (submenu) of the buffer menu.
If we have lots of buffers, divide them into groups of
`mouse-buffer-menu-maxlen' and make a pane (or submenu) for each one."
  :type 'integer
  :group 'mouse)

(defcustom mouse-buffer-menu-mode-mult 4
  "*Group the buffers by the major mode groups on \\[mouse-buffer-menu]?
This number which determines (in a hairy way) whether \\[mouse-buffer-menu]
will split the buffer menu by the major modes (see
`mouse-buffer-menu-mode-groups') or just by menu length.
Set to 1 (or even 0!) if you want to group by major mode always, and to
a large number if you prefer a mixed multitude.  The default is 4."
  :type 'integer
  :group 'mouse
  :version "20.3")

(defvar mouse-buffer-menu-mode-groups
  '(("Info\\|Help\\|Apropos\\|Man" . "Help")
    ("\\bVM\\b\\|\\bMH\\b\\|Message\\|Mail\\|Group\\|Score\\|Summary\\|Article"
     . "Mail/News")
    ("\\<C\\>" . "C")
    ("ObjC" . "C")
    ("Text" . "Text")
    ("Outline" . "Text")
    ("Lisp" . "Lisp"))
  "How to group various major modes together in \\[mouse-buffer-menu].
Each element has the form (REGEXP . GROUPNAME).
If the major mode's name string matches REGEXP, use GROUPNAME instead.")

(defun mouse-buffer-menu (event)
  "Pop up a menu of buffers for selection with the mouse.
This switches buffers in the window that you clicked on,
and selects that window."
  (interactive "e")
  (mouse-minibuffer-check event)
  (let ((buffers (buffer-list))  alist menu split-by-major-mode sum-of-squares)
    ;; Make an alist of elements that look like (MENU-ITEM . BUFFER).
    (let ((tail buffers))
      (while tail
	;; Divide all buffers into buckets for various major modes.
	;; Each bucket looks like (MODE NAMESTRING BUFFERS...).
	(with-current-buffer (car tail)
	  (let* ((adjusted-major-mode major-mode) elt)
	    (let ((tail mouse-buffer-menu-mode-groups))
	      (while tail
		(if (string-match (car (car tail)) mode-name)
		    (setq adjusted-major-mode (cdr (car tail))))
		(setq tail (cdr tail))))
	    (setq elt (assoc adjusted-major-mode split-by-major-mode))
	    (if (null elt)
		(setq elt (list adjusted-major-mode
				(if (stringp adjusted-major-mode)
				    adjusted-major-mode
				  mode-name))
		      split-by-major-mode (cons elt split-by-major-mode)))
	    (or (memq (car tail) (cdr (cdr elt)))
		(setcdr (cdr elt) (cons (car tail) (cdr (cdr elt)))))))
	(setq tail (cdr tail))))
    ;; Compute the sum of squares of sizes of the major-mode buckets.
    (let ((tail split-by-major-mode))
      (setq sum-of-squares 0)
      (while tail
	(setq sum-of-squares
	      (+ sum-of-squares
		 (let ((len (length (cdr (cdr (car tail)))))) (* len len))))
	(setq tail (cdr tail))))
    (if (< (* sum-of-squares mouse-buffer-menu-mode-mult)
	   (* (length buffers) (length buffers)))
	;; Subdividing by major modes really helps, so let's do it.
	(let (subdivided-menus (buffers-left (length buffers)))
	  ;; Sort the list to put the most popular major modes first.
	  (setq split-by-major-mode
		(sort split-by-major-mode
		      (function (lambda (elt1 elt2)
				  (> (length elt1) (length elt2))))))
	  ;; Make a separate submenu for each major mode
	  ;; that has more than one buffer,
	  ;; unless all the remaining buffers are less than 1/10 of them.
	  (while (and split-by-major-mode
		      (and (> (length (car split-by-major-mode)) 3)
			   (> (* buffers-left 10) (length buffers))))
	    (setq subdivided-menus
		  (cons (cons
			 (nth 1 (car split-by-major-mode))
			 (mouse-buffer-menu-alist
			  (cdr (cdr (car split-by-major-mode)))))
			subdivided-menus))
	    (setq buffers-left
		  (- buffers-left (length (cdr (car split-by-major-mode)))))
	    (setq split-by-major-mode (cdr split-by-major-mode)))
	  ;; If any major modes are left over,
	  ;; make a single submenu for them.
	  (if split-by-major-mode
	      (setq subdivided-menus
		    (cons (cons
			   "Others"
			   (mouse-buffer-menu-alist
			    ;; we don't need split-by-major-mode any
			    ;; more, so we can ditch it with nconc.
			    (apply 'nconc (mapcar 'cddr split-by-major-mode))))
			  subdivided-menus)))
	  (setq menu (cons "Buffer Menu" (nreverse subdivided-menus))))
      (progn
	(setq alist (mouse-buffer-menu-alist buffers))
	(setq menu (cons "Buffer Menu"
			 (mouse-buffer-menu-split "Select Buffer" alist)))))
    (let ((buf (x-popup-menu event menu))
	  (window (posn-window (event-start event))))
      (when buf
	    (or (framep window) (select-window window))
	(switch-to-buffer buf)))))

