]> code.delx.au - gnu-emacs/blobdiff - lisp/ediff.el
Fix typo.
[gnu-emacs] / lisp / ediff.el
index a3ffdf04229b43bc21ddb951ae5f900ec2699bed..bb6cfc6b72eb4d31c8f9b3d304ba65d2d3b32512 100644 (file)
@@ -1,10 +1,15 @@
-;;; ediff.el --- a visual interface to diff & patch
-;;; Copyright (C) 1994 Free Software Foundation, Inc.
+;;; ediff.el --- a comprehensive visual interface to diff & patch
 
-;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+;; Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
+;;   2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.stonybrook.edu>
 ;; Created: February 2, 1994
-;; Version: 1.31
-;; Keywords: comparing, merging, patching, version control.
+;; Keywords: comparing, merging, patching, tools, unix
+
+(defconst ediff-version "2.81" "The current version of Ediff")
+(defconst ediff-date "February 18, 2006" "Date of last update")
+
 
 ;; This file is part of GNU Emacs.
 
 ;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
-
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
-;;  ----------
 
-;; Never read those diff outputs again!
-;; Apply patch selectively, like a pro!
+;; Never read that diff output again!
+;; Apply patch interactively!
+;; Merge with ease!
 
-;; This package provides a convenient way of simultaneous brousing through
-;; the differences between a pair of files or buffers.  The two files being
-;; compared (file-A and file-B) are shown in separate windows (side by
-;; side, one above the another, or in separate frames), and the differences
-;; are highlighted as you step through them.  You can also copy difference
-;; regions from one buffer to another (and recover old differences if you
-;; change your mind).
+;; This package provides a convenient way of simultaneous browsing through
+;; the differences between a pair (or a triple) of files or buffers.  The
+;; files being compared, file-A, file-B, and file-C (if applicable) are
+;; shown in separate windows (side by side, one above the another, or in
+;; separate frames), and the differences are highlighted as you step
+;; through them.  You can also copy difference regions from one buffer to
+;; another (and recover old differences if you change your mind).
+
+;; Ediff also supports merging operations on files and buffers, including
+;; merging using ancestor versions.  Both comparison and merging operations can
+;; be performed on directories, i.e., by pairwise comparison of files in those
+;; directories.
 
 ;; In addition, Ediff can apply a patch to a file and then let you step
-;; though both files, the patched and the original one, simultateously,
+;; though both files, the patched and the original one, simultaneously,
 ;; difference-by-difference.  You can even apply a patch right out of a
 ;; mail buffer, i.e., patches received by mail don't even have to be saved.
 ;; Since Ediff lets you copy differences between buffers, you can, in
 ;; effect, apply patches selectively (i.e., you can copy a difference
-;; region from file.orig to file, thereby undoing any particular patch that
+;; region from file_orig to file, thereby undoing any particular patch that
 ;; you don't like).
 
-;; This package is based on emerge.el.  It uses a few utilities and
-;; variables defined there and several other Ediff's functions are
-;; adaptations from emerge.el.
-
-;; Ediff is complimentary to Emerge.  While Emerge is better at heavy-duty
-;; tasks that involve merging of files, Ediff is by far superior
-;; for browsing through files compared via diff and for patching files
-;; with patch.  Furthermore, I feel that Ediff is more convenient for
-;; merging tasks where one of the files is a designated output.  This
-;; situation arises while patching files or when comparing an old version
-;; of a file with a newer version (in such cases, it is often desirable to
-;; selectively revert some portions of the new file to its old state). 
-
-;; This version of Ediff is much faster than the previous ones and than
-;; Emerge (in Emacs 19.23, Emerge will become much faster as well).
-;; The difference in startup time is dramatic for large files with many
-;; differences.
-
-;; Window configuration:
-;; ----------------------
-
-;; By default, Ediff sets things up in one frame, splitting it between a
-;; small control window and the two windows for file-A and file-B.  The
-;; split between these latter windows can be horizontal or vertical, which
-;; can be changed interactively by hitting 's' while the cursor is in the
-;; control window.
-;;
-;; In a multi-frame situation, Ediff would work as follows.  When it starts,
-;; it will place the control window in the frame that was selected at the
-;; time of the invocation.  If file-A or file-B is seen in one of the
-;; frames, Ediff will leave it there.  If a file (A/B) is not visible in any
-;; frame, Ediff will arrange that it will share a frame with the control
-;; window. (If none of the files is visible, then both will share the
-;; control window frame.) The same algorithm works when you hit 'c'
-;; (ediff-recenter), 'p' (ediff-previous-difference), 'n', etc.
-;;
-;; Thus, you can compare files in one frame or in different frames.
-;; The former is done by default, while the latter can be achieved by
-;; arranging files A and B to be seen in different frames.  Ediff
-;; respects these arrangements, automatically adapting itself to 
-;; the multi-frame mode.
-
-
-;; A note to heavy-duty users: 
-
-;;  Ediff lets the user run multiple sessions at once, i.e., you can invoke
-;;  Ediff on different functions several times in a row, without exiting
-;;  the previous Ediff sessions. Different sessions may even operate on the
-;;  same pair of files.  So, in principle, it is possible to do, say,
-;;  pairwise comparison of three (or more) different files.  Each session
-;;  would have its own *ediff-control* buffer and all the regarding a
-;;  particular session is local to the associated *ediff-control* buffer.
-;;  You can switch between sessions by suspending one session and then
-;;  switching to another *ediff-control* buffer. (Different such buffers
-;;  are distinguished by a numerical suffix, e.g., *ediff-control*<3>.)
-;;  This, if you would like to compare three files pairwise, you can do
-;;  this by preparing three different frames, each with its own control
-;;  window.  (This would require a very wide screen, and I never claimed
-;;  that such 3-way comparison is very easy to do.)
-;;
-;; If you need to conduct multiple Ediff sessions on the same file, one
-;; thing should be kept in mind: each time you invoke Ediff on a buffer that
-;; already participates in another Ediff session, that buffer should not
-;; have any ASCII Ediff flags in it. (Highlighting with faces is OK.)  If
-;; flags are not removed, difference overlays won't be set correctly
-;; for the second invocation of Ediff.  The simplest way to remove ASCII
-;; flags from an Ediff buffer is to switch to that buffer and try to insert
-;; or delete something.  If ASCII flags have been inserted by an Ediff
-;; session, Ediff will ignore this first editing operation, but it will
-;; remove all flags and notify you that this buffer can now be edited.
-;;
-;; To rehighlight Ediff buffers, hit 'c' in ediff-control buffer.
-
+;; Ediff is aware of version control, which lets the user compare
+;; files with their older versions.  Ediff can also work with remote and
+;; compressed files.  Details are given below.
 
-;;; Remarks: 
-;;  -------
+;; Finally, Ediff supports directory-level comparison, merging and patching.
+;; See the on-line manual for details.
 
-;;  1. Ediff is unlikely to run under Emacs 18 without some further work.
-;;  2. If running Lucid Emacs, Ediff requires at least version 19.9.
-;;  3. I didn't test Ediff on Emacs versions older than 19.19.
-;;  4. The function vc-ediff requires the vc.el version that comes with
-;;     Emacs 19.22.
+;; This package builds upon the ideas borrowed from emerge.el and several
+;; Ediff's functions are adaptations from emerge.el.  Much of the functionality
+;; Ediff provides is also influenced by emerge.el.
 
+;; The present version of Ediff supersedes Emerge.  It provides a superior user
+;; interface and has numerous major features not found in Emerge.  In
+;; particular, it can do patching, and 2-way and 3-way file comparison,
+;; merging, and directory operations.
 
-;;; Installation and use:
-;;  --------------------
 
-;; You can invoke Ediff interactively using the following functions:
-;;
-;;         ediff-buffers                        - compare buffers
-;;         ediff   (alias for ediff-files)
-;;         ediff-files                          - compare files
-;;         ediff-patch-file                     - patch file then compare
-;;         epatch  (alias for ediff-patch-file)
-;;         ediff-patch-buffer                   - patch buffer then compare
-;;         vc-ediff                             - compare buffer & version
-;;                                                using vc.el package
-;;                                                (Emacs 19.22 and up).
-;;         rcs-ediff                            - same using rcs.el; rcs.el
-;;                                                is not part of the
-;;                                                standard Emacs distribution.
-;;
-;; There is also the function ediff-files-remote, which can be invoked only
-;; from within another Emacs Lisp function, i.e., non-interactively.
-;;
-;; To use Ediff, put this in your .emacs file:
-;;
-;;  (autoload 'ediff-buffers "ediff" "Visual interface to diff" t)
-;;  (autoload 'ediff  "ediff"  "Visual interface to diff" t)
-;;  (autoload 'ediff-files "ediff" "Visual interface to diff" t)
-;;  (autoload 'ediff-files-remote "ediff" "Visual interface to diff") 
-;;  (autoload 'epatch  "ediff"  "Visual interface to patch" t)
-;;  (autoload 'ediff-patch-file "ediff" "Visual interface to patch" t)
-;;  (autoload 'ediff-patch-buffer "ediff" "Visual interface to patch" t)
-;;  (autoload 'vc-ediff "ediff"
-;;                     "Interface to diff & version control via vc.el" t) 
-;;  (autoload 'rcs-ediff "ediff"
-;;                      "Interface to diff & version control via rcs.el" t)
-;;
-;;
-;; If you want Ediff to be loaded from the very beginning, you should have
-;;
-;;  (require 'ediff)
-;;
-;; in your .emacs file.  This way it is also easier to figure out changes
-;; to the default Ediff setting, if such changes become necessary --- see
-;; Customization.
-;;
 
