X-Git-Url: http://git.hcoop.net/bpt/emacs.git/blobdiff_plain/99f08df44ecbc2353900264624e40554092e8e45..4837b516ea56c6cc2b3ce823b04078b10b2defc6:/lisp/hilit-chg.el

diff --git a/lisp/hilit-chg.el b/lisp/hilit-chg.el
index 2fad6bfff7..a167b2bc1e 100644
--- a/lisp/hilit-chg.el
+++ b/lisp/hilit-chg.el
@@ -1,27 +1,27 @@
 ;;; hilit-chg.el --- minor mode displaying buffer changes with special face
 
-;; Copyright (C) 1998 Free Software Foundation, Inc.
+;; Copyright (C) 1998, 2000, 2001, 2002, 2003, 2004,
+;;   2005, 2006, 2007 Free Software Foundation, Inc.
 
-;; Author: Richard Sharman <rsharman@magma.ca>
+;; Author: Richard Sharman <rsharman@pobox.com>
 ;; Keywords: faces
 
 ;; This file is part of GNU Emacs.
 
-;; This program is free software; you can redistribute it and/or modify
+;; 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)
+;; the Free Software Foundation; either version 3, or (at your option)
 ;; any later version.
 
-;; This program is distributed in the hope that it will be useful,
+;; 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.
-
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
 
@@ -37,22 +37,22 @@
 ;; Highlight Changes mode in passive state while you make your changes, toggle
 ;; it on to active mode to see them, then toggle it back off to avoid
 ;; distraction.
-;; 
-;; When active, changes are displayed in `highlight-changes-face'.  When
-;; text is deleted,  the following character is displayed in
-;; `highlight-changes-delete-face' face.
+;;
+;; When active, changes are displayed in the `highlight-changes' face.
+;; When text is deleted, the following character is displayed in the
+;; `highlight-changes-delete' face.
 ;;
 ;;
 ;; You can "age" different sets of changes by using
-;; `highlight-changes-rotate-faces'.  This rotates different through a series
+;; `highlight-changes-rotate-faces'.  This rotates through a series
 ;; of different faces, so you can distinguish "new" changes from "older"
 ;; changes.  You can customize these "rotated" faces in two ways.  You can
 ;; either explicitly define each face by customizing
 ;; `highlight-changes-face-list'.  If, however, the faces differ from
-;; `highlight-changes-face' only in the foreground colour, you can simply set
-;; `highlight-changes-colours'.  If `highlight-changes-face-list' is nil when
+;; the `highlight-changes' face only in the foreground color, you can simply set
+;; `highlight-changes-colors'.  If `highlight-changes-face-list' is nil when
 ;; the faces are required they will be constructed from
-;; `highlight-changes-colours'.
+;; `highlight-changes-colors'.
 ;;
 ;;
 ;; When a Highlight Changes mode is on (either active or passive) you can go
@@ -62,7 +62,8 @@
 ;;
 ;; You can also use the command highlight-compare-with-file to show changes
 ;; in this file compared with another file (typically the previous version
-;; of the file).
+;; of the file).  The command highlight-compare-buffers can be used to
+;; compare two buffers.
 ;;
 ;;
 ;; There are currently three hooks run by `highlight-changes-mode':
@@ -76,64 +77,64 @@
 ;;				    modes.  The variable
 ;;				    `highlight-changes-mode' contains the new
 ;;				    state (`active' or `passive'.)
-;;				    
 ;;
-;; 
+;;
+;;
 ;; Example usage:
 ;; (defun my-highlight-changes-enable-hook ()
-;;   (add-hook 'local-write-file-hooks 'highlight-changes-rotate-faces)
+;;   (add-hook 'write-file-functions 'highlight-changes-rotate-faces nil t)
 ;; )
-;; 
+;;
 ;; (defun my-highlight-changes-disable-hook ()
-;;   (remove-hook 'local-write-file-hooks 'highlight-changes-rotate-faces)
+;;   (remove-hook 'write-file-functions 'highlight-changes-rotate-faces t)
 ;; )
-;; 
+;;
 ;; (add-hook 'highlight-changes-enable-hook 'my-highlight-changes-enable-hook)
 ;; (add-hook 'highlight-changes-disable-hook
 ;;		'my-highlight-changes-disable-hook)
 
 
-;;           Explciit vs. Implicit
+;;           Explicit vs. Implicit
 ;;
 
 ;; Normally, Highlight Changes mode is turned on explicitly in a buffer.
 ;;
 ;; If you prefer to have it automatically invoked you can do it as
 ;; follows.
-;; 
+;;
 ;; 1. Most modes have a major-hook, typically called MODE-hook.  You
-;; can use `add-hook' to call `highlight-changes-mode'.  
+;; can use `add-hook' to call `highlight-changes-mode'.
 ;;
 ;;   Example:
 ;;	(add-hook 'c-mode-hook 'highlight-changes-mode)
 ;;
 ;;  If you want to make it start up in passive mode (regardless of the
 ;;  setting of highlight-changes-initial-state):
-;;      (add-hook 'emacs-lisp-mode-hook 
+;;      (add-hook 'emacs-lisp-mode-hook
 ;; 	    (lambda ()
 ;; 	      (highlight-changes-mode 'passive)))
 ;;
 ;; However, this cannot be done for Fundamental mode for there is no
 ;; such hook.
 ;;
-;; 2. You can use the function `global-highlight-changes' 
+;; 2. You can use the function `global-highlight-changes'
 ;;
 ;; This function, which is fashioned after the way `global-font-lock' works,
 ;; toggles on or off global Highlight Changes mode.  When activated, it turns
-;; on Highlight Changes mode in all "suitable" existings buffers and will turn
+;; on Highlight Changes mode in all "suitable" existing buffers and will turn
 ;; it on in new "suitable" buffers to be created.
-;; 
+;;
 ;; A buffer's "suitability" is determined by variable
-;; `highlight-changes-global-modes',  as follows.  If the variable is
+;; `highlight-changes-global-modes', as follows.  If the variable is
 ;; * nil  -- then no buffers are suitable;
 ;; * a function -- this function is called and the result is used.  As
-;;   an example,  if the value is 'buffer-file-name then all buffers
+;;   an example, if the value is `buffer-file-name' then all buffers
 ;;   who are visiting files are suitable, but others (like dired
 ;;   buffers) are not;
-;; * a list -- then if the buufer is suitable iff its mode is in the
-;;   list,  exccept if the first element is nil in which case the test
+;; * a list -- then the buffer is suitable if its mode is in the
+;;   list, except if the first element is `not', in which case the test
 ;;   is reversed (i.e. it is a list of unsuitable modes).
-;; * Otherwise,  the buffer is suitable if its name does not begin with
+;; * Otherwise, the buffer is suitable if its name does not begin with
 ;;   ` ' or `*' and if `buffer-file-name' returns true.
 ;;
 
@@ -148,8 +149,9 @@
 ;; highlight-changes-remove-highlight
 ;; highlight-changes-rotate-faces
 ;; highlight-compare-with-file
+;; highlight-compare-buffers
 
-;; 
+;;
 ;; You can automatically rotate faces when the buffer is saved;
 ;; see function `highlight-changes-rotate-faces' for how to do this.
 ;;
@@ -158,11 +160,11 @@
 ;;; Bugs:
 
 ;; - the next-change and previous-change functions are too literal;
-;;   they should find the next "real" change,  in other words treat
+;;   they should find the next "real" change, in other words treat
 ;;   consecutive changes as one.
 
 
-;;; To do (maybe),  notes, ...
+;;; To do (maybe), notes, ...
 