(defun mouse-buffer-menu-alist (buffers)
  (let (tail
	(maxlen 0)
	head)
    (setq buffers
	  (sort buffers
		(function (lambda (elt1 elt2)
			    (string< (buffer-name elt1) (buffer-name elt2))))))
    (setq tail buffers)
    (while tail
      (or (eq ?\ (aref (buffer-name (car tail)) 0))
	  (setq maxlen
		(max maxlen
		     (length (buffer-name (car tail))))))
      (setq tail (cdr tail)))
    (setq tail buffers)
    (while tail
      (let ((elt (car tail)))
	(if (/= (aref (buffer-name elt) 0) ?\ )
	    (setq head
		  (cons
		   (cons
		    (format
		     (format "%%%ds  %%s%%s  %%s" maxlen)
		     (buffer-name elt)
		     (if (buffer-modified-p elt) "*" " ")
		     (save-excursion
		       (set-buffer elt)
		       (if buffer-read-only "%" " "))
		     (or (buffer-file-name elt) 
			 (save-excursion
			   (set-buffer elt)
			   (if list-buffers-directory
			       (expand-file-name
				list-buffers-directory)))
			 ""))
		    elt)
		   head))))
      (setq tail (cdr tail)))
    ;; Compensate for the reversal that the above loop does.
    (nreverse head)))

(defun mouse-buffer-menu-split (title alist)
  ;; If we have lots of buffers, divide them into groups of 20
  ;; and make a pane (or submenu) for each one.
  (if (> (length alist) (/ (* mouse-buffer-menu-maxlen 3) 2))
      (let ((alist alist) sublists next
	    (i 1))
	(while alist
	  ;; Pull off the next mouse-buffer-menu-maxlen buffers
	  ;; and make them the next element of sublist.
	  (setq next (nthcdr mouse-buffer-menu-maxlen alist))
	  (if next
	      (setcdr (nthcdr (1- mouse-buffer-menu-maxlen) alist)
		      nil))
	  (setq sublists (cons (cons (format "Buffers %d" i) alist)
			       sublists))
	  (setq i (1+ i))
	  (setq alist next))
	(nreverse sublists))
    ;; Few buffers--put them all in one pane.
    (list (cons title alist))))
\f
;;; These need to be rewritten for the new scroll bar implementation.