-;;; Compilation
-;;  -----------
-;;
-;; When you byte-compile Ediff, you will get some warnings about functions
-;; being undefined.  These can be safely ignored.
-
-;;; Customization:
-;;  -------------
-
-;; If you don't like the default setting, you can change it through the
-;; various variables and hooks.  In particular, the following hooks are
-;; available: 
-
-;;         ediff-load-hooks
-;;         ediff-before-setup-windows-hooks
-;;         ediff-startup-hooks
-;;         ediff-select-hooks
-;;         ediff-unselect-hooks
-;;         ediff-suspend-hooks
-;;         ediff-quit-hooks
-;;         ediff-prepare-buffer-hooks
-
-;; The hooks in ediff-load-hooks can be used to change defaults after Ediff
-;; is loaded.
-;; The hooks in ediff-before-setup-windows-hooks, ediff-suspend-hooks, and
-;; ediff-quit-hooks can be used to save and then restore whatever window
-;; configuration you want.  However, make sure you understand what you are
-;; doing.  Many variables that drive Ediff are local to the different
-;; *ediff-control* buffers.  Take a look at ediff-default-suspend-hook and
-;; ediff-default-quit-hook to see what's involved.
-;; The hooks in ediff-prepare-buffer-hooks are executed for each Ediff buffer
-;; (A and B) right after these buffers are arranged.
-;;
-;; The second group of Ediff variables that could be changed, if you so
-;; wish, is: 
-;;
-;;         ediff-before-flag-eol
-;;         ediff-after-flag-eol
-;;         ediff-before-flag-mol
-;;         ediff-after-flag-mol
-;;
-;;         ediff-current-diff-face-A
-;;         ediff-current-diff-face-B
-;;         ediff-even-diff-face-A
-;;         ediff-even-diff-face-B
-;;         ediff-odd-diff-face-A
-;;         ediff-odd-diff-face-B
-;
-;; The first four are ASCII strings that mark the beginning and the end of
-;; the differences found in file-A and file-B. Ediff uses different flags
-;; to highlight regions that begin/end at the beginning of a line or in a
-;; middle of a line.
-
-;; The rest are the faces used to highlight text on X displays.  On X
-;; displays, Ediff uses ediff-current-diff-face-A and
-;; ediff-current-diff-face-B to highlight the current difference regions.
-;; Other (non-current) difference regions are displayed in alternating
-;; faces: ediff-even/odd-diff-face-A/B.   The odd and the even
-;; faces are actually identical on monochrome displays, because it is
-;; rather poor in what you can do on such a display.  So, I chose to use
-;; italics to highlight other differences. Any ideas would be welcome.
-;;
-;; There are two ways to change the default setting for highlighting faces:
-;; either change the variables, as in
-;;
-;; (setq ediff-current-diff-face-A (internal-get-face 'bold-italic))
-;;
-;; (`internal-get-face' should be `get-face' if you are using Lucid Emacs)
-;; or by selectively modifying the defaults:
-;;
-;; (add-hook 'ediff-load-hooks
-;;   (function (lambda () 
-;;                (set-face-foreground ediff-current-diff-face-B "blue")
-;;                (set-face-background ediff-current-diff-face-B "red")
-;;                (make-face-italic ediff-current-diff-face-B))))
-;;
-;; You may also want to take a look at how the above faces are defined in
-;; Ediff. 
-;;
-;; The last pair of variables in this group,
-;;
-;;         ediff-want-faces
-;;         ediff-highlight-selected-only
-;;
-;; indicate whether---on a window system---you want differences to be
-;; marked using ASCII strings (like on a dumb terminal) or using colors and
-;; highlighting. If ediff-want-faces is t, then highlighting with faces is
-;; used. Normally, Ediff highlights all differences, but the selected
-;; difference is highlighted more visibly. If you prefer that unselected
-;; differences won't be highlighted, you can set
-;; ediff-highlight-selected-only to t.
-;;
-;; If you plan on changing these variables, they must be set
-;; BEFORE ediff.el is loaded. 
-;;
-;; Note: Ediff lets you switch between the two types of highlighting.  That
-;; is you can switch, interactively, from highlighting using faces to
-;; highlighting using ASCII flags, and back.  Of course, toggling has
-;; effect only on a window system.  On a dumb terminal or in an xterm
-;; window, the only available option is highlighting with ASCII flags.
-;;
-;; The third group of variables controls miscellaneous functions:
-;;
-;;         ediff-patch-program
-;;         ediff-patch-options
-;;         ediff-diff-program
-;;         ediff-diff-options
-;;
-;; These specify the functions that produce differences and do patching.
-;; The *-options variables specify which options to pass to these programs.
-;; It is unlikely that you would want to change these.  One possible
-;; exception is when you may want to generate differences with context
-;; lines in order to send a patch file through email.  Then, you might want
-;; to set ediff-diff-options to '-c'. Sometimes, you may also want to tell
-;; diff to ignore spaces and such. Use the option '-w' for that. Diff
-;; has several other useful options (type 'man diff' to find out).
-;;
-;; The output from diff is found in *ediff-diff* buffer.  However, this
-;; makes sense only if you also intend to use Ediff to browse through the
-;; diff'ed files before sending the patch.  This is because diff.el is much
-;; faster in yielding the output of diff ;; (Ediff is a big gun, if used
-;; for this simple purpose).
-;;
-;; The last set of variables that can be modified is
-;;
-;;         ediff-split-window-function
-;;         ediff-use-last-dir
-;;         ediff-nix-help-in-control-buffer
-;;
-;; ediff-split-window-function controls the way you want the window be
-;; split between file-A and file-B.  It defaults to vertical split, but you
-;; can set it to 'split-window-horizontally, if you want.  Ediff lets you
-;; toggle the way windows are split, so you can try different settings
-;; interactively.  Note: if file-A and file-B are in different frames,
-;; windows are not split, regardless of the value
-;; ediff-split-window-function.  Instead, other windows on these frames are
-;; deleted and Ediff starts displaying file-A and file-B using these two
-;; frames, one file per frame.  You can then switch to one-frame mode
-;; simply by hiding the file-A/B buffer that is displayed on a frame other
-;; than the control-window frame.
-;;
-;; Note that if Ediff sees that the two buffers it compares are residing in
-;; separate frames, it assumes that the user wants them to be so displayed
-;; and stops splitting windows.  Instead, it will arrange each buffer to
-;; occupy its own frame (possibly shared with Ediff's help window).
-;;
-;; The variable ediff-use-last-dir controls the way Ediff presents the
-;; default directory when it prompts the user for files to compare.  If nil,
-;; Ediff will use the default directory of the current buffer when it
-;; prompts the user for file names.  Otherwise, it will use the
-;; directories it had previously used for file-A and file-B. 
-;;
-;; The ediff-nix-help-in-control-buffer, if set to t, makes C-h behave like
-;; the DEL key, i.e., it will move you back to the previous difference
-;; rather than invoking help.  This is useful when, in an xterm window or on
-;; a dumb terminal, the Backspace key is bound to C-h and is positioned
-;; more conveniently than the DEL key.
-
-
-;;; Commands
-;;  --------
+;;; Bugs:
 
-;; All Ediff commands are displayed in a help window, unless you hit '?' to
-;; shrink it to just one line.  You can redisplay the help window by hitting
-;; '?' again.
-;;
-;; Many Ediff commands take numeric prefix arguments.  For instance, if you
-;; hit a number, n, and then 'j' (ediff-jump-to-difference), Ediff will
-;; take you to Nth difference.  Hitting a number, n, and then 'ab'
-;; (ediff-diff-to-diff) will copy Nth difference from buffer A to buffer B.
-;; Hitting 'ba' does copying in the other direction.
-;; Likewise, a number, n, followed by 'ra' will restore the Nth difference
-;; region in buffer A (if it was previously saved as a result of copying
-;; from B to A). 
-;;
-;; Without the prefix argument, all commands operate on the current
-;; difference region.
+;;  1. The undo command doesn't restore deleted regions well.  That is, if
+;;  you delete all characters in a difference region and then invoke
+;;  `undo', the reinstated text will most likely be inserted outside of
+;;  what Ediff thinks is the current difference region. (This problem
+;;  doesn't seem to exist with XEmacs.)
 ;;
-;; The total number of differences and the current difference number are
-;; always displayed in the mode line of the control window. 
+;;  If at any point you feel that difference regions are no longer correct,
+;;  you can hit '!' to recompute the differences.
 
-;;; Display Modes
-;;  -------------
+;;  2. On a monochrome display, the repertoire of faces with which to
+;;  highlight fine differences is limited.  By default, Ediff is using
+;;  underlining.  However, if the region is already underlined by some other
+;;  overlays, there is no simple way to temporarily remove that residual
+;;  underlining.  This problem occurs when a buffer is highlighted with
+;;  hilit19.el or font-lock.el packages.  If this residual highlighting gets
+;;  in the way, you can do the following.  Both font-lock.el and hilit19.el
+;;  provide commands for unhighlighting buffers.  You can either place these
+;;  commands in `ediff-prepare-buffer-hook' (which will unhighlight every
+;;  buffer used by Ediff) or you can execute them interactively, at any time
+;;  and on any buffer.
 
-;; Ediff can display files in one frame, stacked side-by-side or one on top
-;; of another; or it can display the files in different frames.  When you
-;; start Ediff, it assumes a 1-frame mode.  You can toggle the side-by-side
-;; and one-on-top-of-another displays by simply hitting 's'.
-;;
-;; Ediff switches to the multi-frame mode when:
-;;
-;;  1. file-A and file-B are in different frames (you have to put them into
-;;     different frames manually); or
-;;  2. *ediff-control* buffer is visible in one frame and one other file (A
-;;     or B) is visible in another frame.  If, say, fileA is visible in a
-;;     different frame than *ediff-control*, fileB doesn't have to be
-;;     visible.  If it is, Ediff will continue displaying fileB in the frame
-;;     where it was visible before.  If it isn't then Ediff will arrange for
-;;     fileB to share a frame with *ediff-control*.
-;;
-;;  If all three buffers are in separate frames, Ediff will switch to a
-;;  3-frame mode.  If Ediff buffers are currently visible only in two
-;;  frames, Ediff will work in a 2-frame mode.  In this mode, one of the
-;;  frames will be shared by *ediff-control* and file-A or file-B
-;;  (whichever is appropriate).
 
+;;; Acknowledgements:
 
-;;; Bugs:
-;;  ----
+;; Ediff was inspired by Dale R. Worley's <drw@math.mit.edu> emerge.el.
+;; Ediff would not have been possible without the help and encouragement of
+;; its many users.  See Ediff on-line Info for the full list of those who
+;; helped.  Improved defaults in Ediff file-name reading commands.
 
-;;  1. The undo command doesn't restore deleted regions well. That is, if
-;;  you delete all characters in a difference region and then invoke
-;;  `undo', the reinserted text will most likely be reinserted outside of
-;;  what Ediff thinks is the current difference region.
+;;; Code:
 
-;;  2. You may get an error if your colormap doesn't have the colors requested
-;;  by Ediff (on a color display). If this happens, you should create your 
-;;  own faces using available colors. See `ediff-current-diff-face-A',
-;;  ediff-current-diff-face-B, ediff-even-diff-face-A, ediff-even-diff-face-B,
-;;  ediff-odd-diff-face-A, and ediff-odd-diff-face-B to get an idea on how
-;;  to do this.
 
+;; Compiler pacifier
+(defvar cvs-cookie-handle)
+(defvar ediff-last-dir-patch)
+(defvar ediff-patch-default-directory)
+
+(and noninteractive
+     (eval-when-compile
+        (load-library "dired")
+        (load-library "info")
+        (load "pcl-cvs" 'noerror)))
+(eval-when-compile
+  (let ((load-path (cons (expand-file-name ".") load-path)))
+    (provide 'ediff) ; to break recursive load cycle
+    (or (featurep 'ediff-init)
+       (load "ediff-init.el" nil nil 'nosuffix))
+    (or (featurep 'ediff-mult)
+       (load "ediff-mult.el" nil nil 'nosuffix))
+    (or (featurep 'ediff-ptch)
+       (load "ediff-ptch.el" nil nil 'nosuffix))
+    (or (featurep 'ediff-vers)
+       (load "ediff-vers.el" nil nil 'nosuffix))
+    ))
+;; end pacifier
+
+(require 'ediff-init)
+(require 'ediff-mult)  ; required because of the registry stuff
+
+(defgroup ediff nil
+  "A comprehensive visual interface to diff & patch."
+  :tag "Ediff"
+  :group 'tools)
+
+
+(defcustom ediff-use-last-dir nil
+  "*If t, Ediff will use previous directory as default when reading file name."
+  :type 'boolean
+  :group 'ediff)
+
+;; Last directory used by an Ediff command for file-A.
+(defvar ediff-last-dir-A nil)
+;; Last directory used by an Ediff command for file-B.
+(defvar ediff-last-dir-B nil)
+;; Last directory used by an Ediff command for file-C.
+(defvar ediff-last-dir-C nil)
+;; Last directory used by an Ediff command for the ancestor file.
+(defvar ediff-last-dir-ancestor nil)
+;; Last directory used by an Ediff command as the output directory for merge.
+(defvar ediff-last-merge-autostore-dir nil)
+
+
+;; Used as a startup hook to set `_orig' patch file read-only.
+(defun ediff-set-read-only-in-buf-A ()
+  (ediff-with-current-buffer ediff-buffer-A
+    (toggle-read-only 1)))
+
+;; Return a plausible default for ediff's first file:
+;; In dired, return the file number FILENO (or 0) in the list
+;; (all-selected-files, filename under the cursor), where directories are
+;; ignored. Otherwise, return DEFAULT file name, if non-nil. Else,
+;; if the buffer is visiting a file, return that file name.
+(defun ediff-get-default-file-name (&optional default fileno)
+  (cond ((eq major-mode 'dired-mode)
+        (let ((current (dired-get-filename nil 'no-error))
+              (marked (condition-case nil
+                          (dired-get-marked-files 'no-dir)
+                        (error nil)))
+              aux-list choices result)
+          (or (integerp fileno) (setq fileno 0))
+          (if (stringp default)
+              (setq aux-list (cons default aux-list)))
+          (if (and (stringp current) (not (file-directory-p current)))
+              (setq aux-list (cons current aux-list)))
+          (setq choices (nconc  marked aux-list))
+          (setq result (elt choices fileno))
+          (or result
+              default)))
+       ((stringp default) default)
+       ((buffer-file-name (current-buffer))
+        (file-name-nondirectory (buffer-file-name (current-buffer))))
+       ))
 