 ;; - having different faces for deletion and non-deletion: is it
 ;;   really worth the hassle?
@@ -175,10 +177,10 @@
 
 ;;; History:
 
-;; R Sharman (rsharman@magma.ca) Feb 1998:
+;; R Sharman (rsharman@pobox.com) Feb 1998:
 ;; - initial release as change-mode.
 ;; Jari Aalto <jari.aalto@ntc.nokia.com> Mar 1998
-;; - fixes for byte compile errors 
+;; - fixes for byte compile errors
 ;; - use eval-and-compile for autoload
 ;; Marijn Ros <J.M.Ros@fys.ruu.nl> Mar 98
 ;; - suggested turning it on by default
@@ -187,8 +189,10 @@
 ;; - global mode and various stuff added
 ;; - Changed to use overlays
 ;; August 98
-;; - renmaed to Highlight Changes mode.
-
+;; - renamed to Highlight Changes mode.
+;; Dec 2003
+;; - Use require for ediff stuff
+;; - Added highlight-compare-buffers
 
 ;;; Code:
 
@@ -197,6 +201,7 @@
 ;; ====================== Customization =======================
 (defgroup highlight-changes nil
   "Highlight Changes mode."
+  :version "20.4"
   :group 'faces)
 
 
@@ -204,108 +209,111 @@
 
 ;; Defaults for face: red foreground, no change to background,
 ;; and underlined if a change is because of a deletion.
-;; Note: underlining is helpful in that is shows up changes in white space.
+;; Note: underlining is helpful in that it shows up changes in white space.
 ;; However, having it set for non-delete changes can be annoying because all
 ;; indentation on inserts gets underlined (which can look pretty ugly!).
 
-(defface highlight-changes-face
-  '((((class color)) (:foreground "red" ))
+(defface highlight-changes
+  '((((min-colors 88) (class color)) (:foreground "red1"))
+    (((class color)) (:foreground "red" ))
     (t (:inverse-video t)))
   "Face used for highlighting changes."
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
+;; backward-compatibility alias
+(put 'highlight-changes-face 'face-alias 'highlight-changes)
 
 ;; This looks pretty ugly, actually.  Maybe the underline should be removed.
-(defface highlight-changes-delete-face
-  '((((class color)) (:foreground "red" :underline t))
+(defface highlight-changes-delete
+  '((((min-colors 88) (class color)) (:foreground "red1" :underline t))
+    (((class color)) (:foreground "red" :underline t))
     (t (:inverse-video t)))
   "Face used for highlighting deletions."
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
+;; backward-compatibility alias
+(put 'highlight-changes-delete-face 'face-alias 'highlight-changes-delete)
 
 
 
-;; A (not very good) default list of colours to rotate through.
+;; A (not very good) default list of colors to rotate through.
 ;;
-(defcustom highlight-changes-colours 
+(defcustom highlight-changes-colors
   (if (eq (frame-parameter nil 'background-mode) 'light)
       ;; defaults for light background:
       '( "magenta" "blue" "darkgreen" "chocolate" "sienna4" "NavyBlue")
       ;; defaults for dark background:
     '("yellow" "magenta" "blue" "maroon" "firebrick" "green4" "DarkOrchid"))
-  "*Colours used by `highlight-changes-rotate-faces'.
-The newest rotated change will be displayed in the first element of this list, 
+  "*Colors used by `highlight-changes-rotate-faces'.
+The newest rotated change will be displayed in the first element of this list,
 the next older will be in the second element etc.
 
-This list is used if `highlight-changes-face-list' is nil,  otherwise that
-variable overrides this list.   If you only care about foreground
-colours then use this,  if you want fancier faces then set
+This list is used if `highlight-changes-face-list' is nil, otherwise that
+variable overrides this list.  If you only care about foreground
+colors then use this, if you want fancier faces then set
 `highlight-changes-face-list'."
-   :type '(repeat color)
-  :group 'highlight-changes
-  )
- 
+  :type '(repeat color)
+  :group 'highlight-changes)
+
+(define-obsolete-variable-alias 'highlight-changes-colours
+                                'highlight-changes-colors "22.1")
+
 
-;; If you invoke highlight-changes-mode with no argument,  should it start in
+;; If you invoke highlight-changes-mode with no argument, should it start in
 ;; active or passive mode?
 ;;
 (defcustom highlight-changes-initial-state 'active
-  "*What state (active or passive) `highlight-changes' should start in.
-This is used when `highlight-changes' is called with no argument.
+  "*What state (active or passive) Highlight Changes mode should start in.
+This is used when `highlight-changes-mode' is called with no argument.
 This variable must be set to one of the symbols `active' or `passive'."
   :type '(choice (const :tag "Active" active)
 		 (const :tag "Passive" passive))
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
 
 (defcustom highlight-changes-global-initial-state 'passive
-  "*What state `global-highlight-changes' should start in.
+  "*What state global Highlight Changes mode should start in.
 This is used if `global-highlight-changes' is called with no argument.
-This variable must be set to either `active' or `passive'"
+This variable must be set to either `active' or `passive'."
   :type '(choice (const :tag "Active" active)
 		 (const :tag "Passive" passive))
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
 
 ;; The strings displayed in the mode-line for the minor mode:
-(defcustom highlight-changes-active-string nil
+(defcustom highlight-changes-active-string " +Chg"
   "*The string used when Highlight Changes mode is in the active state.
-This should be set to nil if no indication is desired,  or to
+This should be set to nil if no indication is desired, or to
 a string with a leading space."
   :type '(choice string
 		 (const :tag "None"  nil))
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
 
-(defcustom highlight-changes-passive-string " Chg"
+(defcustom highlight-changes-passive-string " -Chg"
   "*The string used when Highlight Changes mode is in the passive state.
-This should be set to nil if no indication is desired,  or to
+This should be set to nil if no indication is desired, or to
 a string with a leading space."
   :type '(choice string
 		 (const :tag "None"  nil))
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
 
 (defcustom highlight-changes-global-modes t
   "*Determine whether a buffer is suitable for global Highlight Changes mode.
 
-A function means that function is called:  if it returns non-nil the
-buffer is suitable.
+A function means call that function to decide: if it returns non-nil,
+the buffer is suitable.
 
-A list is a list of modes for which it is suitable,  or a list whose
-first element is 'not followed by modes which are not suitable.
+A list means the elements are major modes suitable for Highlight
+Changes mode, or a list whose first element is `not' followed by major
+modes which are not suitable.
 
-t means the buffer is suitable if its name does not begin with ` ' nor
-`*' and the buffer has a filename.
+A value of t means the buffer is suitable if it is visiting a file and
+its name does not begin with ` ' or `*'.
 
-nil means no buffers are suitable for `global-highlight-changes'
-(effectively disabling the mode).
+A value of nil means no buffers are suitable for `global-highlight-changes'
+\(effectively disabling the mode).
 