;;;!! ;; Commands for the scroll bar.
;;;!! 
;;;!! (defun mouse-scroll-down (click)
;;;!!   (interactive "@e")
;;;!!   (scroll-down (1+ (cdr (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-up (click)
;;;!!   (interactive "@e")
;;;!!   (scroll-up (1+ (cdr (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-down-full ()
;;;!!   (interactive "@")
;;;!!   (scroll-down nil))
;;;!! 
;;;!! (defun mouse-scroll-up-full ()
;;;!!   (interactive "@")
;;;!!   (scroll-up nil))
;;;!! 
;;;!! (defun mouse-scroll-move-cursor (click)
;;;!!   (interactive "@e")
;;;!!   (move-to-window-line (1+ (cdr (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-absolute (event)
;;;!!   (interactive "@e")
;;;!!   (let* ((pos (car event))
;;;!! 	 (position (car pos))
;;;!! 	 (length (car (cdr pos))))
;;;!!     (if (<= length 0) (setq length 1))
;;;!!     (let* ((scale-factor (max 1 (/ length (/ 8000000 (buffer-size)))))
;;;!! 	   (newpos (* (/ (* (/ (buffer-size) scale-factor)
;;;!! 			    position)
;;;!! 			 length)
;;;!! 		      scale-factor)))
;;;!!       (goto-char newpos)
;;;!!       (recenter '(4)))))
;;;!! 
;;;!! (defun mouse-scroll-left (click)
;;;!!   (interactive "@e")
;;;!!   (scroll-left (1+ (car (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-right (click)
;;;!!   (interactive "@e")
;;;!!   (scroll-right (1+ (car (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-left-full ()
;;;!!   (interactive "@")
;;;!!   (scroll-left nil))
;;;!! 
;;;!! (defun mouse-scroll-right-full ()
;;;!!   (interactive "@")
;;;!!   (scroll-right nil))
;;;!! 
;;;!! (defun mouse-scroll-move-cursor-horizontally (click)
;;;!!   (interactive "@e")
;;;!!   (move-to-column (1+ (car (mouse-coords click)))))
;;;!! 
;;;!! (defun mouse-scroll-absolute-horizontally (event)
;;;!!   (interactive "@e")
;;;!!   (let* ((pos (car event))
;;;!! 	 (position (car pos))
;;;!! 	 (length (car (cdr pos))))
;;;!!   (set-window-hscroll (selected-window) 33)))
;;;!! 
;;;!! (global-set-key [scroll-bar mouse-1] 'mouse-scroll-up)
;;;!! (global-set-key [scroll-bar mouse-2] 'mouse-scroll-absolute)
;;;!! (global-set-key [scroll-bar mouse-3] 'mouse-scroll-down)
;;;!! 
;;;!! (global-set-key [vertical-slider mouse-1] 'mouse-scroll-move-cursor)
;;;!! (global-set-key [vertical-slider mouse-2] 'mouse-scroll-move-cursor)
;;;!! (global-set-key [vertical-slider mouse-3] 'mouse-scroll-move-cursor)
;;;!! 
;;;!! (global-set-key [thumbup mouse-1] 'mouse-scroll-up-full)
;;;!! (global-set-key [thumbup mouse-2] 'mouse-scroll-up-full)
;;;!! (global-set-key [thumbup mouse-3] 'mouse-scroll-up-full)
;;;!! 
;;;!! (global-set-key [thumbdown mouse-1] 'mouse-scroll-down-full)
;;;!! (global-set-key [thumbdown mouse-2] 'mouse-scroll-down-full)
;;;!! (global-set-key [thumbdown mouse-3] 'mouse-scroll-down-full)
;;;!! 
;;;!! (global-set-key [horizontal-scroll-bar mouse-1] 'mouse-scroll-left)
;;;!! (global-set-key [horizontal-scroll-bar mouse-2]
;;;!! 		'mouse-scroll-absolute-horizontally)
;;;!! (global-set-key [horizontal-scroll-bar mouse-3] 'mouse-scroll-right)
;;;!! 
;;;!! (global-set-key [horizontal-slider mouse-1]
;;;!! 		'mouse-scroll-move-cursor-horizontally)
;;;!! (global-set-key [horizontal-slider mouse-2]
;;;!! 		'mouse-scroll-move-cursor-horizontally)
;;;!! (global-set-key [horizontal-slider mouse-3]
;;;!! 		'mouse-scroll-move-cursor-horizontally)
;;;!! 
;;;!! (global-set-key [thumbleft mouse-1] 'mouse-scroll-left-full)
;;;!! (global-set-key [thumbleft mouse-2] 'mouse-scroll-left-full)
;;;!! (global-set-key [thumbleft mouse-3] 'mouse-scroll-left-full)
;;;!! 
;;;!! (global-set-key [thumbright mouse-1] 'mouse-scroll-right-full)
;;;!! (global-set-key [thumbright mouse-2] 'mouse-scroll-right-full)
;;;!! (global-set-key [thumbright mouse-3] 'mouse-scroll-right-full)
;;;!! 
;;;!! (global-set-key [horizontal-scroll-bar S-mouse-2]
;;;!! 		'mouse-split-window-horizontally)
;;;!! (global-set-key [mode-line S-mouse-2]
;;;!! 		'mouse-split-window-horizontally)
;;;!! (global-set-key [vertical-scroll-bar S-mouse-2]
;;;!! 		'mouse-split-window)
\f
;;;!! ;;;;