-;;; Change Log:
-;;  ----------
+;;; Compare files/buffers
 
-;; Thu Feb  3, 1994 
+;;;###autoload
+(defun ediff-files (file-A file-B &optional startup-hooks)
+  "Run Ediff on a pair of files, FILE-A and FILE-B."
+  (interactive
+   (let ((dir-A (if ediff-use-last-dir
+                   ediff-last-dir-A
+                 default-directory))
+        dir-B f)
+     (list (setq f (ediff-read-file-name
+                   "File A to compare"
+                   dir-A
+                   (ediff-get-default-file-name)
+                   'no-dirs))
+          (ediff-read-file-name "File B to compare"
+                                (setq dir-B
+                                      (if ediff-use-last-dir
+                                          ediff-last-dir-B
+                                        (file-name-directory f)))
+                                (progn
+                                  (setq file-name-history
+                                        (cons (ediff-abbreviate-file-name
+                                               (expand-file-name
+                                                (file-name-nondirectory f)
+                                                dir-B))
+                                              file-name-history))
+                                  (ediff-get-default-file-name f 1)))
+          )))
+  (ediff-files-internal file-A
+                       (if (file-directory-p file-B)
+                           (expand-file-name
+                            (file-name-nondirectory file-A) file-B)
+                         file-B)
+                       nil ; file-C
+                       startup-hooks
+                       'ediff-files))
 
-;;     Added ediff-read-file-name, which is a stub that takes care of Lemacs
-;;     versions of Emerge. (Thanks to Alastair Burt <burt@dfki.uni-kl.de>.)
-;;
-;;     Fixed a bug in ediff-setup-windows that caused control window to
-;;     appear in a wrong place when split-window-keep-point is nil
-;;     (Thanks to Kevin Broadey <KevinB@bartley.demon.co.uk>.)
-;;
-;;     Added mechanism for using faces instead of before/after flags.  This
-;;     looks much better on an X display, especially on a color one.
-;;     (Thanks to Boris Goldowsky <boris@cs.rochester.edu> for the code
-;;     that led to ediff-highlight-diff.
-;;     Also, thanks to Kevin Esler <esler@ch.hp.com> for suggestions
-;;     regarding highlighting differences on X displays.)
-;;
-;;     Added functions to apply patches.
-;;     (Thanks to Kevin Broadey <KevinB@bartley.demon.co.uk> for this
-;;     suggestion.)
+;;;###autoload
+(defun ediff-files3 (file-A file-B file-C &optional startup-hooks)
+  "Run Ediff on three files, FILE-A, FILE-B, and FILE-C."
+  (interactive
+   (let ((dir-A (if ediff-use-last-dir
+                   ediff-last-dir-A
+                 default-directory))
+        dir-B dir-C f ff)
+     (list (setq f (ediff-read-file-name
+                   "File A to compare"
+                   dir-A
+                   (ediff-get-default-file-name)
+                   'no-dirs))
+          (setq ff (ediff-read-file-name "File B to compare"
+                                         (setq dir-B
+                                               (if ediff-use-last-dir
+                                                   ediff-last-dir-B
+                                                 (file-name-directory f)))
+                                         (progn
+                                           (setq file-name-history
+                                                 (cons
+                                                  (ediff-abbreviate-file-name
+                                                   (expand-file-name
+                                                    (file-name-nondirectory f)
+                                                    dir-B))
+                                                  file-name-history))
+                                           (ediff-get-default-file-name f 1))))
+          (ediff-read-file-name "File C to compare"
+                                (setq dir-C (if ediff-use-last-dir
+                                                ediff-last-dir-C
+                                              (file-name-directory ff)))
+                                (progn
+                                  (setq file-name-history
+                                        (cons (ediff-abbreviate-file-name
+                                               (expand-file-name
+                                                (file-name-nondirectory ff)
+                                                dir-C))
+                                              file-name-history))
+                                  (ediff-get-default-file-name ff 2)))
+          )))
+  (ediff-files-internal file-A
+                       (if (file-directory-p file-B)
+                           (expand-file-name
+                            (file-name-nondirectory file-A) file-B)
+                         file-B)
+                       (if (file-directory-p file-C)
+                           (expand-file-name
+                            (file-name-nondirectory file-A) file-C)
+                         file-C)
+                       startup-hooks
+                       'ediff-files3))
 
-;; Fri Feb  4, 1994 
+;;;###autoload
+(defalias 'ediff3 'ediff-files3)
+
+
+;; Visit FILE and arrange its buffer to Ediff's liking.
+;; FILE is actually a variable symbol that must contain a true file name.
+;; BUFFER-NAME is a variable symbol, which will get the buffer object into
+;; which FILE is read.
+;; LAST-DIR is the directory variable symbol where FILE's
+;; directory name should be returned.  HOOKS-VAR is a variable symbol that will
+;; be assigned the hook to be executed after `ediff-startup' is finished.
+;; `ediff-find-file' arranges that the temp files it might create will be
+;; deleted.
+(defun ediff-find-file (file-var buffer-name &optional last-dir hooks-var)
+  (let* ((file (symbol-value file-var))
+        (file-magic (ediff-filename-magic-p file))
+        (temp-file-name-prefix (file-name-nondirectory file)))
+    (cond ((not (file-readable-p file))
+          (error "File `%s' does not exist or is not readable" file))
+         ((file-directory-p file)
+          (error "File `%s' is a directory" file)))
+
+    ;; some of the commands, below, require full file name
+    (setq file (expand-file-name file))
+
+    ;; Record the directory of the file
+    (if last-dir
+       (set last-dir (expand-file-name (file-name-directory file))))
+
+    ;; Setup the buffer
+    (set buffer-name (find-file-noselect file))
+
+    (ediff-with-current-buffer (symbol-value buffer-name)
+      (widen) ; Make sure the entire file is seen
+      (cond (file-magic  ;   file has a handler, such as jka-compr-handler or
+                        ;;; ange-ftp-hook-function--arrange for temp file
+            (ediff-verify-file-buffer 'magic)
+            (setq file
+                  (ediff-make-temp-file
+                   (current-buffer) temp-file-name-prefix))
+            (set hooks-var (cons `(lambda () (delete-file ,file))
+                                 (symbol-value hooks-var))))
+           ;; file processed via auto-mode-alist, a la uncompress.el
+           ((not (equal (file-truename file)
+                        (file-truename (buffer-file-name))))
+            (setq file
+                  (ediff-make-temp-file
+                   (current-buffer) temp-file-name-prefix))
+            (set hooks-var (cons `(lambda () (delete-file ,file))
+                                 (symbol-value hooks-var))))
+           (t ;; plain file---just check that the file matches the buffer
+            (ediff-verify-file-buffer))))
+    (set file-var file)))
+
+;; MERGE-BUFFER-FILE is the file to be associated with the merge buffer
+(defun ediff-files-internal (file-A file-B file-C startup-hooks job-name
+                                   &optional merge-buffer-file)
+  (let (buf-A buf-B buf-C)
+    (if (string= file-A file-B)
+       (error "Files A and B are the same"))
+    (if (stringp file-C)
+       (or (and (string= file-A file-C) (error "Files A and C are the same"))
+           (and (string= file-B file-C) (error "Files B and C are the same"))))
+    (message "Reading file %s ... " file-A)
+    ;;(sit-for 0)
+    (ediff-find-file 'file-A 'buf-A 'ediff-last-dir-A 'startup-hooks)
+    (message "Reading file %s ... " file-B)
+    ;;(sit-for 0)
+    (ediff-find-file 'file-B 'buf-B 'ediff-last-dir-B 'startup-hooks)
+    (if (stringp file-C)
+       (progn
+         (message "Reading file %s ... " file-C)
+         ;;(sit-for 0)
+         (ediff-find-file
+          'file-C 'buf-C
+          (if (eq job-name 'ediff-merge-files-with-ancestor)
+              'ediff-last-dir-ancestor 'ediff-last-dir-C)
+          'startup-hooks)))
+    (ediff-setup buf-A file-A
+                buf-B file-B
+                buf-C file-C
+                startup-hooks
+                (list (cons 'ediff-job-name job-name))
+                merge-buffer-file)))
 
-;;     Added mechanism for toggling vertical/horizontal window split.
-;;     (Inspired by a suggestion from Allan Gottlieb
-;;     <gottlieb@allan.ultra.nyu.edu> -- thanks.)
-;;
-;;     Added mechanism for toggling between highlighting using faces and
-;;     highlighting using ASCII flags.
-;;
-;;     Fixed a problem with undo.  Now, Ediff has smartened up and doesn't
-;;     keep undo info on ASCII flags inserted in buffer-A and buffer-B.
-;;     So, if you edit the files while browsing through them, undo behaves
-;;     as you would expect, i.e., faces/flags don't get in the way.
-
-;; Sun Feb  6, 1994 
-
-;;     Added horizontal scrolling.  Added ediff-position-region to ensure
-;;     that difference regions in buffer-A and buffer-B are aligned with
-;;     each other.  Disabled ediff-toggle-split when buffers are displayed
-;;     in different frames.
-
-;; Mon Feb  7, 1994
-
-;;     Added toggle-window help (Suggested by Boris Goldowsky
-;;     <boris@cs.rochester.edu>.)
-;;     Added functions to copy differences from one buffer to another and to
-;;     recover old differences.
-;;     Added prefix arguments to ediff-next-difference and
-;;     ediff-previous-difference.
-
-;; Tue Feb  8, 1994
-
-;;     Replaced text properties with overlays.  Fixed ediff-setup-windows.
-;;     Added ediff-save-buffer to local-write-file-hooks to prevent user
-;;     from saving corrupted states. (Thanks to <boris@cs.rochester.edu>
-;;     for suggestion.)  Instead, Ediff now has a pair of functions for
-;;     safe saving of buffers. 
-;;     Changed ediff-read-file-name to be more intuitive on ediff-files.
-;;     Added ediff-prepare-buffer-hooks. (Thanks to Kevin Esler
-;;     <esler@ch.hp.com> for the idea.)
-
-;; Wed Feb  9, 1994
-
-;;     Cleanups in ediff-patch-file.  Protected ediff-copy-diff against
-;;     a bug that Emacs has in kill-region.
-
-;; Thu Feb 10, 1994
-
-;;     Added support for Lemacs. (Thanks to Alastair Burt
-;;     <burt@dfki.uni-kl.de> for coercing Ediff into working under Lemacs.)
-;;     Added ediff-kill-buffer-carefully and other suggestions by Boris
-;;     Goldowsky <boris@cs.rochester.edu>.
-;;     Refined the protection against interference with highlighting caused
-;;     by Hilit19.  Added the variable ediff-third-party-highlighting.
-;;     Added mechanisn for unhighlighting regions highlighted with Hilit19
-;;     before hightlighting them with Ediff's overlays. (And for
-;;     rehighlighting them with Hilit19, when the current difference moves on.)
-
-;; Sun Feb 13, 1994
-
-;;     Added ediff-place-flags-in-buffer and ediff-remote-exit, which are
-;;     modifications of Emerge's similar functions.  The difference is that
-;;     in Ediff they make ediff-before-flag and ediff-after-flag into
-;;     read-only regions, so the user can't change them by mistake.
-;;
-;;     Adopted a suggestion by Boris Goldowsky <boris@cs.rochester.edu>
-;;     that led to a more elegant treatment of faces.
-;;
-;;     Added protection against interference with Font-Lock highlighting
-;;     similar to that of Hilit19's protection.
 