-Examples:
+Example:
         (c-mode c++-mode)
 means that Highlight Changes mode is turned on for buffers in C and C++
 modes only."
-  :type '(choice 
+  :type '(choice
 	  (const :tag "all non-special buffers visiting files" t)
 	  (set :menu-tag "specific modes" :tag "modes"
 	       :value (not)
@@ -315,26 +323,24 @@ modes only."
 			   :value buffer-file-name)
 	  (const :tag "none" nil)
 	  )
-  :group 'highlight-changes
-  )
-
+  :group 'highlight-changes)
 
 (defvar global-highlight-changes nil)
 
 (defcustom highlight-changes-global-changes-existing-buffers nil
-  "*If non-nil toggling global Highlight Changes mode affects existing buffers.
-Normally, `global-highlight-changes' means affects only new buffers (to be
-created).  However, if highlight-changes-global-changes-existing-buffers
-is non-nil then turning on `global-highlight-changes' will turn on
-highlight-changes-mode in suitable buffers and turning the mode off will
+  "*If non-nil, toggling global Highlight Changes mode affects existing buffers.
+Normally, `global-highlight-changes' affects only new buffers (to be
+created).  However, if `highlight-changes-global-changes-existing-buffers'
+is non-nil, then turning on `global-highlight-changes' will turn on
+Highlight Changes mode in suitable buffers, and turning the mode off will
 remove it from existing buffers."
   :type 'boolean
   :group 'highlight-changes)
 
 (defun hilit-chg-cust-fix-changes-face-list (w wc &optional event)
   ;; When customization function `highlight-changes-face-list' inserts a new
-  ;; face it uses the default face.   We don't want the user to modify this
-  ;; face,  so we rename the faces in the list on an insert.  The rename is
+  ;; face it uses the default face.  We don't want the user to modify this
+  ;; face, so we rename the faces in the list on an insert.  The rename is
   ;; actually done by copying the faces so user-defined faces still remain
   ;; in the same order.
   ;; The notifying the parent is needed because without it changes to the
@@ -349,18 +355,18 @@ remove it from existing buffers."
 	     )
 	  (while p
 	    (setq old-name (car p))
-	    (setq new-name (intern (format "highlight-changes-face-%d" n)))
+	    (setq new-name (intern (format "highlight-changes-%d" n)))
 	    (if (eq old-name new-name)
 		nil
 	      ;; A new face has been inserted: we don't want to modify the
-	      ;; default face so copy it.   Better, though, (I think) is to
+	      ;; default face so copy it.  Better, though, (I think) is to
 	      ;; make a new face have the same attributes as
-	      ;; highlight-changes-face .
+	      ;; the `highlight-changes' face.
 	      (if (eq old-name 'default)
-		  (copy-face 'highlight-changes-face  new-name)
+		  (copy-face 'highlight-changes new-name)
 		(copy-face old-name new-name)
 		))
-	    (setq new-list (append  (list new-name) new-list))
+	    (setq new-list (append (list new-name) new-list))
 	    (setq n (1- n))
 	    (setq p (cdr p)))
 	  (if (equal new-list (widget-value w))
@@ -373,26 +379,24 @@ remove it from existing buffers."
       ))
   (let ((parent (widget-get w :parent)))
     (when parent
-      (widget-apply parent :notify w event)))
-    )
+      (widget-apply parent :notify w event))))
 
 
 (defcustom highlight-changes-face-list nil
-  "*A list of faces used when rotatating changes.
+  "*A list of faces used when rotating changes.
 Normally the variable is initialized to nil and the list is created from
-`highlight-changes-colours' when needed.  However, you can set this variable
+`highlight-changes-colors' when needed.  However, you can set this variable
 to any list of faces.  You will have to do this if you want faces which
-don't just differ from `highlight-changes-face' by the foreground colour.
+don't just differ from the `highlight-changes' face by the foreground color.
 Otherwise, this list will be constructed when needed from
-`highlight-changes-colours'."
+`highlight-changes-colors'."
   :type '(choice
-	  (repeat 
+	  (repeat
 	    :notify hilit-chg-cust-fix-changes-face-list
 	    face  )
-	  (const :tag "Derive from highlight-changes-colours"  nil)
+	  (const :tag "Derive from highlight-changes-colors"  nil)
 	  )
-  :group 'highlight-changes
-  )
+  :group 'highlight-changes)
 
 ;; ========================================================================
 
@@ -409,23 +413,13 @@ Otherwise, this list will be constructed when needed from
 (make-variable-buffer-local 'hilit-chg-string)
 
 
-
-(eval-and-compile
-  ;;  For highlight-compare-with-file
-  (defvar ediff-number-of-differences)
-  (autoload 'ediff-setup		"ediff")
-  (autoload 'ediff-with-current-buffer	"ediff")
-  (autoload 'ediff-really-quit		"ediff")
-  (autoload 'ediff-make-fine-diffs	"ediff")
-  (autoload 'ediff-get-fine-diff-vector "ediff")
-  (autoload 'ediff-get-difference	"ediff")
-  )
-
+(require 'ediff-init)
+(require 'ediff-util)
 
 
 ;;; Functions...
 
-(defun hilit-chg-map-changes  (func &optional start-position end-position)
+(defun hilit-chg-map-changes (func &optional start-position end-position)
   "Call function FUNC for each region used by Highlight Changes mode."
   ;; if start-position is nil, (point-min) is used
   ;; if end-position is nil, (point-max) is used
@@ -438,33 +432,32 @@ Otherwise, this list will be constructed when needed from
       (setq end (text-property-not-all start limit 'hilit-chg prop))
       (if prop
 	  (funcall func prop start (or end limit)))
-      (setq start end)
-      )))
+      (setq start end))))
 
 
 (defun hilit-chg-display-changes (&optional beg end)
   "Display face information for Highlight Changes mode.
 
-An overlay containing a change face is added,  from the information
-in the text property of type change.
+An overlay containing a change face is added from the information
+in the text property of type `hilit-chg'.
 
-This is the opposite of hilit-chg-hide-changes."
+This is the opposite of `hilit-chg-hide-changes'."
   (hilit-chg-map-changes 'hilit-chg-make-ov beg end))
 
 
 (defun hilit-chg-make-ov (prop start end)
+  (or prop
+      (error "hilit-chg-make-ov: prop is nil"))
   ;; for the region make change overlays corresponding to
   ;; the text property 'hilit-chg
   (let ((ov (make-overlay start end))
 	face)
-    (or prop
-	(error "hilit-chg-make-ov: prop is nil"))
     (if (eq prop 'hilit-chg-delete)
-	(setq face 'highlight-changes-delete-face)
+	(setq face 'highlight-changes-delete)
       (setq face (nth 1 (member prop hilit-chg-list))))
     (if face
 	(progn
-	  ;; We must mark the face,  that is the purpose of the overlay
+	  ;; We must mark the face, that is the purpose of the overlay
 	  (overlay-put ov 'face face)
 	  ;; I don't think we need to set evaporate since we should
 	  ;; be controlling them!
@@ -473,17 +466,15 @@ This is the opposite of hilit-chg-hide-changes."
 	  ;; of our overlays (so we don't delete someone else's).
 	  (overlay-put ov 'hilit-chg t)
 	  )
-      (error "hilit-chg-make-ov: no face for prop: %s" prop)
-      )
-    ))
+      (error "hilit-chg-make-ov: no face for prop: %s" prop))))
 
 (defun hilit-chg-hide-changes (&optional beg end)
   "Remove face information for Highlight Changes mode.
 
-The overlay containing the face is removed,  but the text property
+The overlay containing the face is removed, but the text property
 containing the change information is retained.
 
-This is the opposite of hilit-chg-display-changes."
+This is the opposite of `hilit-chg-display-changes'."
   (let ((start (or beg (point-min)))
 	(limit (or end (point-max)))
 	p ov)
@@ -492,62 +483,49 @@ This is the opposite of hilit-chg-display-changes."
       ;; don't delete the overlay if it isn't ours!
       (if (overlay-get (car p) 'hilit-chg)
 	  (delete-overlay (car p)))
-      (setq p (cdr p))
-      )))
+      (setq p (cdr p)))))
 
 (defun hilit-chg-fixup (beg end)
-  "Fix change overlays in region beg .. end.
+  "Fix change overlays in region between BEG and END.
 