;;;!! ;;;; Here are experimental things being tested.  Mouse events
;;;!! ;;;; are of the form:
;;;!! ;;;;	((x y) window screen-part key-sequence timestamp)
;;;!! ;;
;;;!! ;;;;
;;;!! ;;;; Dynamically track mouse coordinates
;;;!! ;;;;
;;;!! ;;
;;;!! ;;(defun track-mouse (event)
;;;!! ;;  "Track the coordinates, absolute and relative, of the mouse."
;;;!! ;;  (interactive "@e")
;;;!! ;;  (while mouse-grabbed
;;;!! ;;    (let* ((pos (read-mouse-position (selected-screen)))
;;;!! ;;	   (abs-x (car pos))
;;;!! ;;	   (abs-y (cdr pos))
;;;!! ;;	   (relative-coordinate (coordinates-in-window-p
;;;!! ;;				 (list (car pos) (cdr pos))
;;;!! ;;				 (selected-window))))
;;;!! ;;      (if (consp relative-coordinate)
;;;!! ;;	  (message "mouse: [%d %d], (%d %d)" abs-x abs-y
;;;!! ;;		   (car relative-coordinate)
;;;!! ;;		   (car (cdr relative-coordinate)))
;;;!! ;;	(message "mouse: [%d %d]" abs-x abs-y)))))
;;;!! 
;;;!! ;;
;;;!! ;; Dynamically put a box around the line indicated by point
;;;!! ;;
;;;!! ;;
;;;!! ;;(require 'backquote)
;;;!! ;;
;;;!! ;;(defun mouse-select-buffer-line (event)
;;;!! ;;  (interactive "@e")
;;;!! ;;  (let ((relative-coordinate
;;;!! ;;	 (coordinates-in-window-p (car event) (selected-window)))
;;;!! ;;	(abs-y (car (cdr (car event)))))
;;;!! ;;    (if (consp relative-coordinate)
;;;!! ;;	(progn
;;;!! ;;	  (save-excursion
;;;!! ;;	    (move-to-window-line (car (cdr relative-coordinate)))
;;;!! ;;	    (x-draw-rectangle
;;;!! ;;	     (selected-screen)
;;;!! ;;	     abs-y 0
;;;!! ;;	     (save-excursion
;;;!! ;;		 (move-to-window-line (car (cdr relative-coordinate)))
;;;!! ;;		 (end-of-line)
;;;!! ;;		 (push-mark nil t)
;;;!! ;;		 (beginning-of-line)
;;;!! ;;		 (- (region-end) (region-beginning))) 1))
;;;!! ;;	  (sit-for 1)
;;;!! ;;	  (x-erase-rectangle (selected-screen))))))
;;;!! ;;
;;;!! ;;(defvar last-line-drawn nil)
;;;!! ;;(defvar begin-delim "[^ \t]")
;;;!! ;;(defvar end-delim   "[^ \t]")
;;;!! ;;
;;;!! ;;(defun mouse-boxing (event)
;;;!! ;;  (interactive "@e")
;;;!! ;;  (save-excursion
;;;!! ;;    (let ((screen (selected-screen)))
;;;!! ;;      (while (= (x-mouse-events) 0)
;;;!! ;;	(let* ((pos (read-mouse-position screen))
;;;!! ;;	       (abs-x (car pos))
;;;!! ;;	       (abs-y (cdr pos))
;;;!! ;;	       (relative-coordinate
;;;!! ;;		(coordinates-in-window-p (` ((, abs-x) (, abs-y)))
;;;!! ;;					 (selected-window)))
;;;!! ;;	       (begin-reg nil)
;;;!! ;;	       (end-reg nil)
;;;!! ;;	       (end-column nil)
;;;!! ;;	       (begin-column nil))
;;;!! ;;	  (if (and (consp relative-coordinate)
;;;!! ;;		   (or (not last-line-drawn)
;;;!! ;;		       (not (= last-line-drawn abs-y))))
;;;!! ;;	      (progn
;;;!! ;;		(move-to-window-line (car (cdr relative-coordinate)))
;;;!! ;;		(if (= (following-char) 10)
;;;!! ;;		    ()
;;;!! ;;		  (progn
;;;!! ;;		    (setq begin-reg (1- (re-search-forward end-delim)))
;;;!! ;;		    (setq begin-column (1- (current-column)))
;;;!! ;;		    (end-of-line)
;;;!! ;;		    (setq end-reg (1+ (re-search-backward begin-delim)))
;;;!! ;;		    (setq end-column (1+ (current-column)))
;;;!! ;;		    (message "%s" (buffer-substring begin-reg end-reg))
;;;!! ;;		    (x-draw-rectangle screen
;;;!! ;;				      (setq last-line-drawn abs-y)
;;;!! ;;				      begin-column
;;;!! ;;				      (- end-column begin-column) 1))))))))))
;;;!! ;;
;;;!! ;;(defun mouse-erase-box ()
;;;!! ;;  (interactive)
;;;!! ;;  (if last-line-drawn
;;;!! ;;      (progn
;;;!! ;;	(x-erase-rectangle (selected-screen))
;;;!! ;;	(setq last-line-drawn nil))))
;;;!! 
;;;!! ;;; (defun test-x-rectangle ()
;;;!! ;;;   (use-local-mouse-map (setq rectangle-test-map (make-sparse-keymap)))
;;;!! ;;;   (define-key rectangle-test-map mouse-motion-button-left 'mouse-boxing)
;;;!! ;;;   (define-key rectangle-test-map mouse-button-left-up 'mouse-erase-box))
;;;!! 
;;;!! ;;
;;;!! ;; Here is how to do double clicking in lisp.  About to change.
;;;!! ;;
;;;!! 
;;;!! (defvar double-start nil)
;;;!! (defconst double-click-interval 300
;;;!!   "Max ticks between clicks")
;;;!! 