-;; Tue Feb 15, 1994
+;;;###autoload
+(defalias 'ediff 'ediff-files)
 
-;;     Deleted spurious (auto-save-mode 1) in ediff-control-buffer, which
-;;     was causing this buffer to be auto-saved for no good reason.
-;;     Added read-only protection to ediff-before/after-flags in Lemacs.
-;;     (Thanks to Alastair Burt <burt@dfki.uni-kl.de> for help in testing.)
+;;;###autoload
+(defun ediff-backup (file)
+  "Run Ediff on FILE and its backup file.
+Uses the latest backup, if there are several numerical backups.
+If this file is a backup, `ediff' it with its original."
+  (interactive (list (read-file-name "Ediff (file with backup): ")))
+  ;; The code is taken from `diff-backup'.
+  (require 'diff)
+  (let (bak ori)
+    (if (backup-file-name-p file)
+       (setq bak file
+             ori (file-name-sans-versions file))
+      (setq bak (or (diff-latest-backup-file file)
+                   (error "No backup found for %s" file))
+           ori file))
+    (ediff-files bak ori)))
 
-;; Wed Feb 16, 1994
+;;;###autoload
+(defun ediff-buffers (buffer-A buffer-B &optional startup-hooks job-name)
+  "Run Ediff on a pair of buffers, BUFFER-A and BUFFER-B."
+  (interactive
+   (let (bf)
+     (list (setq bf (read-buffer "Buffer A to compare: "
+                                (ediff-other-buffer "") t))
+          (read-buffer "Buffer B to compare: "
+                       (progn
+                         ;; realign buffers so that two visible bufs will be
+                         ;; at the top
+                         (save-window-excursion (other-window 1))
+                         (ediff-other-buffer bf))
+                       t))))
+  (or job-name (setq job-name 'ediff-buffers))
+  (ediff-buffers-internal buffer-A buffer-B nil startup-hooks job-name))
 
-;;     Further fixes in the Lemacs part.  Changed highlighted region in
-;;     ediff-highlight-diff so that an extra character will be highlighted
-;;     only if a difference is empty (thereby allowing the user to see where an
-;;     insertion or a deletion has taken place).
-;;
-;;     Simplified interaction with other highlighting packages by giving
-;;     Ediff overlays the highest priority. (Taking a cue from
-;;     ediff-highlight-diff-lemacs written by Alastair Burt
-;;     <burt@dfki.uni-kl.de>.) Zapped ediff-third-party-highlighting
-;;     variable and hooks that were previously used to
-;;     unhighlight/rehighlight buffers when hilit19/font-lock are on.
+;;;###autoload
+(defalias 'ebuffers 'ediff-buffers)
 
-;; Fri Feb 18, 1994
 
-;;     Added a bit more sophistication to ediff-read-file-name.  Now,
-;;     ediff-files remembers both, the file-A and the file-B directories.
-;;     They are offered as defaults when ediff-use-last-dir is set to t.
+;;;###autoload
+(defun ediff-buffers3 (buffer-A buffer-B buffer-C
+                                &optional startup-hooks job-name)
+  "Run Ediff on three buffers, BUFFER-A, BUFFER-B, and BUFFER-C."
+  (interactive
+   (let (bf bff)
+     (list (setq bf (read-buffer "Buffer A to compare: "
+                                (ediff-other-buffer "") t))
+          (setq bff (read-buffer "Buffer B to compare: "
+                                 (progn
+                                   ;; realign buffers so that two visible
+                                   ;; bufs will be at the top
+                                   (save-window-excursion (other-window 1))
+                                   (ediff-other-buffer bf))
+                                 t))
+          (read-buffer "Buffer C to compare: "
+                                 (progn
+                                   ;; realign buffers so that three visible
+                                   ;; bufs will be at the top
+                                   (save-window-excursion (other-window 1))
+                                   (ediff-other-buffer (list bf bff)))
+                                 t)
+          )))
+  (or job-name (setq job-name 'ediff-buffers3))
+  (ediff-buffers-internal buffer-A buffer-B buffer-C startup-hooks job-name))
 
-;; Fri Feb 22, 1994
+;;;###autoload
+(defalias 'ebuffers3 'ediff-buffers3)
+
+
+
+;; MERGE-BUFFER-FILE is the file to be associated with the merge buffer
+(defun ediff-buffers-internal (buf-A buf-B buf-C startup-hooks job-name
+                                    &optional merge-buffer-file)
+  (let* ((buf-A-file-name (buffer-file-name (get-buffer buf-A)))
+        (buf-B-file-name (buffer-file-name (get-buffer buf-B)))
+        (buf-C-is-alive (ediff-buffer-live-p buf-C))
+        (buf-C-file-name (if buf-C-is-alive
+                             (buffer-file-name (get-buffer buf-B))))
+        file-A file-B file-C)
+    (if (not (ediff-buffer-live-p buf-A))
+       (error "Buffer %S doesn't exist" buf-A))
+    (if (not (ediff-buffer-live-p buf-B))
+       (error "Buffer %S doesn't exist" buf-B))
+    (let ((ediff-job-name job-name))
+      (if (and ediff-3way-comparison-job
+              (not buf-C-is-alive))
+         (error "Buffer %S doesn't exist" buf-C)))
+    (if (stringp buf-A-file-name)
+       (setq buf-A-file-name (file-name-nondirectory buf-A-file-name)))
+    (if (stringp buf-B-file-name)
+       (setq buf-B-file-name (file-name-nondirectory buf-B-file-name)))
+    (if (stringp buf-C-file-name)
+       (setq buf-C-file-name (file-name-nondirectory buf-C-file-name)))
+
+    (setq file-A (ediff-make-temp-file buf-A buf-A-file-name)
+         file-B (ediff-make-temp-file buf-B buf-B-file-name))
+    (if buf-C-is-alive
+       (setq file-C (ediff-make-temp-file buf-C buf-C-file-name)))
+
+    (ediff-setup (get-buffer buf-A) file-A
+                (get-buffer buf-B) file-B
+                (if buf-C-is-alive (get-buffer buf-C))
+                file-C
+                (cons `(lambda ()
+                         (delete-file ,file-A)
+                         (delete-file ,file-B)
+                         (if (stringp ,file-C) (delete-file ,file-C)))
+                      startup-hooks)
+                (list (cons 'ediff-job-name job-name))
+                merge-buffer-file)))
 
-;;     Added ediff-before-change-guard to remove ASCII highlighting when
-;;     the user attempts to change buffer-A/B.  This is needed because
-;;     otherwise the undo info may become screwed up in those buffers.
-;;     Hitting 'h' (ediff-toggle-hilit) on a dumb terminal will toggle
-;;     between ASCII highlighting and no highlighting.
 
-;; Fri Feb 24, 1994
+;;; Directory and file group operations
 
-;;     Fixed problems with multiple Ediff sessions running simultaneously.
+;; Get appropriate default name for directory:
+;; If ediff-use-last-dir, use ediff-last-dir-A.
+;; In dired mode, use the directory that is under the point (if any);
+;; otherwise, use default-directory
+(defun ediff-get-default-directory-name ()
+  (cond (ediff-use-last-dir ediff-last-dir-A)
+       ((eq major-mode 'dired-mode)
+        (let ((f (dired-get-filename nil 'noerror)))
+          (if (and (stringp f) (file-directory-p f))
+              f
+            default-directory)))
+       (t default-directory)))
 
-;; Tue Mar 1, 1994
 
-;;     Added vc-ediff, the Ediff interface to vc.el. (Thanks to Eric
-;;     Freudenthal <freudent@jan.ultra.nyu.edu> for contributing this
-;;     function.) 
+;;;###autoload
+(defun ediff-directories (dir1 dir2 regexp)
+  "Run Ediff on a pair of directories, DIR1 and DIR2, comparing files that have
+the same name in both.  The third argument, REGEXP, is nil or a regular
+expression; only file names that match the regexp are considered."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        f)
+     (list (setq f (ediff-read-file-name "Directory A to compare:" dir-A nil))
+          (ediff-read-file-name "Directory B to compare:"
+                                (if ediff-use-last-dir
+                                    ediff-last-dir-B
+                                  (ediff-strip-last-dir f))
+                                nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directories-internal
+   dir1 dir2 nil regexp 'ediff-files 'ediff-directories
+   ))
 
-;; Sun Mar 6, 1994
+;;;###autoload
+(defalias 'edirs 'ediff-directories)
 
-;;     Added rcs-ediff, an Ediff interface to RCS via rcs.el. (Thanks to
-;;     Alastair Burt  <burt@dfki.uni-kl.de>.)
-;;     Some minor improvements.
 
-;; Tue March 15, 1994
+;;;###autoload
+(defun ediff-directory-revisions (dir1 regexp)
+  "Run Ediff on a directory, DIR1, comparing its files with their revisions.
+The second argument, REGEXP, is a regular expression that filters the file
+names.  Only the files that are under revision control are taken into account."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        )
+     (list (ediff-read-file-name
+           "Directory to compare with revision:" dir-A nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directory-revisions-internal
+   dir1 regexp 'ediff-revision 'ediff-directory-revisions
+   ))
 
-;;     Fixed a buglet in defining ediff-current-diff-face-A/B.
-;;     (Thanks to Job Ganzevoort  <Job.Ganzevoort@cwi.nl>.) 
+;;;###autoload
+(defalias 'edir-revisions 'ediff-directory-revisions)
 
-;; Tue March 22, 1994
 
-;;     Fixed a bug with ediffing narrowed buffers, reported by Kevin
-;;     Broadey <KevinB@bartley.demon.co.uk>.
-;;     Made Ediff to work with files that have incomplete last line.
-;;     Made Ediff execute diff and patch using Bourne Shell, which
-;;     should eliminate problems with $prompt that some people had.
+;;;###autoload
+(defun ediff-directories3 (dir1 dir2 dir3 regexp)
+  "Run Ediff on three directories, DIR1, DIR2, and DIR3, comparing files that
+have the same name in all three.  The last argument, REGEXP, is nil or a
+regular expression; only file names that match the regexp are considered."
 