 Ensure the overlays agree with the changes as determined from
-the text properties of type `hilit-chg' ."
+the text properties of type `hilit-chg'."
   ;; Remove or alter overlays in region beg..end
-  (let (p ov ov-start ov-end
-	 props q)
-    (setq p (overlays-in beg end))
+  (let (ov-start ov-end	 props q)
     ;; temp for debugging:
     ;; (or (eq highlight-changes-mode 'active)
     ;;	 (error "hilit-chg-fixup called but Highlight Changes mode not active"))
-    (while p
-      (setq ov (car p))
-      (setq ov-start (overlay-start ov))
-      (setq ov-end (overlay-end ov))
-      (if (< ov-start beg)
-	  (progn
-	    (move-overlay ov ov-start beg)
+    (dolist (ov (overlays-in beg end))
+      ;; Don't alter overlays that are not ours.
+      (when (overlay-get ov 'hilit-chg)
+	(let ((ov-start (overlay-start ov))
+	      (ov-end (overlay-end ov)))
+	  (if (< ov-start beg)
+	      (progn
+		(move-overlay ov ov-start beg)
+		(if (> ov-end end)
+		    (progn
+		      (setq props (overlay-properties ov))
+		      (setq ov (make-overlay end ov-end))
+		      (while props
+			(overlay-put ov (car props)(car (cdr props)))
+			(setq props (cdr (cdr props)))))))
 	    (if (> ov-end end)
-		(progn
-		  (setq props (overlay-properties ov))
-		  (setq ov (make-overlay end ov-end))
-		  (while props
-		    (overlay-put ov (car props)(car (cdr props)))
-		    (setq props (cdr (cdr props))))
-		  )
-	      )
-	    )
-	(if (> ov-end end)
-	    (move-overlay ov end ov-end)
-	  (delete-overlay ov)
-	  ))
-      (setq p (cdr p)))
-    (hilit-chg-display-changes beg end)
-    ))
-
-
-
-
-
+		(move-overlay ov end ov-end)
+	      (delete-overlay ov))))))
+    (hilit-chg-display-changes beg end)))
 
 ;;;###autoload
-(defun highlight-changes-remove-highlight (beg end) 
-  "Remove the change face from the region.  
+(defun highlight-changes-remove-highlight (beg end)
+  "Remove the change face from the region between BEG and END.
 This allows you to manually remove highlighting from uninteresting changes."
   (interactive "r")
   (let ((after-change-functions nil))
-    (remove-text-properties beg end  '(hilit-chg nil))
+    (remove-text-properties beg end '(hilit-chg nil))
     (hilit-chg-fixup beg end)))
 
-(defun hilit-chg-set-face-on-change (beg end leng-before 
-	&optional no-proerty-change)
+(defun hilit-chg-set-face-on-change (beg end leng-before
+					 &optional no-property-change)
   "Record changes and optionally display them in a distinctive face.
 `hilit-chg-set' adds this function to the `after-change-functions' hook."
   ;;
@@ -557,7 +535,7 @@ This allows you to manually remove highlighting from uninteresting changes."
   ;;
   ;; We do NOT want to simply do this if this is an undo command, because
   ;; otherwise an undone change shows up as changed.  While the properties
-  ;; are automatically restored by undo,  we must fixup the overlay.
+  ;; are automatically restored by undo, we must fix up the overlay.
   (save-match-data
     (let ((beg-decr 1) (end-incr 1)
 	  (type 'hilit-chg)
@@ -569,9 +547,9 @@ This allows you to manually remove highlighting from uninteresting changes."
 	    ;; deletion
 	    (progn
 	      ;; The eolp and bolp tests are a kludge!  But they prevent
-	      ;; rather nasty looking displays when deleting text at the end 
-	      ;; of line,  such as normal corrections as one is typing and
-	      ;; immediately makes a corrections,  and when deleting first
+	      ;; rather nasty looking displays when deleting text at the end
+	      ;; of line, such as normal corrections as one is typing and
+	      ;; immediately makes a correction, and when deleting first
 	      ;; character of a line.
 ;;;	      (if (= leng-before 1)
 ;;;		  (if (eolp)
@@ -582,10 +560,10 @@ This allows you to manually remove highlighting from uninteresting changes."
 	      (setq end (min (+ end end-incr) (point-max)))
 	      (setq type 'hilit-chg-delete))
 	  ;; Not a deletion.
-	  ;; Most of the time the following is not necessary,  but
+	  ;; Most of the time the following is not necessary, but
 	  ;; if the current text was marked as a deletion then
 	  ;; the old overlay is still in effect, so if we add some
-	  ;; text then remove the deletion marking,  but set it to
+	  ;; text then remove the deletion marking, but set it to
 	  ;; changed otherwise its highlighting disappears.
 	  (if (eq (get-text-property end 'hilit-chg) 'hilit-chg-delete)
 	      (progn
@@ -593,15 +571,10 @@ This allows you to manually remove highlighting from uninteresting changes."
 		(put-text-property end (+ end 1) 'hilit-chg 'hilit-chg)
 		(if (eq highlight-changes-mode 'active)
 		    (hilit-chg-fixup beg (+ end 1))))))
-	(unless no-proerty-change
+	(unless no-property-change
 		(put-text-property beg end 'hilit-chg type))
-	(if (or (eq highlight-changes-mode 'active) no-proerty-change)
-	    (hilit-chg-make-ov type beg end))
-	))))
-
-
-
-
+	(if (or (eq highlight-changes-mode 'active) no-property-change)
+	    (hilit-chg-make-ov type beg end))))))
 
 (defun hilit-chg-set (value)
   "Turn on Highlight Changes mode for this buffer."
@@ -616,12 +589,9 @@ This allows you to manually remove highlighting from uninteresting changes."
     ;; mode is passive
     (setq hilit-chg-string highlight-changes-passive-string)
     (or buffer-read-only
-	(hilit-chg-hide-changes))
-    )
+	(hilit-chg-hide-changes)))
   (force-mode-line-update)
-  (make-local-hook 'after-change-functions)
-  (add-hook 'after-change-functions 'hilit-chg-set-face-on-change nil t)
-  )
+  (add-hook 'after-change-functions 'hilit-chg-set-face-on-change nil t))
 
 (defun hilit-chg-clear ()
   "Remove Highlight Changes mode for this buffer.
@@ -634,54 +604,53 @@ This removes all saved change information."
     (remove-hook 'after-change-functions 'hilit-chg-set-face-on-change t)
     (let ((after-change-functions nil))
       (hilit-chg-hide-changes)
-      (hilit-chg-map-changes 
+      (hilit-chg-map-changes
        '(lambda (prop start stop)
 	  (remove-text-properties start stop '(hilit-chg nil))))
       )
     (setq highlight-changes-mode nil)
     (force-mode-line-update)
     ;; If we type:  C-u -1 M-x highlight-changes-mode
-    ;; we want to turn it off,  but hilit-chg-post-command-hook
+    ;; we want to turn it off, but hilit-chg-post-command-hook
     ;; runs and that turns it back on!
-    (remove-hook 'post-command-hook 'hilit-chg-post-command-hook)
-    ))
+    (remove-hook 'post-command-hook 'hilit-chg-post-command-hook)))
 
 ;;;###autoload
 (defun highlight-changes-mode (&optional arg)
   "Toggle (or initially set) Highlight Changes mode.
 