;;;!! (defun double-down (event)
;;;!!   (interactive "@e")
;;;!!   (if double-start
;;;!!       (let ((interval (- (nth 4 event) double-start)))
;;;!! 	(if (< interval double-click-interval)
;;;!! 	    (progn
;;;!! 	      (backward-up-list 1)
;;;!! 	      ;;      (message "Interval %d" interval)
;;;!! 	      (sleep-for 1)))
;;;!! 	(setq double-start nil))
;;;!!     (setq double-start (nth 4 event))))
;;;!!     
;;;!! (defun double-up (event)
;;;!!   (interactive "@e")
;;;!!   (and double-start
;;;!!        (> (- (nth 4 event ) double-start) double-click-interval)
;;;!!        (setq double-start nil)))
;;;!! 
;;;!! ;;; (defun x-test-doubleclick ()
;;;!! ;;;   (use-local-mouse-map (setq doubleclick-test-map (make-sparse-keymap)))
;;;!! ;;;   (define-key doubleclick-test-map mouse-button-left 'double-down)
;;;!! ;;;   (define-key doubleclick-test-map mouse-button-left-up 'double-up))
;;;!! 
;;;!! ;;
;;;!! ;; This scrolls while button is depressed.  Use preferable in scroll bar.
;;;!! ;;
;;;!! 
;;;!! (defvar scrolled-lines 0)
;;;!! (defconst scroll-speed 1)
;;;!! 
;;;!! (defun incr-scroll-down (event)
;;;!!   (interactive "@e")
;;;!!   (setq scrolled-lines 0)
;;;!!   (incremental-scroll scroll-speed))
;;;!! 
;;;!! (defun incr-scroll-up (event)
;;;!!   (interactive "@e")
;;;!!   (setq scrolled-lines 0)
;;;!!   (incremental-scroll (- scroll-speed)))
;;;!! 
;;;!! (defun incremental-scroll (n)
;;;!!   (while (= (x-mouse-events) 0)
;;;!!     (setq scrolled-lines (1+ (* scroll-speed scrolled-lines)))
;;;!!     (scroll-down n)
;;;!!     (sit-for 300 t)))
;;;!! 
;;;!! (defun incr-scroll-stop (event)
;;;!!   (interactive "@e")
;;;!!   (message "Scrolled %d lines" scrolled-lines)
;;;!!   (setq scrolled-lines 0)
;;;!!   (sleep-for 1))
;;;!! 
;;;!! ;;; (defun x-testing-scroll ()
;;;!! ;;;   (let ((scrolling-map (function mouse-vertical-scroll-bar-prefix)))
;;;!! ;;;     (define-key scrolling-map mouse-button-left 'incr-scroll-down)
;;;!! ;;;     (define-key scrolling-map mouse-button-right 'incr-scroll-up)
;;;!! ;;;     (define-key scrolling-map mouse-button-left-up 'incr-scroll-stop)
;;;!! ;;;     (define-key scrolling-map mouse-button-right-up 'incr-scroll-stop)))
;;;!! 
;;;!! ;;
;;;!! ;; Some playthings suitable for picture mode?  They need work.
;;;!! ;;
;;;!! 
;;;!! (defun mouse-kill-rectangle (event)
;;;!!   "Kill the rectangle between point and the mouse cursor."
;;;!!   (interactive "@e")
;;;!!   (let ((point-save (point)))
;;;!!     (save-excursion
;;;!!       (mouse-set-point event)
;;;!!       (push-mark nil t)
;;;!!       (if (> point-save (point))
;;;!! 	  (kill-rectangle (point) point-save)
;;;!! 	(kill-rectangle point-save (point))))))
;;;!! 
;;;!! (defun mouse-open-rectangle (event)
;;;!!   "Kill the rectangle between point and the mouse cursor."
;;;!!   (interactive "@e")
;;;!!   (let ((point-save (point)))
;;;!!     (save-excursion
;;;!!       (mouse-set-point event)
;;;!!       (push-mark nil t)
;;;!!       (if (> point-save (point))
;;;!! 	  (open-rectangle (point) point-save)
;;;!! 	(open-rectangle point-save (point))))))
;;;!! 
;;;!! ;; Must be a better way to do this.
;;;!! 
;;;!! (defun mouse-multiple-insert (n char)
;;;!!   (while (> n 0)
;;;!!     (insert char)
;;;!!     (setq n (1- n))))
;;;!! 
;;;!! ;; What this could do is not finalize until button was released.
;;;!! 
;;;!! (defun mouse-move-text (event)
;;;!!   "Move text from point to cursor position, inserting spaces."
;;;!!   (interactive "@e")
;;;!!   (let* ((relative-coordinate
;;;!! 	  (coordinates-in-window-p (car event) (selected-window))))
;;;!!     (if (consp relative-coordinate)
;;;!! 	(cond ((> (current-column) (car relative-coordinate))
;;;!! 	       (delete-char
;;;!! 		(- (car relative-coordinate) (current-column))))
;;;!! 	      ((< (current-column) (car relative-coordinate))
;;;!! 	       (mouse-multiple-insert
;;;!! 		(- (car relative-coordinate) (current-column)) " "))
;;;!! 	      ((= (current-column) (car relative-coordinate)) (ding))))))
\f
;; Choose a completion with the mouse.