-;; Thu March 24, 1994
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        f)
+     (list (setq f (ediff-read-file-name "Directory A to compare:" dir-A nil))
+          (setq f (ediff-read-file-name "Directory B to compare:"
+                                        (if ediff-use-last-dir
+                                            ediff-last-dir-B
+                                          (ediff-strip-last-dir f))
+                                        nil))
+          (ediff-read-file-name "Directory C to compare:"
+                                (if ediff-use-last-dir
+                                    ediff-last-dir-C
+                                  (ediff-strip-last-dir f))
+                                nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directories-internal
+   dir1 dir2 dir3 regexp 'ediff-files3 'ediff-directories3
+   ))
 
-;;     Achieved quadratic speedup in the size of the file by replacing the
-;;     slow goto-line by forward-line.  Ediff is now *much* faster than
-;;     Emerge on large files.  Converted demarkation of difference regions
-;;     from markers to overlays.  This will later allow us to highlight all
-;;     diffs, not just the current one.
+;;;###autoload
+(defalias 'edirs3 'ediff-directories3)
 
-;; Wed March 30, 1994
+;;;###autoload
+(defun ediff-merge-directories (dir1 dir2 regexp &optional merge-autostore-dir)
+  "Run Ediff on a pair of directories, DIR1 and DIR2, merging files that have
+the same name in both.  The third argument, REGEXP, is nil or a regular
+expression; only file names that match the regexp are considered."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        f)
+     (list (setq f (ediff-read-file-name "Directory A to merge:" dir-A nil))
+          (ediff-read-file-name "Directory B to merge:"
+                                (if ediff-use-last-dir
+                                    ediff-last-dir-B
+                                  (ediff-strip-last-dir f))
+                                nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directories-internal
+   dir1 dir2 nil regexp 'ediff-merge-files 'ediff-merge-directories
+   nil merge-autostore-dir
+   ))
 
-;;     Under X, Ediff now highlights all differences in dim colors and the
-;;     current difference in bright colors. Improved Lucid Emacs support.
+;;;###autoload
+(defalias 'edirs-merge 'ediff-merge-directories)
 
-;; Thu March 31, 1994
+;;;###autoload
+(defun ediff-merge-directories-with-ancestor (dir1 dir2 ancestor-dir regexp
+                                                  &optional
+                                                  merge-autostore-dir)
+  "Merge files in directories DIR1 and DIR2 using files in ANCESTOR-DIR as ancestors.
+Ediff merges files that have identical names in DIR1, DIR2.  If a pair of files
+in DIR1 and DIR2 doesn't have an ancestor in ANCESTOR-DIR, Ediff will merge
+without ancestor.  The fourth argument, REGEXP, is nil or a regular expression;
+only file names that match the regexp are considered."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        f)
+     (list (setq f (ediff-read-file-name "Directory A to merge:" dir-A nil))
+          (setq f (ediff-read-file-name "Directory B to merge:"
+                                (if ediff-use-last-dir
+                                    ediff-last-dir-B
+                                  (ediff-strip-last-dir f))
+                                nil))
+          (ediff-read-file-name "Ancestor directory:"
+                                (if ediff-use-last-dir
+                                    ediff-last-dir-C
+                                  (ediff-strip-last-dir f))
+                                nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directories-internal
+   dir1 dir2 ancestor-dir regexp
+   'ediff-merge-files-with-ancestor 'ediff-merge-directories-with-ancestor
+   nil merge-autostore-dir
+   ))
 
-;;     Changed toggle hilit to cycle through 3 states: highlighting all
-;;     diffs, highlighting only the current diff, and highlighting using
-;;     ASCII flags.
-;;     Added support for difference regions that are not full lines.
+;;;###autoload
+(defun ediff-merge-directory-revisions (dir1 regexp
+                                            &optional merge-autostore-dir)
+  "Run Ediff on a directory, DIR1, merging its files with their revisions.
+The second argument, REGEXP, is a regular expression that filters the file
+names.  Only the files that are under revision control are taken into account."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        )
+     (list (ediff-read-file-name
+           "Directory to merge with revisions:" dir-A nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directory-revisions-internal
+   dir1 regexp 'ediff-merge-revisions 'ediff-merge-directory-revisions
+   nil merge-autostore-dir
+   ))
 
-;; Fri April 1, 1994
+;;;###autoload
+(defalias 'edir-merge-revisions 'ediff-merge-directory-revisions)
 
-;;     Fixed bugs related to writing buffers A and B.
-;;     Added commands 'ga', 'gb' to jump directly to the closest diff in
-;;     buffer A and B, respectively.
+;;;###autoload
+(defun ediff-merge-directory-revisions-with-ancestor (dir1 regexp
+                                                          &optional
+                                                          merge-autostore-dir)
+  "Run Ediff on a directory, DIR1, merging its files with their revisions and ancestors.
+The second argument, REGEXP, is a regular expression that filters the file
+names.  Only the files that are under revision control are taken into account."
+  (interactive
+   (let ((dir-A (ediff-get-default-directory-name))
+        (default-regexp (eval ediff-default-filtering-regexp))
+        )
+     (list (ediff-read-file-name
+           "Directory to merge with revisions and ancestors:" dir-A nil)
+          (read-string
+           (if (stringp default-regexp)
+               (format "Filter through regular expression (default %s): "
+                        default-regexp)
+             "Filter through regular expression: ")
+           nil
+           'ediff-filtering-regexp-history
+           (eval ediff-default-filtering-regexp))
+          )))
+  (ediff-directory-revisions-internal
+   dir1 regexp 'ediff-merge-revisions-with-ancestor
+   'ediff-merge-directory-revisions-with-ancestor
+   nil merge-autostore-dir
+   ))
 
+;;;###autoload
+(defalias
+  'edir-merge-revisions-with-ancestor
+  'ediff-merge-directory-revisions-with-ancestor)
 
-;;; Code:
+;;;###autoload
+(defalias 'edirs-merge-with-ancestor 'ediff-merge-directories-with-ancestor)
+
+;; Run ediff-action (ediff-files, ediff-merge, ediff-merge-with-ancestors)
+;; on a pair of directories (three directories, in case of ancestor).
+;; The third argument, REGEXP, is nil or a regular expression;
+;; only file names that match the regexp are considered.
+;; JOBNAME is the symbol indicating the meta-job to be performed.
+;; MERGE-AUTOSTORE-DIR is the directory in which to store merged files.
+(defun ediff-directories-internal (dir1 dir2 dir3 regexp action jobname
+                                       &optional startup-hooks
+                                       merge-autostore-dir)
+  ;; ediff-read-file-name is set to attach a previously entered file name if
+  ;; the currently entered file is a directory.  This code takes care of that.
+  (setq dir1 (if (file-directory-p dir1) dir1 (file-name-directory dir1))
+       dir2 (if (file-directory-p dir2) dir2 (file-name-directory dir2)))
+
+  (if (stringp dir3)
+      (setq dir3 (if (file-directory-p dir3) dir3 (file-name-directory dir3))))
+
+  (cond ((string= dir1 dir2)
+        (error "Directories A and B are the same: %s" dir1))
+       ((and (eq jobname 'ediff-directories3)
+             (string= dir1 dir3))
+        (error "Directories A and C are the same: %s" dir1))
+       ((and (eq jobname 'ediff-directories3)
+             (string= dir2 dir3))
+        (error "Directories B and C are the same: %s" dir1)))
+
+  (if merge-autostore-dir
+      (or (stringp merge-autostore-dir)
+         (error "%s: Directory for storing merged files must be a string"
+                jobname)))
+  (let (;; dir-diff-struct is of the form (common-list diff-list)
+       ;; It is a structure where ediff-intersect-directories returns
+       ;; commonalities and differences among directories
+       dir-diff-struct
+       meta-buf)
+    (if (and ediff-autostore-merges
+            (ediff-merge-metajob jobname)
+            (not merge-autostore-dir))
+       (setq merge-autostore-dir
+             (read-file-name "Save merged files in directory: "
+                             (if ediff-use-last-dir
+                                       ediff-last-merge-autostore-dir
+                                     (ediff-strip-last-dir dir1))
+                             nil
+                             'must-match)))
+    ;; verify we are not merging into an orig directory
+    (if merge-autostore-dir
+       (cond ((and (stringp dir1) (string= merge-autostore-dir dir1))
+              (or (y-or-n-p
+                   "Directory for saving merged files = Directory A.  Sure? ")
+                  (error "Directory merge aborted")))
+             ((and (stringp dir2) (string= merge-autostore-dir dir2))
+              (or (y-or-n-p
+                   "Directory for saving merged files = Directory B.  Sure? ")
+                  (error "Directory merge aborted")))
+             ((and (stringp dir3) (string= merge-autostore-dir dir3))
+              (or (y-or-n-p
+                   "Directory for saving merged files = Ancestor Directory.  Sure? ")
+                  (error "Directory merge aborted")))))
+
+    (setq dir-diff-struct (ediff-intersect-directories
+                          jobname
+                          regexp dir1 dir2 dir3 merge-autostore-dir))
+    (setq startup-hooks
+         ;; this sets various vars in the meta buffer inside
+         ;; ediff-prepare-meta-buffer
+         (cons `(lambda ()
+                  ;; tell what to do if the user clicks on a session record
+                  (setq ediff-session-action-function (quote ,action))
+                  ;; set ediff-dir-difference-list
+                  (setq ediff-dir-difference-list
+                        (cdr (quote ,dir-diff-struct))))
+               startup-hooks))
+    (setq meta-buf (ediff-prepare-meta-buffer
+                   'ediff-filegroup-action
+                   (car dir-diff-struct)
+                   "*Ediff Session Group Panel"
+                   'ediff-redraw-directory-group-buffer
+                   jobname
+                   startup-hooks))
+    (ediff-show-meta-buffer meta-buf)
+    ))
 
-(require 'emerge) ;; Ediff is based on emerge
-
-
-;;; Macros
-(defmacro ediff-if-lucid ()
-  (` (string-match "Lucid" emacs-version)))
-(defmacro ediff-odd-p (arg)
-  (` (eq (logand (, arg) 1) 1)))
-(defmacro ediff-buffer-live-p (buf)
-  (` (and (, buf) (get-buffer (, buf)) (buffer-name (get-buffer (, buf))))))
-
-
-(defun ediff-mode ()
-  "Ediff mode is used by the Ediff file-difference package.
-It is entered only through one of the following commands:
-       `ediff'
-       `ediff-files'
-       `ediff-buffers'
-       `epatch'
-       `ediff-patch-file'
-       `ediff-patch-buffer'
-       `vc-ediff'
-       `rcs-ediff'
-or through a non-interactive Emacs Lisp function       
-       `ediff-files-remote'
-
-Commands:
-\\{ediff-mode-map}"
-  (interactive)
-  (kill-all-local-variables)
-  (setq major-mode 'ediff-mode)
-  (setq mode-name "Ediff"))
+;; MERGE-AUTOSTORE-DIR can be given to tell ediff where to store the merged
+;; files
+(defun ediff-directory-revisions-internal (dir1 regexp action jobname
+                                               &optional startup-hooks
+                                               merge-autostore-dir)
+  (setq dir1 (if (file-directory-p dir1) dir1 (file-name-directory dir1)))
+
+  (if merge-autostore-dir
+      (or (stringp merge-autostore-dir)
+         (error "%S: Directory for storing merged files must be a string"
+                jobname)))
+  (let (file-list meta-buf)
+    (if (and ediff-autostore-merges
+            (ediff-merge-metajob jobname)
+            (not merge-autostore-dir))
+       (setq merge-autostore-dir
+             (read-file-name "Save merged files in directory: "
+                             (if ediff-use-last-dir
+                                 ediff-last-merge-autostore-dir
+                               (ediff-strip-last-dir dir1))
+                             nil
+                             'must-match)))
+    ;; verify merge-autostore-dir != dir1
+    (if (and merge-autostore-dir
+            (stringp dir1)
+            (string= merge-autostore-dir dir1))
+       (or (y-or-n-p
+            "Directory for saving merged file = directory A.  Sure? ")
+           (error "Merge of directory revisions aborted")))
+
+    (setq file-list
+         (ediff-get-directory-files-under-revision
+          jobname regexp dir1 merge-autostore-dir))
+    (setq startup-hooks
+         ;; this sets various vars in the meta buffer inside
+         ;; ediff-prepare-meta-buffer
+         (cons `(lambda ()
+                  ;; tell what to do if the user clicks on a session record
+                  (setq ediff-session-action-function (quote ,action)))
+               startup-hooks))
+    (setq meta-buf (ediff-prepare-meta-buffer
+                   'ediff-filegroup-action
+                   file-list
+                   "*Ediff Session Group Panel"
+                   'ediff-redraw-directory-group-buffer
+                   jobname
+                   startup-hooks))
+    (ediff-show-meta-buffer meta-buf)
+    ))
 
-(defvar ediff-version "1.31"
-  "The current version of Ediff.")
 