-Without an argument,  
-  if Highlight Changes mode is not enabled, then enable it (to either active
-  or passive as determined by variable highlight-changes-initial-state);
-  otherwise, toggle between active and passive states.
+Without an argument:
+  If Highlight Changes mode is not enabled, then enable it (in either active
+  or passive state as determined by the variable
+  `highlight-changes-initial-state'); otherwise, toggle between active
+  and passive state.
 
-With an argument,
-  if just C-u  or  a positive argument,  set state to active;
-  with a zero argument,  set state to passive;
-  with a negative argument,  disable Highlight Changes mode completely.
+With an argument ARG:
+  If ARG is positive, set state to active;
+  If ARG is zero, set state to passive;
+  If ARG is negative, disable Highlight Changes mode completely.
 
-Active state -  means changes are shown in a distinctive face.
+Active state  - means changes are shown in a distinctive face.
 Passive state - means changes are kept and new ones recorded but are
 		not displayed in a different face.
 
 Functions:
 \\[highlight-changes-next-change] - move point to beginning of next change
-\\[highlight-changes-previous-change] - move to beginning of previous change 
+\\[highlight-changes-previous-change] - move to beginning of previous change
 \\[highlight-compare-with-file] - mark text as changed by comparing this
 	buffer with the contents of a file
 \\[highlight-changes-remove-highlight] - remove the change face from the region
 \\[highlight-changes-rotate-faces] - rotate different \"ages\" of changes \
-through 
-	various faces.
-
+through
+	various faces
 
 Hook variables:
-highlight-changes-enable-hook - when Highlight Changes mode enabled.
-highlight-changes-toggle-hook - when entering active or passive state
-highlight-changes-disable-hook - when turning off Highlight Changes mode.
-"
+`highlight-changes-enable-hook'  - when enabling Highlight Changes mode
+`highlight-changes-toggle-hook'  - when entering active or passive state
+`highlight-changes-disable-hook' - when turning off Highlight Changes mode"
   (interactive "P")
-  (if window-system
+  (if (or (display-color-p)
+	  (and (fboundp 'x-display-grayscale-p) (x-display-grayscale-p)))
       (let ((was-on highlight-changes-mode)
 	    (new-highlight-changes-mode
 	     (cond
@@ -693,15 +662,14 @@ highlight-changes-disable-hook - when turning off Highlight Changes mode.
 	      ;; an argument is given
 	      ((eq arg 'active)
 	       'active)
-	      ((eq arg  'passive)
+	      ((eq arg 'passive)
 	       'passive)
 	      ((> (prefix-numeric-value arg) 0)
 	       'active)
 	      ((< (prefix-numeric-value arg) 0)
 	       nil)
 	      (t
-	       'passive)
-	      )))
+	       'passive))))
 	(if new-highlight-changes-mode
 	    ;; mode is turned on -- but may be passive
 	    (progn
@@ -712,12 +680,8 @@ highlight-changes-disable-hook - when turning off Highlight Changes mode.
 	      (run-hooks 'highlight-changes-toggle-hook))
 	  ;; mode is turned off
 	  (run-hooks 'highlight-changes-disable-hook)
-	  (hilit-chg-clear))
-	)
-    (message "Highlight Changes mode only works when using a window system"))
-  )
-
-
+	  (hilit-chg-clear)))
+    (message "Highlight Changes mode requires color or grayscale display")))
 
 ;;;###autoload
 (defun highlight-changes-next-change ()
@@ -761,36 +725,34 @@ highlight-changes-disable-hook - when turning off Highlight Changes mode.
 	  (message "no previous change")))
     (message "This buffer is not in Highlight Changes mode.")))
 
-
 ;; ========================================================================
 
-
 (defun hilit-chg-make-list (&optional force)
-  "Construct hilit-chg-list and highlight-changes-face-list."
-  ;; Constructs highlight-changes-face-list if necessary,  
+  "Construct `hilit-chg-list' and `highlight-changes-face-list'."
+  ;; Constructs highlight-changes-face-list if necessary,
   ;; and hilit-chg-list always:
   ;; Maybe this should always be called when rotating a face
   ;; so we pick up any changes?
   (if (or (null highlight-changes-face-list)  ; Don't do it if it
 	  force) ; already exists unless FORCE non-nil.
-      (let ((p highlight-changes-colours) 
+      (let ((p highlight-changes-colors)
 	    (n 1) name)
 	(setq highlight-changes-face-list nil)
 	(while p
-	  (setq name (intern (format "highlight-changes-face-%d" n)))
-	  (copy-face 'highlight-changes-face name)
+	  (setq name (intern (format "highlight-changes-%d" n)))
+	  (copy-face 'highlight-changes name)
 	  (set-face-foreground name (car p))
-	  (setq highlight-changes-face-list 
+	  (setq highlight-changes-face-list
 		(append highlight-changes-face-list (list name)))
 	  (setq p (cdr p))
 	  (setq n (1+ n)))))
-  (setq hilit-chg-list (list 'hilit-chg 'highlight-changes-face))
+  (setq hilit-chg-list (list 'hilit-chg 'highlight-changes))
   (let ((p highlight-changes-face-list)
-	(n 1) 
+	(n 1)
 	last-category last-face)
     (while p
       (setq last-category (intern (format "change-%d" n)))
-      ;; (setq last-face (intern (format "highlight-changes-face-%d" n)))
+      ;; (setq last-face (intern (format "highlight-changes-%d" n)))
       (setq last-face (car p))
       (setq hilit-chg-list
 	    (append hilit-chg-list
@@ -799,77 +761,181 @@ highlight-changes-disable-hook - when turning off Highlight Changes mode.
       (setq n (1+ n)))
     (setq hilit-chg-list
 	  (append hilit-chg-list
-		  (list last-category last-face)))
-    ))
-
+		  (list last-category last-face)))))
 
 (defun hilit-chg-bump-change (prop start end)
-  "Increment (age) the Highlight Changes mode text property of type change."
+  "Increment (age) the Highlight Changes mode text property."
   (let ( new-prop )
     (if (eq prop 'hilit-chg-delete)
 	(setq new-prop (nth 2 hilit-chg-list))
-      (setq new-prop (nth 2 (member prop hilit-chg-list)))
-      )
+      (setq new-prop (nth 2 (member prop hilit-chg-list))))
     (if prop
 	(put-text-property start end 'hilit-chg new-prop)
-      (message "%d-%d unknown property %s not changed" start end prop)
-      )
-    ))
+      (message "%d-%d unknown property %s not changed" start end prop))))
 
 ;;;###autoload
 (defun highlight-changes-rotate-faces ()
   "Rotate the faces used by Highlight Changes mode.
 
-Current changes will be display in the face described by the first element
-of highlight-changes-face-list, those (older) changes will be shown in the
+Current changes are displayed in the face described by the first element
+of `highlight-changes-face-list', one level older changes are shown in
 face described by the second element, and so on.  Very old changes remain
 shown in the last face in the list.
 