(defun mouse-choose-completion (event)
  "Click on an alternative in the `*Completions*' buffer to choose it."
  (interactive "e")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (let ((buffer (window-buffer))
        choice
	base-size)
    (save-excursion
      (set-buffer (window-buffer (posn-window (event-start event))))
      (if completion-reference-buffer
	  (setq buffer completion-reference-buffer))
      (setq base-size completion-base-size)
      (save-excursion
	(goto-char (posn-point (event-start event)))
	(let (beg end)
	  (if (and (not (eobp)) (get-text-property (point) 'mouse-face))
	      (setq end (point) beg (1+ (point))))
	  (if (null beg)
	      (error "No completion here"))
	  (setq beg (previous-single-property-change beg 'mouse-face))
	  (setq end (or (next-single-property-change end 'mouse-face)
			(point-max)))
	  (setq choice (buffer-substring beg end)))))
    (let ((owindow (selected-window)))
      (select-window (posn-window (event-start event)))
      (if (and (one-window-p t 'selected-frame)
	       (window-dedicated-p (selected-window)))
	  ;; This is a special buffer's frame
	  (iconify-frame (selected-frame))
	(or (window-dedicated-p (selected-window))
	    (bury-buffer)))
      (select-window owindow))
    (choose-completion-string choice buffer base-size)))
\f
;; Font selection.