-(defun ediff-version ()
-  "Return string describing the version of Ediff.
-When called interactively, displays the version."
-  (interactive)
-  (if (interactive-p)
-      (message "Ediff version %s" (ediff-version))
-    ediff-version))
-
-
-;; Hook variables
-
-(defvar ediff-before-setup-windows-hooks nil
-  "* Hooks to run before Ediff sets its own window config.
-This can be used to save the previous window config, which can be
-restored by `ediff-quit' or `ediff-suspend'.")
-
-(defvar ediff-startup-hooks nil
-  "*Hooks to run in the control buffer after Ediff has been set up.")
-(defvar ediff-select-hooks nil
-  "*Hooks to run after a difference has been selected.")
-(defvar ediff-unselect-hooks nil
-  "*Hooks to run after a difference has been unselected.")
-(defvar ediff-prepare-buffer-hooks  nil
-  "*Hooks called after buffers A and B are set up.")
-(defvar ediff-load-hooks nil
-  "*Hook run after Ediff is loaded.  Can be used to change defaults.")
-
-(defvar ediff-suspend-hooks 'ediff-default-suspend-hook
-  "*Hooks to run in the Ediff control buffer when Ediff is suspended.")
-(defvar ediff-quit-hooks 'ediff-default-quit-hook
-  "*Hooks to run in the Ediff control buffer after finishing Ediff.") 
-
-(make-variable-buffer-local 'local-write-file-hooks)
-(make-variable-buffer-local 'before-change-function)
-
-;; Help messages
-
-(defconst ediff-help-message-long
-"p,DEL - prev diff         c - recenter      ab - diff A to B  l - line numbers
-n,SPC - next diff       v/V - scroll up/dn  ba - diff B to A  f - file names
-    j - jump to diff    </> - scroll lt/rt  ra - restore A    z - suspend Ediff
-   ga - goto pt in A      s - toggle split  rb - restore B    q - quit Ediff
-   gb - goto pt in B      h - toggle hilit
-wa/wb - save buf A/B    A/B - toggle read-only buf A/B        ? - toggle help")
-                         
-(defconst ediff-help-message-short
-"                         ? - toggle help window")                       
-
-(defvar ediff-help-message ediff-help-message-long
-  "*The actual help message.")
-(defvar ediff-diff-program "diff"
-  "*Name of the program that compares two files.")
-(defvar ediff-diff-options ""  
-  "*Options to pass to `ediff-diff-program'.")
-  
-
-;; Support for patches 
-
-(defvar ediff-patch-program "patch"
-  "*Name of the program that applies patches.")
-(defvar ediff-patch-options ""
-  "*Options to pass to ediff-patch-program.")
-  
-(defvar ediff-shell "sh"
-  "*The shell used to run diff and patch.
-If user's .profile or .cshrc files are set up correctly, any shell will do.
-However, some people set `$prompt' or other things incorrectly, which
-leads to undesirable output messages.  These may cause Ediff to fail.
-In such a case, set `ediff-shell' to a shell that you are not using or,
-better, fix your shell's startup file.")
-
-(defvar ediff-diff-ok-lines-regexp  
-  "^\\([0-9,]+[acd][0-9,]+$\\|[<>] \\|---\\|Warning:\\)"
-  "*Regexp that matches normal output lines from `ediff-diff-program'.
-This is mostly lifted from Emerge, except that Ediff also considers the
-'Missing newline' message to be 'normal output.'
-Lines that do not match are assumed to be error messages.")
-
-(defvar ediff-match-diff-line (let ((x "\\([0-9]+\\)\\(\\|,\\([0-9]+\\)\\)"))
-                               (concat "^" x "\\([acd]\\)" x "$"))
-  "*Pattern to match lines produced by diff that describe differences.")
-  
-(defvar ediff-patch-buf nil
-  "The buffer of the patch file.")
-(defvar ediff-patch-diagnostics nil
-  "The buffer where patch would display its diagnostics.")
-  
-
-;; Copying diffs betw buffers.    
-
-(emerge-defvar-local ediff-killed-diffs-alist nil
-  "A list of killed diffs.
-A diff is saved here if it is replaced by a diff
-from another buffer.  This alist has the form:
-\((num (A . diff) (B . diff)) ...),
-where A or B parts may be missing.")
-
-
-;; Highlighting
-(defvar ediff-before-flag-bol
-  ;"vvvvvvvvvvvvvvvv---- ediff ----vvvvvvvvvvvvvvv\n"
-  ">>--->>>\n"
-  "*Flag placed above the highlighted block of differences.
-Must end with newline.  Must be set before Ediff is loaded.
-nil means use a default flag string.")
-(defvar ediff-after-flag-bol
-  ;"^^^^^^^^^^^^^^^^---- ediff ----^^^^^^^^^^^^^^^\n"
-  "<<<---<<\n"
-  "*Flag placed below the highlighted block of differences.
-Must end with newline.  Must be set before Ediff is loaded.
-nil means use a default flag string.")
-
-(defvar ediff-before-flag-mol ">>--->>>"
-  "*Like ediff-before-flag, used when a difference starts in mid-line.")
-(defvar ediff-after-flag-mol "<<<---<<"
-  "*Like ediff-after-flag, used when a difference starts in mid-line.")
-
-(emerge-defvar-local ediff-before-flag-A nil
-  "This is the actual ASCII before-flag in effect in buffer A.
-It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
-on whether the selected difference region starts in the middle of a line 
-or at the beginning of a line.")
-(emerge-defvar-local ediff-after-flag-A nil
-  "This is the actual ASCII after-flag in effect in buffer A.
-It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
-on whether the selected difference region starts in the middle of a line 
-or at the beginning of a line.")
-(emerge-defvar-local ediff-before-flag-B nil
-  "This is the actual ASCII before-flag in effect in buffer B.
-It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
-on whether the selected difference region starts in the middle of a line 
-or at the beginning of a line.")
-(emerge-defvar-local ediff-after-flag-B nil
-  "This is the actual ASCII after-flag in effect in buffer B.
-It is either `ediff-before-flag-mol' or `ediff-before-flag-bol' depending
-on whether the selected difference region starts in the middle of a line 
-or at the beginning of a line.")
-
-  
-(emerge-defvar-local ediff-want-faces t
-  "If t, differences are highlighted using faces on a window system.
-If nil, they are highlighted using ASCII flags, ediff-before-flag
-and ediff-after-flag.  On a non-window system, differences are always
-highlighted using ASCII flags.
-
-This is not a user option.  Can be set either in .emacs or toggled
-interactively, using ediff-toggle-hilit.")
-
-(emerge-defvar-local ediff-highlight-selected-only nil
-  "If t, only the selected differences are highlighted.
-This is not a user option.  Can be set either in `.emacs' or toggled
-interactively, using `ediff-toggle-hilit'.")
-
-(emerge-defvar-local ediff-highlighting-style nil
-  "A var local to each ediff-control buffer.
-Indicates highlighting style in effect for this buffer: `face', `ascii',
-nil -- temporarily unhighlighted, `off' -- turned off \(on a dumb
-terminal only\).")
-
-  
-
-;; Variables that control each Ediff session.  They are local to the
-;; control buffer. 
-
-;; Mode variables
-(emerge-defvar-local ediff-A-buffer nil
-  "The buffer in which the A variant is stored.")
-(emerge-defvar-local ediff-B-buffer nil
-  "The buffer in which the B variant is stored.")
-(emerge-defvar-local ediff-control-buffer nil
-  "The control buffer of ediff. ")
-
-(emerge-defvar-local ediff-control-buffer-suffix nil
-  "The suffix of the control buffer name. ")
-  
-(defvar ediff-control-window nil
-  "The control window.")
-
-
-(emerge-defvar-local ediff-A-buffer-values nil
-  "Keeps working values of ediff-saved-variables for ediff-A-buffer.")
-(emerge-defvar-local ediff-B-buffer-values nil
-  "Keeps working values of ediff-saved-variables for ediff-B-buffer.")
-
-(emerge-defvar-local ediff-A-buffer-values-setup nil
-  "Remembers ediff-saved-variables for ediff-A-buffer as they were at setup.")
-(emerge-defvar-local ediff-B-buffer-values-setup nil
-  "Remembers ediff-saved-variables for ediff-B-buffer as they were at setup.")
-
-(emerge-defvar-local ediff-difference-vector nil
-  "Vector of differences between the variants.
-Each difference is represented by a vector of two overlays.  The first
-overlays the difference section in the A buffer and the second
-overlays the diff in the B buffer.  If a difference section is empty,
-the corresponding overlay's endpoints councide. ")
-
-(emerge-defvar-local ediff-current-difference -1
-  "The difference that is currently selected.")
-(emerge-defvar-local ediff-number-of-differences nil
-  "Number of differences found.")
-  
-(emerge-defvar-local ediff-diff-buffer nil
-  "Buffer containing the output of diff, used by Ediff to step through files.")
-(emerge-defvar-local ediff-diff-error-buffer nil
-  "Buffer containing the output of diff, when diff returns errors.")
-  
-(emerge-defvar-local ediff-this-buffer-control-sessions  nil
-  "List of ediff-control buffers associated with each buffer A/B.")
-
-(defvar ediff-disturbed-overlays nil
-  "List of difference overlays disturbed by working with the current diff.")
-  
-(defvar ediff-shaded-overlay-priority 
-  (if (ediff-if-lucid)
-      (1+ mouse-highlight-priority)
-    100)       ;; 100 is a kludge. There is a bug in insert-in-front-hooks
-               ;; in Emacs < 19.23. When this is fixed, I will get rid of
-               ;; this kludge.
-  "Priority of non-selected overlays.")
-
-
-(if (ediff-if-lucid)
-    (progn
-      (fset 'ediff-overlayp (symbol-function 'extentp))
-      (fset 'ediff-make-overlay (symbol-function 'make-extent))
-      (fset 'ediff-delete-overlay (symbol-function 'delete-extent))
-      (fset 'ediff-overlay-put (symbol-function 'set-extent-property))
-      (fset 'ediff-move-overlay (symbol-function 'set-extent-endpoints))
-      (fset 'ediff-overlay-start (symbol-function 'extent-start-position))
-      (fset 'ediff-overlay-end (symbol-function 'extent-end-position))
-      (fset 'ediff-overlay-get (symbol-function 'extent-property)))
-  (fset 'ediff-overlayp (symbol-function 'overlayp))
-  (fset 'ediff-make-overlay (symbol-function 'make-overlay))
-  (fset 'ediff-delete-overlay (symbol-function 'delete-overlay))
-  (fset 'ediff-overlay-put (symbol-function 'overlay-put))
-  (fset 'ediff-move-overlay (symbol-function 'move-overlay))
-  (fset 'ediff-overlay-start (symbol-function 'overlay-start))
-  (fset 'ediff-overlay-end (symbol-function 'overlay-end))
-  (fset 'ediff-overlay-get (symbol-function 'overlay-get)))
-  
-(if window-system
-    (if (ediff-if-lucid)
-       (progn
-         (fset 'ediff-select-frame (symbol-function 'select-screen))
-         (fset 'ediff-window-frame (symbol-function 'window-screen))
-         (fset 'ediff-display-color-p (symbol-function 'x-color-display-p))
-         (fset 'ediff-get-face (symbol-function 'get-face)))
-      (fset 'ediff-window-frame (symbol-function 'window-frame))
-      (fset 'ediff-select-frame (symbol-function 'select-frame))
-      (fset 'ediff-display-color-p (symbol-function 'x-display-color-p))
-      (fset 'ediff-get-face (symbol-function 'internal-get-face)))
-  ;; not a window system
-  (fset 'ediff-window-frame (function (lambda (wind) (if wind 1 nil)) ))
-  (fset 'ediff-select-frame (symbol-function 'identity))
-  (fset 'ediff-make-current-diff-overlay (function (lambda (type) nil)))
-  (fset 'ediff-unhighlight-diffs-totally (function (lambda () nil))))
-  
-
-(if (not window-system)
-    ()
-  (defvar ediff-current-diff-face-A
-    (progn
-      (make-face 'ediff-current-diff-face-A)
-      (cond ((ediff-display-color-p)
-            (set-face-foreground 'ediff-current-diff-face-A "firebrick")
-            (set-face-background 'ediff-current-diff-face-A "pale green"))
-           (t
-            (if (ediff-if-lucid)
-                (copy-face 'modeline 'ediff-current-diff-face-A)
-              (copy-face 'highlight 'ediff-current-diff-face-A))
-            ))
-      (ediff-get-face 'ediff-current-diff-face-A))
-  "Face for highlighting the currently selected difference in buffer A of
-the Ediff display") 
-
-  (defvar ediff-current-diff-face-B
-    (progn
-      (make-face 'ediff-current-diff-face-B)
-      (cond ((ediff-display-color-p)
-            (set-face-foreground 'ediff-current-diff-face-B "DarkOrchid")
-            (set-face-background 'ediff-current-diff-face-B "Yellow"))
-           (t 
-            (if (ediff-if-lucid)
-                (copy-face 'modeline 'ediff-current-diff-face-B)