-You can automatically rotate colours when the buffer is saved
-by adding this to local-write-file-hooks,  by evaling (in the
-buffer to be saved):
-  (add-hook 'local-write-file-hooks 'highlight-changes-rotate-faces)
-"
+You can automatically rotate colors when the buffer is saved by adding
+this function to `write-file-functions' as a buffer-local value.  To do
+this, eval the following in the buffer to be saved:
+
+  \(add-hook 'write-file-functions 'highlight-changes-rotate-faces nil t)"
   (interactive)
   ;; If not in active mode do nothing but don't complain because this
   ;; may be bound to a hook.
-  (if (eq highlight-changes-mode 'active)
-      (let ((after-change-functions nil))
-	;; ensure hilit-chg-list is made and up to date
-	(hilit-chg-make-list)
-	;; remove our existing overlays
-	(hilit-chg-hide-changes)
-	;; for each change text property, increment it
-	(hilit-chg-map-changes 'hilit-chg-bump-change)
-	;; and display them all if active
-	(if (eq highlight-changes-mode 'active)
-	    (hilit-chg-display-changes))
-	))
-  ;; This always returns nil so it is safe to use in
-  ;; local-write-file-hook
+  (when (eq highlight-changes-mode 'active)
+    (let ((modified (buffer-modified-p))
+	  (inhibit-modification-hooks t))
+      ;; The `modified' related code tries to combine two goals: (1) Record the
+      ;; rotation in `buffer-undo-list' and (2) avoid setting the modified flag
+      ;; of the current buffer due to the rotation.  We do this by inserting (in
+      ;; `buffer-undo-list') entries restoring buffer-modified-p to nil before
+      ;; and after the entry for the rotation.
+      (unless modified
+	;; Install the "before" entry.
+	(setq buffer-undo-list
+	      (cons '(apply restore-buffer-modified-p nil)
+		    buffer-undo-list)))
+      (unwind-protect
+	  (progn
+	    ;; ensure hilit-chg-list is made and up to date
+	    (hilit-chg-make-list)
+	    ;; remove our existing overlays
+	    (hilit-chg-hide-changes)
+	    ;; for each change text property, increment it
+	    (hilit-chg-map-changes 'hilit-chg-bump-change)
+	    ;; and display them all if active
+	    (if (eq highlight-changes-mode 'active)
+		(hilit-chg-display-changes)))
+	(unless modified
+	  ;; Install the "after" entry.
+	  (setq buffer-undo-list
+		(cons '(apply restore-buffer-modified-p nil)
+		      buffer-undo-list))
+
+	  (restore-buffer-modified-p nil)))))
+  ;; This always returns nil so it is safe to use in write-file-functions
   nil)
 
-
 ;; ========================================================================
-;; Comparing with an existing file.   
-;; This uses ediff to find the differences.
+;; Comparing buffers/files
+;; These use ediff to find the differences.
+
+(defun highlight-markup-buffers
+  (buf-a file-a buf-b file-b &optional markup-a-only)
+  "Get differences between two buffers and set highlight changes.
+Both buffers are done unless optional parameter MARKUP-A-ONLY
+is non-nil."
+  (save-window-excursion
+    (let* (change-info
+	   change-a change-b
+	   a-start a-end len-a
+	   b-start b-end len-b
+	   (bufa-modified (buffer-modified-p buf-a))
+	   (bufb-modified (buffer-modified-p buf-b))
+	   (buf-a-read-only (with-current-buffer buf-a buffer-read-only))
+	   (buf-b-read-only (with-current-buffer buf-b buffer-read-only))
+	   temp-a temp-b)
+      (if (and file-a bufa-modified)
+	  (if (y-or-n-p (format "Save buffer %s?  " buf-a))
+	      (with-current-buffer buf-a
+		(save-buffer)
+		(setq bufa-modified (buffer-modified-p buf-a)))
+	    (setq file-a nil)))
+      (or file-a
+	  (setq temp-a (setq file-a (ediff-make-temp-file buf-a nil))))
+
+      (if (and file-b bufb-modified)
+	  (if (y-or-n-p (format "Save buffer %s?  " buf-b))
+	      (with-current-buffer buf-b
+		(save-buffer)
+		(setq bufb-modified (buffer-modified-p buf-b)))
+	    (setq file-b nil)))
+      (or file-b
+	  (setq temp-b (setq file-b (ediff-make-temp-file buf-b nil))))
+      (set-buffer buf-a)
+      (highlight-changes-mode 'active)
+      (or markup-a-only (with-current-buffer buf-b
+			  (highlight-changes-mode 'active)))
+      (setq change-info (hilit-chg-get-diff-info buf-a file-a buf-b file-b))
+
+
+      (setq change-a (car change-info))
+      (setq change-b (car (cdr change-info)))
+
+      (hilit-chg-make-list)
+      (while change-a
+	(setq a-start (nth 0 (car change-a)))
+	(setq a-end (nth 1 (car change-a)))
+	(setq b-start (nth 0 (car change-b)))
+	(setq b-end (nth 1 (car change-b)))
+	(setq len-a (- a-end a-start))
+	(setq len-b (- b-end b-start))
+	(set-buffer buf-a)
+	(hilit-chg-set-face-on-change a-start a-end len-b buf-a-read-only)
+	(or markup-a-only
+	    (with-current-buffer buf-b
+	      (hilit-chg-set-face-on-change b-start b-end len-a
+					    buf-b-read-only)
+	      ))
+	(setq change-a (cdr change-a))
+	(setq change-b (cdr change-b)))
+      (or bufa-modified
+	  (with-current-buffer buf-a (set-buffer-modified-p nil)))
+      (or bufb-modified
+	  (with-current-buffer buf-b (set-buffer-modified-p nil)))
+      (if temp-a
+	  (delete-file temp-a))
+      (if temp-b
+	  (delete-file temp-b)))
+    ))
+
+;;;###autoload
+(defun highlight-compare-buffers (buf-a buf-b)
+"Compare two buffers and highlight the differences.
+
+The default is the current buffer and the one in the next window.
+
+If either buffer is modified and is visiting a file, you are prompted
+to save the file.
+
+Unless the buffer is unmodified and visiting a file, the buffer is
+written to a temporary file for comparison.
+
+If a buffer is read-only, differences will be highlighted but no property
+changes are made, so \\[highlight-changes-next-change] and
+\\[highlight-changes-previous-change] will not work."
+  (interactive
+   (list
+    (get-buffer (read-buffer "buffer-a " (current-buffer) t))
+    (get-buffer
+     (read-buffer "buffer-b "
+		  (window-buffer (next-window (selected-window))) t))))
+  (let ((file-a (buffer-file-name buf-a))
+	(file-b (buffer-file-name buf-b)))
+    (highlight-markup-buffers buf-a file-a buf-b file-b)
+    ))
 
 ;;;###autoload
 (defun highlight-compare-with-file (file-b)
   "Compare this buffer with a file, and highlight differences.
 
-The current buffer must be an unmodified buffer visiting a file,
-and not in read-only mode.
-
-If the backup filename exists, it is used as the default
-when called interactively.
+If the buffer has a backup filename, it is used as the default when
+this function is called interactively.
 
-If a buffer is visiting the file being compared against,  it also will
-have its differences highlighted.   Otherwise, the file is read in
-temporarily but the buffer is deleted.
+If the current buffer is visiting the file being compared against, it
+also will have its differences highlighted.  Otherwise, the file is
+read in temporarily but the buffer is deleted.
 