(defun font-menu-add-default ()
  (let* ((default (cdr (assq 'font (frame-parameters (selected-frame)))))
	 (font-alist x-fixed-font-alist)
	 (elt (or (assoc "Misc" font-alist) (nth 1 font-alist))))
    (if (assoc "Default" elt)
	(delete (assoc "Default" elt) elt))
    (setcdr elt
	    (cons (list "Default"
			(cdr (assq 'font (frame-parameters (selected-frame)))))
		  (cdr elt)))))

(defvar x-fixed-font-alist
  '("Font menu"
    ("Misc"
     ;; For these, we specify the pixel height and width.
     ("fixed" "fixed")
     ("6x10" "-misc-fixed-medium-r-normal--10-*-*-*-c-60-iso8859-1" "6x10")
     ("6x12"
      "-misc-fixed-medium-r-semicondensed--12-*-*-*-c-60-iso8859-1" "6x12")
     ("6x13"
      "-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1" "6x13")
     ("7x13" "-misc-fixed-medium-r-normal--13-*-*-*-c-70-iso8859-1" "7x13")
     ("7x14" "-misc-fixed-medium-r-normal--14-*-*-*-c-70-iso8859-1" "7x14")
     ("8x13" "-misc-fixed-medium-r-normal--13-*-*-*-c-80-iso8859-1" "8x13")
     ("9x15" "-misc-fixed-medium-r-normal--15-*-*-*-c-90-iso8859-1" "9x15")
     ("10x20" "-misc-fixed-medium-r-normal--20-*-*-*-c-100-iso8859-1" "10x20")
     ("11x18" "-misc-fixed-medium-r-normal--18-*-*-*-c-110-iso8859-1" "11x18")
     ("12x24" "-misc-fixed-medium-r-normal--24-*-*-*-c-120-iso8859-1" "12x24")
     ("")
     ("clean 5x8"
      "-schumacher-clean-medium-r-normal--8-*-*-*-c-50-iso8859-1")
     ("clean 6x8"
      "-schumacher-clean-medium-r-normal--8-*-*-*-c-60-iso8859-1")
     ("clean 8x8"
      "-schumacher-clean-medium-r-normal--8-*-*-*-c-80-iso8859-1")
     ("clean 8x10"
      "-schumacher-clean-medium-r-normal--10-*-*-*-c-80-iso8859-1")
     ("clean 8x14"
      "-schumacher-clean-medium-r-normal--14-*-*-*-c-80-iso8859-1")
     ("clean 8x16"
      "-schumacher-clean-medium-r-normal--16-*-*-*-c-80-iso8859-1")
     ("")
     ("sony 8x16" "-sony-fixed-medium-r-normal--16-*-*-*-c-80-iso8859-1"))
;;; We don't seem to have these; who knows what they are.
;;;    ("fg-18" "fg-18")
;;;    ("fg-25" "fg-25")
;;;    ("lucidasanstypewriter-12" "lucidasanstypewriter-12")
;;;    ("lucidasanstypewriter-bold-14" "lucidasanstypewriter-bold-14")
;;;    ("lucidasanstypewriter-bold-24" "lucidasanstypewriter-bold-24")
;;;    ("lucidatypewriter-bold-r-24" "-b&h-lucidatypewriter-bold-r-normal-sans-24-240-75-75-m-140-iso8859-1")
;;;    ("fixed-medium-20" "-misc-fixed-medium-*-*-*-20-*-*-*-*-*-*-*")
    ("Courier"
     ;; For these, we specify the point height.
     ("8" "-adobe-courier-medium-r-normal--*-80-*-*-m-*-iso8859-1")
     ("10" "-adobe-courier-medium-r-normal--*-100-*-*-m-*-iso8859-1")
     ("12" "-adobe-courier-medium-r-normal--*-120-*-*-m-*-iso8859-1")
     ("14" "-adobe-courier-medium-r-normal--*-140-*-*-m-*-iso8859-1")
     ("18" "-adobe-courier-medium-r-normal--*-180-*-*-m-*-iso8859-1")
     ("24" "-adobe-courier-medium-r-normal--*-240-*-*-m-*-iso8859-1")
     ("8 bold" "-adobe-courier-bold-r-normal--*-80-*-*-m-*-iso8859-1")
     ("10 bold" "-adobe-courier-bold-r-normal--*-100-*-*-m-*-iso8859-1")
     ("12 bold" "-adobe-courier-bold-r-normal--*-120-*-*-m-*-iso8859-1")
     ("14 bold" "-adobe-courier-bold-r-normal--*-140-*-*-m-*-iso8859-1")
     ("18 bold" "-adobe-courier-bold-r-normal--*-180-*-*-m-*-iso8859-1")
     ("24 bold" "-adobe-courier-bold-r-normal--*-240-*-*-m-*-iso8859-1")
     ("8 slant" "-adobe-courier-medium-o-normal--*-80-*-*-m-*-iso8859-1")
     ("10 slant" "-adobe-courier-medium-o-normal--*-100-*-*-m-*-iso8859-1")
     ("12 slant" "-adobe-courier-medium-o-normal--*-120-*-*-m-*-iso8859-1")
     ("14 slant" "-adobe-courier-medium-o-normal--*-140-*-*-m-*-iso8859-1")
     ("18 slant" "-adobe-courier-medium-o-normal--*-180-*-*-m-*-iso8859-1")
     ("24 slant" "-adobe-courier-medium-o-normal--*-240-*-*-m-*-iso8859-1")
     ("8 bold slant" "-adobe-courier-bold-o-normal--*-80-*-*-m-*-iso8859-1")
     ("10 bold slant" "-adobe-courier-bold-o-normal--*-100-*-*-m-*-iso8859-1")
     ("12 bold slant" "-adobe-courier-bold-o-normal--*-120-*-*-m-*-iso8859-1")
     ("14 bold slant" "-adobe-courier-bold-o-normal--*-140-*-*-m-*-iso8859-1")
     ("18 bold slant" "-adobe-courier-bold-o-normal--*-180-*-*-m-*-iso8859-1")
     ("24 bold slant" "-adobe-courier-bold-o-normal--*-240-*-*-m-*-iso8859-1"))
    )
  "X fonts suitable for use in Emacs.")