-              (copy-face 'highlight 'ediff-current-diff-face-B))
-            ))
-      (ediff-get-face 'ediff-current-diff-face-B))
-    "Face for highlighting the currently selected difference in buffer B of
-the Ediff display") 
-
-  (defvar ediff-even-diff-face-A
-    (progn
-      (make-face 'ediff-even-diff-face-A)
-      (cond ((ediff-display-color-p)
-            (set-face-background 'ediff-even-diff-face-A "light grey"))
-           (t 
-            (if (ediff-if-lucid)
-                (progn
-                  (copy-face 'highlight 'ediff-even-diff-face-A)
-                  (invert-face 'ediff-even-diff-face-A))
-              (make-face-italic 'ediff-even-diff-face-A))))
-      (ediff-get-face 'ediff-even-diff-face-A))
-    "Face used to highlight even-numbered differences in buffer A.")
-      
-  (defvar ediff-even-diff-face-B
-    (progn
-      (make-face 'ediff-even-diff-face-B)
-      (cond ((ediff-display-color-p)
-            (set-face-foreground 'ediff-even-diff-face-B "White")
-            (set-face-background 'ediff-even-diff-face-B "Gray"))
-           (t 
-            (if (ediff-if-lucid)
-                (copy-face 'highlight 'ediff-even-diff-face-B)
-              (make-face-italic 'ediff-even-diff-face-B))))
-      (ediff-get-face 'ediff-even-diff-face-B))
-    "Face used to highlight even-numbered differences in buffer B.")
-
-  (defvar ediff-odd-diff-face-A
-    (progn
-      (make-face 'ediff-odd-diff-face-A)
-      (cond ((ediff-display-color-p)
-            (set-face-foreground 'ediff-odd-diff-face-A "White")
-            (set-face-background 'ediff-odd-diff-face-A "Gray"))
-         (t 
-          (if (ediff-if-lucid)
-              (copy-face 'highlight 'ediff-odd-diff-face-A)
-            (make-face-italic 'ediff-odd-diff-face-A))))
-         (ediff-get-face 'ediff-odd-diff-face-A))
-    "Face used to highlight odd-numbered differences in buffer A.")
-      
-  (defvar ediff-odd-diff-face-B
-    (progn
-      (make-face 'ediff-odd-diff-face-B)
-      (cond ((ediff-display-color-p)
-            (set-face-foreground 'ediff-odd-diff-face-B "Black")
-            (set-face-background 'ediff-odd-diff-face-B "light grey"))
-           (t 
-            (if (ediff-if-lucid)
-                (progn
-                  (copy-face 'highlight 'ediff-odd-diff-face-B)
-                  (invert-face 'ediff-odd-diff-face-B))
-              (make-face-italic 'ediff-odd-diff-face-B))))
-      (ediff-get-face 'ediff-odd-diff-face-B))
-    "Face used to highlight odd-numbered differences in buffer B.")
-    
-    
-  ;; Create *-var faces. These are the actual faces used to highlight
-  ;; odd-numbered difference regions.
-  ;; They are used as follows: when highlighting is turned on,
-  ;; ediff-odd/even-diff-face-A/B are copied
-  ;; into ediff-odd/even-diff-face-A/B-var, and all odd/even overlays become
-  ;; highlighted. When highlighting is turned off, then the face 'default is
-  ;; copied into ediff-odd/even-diff-face-A/B-var, thereby unhighlighting all
-  ;; difference regions.
-  (make-face 'ediff-even-diff-face-A-var)
-  (make-face 'ediff-even-diff-face-B-var)
-  (make-face 'ediff-odd-diff-face-A-var)
-  (make-face 'ediff-odd-diff-face-B-var)
-  
-  ;; initialize *-var faces
-  (defun ediff-init-var-faces ()
-    (copy-face (if (and ediff-want-faces (null ediff-highlight-selected-only))
-                  ediff-even-diff-face-A 'default)
-              'ediff-even-diff-face-A-var)
-    (copy-face (if (and ediff-want-faces (null ediff-highlight-selected-only))
-                  ediff-even-diff-face-B 'default)
-              'ediff-even-diff-face-B-var)
-    (copy-face (if (and ediff-want-faces (null ediff-highlight-selected-only))
-                  ediff-odd-diff-face-A 'default)
-              'ediff-odd-diff-face-A-var)
-    (copy-face (if (and ediff-want-faces (null ediff-highlight-selected-only))
-                  ediff-odd-diff-face-B 'default)
-              'ediff-odd-diff-face-B-var))
-      
-
-  ;;; Overlays
-
-  (emerge-defvar-local ediff-current-diff-overlay-A nil
-    "Overlay in buffer A.")
-  (emerge-defvar-local ediff-current-diff-overlay-B nil
-    "Overlay in buffer B.")
-  
-  (defun ediff-make-current-diff-overlay (type)
-      (let ((overlay (if (eq type 'A)
-                        'ediff-current-diff-overlay-A
-                      'ediff-current-diff-overlay-B))
-           (buffer (if (eq type 'A) ediff-A-buffer ediff-B-buffer))
-           (face (if (eq type 'A) 
-                     (face-name ediff-current-diff-face-A)
-                   (face-name ediff-current-diff-face-B))))
-       (set overlay (ediff-make-overlay (point-max) (point-max) buffer))
-       (ediff-overlay-put (eval overlay) 'face face)
-       (ediff-overlay-put (eval overlay) 'ediff ediff-control-buffer)
-       ))
-       
-  ;; Computes priority of ediff overlay.
-  (defun ediff-highest-priority (start end buffer)
-    (let ((pos (max 1 (1- start)))
-         ovr-list)
-      (if (ediff-if-lucid)
-         (+ 2 mouse-highlight-priority)
-       (emerge-eval-in-buffer
-        buffer
-        (while (< pos (min (point-max) (1+ end)))
-          (setq ovr-list (append (overlays-at pos) ovr-list))
-          (setq pos (next-overlay-change pos)))
-        (1+ (eval
-             (cons '+
-                   (mapcar (function
-                            (lambda (ovr)
-                              (if ovr
-                                  (or (ediff-overlay-get ovr 'priority) 0)
-                                0)))
-                           ovr-list)
-                   )))
-        ))))
-
-)  ; end of window-system-only code.
-  
-  
-
-;;; Misc
-
-(defvar ediff-split-window-function 'split-window-vertically
-  "*The function to split the main window between buffer-A and buffer-B.
-You can set it to be split horizontally instead of the
-default verstical split by setting this variable to
-'split-window-horizontally.  You can also have your own function for fancy
-splits.  This variable has no effect when buffer-A and buffer-B are shown in
-different frames.  In this case, Ediff will use those frames to display
-these buffers.")
-                
-(defconst ediff-saved-variables
-  '(buffer-read-only
-    buffer-auto-save-file-name)
-  "Buffer-local variables saved and restored during an Ediff session.")
-
-(defconst ediff-working-values '(nil nil)
-  "Values to be assigned to `ediff-saved-variables' during diff.")
-  
-(defvar ediff-use-last-dir nil
-  "*If t, Ediff uses previous directory as default when reading file name.")
-  
-(defvar ediff-nix-help-in-control-buffer nil
-  "*Non-nil mean C-h should not to invoke Emacs help.
-Instead, C-h jumps to previous difference.")
-  
-(defvar ediff-temp-file-prefix
-  (let ((env (getenv "TMPDIR"))
-       d)
-    (setq d (if (and env (> (length env) 0))
-               env
-             "/tmp"))
-    (if (= (aref d (1- (length d))) ?/)
-       (setq d (substring d 0 -1)))
-    (concat d "/ediff"))
-  "*Prefix to put on Ediff temporary file names.
-Do not start with `~/' or `~user-name/'.")  
-
-(defvar ediff-temp-file-mode 384       ; u=rw only
-  "*Mode for Ediff temporary files.")
-  
-(defvar ediff-last-dir-A nil
-  "Last directory used by an Ediff command for file-A.")
-(defvar ediff-last-dir-B nil
-  "Last directory used by an Ediff command for file-B.")
-  
-;; Build keymaps
-
-(defvar ediff-mode-map nil
-  "Local keymap used in Ediff mode.")
-
-
-(defun ediff-setup-keymap ()
-  "Set up the keymap used in the control buffer of Ediff."
-  (setq ediff-mode-map (make-sparse-keymap))
-  (suppress-keymap ediff-mode-map)
-  
-  (define-key ediff-mode-map "p" 'ediff-previous-difference)
-  (define-key ediff-mode-map "\C-?" 'ediff-previous-difference)
-  (define-key ediff-mode-map "\C-h" (if ediff-nix-help-in-control-buffer
-                                       'ediff-previous-difference nil))
-  (define-key ediff-mode-map "n" 'ediff-next-difference)
-  (define-key ediff-mode-map " " 'ediff-next-difference)
-  (define-key ediff-mode-map "j" 'ediff-jump-to-difference)
-  (define-key ediff-mode-map "g"  nil)
-  (define-key ediff-mode-map "ga" 'ediff-jump-to-difference-at-point)
-  (define-key ediff-mode-map "gb" 'ediff-jump-to-difference-at-point)
-  (define-key ediff-mode-map "q" 'ediff-quit)
-  (define-key ediff-mode-map "z" 'ediff-suspend)
-  (define-key ediff-mode-map "c" 'ediff-recenter)
-  (define-key ediff-mode-map "s" 'ediff-toggle-split)
-  (define-key ediff-mode-map "h" 'ediff-toggle-hilit)
-  (define-key ediff-mode-map "v" 'ediff-scroll-up)
-  (define-key ediff-mode-map "\C-v" 'ediff-scroll-up)
-  (define-key ediff-mode-map "^" 'ediff-scroll-down)
-  (define-key ediff-mode-map "\M-v" 'ediff-scroll-down)
-  (define-key ediff-mode-map "V" 'ediff-scroll-down)
-  (define-key ediff-mode-map "<" 'ediff-scroll-left)
-  (define-key ediff-mode-map ">" 'ediff-scroll-right)
-  (define-key ediff-mode-map "f" 'ediff-file-names)
-  (define-key ediff-mode-map "l" 'ediff-line-numbers)
-  (define-key ediff-mode-map "?" 'ediff-toggle-help)
-  (define-key ediff-mode-map "a"  nil)
-  (define-key ediff-mode-map "ab" 'ediff-diff-to-diff)
-  (define-key ediff-mode-map "b"  nil)
-  (define-key ediff-mode-map "ba" 'ediff-diff-to-diff)
-  (define-key ediff-mode-map "r"  nil)
-  (define-key ediff-mode-map "ra" 'ediff-restore-diff)
-  (define-key ediff-mode-map "rb" 'ediff-restore-diff)
-  (define-key ediff-mode-map "o"   nil)
-  (define-key ediff-mode-map "A"  'ediff-toggle-read-only)
-  (define-key ediff-mode-map "B"  'ediff-toggle-read-only)
-  (define-key ediff-mode-map "w"   nil)
-  (define-key ediff-mode-map "wa"  'ediff-save-buffer)
-  (define-key ediff-mode-map "wb"  'ediff-save-buffer)
-  (define-key ediff-mode-map "k"   nil)
-  (define-key ediff-mode-map "kkk" 'ediff-reload-keymap) ;; for debug
-  ;; Allow ediff-mode-map to be referenced indirectly
-  (fset 'ediff-mode-map ediff-mode-map))
-
-
-;;; Setup functions
-
-(defun ediff-find-file (file buffer &optional last-dir)
-  "Visits FILE for ediff.
-BUFFER is a variable symbol that is supposed to
-get the buffer into which FILE is read.  LAST-DIR is the directory variable
-symbol where FILE's dir name should be returned.
-Arguments: (file 'buffer &optional 'last-dir)"
-  (if (not (file-readable-p file))
-      (error "File `%s' does not exist or is not readable" file))
-  
-  ;; Record the buffer
-  (set buffer (find-file-noselect file))
-  ;; Record the directory of the file
-  (if last-dir
-      (set last-dir (expand-file-name (file-name-directory file))))
-  
-  ;; Make sure the entire file is seen, and it reflects what is on disk
-  (emerge-eval-in-buffer 
-   (eval buffer)
-   (widen)
-   (let ((temp (file-local-copy file))
-        startup-hooks)
-     (if temp
-        (setq file temp
-              startup-hooks
-              (cons (` (lambda () (delete-file (, file))))
-                    startup-hooks))
-       ;; Verify that the file matches the buffer
-       (emerge-verify-file-buffer)))))
-
-(defun ediff-files-internal (file-A file-B &optional startup-hooks)
-  (let (buffer-A buffer-B)
-    (message "Ediff: Reading file %s ... " file-A)(sit-for .5)
-    (ediff-find-file file-A 'buffer-A 'ediff-last-dir-A)
-    (message "Ediff: Reading file %s ... " file-B)(sit-for .5)
-    (ediff-find-file file-B 'buffer-B 'ediff-last-dir-B)
-    (ediff-setup buffer-A file-A buffer-B file-B startup-hooks)))
-  
-(defun ediff-get-patch-buffer (dir)
-  "Obtain patch buffer.  If patch is already in a buffer---use it.
-Else, read patch file into a new buffer."
-  (if (y-or-n-p "Is the patch file already in a buffer? ")
-      (setq ediff-patch-buf
-           (get-buffer (read-buffer "Patch buffer name: " nil t))) ;must match
-    (setq ediff-patch-buf
-         (find-file-noselect (read-file-name "Patch file name: "
-                                             dir))))
-  (emerge-eval-in-buffer
-   ediff-patch-buf
-   (toggle-read-only 1))
-  (setq ediff-patch-diagnostics
-       (get-buffer-create "*ediff patch diagnostics*"))
-  (emerge-eval-in-buffer
-   ediff-patch-diagnostics
-   (insert-buffer ediff-patch-buf))
-  )
+;;; Compare regions and windows
 