-If a buffer is read-only,  differences will be highlighted but no property
-changes made,  so \\[highlight-changes-next-change] and
+If the buffer is read-only, differences will be highlighted but no property
+changes are made, so \\[highlight-changes-next-change] and
 \\[highlight-changes-previous-change] will not work."
   (interactive (list
 	      (read-file-name
@@ -877,66 +943,22 @@ changes made,  so \\[highlight-changes-next-change] and
 	       ""			;; directory
 	       nil			;; default
 	       'yes			;; must exist
-	       (let ((f (make-backup-file-name 
-			 (or (buffer-file-name (current-buffer))
-			     (error "no file for this buffer")))))
-		 (if (file-exists-p f) f ""))
-	       )))
-
+	       (let ((f (buffer-file-name (current-buffer))))
+		 (if f
+		     (progn
+		       (setq f (make-backup-file-name f))
+		       (or (file-exists-p f)
+			   (setq f nil)))
+		   )
+		 f))))
   (let* ((buf-a (current-buffer))
-	 (buf-a-read-only buffer-read-only)
-	 (orig-pos (point))
 	 (file-a (buffer-file-name))
 	 (existing-buf (get-file-buffer file-b))
 	 (buf-b (or existing-buf
 		    (find-file-noselect file-b)))
-	 (buf-b-read-only (with-current-buffer buf-b buffer-read-only))
-	 xy  xx yy p q
-	 a-start a-end len-a
-	 b-start b-end len-b
-	 )
-
-    ;; We use the fact that the buffer is not marked modified at the
-    ;; end where we clear its modified status
-    (if (buffer-modified-p buf-a)
-	(if (y-or-n-p (format "OK to save %s?  " file-a))
-		       (save-buffer buf-a)
-	  (error "Buffer must be saved before comparing with a file.")))
-    (if (and existing-buf (buffer-modified-p buf-b))
-	(if (y-or-n-p (format "OK to save %s?  " file-b))
-		       (save-buffer buf-b)
-	  (error "Cannot compare with a file in an unsaved buffer.")))
-    (highlight-changes-mode 'active)
-    (if existing-buf (with-current-buffer buf-b
-		       (highlight-changes-mode 'active)))
-    (save-window-excursion
-      (setq xy (hilit-chg-get-diff-info buf-a file-a buf-b file-b)))
-    (setq xx (car xy))
-    (setq p xx)
-    (setq yy (car (cdr xy)))
-    (setq q yy)
-    (hilit-chg-make-list)
-    (while p
-      (setq a-start (nth 0 (car p)))
-      (setq a-end (nth 1 (car p)))
-      (setq b-start (nth 0 (car q)))
-      (setq b-end (nth 1 (car q)))
-      (setq len-a (- a-end a-start))
-      (setq len-b (- b-end b-start))
-      (set-buffer buf-a)
-      (hilit-chg-set-face-on-change a-start a-end len-b buf-a-read-only)
-      (set-buffer-modified-p nil)
-      (goto-char orig-pos)
-      (if existing-buf
-	  (with-current-buffer buf-b
-	    (hilit-chg-set-face-on-change b-start b-end len-a
-					  buf-b-read-only )
-	    ))
-      (setq p (cdr p))
-      (setq q (cdr q))
-      )
-    (if existing-buf
-	(set-buffer-modified-p nil) 
+	 (buf-b-read-only (with-current-buffer buf-b buffer-read-only)))
+    (highlight-markup-buffers buf-a file-a buf-b file-b (not existing-buf))
+    (unless existing-buf
       (kill-buffer buf-b))
     ))
 
@@ -953,69 +975,63 @@ changes made,  so \\[highlight-changes-next-change] and
 
 
 (defun hilit-chg-get-diff-list-hk ()
-  ;; x and y are dynamically bound by hilit-chg-get-diff-info 
+  ;; x and y are dynamically bound by hilit-chg-get-diff-info
   ;; which calls this function as a hook
   (defvar x)  ;; placate the byte-compiler
   (defvar y)
-  (setq  e (current-buffer))
+  (setq e (current-buffer))
   (let ((n 0) extent p va vb a b)
-    (setq  x nil  y nil)    ;; x and y are bound by hilit-chg-get-diff-info
+    (setq x nil y nil)    ;; x and y are bound by hilit-chg-get-diff-info
     (while (< n ediff-number-of-differences)
       (ediff-make-fine-diffs n)
       (setq va (ediff-get-fine-diff-vector n 'A))
       ;; va is a vector if there are fine differences
       (if va
 	  (setq a (append va nil))
-	;; if not,  get the unrefined difference
+	;; if not, get the unrefined difference
 	(setq va (ediff-get-difference n 'A))
-	(setq a (list (elt va 0)))
-	)
+	(setq a (list (elt va 0))))
       ;; a list a list
       (setq p a)
       (while p
 	(setq extent (list (overlay-start (car p))
 			   (overlay-end (car p))))
 	(setq p (cdr p))
-	(setq x (append x (list extent) ))
-	);; while p
+	(setq x (append x (list extent) )));; while p
       ;;
       (setq vb (ediff-get-fine-diff-vector n 'B))
       ;; vb is a vector
       (if vb
 	  (setq b (append vb nil))
-	;; if not,  get the unrefined difference
+	;; if not, get the unrefined difference
 	(setq vb (ediff-get-difference n 'B))
-	(setq b (list (elt vb 0)))
-	)
+	(setq b (list (elt vb 0))))
       ;; b list a list
       (setq p b)
       (while p
 	(setq extent (list (overlay-start (car p))
 			   (overlay-end (car p))))
 	(setq p (cdr p))
-	(setq y (append y (list extent) ))
-	);; while p
-      ;;
-      (setq n (1+ n))
-      );; while
+	(setq y (append y (list extent) )))
+      (setq n (1+ n)));; while
     ;; ediff-quit doesn't work here.
     ;; No point in returning a value, since this is a hook function.
     ))
 
 ;; ======================= automatic stuff ==============
 
-;; Global Highlight Changes mode is modelled after Global Font-lock mode.
+;; Global Highlight Changes mode is modeled after Global Font-lock mode.
 ;; Three hooks are used to gain control.  When Global Changes Mode is
-;; enabled, `find-file-hooks' and `change-major-mode-hook' are set.
-;; `find-file-hooks' is called when visiting a file,  the new mode is
+;; enabled, `find-file-hook' and `change-major-mode-hook' are set.
+;; `find-file-hook' is called when visiting a file, the new mode is
 ;; known at this time.
 ;; `change-major-mode-hook' is called when a buffer is changing mode.
 ;; This could be because of finding a file in which case
-;; `find-file-hooks' has already been called and has done its work.
+;; `find-file-hook' has already been called and has done its work.
 ;; However, it also catches the case where a new mode is being set by
 ;; the user.  However, it is called from `kill-all-variables' and at
-;; this time the mode is the old mode,  which is not what we want.
-;; So,  our function temporarily sets `post-command-hook' which will
+;; this time the mode is the old mode, which is not what we want.
+;; So, our function temporarily sets `post-command-hook' which will
 ;; be called after the buffer has been completely set up (with the new
 ;; mode).  It then removes the `post-command-hook'.
 ;; One other wrinkle - every M-x command runs the `change-major-mode-hook'
@@ -1023,30 +1039,27 @@ changes made,  so \\[highlight-changes-next-change] and
 
 
 (defun hilit-chg-major-mode-hook ()
-  (add-hook 'post-command-hook 'hilit-chg-post-command-hook)
-  )
+  (add-hook 'post-command-hook 'hilit-chg-post-command-hook))
 
 (defun hilit-chg-post-command-hook ()
   ;; This is called after changing a major mode, but also after each
-  ;; M-x command,  in which case the current buffer is a minibuffer.
-  ;; In that case, do not act on it here,  but don't turn it off
-  ;; either,  we will get called here again soon-after. 
-  ;; Also,  don't enable it for other special buffers.
+  ;; M-x command, in which case the current buffer is a minibuffer.
+  ;; In that case, do not act on it here, but don't turn it off
+  ;; either, we will get called here again soon-after.
+  ;; Also, don't enable it for other special buffers.
   (if (string-match "^[ *]"  (buffer-name))
       nil ;; (message "ignoring this post-command-hook")
     (remove-hook 'post-command-hook 'hilit-chg-post-command-hook)
-    ;; The following check isn't necessary,  since 
+    ;; The following check isn't necessary, since
     ;; hilit-chg-turn-on-maybe makes this check too.
     (or highlight-changes-mode	;; don't turn it on if it already is
-	(hilit-chg-turn-on-maybe highlight-changes-global-initial-state))
-    ))
+	(hilit-chg-turn-on-maybe highlight-changes-global-initial-state))))
 