(defun mouse-set-font (&rest fonts)
  "Select an emacs font from a list of known good fonts and fontsets."
  (interactive
   (x-popup-menu
    last-nonmenu-event
    ;; Append list of fontsets currently defined.
    (append x-fixed-font-alist (list (generate-fontset-menu)))))
  (if fonts
      (let (font)
	(while fonts
	  (condition-case nil
	      (progn
		(set-default-font (car fonts))
		(setq font (car fonts))
		(setq fonts nil))
	    (error
	     (setq fonts (cdr fonts)))))
	(if (null font)
	    (error "Font not found")))))
\f
;;; Bindings for mouse commands.

(define-key global-map [down-mouse-1] 'mouse-drag-region)
(global-set-key [mouse-1]	'mouse-set-point)
(global-set-key [drag-mouse-1]	'mouse-set-region)

;; These are tested for in mouse-drag-region.
(global-set-key [double-mouse-1] 'mouse-set-point)
(global-set-key [triple-mouse-1] 'mouse-set-point)

(global-set-key [mouse-2]	'mouse-yank-at-click)
(global-set-key [mouse-3]	'mouse-save-then-kill)

;; By binding these to down-going events, we let the user use the up-going
;; event to make the selection, saving a click.
(global-set-key [C-down-mouse-1] 'mouse-buffer-menu)
(if (not (eq system-type 'ms-dos))
    (global-set-key [S-down-mouse-1] 'mouse-set-font))
;; C-down-mouse-2 is bound in facemenu.el.
(global-set-key [C-down-mouse-3] 'mouse-major-mode-menu)


;; Replaced with dragging mouse-1
;; (global-set-key [S-mouse-1]	'mouse-set-mark)

(global-set-key [mode-line mouse-1] 'mouse-select-window)
(global-set-key [mode-line drag-mouse-1] 'mouse-select-window)
(global-set-key [mode-line down-mouse-1] 'mouse-drag-mode-line)
(global-set-key [mode-line mouse-2] 'mouse-delete-other-windows)
(global-set-key [mode-line mouse-3] 'mouse-delete-window)
(global-set-key [mode-line C-mouse-2] 'mouse-split-window-horizontally)
(global-set-key [vertical-scroll-bar C-mouse-2] 'mouse-split-window-vertically)
(global-set-key [vertical-line C-mouse-2] 'mouse-split-window-vertically)
(global-set-key [vertical-line down-mouse-1] 'mouse-drag-vertical-line)
(global-set-key [vertical-line mouse-1] 'mouse-select-window)

(provide 'mouse)

;;; mouse.el ends here