 (defun hilit-chg-check-global ()
   ;; This is called from the find file hook.
   (hilit-chg-turn-on-maybe highlight-changes-global-initial-state))
 
 
-
 ;;;###autoload
 (defun global-highlight-changes (&optional arg)
   "Turn on or off global Highlight Changes mode.
@@ -1054,21 +1067,21 @@ changes made,  so \\[highlight-changes-next-change] and
 When called interactively:
 - if no prefix, toggle global Highlight Changes mode on or off
 - if called with a positive prefix (or just C-u) turn it on in active mode
-- if called with a zero prefix  turn it on in passive mode
+- if called with a zero prefix turn it on in passive mode
 - if called with a negative prefix turn it off
 
 When called from a program:
 - if ARG is nil or omitted, turn it off
-- if ARG is 'active,  turn it on in active mode
-- if ARG is 'passive, turn it on in passive mode
-- otherwise just turn it on 
+- if ARG is `active', turn it on in active mode
+- if ARG is `passive', turn it on in passive mode
+- otherwise just turn it on
 
 When global Highlight Changes mode is enabled, Highlight Changes mode is turned
 on for future \"suitable\" buffers (and for \"suitable\" existing buffers if
 variable `highlight-changes-global-changes-existing-buffers' is non-nil).
-\"Suitablity\" is determined by variable `highlight-changes-global-modes'."
+\"Suitability\" is determined by variable `highlight-changes-global-modes'."
 
-  (interactive 
+  (interactive
    (list
     (cond
      ((null current-prefix-arg)
@@ -1084,51 +1097,46 @@ variable `highlight-changes-global-changes-existing-buffers' is non-nil).
       'passive)
      ;; negative interactive arg - turn it off
      (t
-      (setq global-highlight-changes nil)      
+      (setq global-highlight-changes nil)
       nil))))
 
   (if arg
       (progn
 	(if (eq arg 'active)
 	    (setq highlight-changes-global-initial-state 'active)
-	  (if (eq arg  'passive)
+	  (if (eq arg 'passive)
 	      (setq highlight-changes-global-initial-state 'passive)))
 	(setq global-highlight-changes t)
-	(message "turning ON Global Highlight Changes mode in %s state"
+	(message "Turning ON Global Highlight Changes mode in %s state"
 		 highlight-changes-global-initial-state)
-	(add-hook 'hilit-chg-major-mode-hook 'hilit-chg-major-mode-hook)
-	(add-hook 'find-file-hooks 'hilit-chg-check-global)
+	;; FIXME: Not sure what this was intended to do.  --Stef
+	;; (add-hook 'hilit-chg-major-mode-hook 'hilit-chg-major-mode-hook)
+	(add-hook 'find-file-hook 'hilit-chg-check-global)
 	(if highlight-changes-global-changes-existing-buffers
-	    (hilit-chg-update-all-buffers 
-	     highlight-changes-global-initial-state))
-	)
-    (message "turning OFF global Highlight Changes mode")
-    (remove-hook 'hilit-chg-major-mode-hook 'hilit-chg-major-mode-hook)
-    (remove-hook 'find-file-hooks 'hilit-chg-check-global)
-    (remove-hook 'post-command-hook
-		 'hilit-chg-post-command-hook)
-    (remove-hook 'find-file-hooks 'hilit-chg-check-global)
-    (if highlight-changes-global-changes-existing-buffers
-	(hilit-chg-update-all-buffers nil))
-    )
-  )
-
-
+	    (hilit-chg-update-all-buffers
+	     highlight-changes-global-initial-state)))
 
+    (message "Turning OFF global Highlight Changes mode")
+    ;; FIXME: Not sure what this was intended to do.  --Stef
+    ;; (remove-hook 'hilit-chg-major-mode-hook 'hilit-chg-major-mode-hook)
+    (remove-hook 'post-command-hook 'hilit-chg-post-command-hook)
+    (remove-hook 'find-file-hook 'hilit-chg-check-global)
+    (if highlight-changes-global-changes-existing-buffers
+	(hilit-chg-update-all-buffers nil))))
 
 
 (defun hilit-chg-turn-on-maybe (value)
   "Turn on Highlight Changes mode if it is appropriate for this buffer.
 
 A buffer is appropriate for Highlight Changes mode if all these are true:
-- the buffer is not a special buffer (one whose name begins with 
-  `*' or ` ')
-- the buffer's mode is suitable as per variable highlight-changes-global-modes
+- the buffer is not a special buffer (one whose name begins with
+  `*' or ` '),
+- the buffer's mode is suitable as per variable
+  `highlight-changes-global-modes',
 - Highlight Changes mode is not already on for this buffer.
 
-This function is called from hilit-chg-update-all-buffers 
-from `global-highlight-changes' when turning on global Highlight Changes mode.
-"
+This function is called from `hilit-chg-update-all-buffers' or
+from `global-highlight-changes' when turning on global Highlight Changes mode."
   (or highlight-changes-mode			; do nothing if already on
       (if
 	  (cond
@@ -1141,15 +1149,13 @@ from `global-highlight-changes' when turning on global Highlight Changes mode.
 		 (not (memq major-mode (cdr highlight-changes-global-modes)))
 	       (memq major-mode highlight-changes-global-modes)))
 	    (t
-	     (and 
-	      (not (string-match "^[ *]"  (buffer-name)))
-	      (buffer-file-name))
-	     ))
+	     (and
+	      (not (string-match "^[ *]" (buffer-name)))
+	      (buffer-file-name))))
 	  (progn
 	    (hilit-chg-set value)
-	    (run-hooks 'highlight-changes-enable-hook)))
-      ))
-    
+	    (run-hooks 'highlight-changes-enable-hook)))))
+
 
 (defun hilit-chg-turn-off-maybe ()
   (if highlight-changes-mode
@@ -1158,16 +1164,28 @@ from `global-highlight-changes' when turning on global Highlight Changes mode.
 	(hilit-chg-clear))))
 
 
-
 (defun hilit-chg-update-all-buffers (value)
-  (mapcar
+  (mapc
    (function (lambda (buffer)
 	       (with-current-buffer buffer
 		 (if value
 		     (hilit-chg-turn-on-maybe value)
 		   (hilit-chg-turn-off-maybe))
 		 )))
-   (buffer-list)))
+   (buffer-list))
+  nil)
+
+;;;; Desktop support.
+
+;; Called by `desktop-create-buffer' to restore `highlight-changes-mode'.
+(defun hilit-chg-desktop-restore (desktop-buffer-locals)
+  (highlight-changes-mode
+   (or (cdr (assq 'highlight-changes-mode desktop-buffer-locals)) 1)))
+
+(add-to-list 'desktop-minor-mode-handlers
+             '(highlight-changes-mode . hilit-chg-desktop-restore))
+
+(add-to-list 'desktop-locals-to-save 'highlight-changes-mode)
 
 ;; ===================== debug ==================
 ;; For debug & test use:
@@ -1180,10 +1198,10 @@ from `global-highlight-changes' when turning on global Highlight Changes mode.
 ;; 			      )
 ;; 			   beg end
 ;; 			   ))
-;; 
+;;
 ;; ================== end of debug ===============
 
-
 (provide 'hilit-chg)
 
+;; arch-tag: de00301d-5bad-44da-aa82-e0e010b0c463
 ;;; hilit-chg.el ends here