-;; Start up Ediff on two files
-(defun ediff-setup (buffer-A file-A buffer-B file-B startup-hooks)
-  (setq file-A (expand-file-name file-A))
-  (setq file-B (expand-file-name file-B))
-  (let* ((control-buffer-name (emerge-unique-buffer-name "*ediff-control" "*"))
-        (control-buffer (emerge-eval-in-buffer
-                         buffer-A
-                         (get-buffer-create control-buffer-name))))
-    (emerge-eval-in-buffer
-     control-buffer
-     (ediff-mode) ;; in control buffer only
-     (setq buffer-read-only nil)
-     (setq ediff-A-buffer buffer-A)
-     (setq ediff-B-buffer buffer-B)
-     (setq ediff-control-buffer control-buffer)
-     (setq ediff-control-buffer-suffix
-          (if (string-match "<[0-9]*>" control-buffer-name)
-              (substring control-buffer-name
-                         (match-beginning 0) (match-end 0))
-            "<1>"))
-     (ediff-remember-buffer-characteristics t) ;; remember at setup
-     
-     (ediff-set-keys)
-     (setq ediff-difference-vector (ediff-make-diff-list file-A file-B))
-     (setq ediff-number-of-differences (length ediff-difference-vector))
-     (setq ediff-current-difference -1)
-     (ediff-make-current-diff-overlay 'A)
-     (ediff-make-current-diff-overlay 'B)
-     (if window-system
-        (ediff-init-var-faces))
-     (run-hooks 'ediff-before-setup-windows-hooks)
-     (ediff-setup-windows buffer-A buffer-B control-buffer t)
-         
-     ;; all these must be inside emerge-eval-in-buffer control-buffer,
-     ;; since these vars are local to control-buffer
-     ;; These won't run if there are errors in diff
-     (emerge-eval-in-buffer
-      ediff-A-buffer
-      (run-hooks 'ediff-prepare-buffer-hooks)
-      (add-hook 'local-write-file-hooks 'ediff-block-write-file)
-      (setq before-change-function 'ediff-before-change-guard)
-      ;; add control-buffer to the list of sessions
-      (or (memq control-buffer ediff-this-buffer-control-sessions)
-         (setq ediff-this-buffer-control-sessions
-               (cons control-buffer ediff-this-buffer-control-sessions)))
-      (setq mode-line-buffer-identification '("A: %b")))
-     (emerge-eval-in-buffer
-      ediff-B-buffer
-      (run-hooks 'ediff-prepare-buffer-hooks)
-      (add-hook 'local-write-file-hooks 'ediff-block-write-file)
-      (setq before-change-function 'ediff-before-change-guard)
-      ;; add control-buffer to the list of sessions
-      (or (memq control-buffer ediff-this-buffer-control-sessions)
-         (setq ediff-this-buffer-control-sessions
-               (cons control-buffer ediff-this-buffer-control-sessions)))
-      (setq mode-line-buffer-identification '("B: %b")))
-
-     (emerge-eval-in-buffer control-buffer
-                           (run-hooks 'startup-hooks 'ediff-startup-hooks)
-                           (setq buffer-read-only t)))))
-
-;; Generate the Ediff difference list between two files
-(defun ediff-make-diff-list (file-A file-B)
-  (setq ediff-diff-buffer 
-       (get-buffer-create (emerge-unique-buffer-name "*ediff-diff" "*")))
-  (emerge-eval-in-buffer
-   ediff-diff-buffer
-   (erase-buffer)
-   ;; shell-command tends to display old shell command buffers even when it
-   ;; puts output in another buffer---probably an Emacs bug.
-   (ediff-kill-buffer-carefully "*Shell Command Output*")
-   (let ((shell-file-name ediff-shell))
-     (message "Ediff: Computing differences ...")(sit-for .5)
-     (shell-command
-      (format "%s %s %s %s"
-             ediff-diff-program ediff-diff-options
-             (emerge-protect-metachars file-A)
-             (emerge-protect-metachars file-B))
-      t)
-     ))
-  (ediff-prepare-error-list ediff-diff-ok-lines-regexp)
-  (message "Ediff: Computing differences ... Done.")(sit-for .5)
-  (ediff-convert-diffs-to-overlays
-   ediff-A-buffer ediff-B-buffer
-   (ediff-extract-diffs ediff-diff-buffer ediff-A-buffer ediff-B-buffer)))
-    
-(defun ediff-prepare-error-list (ok-regexp)
-  (let ((diff-buff ediff-diff-buffer))
-    (setq ediff-diff-error-buffer
-         (get-buffer-create (emerge-unique-buffer-name
-                             "*ediff-diff-errors" "*")))
-    (emerge-eval-in-buffer
-     ediff-diff-error-buffer
-     (erase-buffer)
-     (insert-buffer diff-buff)
-     (delete-matching-lines ok-regexp))))
-
-;;; Function to start Ediff by patching a file
+;;;###autoload
+(defun ediff-windows-wordwise (dumb-mode &optional wind-A wind-B startup-hooks)
+  "Compare WIND-A and WIND-B, which are selected by clicking, wordwise.
+With prefix argument, DUMB-MODE, or on a non-windowing display, works as
+follows:
+If WIND-A is nil, use selected window.
+If WIND-B is nil, use window next to WIND-A."
+  (interactive "P")
+  (ediff-windows dumb-mode wind-A wind-B
+                startup-hooks 'ediff-windows-wordwise 'word-mode))
 
 ;;;###autoload
-(defun ediff-patch-file (file-to-patch &optional startup-hooks)
-  "Run Ediff by patching FILE-TO-PATCH."
-  (interactive "fFile to patch: ")
-  
-  (ediff-get-patch-buffer (file-name-directory file-to-patch))
-  (let ((buf (get-file-buffer file-to-patch)))
-    (if buf 
-       (progn
-         (emerge-eval-in-buffer
-          buf
-          (if (buffer-modified-p buf)
-              (if (y-or-n-p 
-                   (format 
-                    "File '%s' is already in buffer %s.  Save before killing? "
-                    file-to-patch (buffer-name buf)))
-                  (save-buffer buf)))
-          (set-buffer-modified-p nil))
-         (ediff-kill-buffer-carefully buf))))
-  (emerge-eval-in-buffer
-   ediff-patch-diagnostics
-   (let ((shell-file-name ediff-shell))
-     (message "Ediff: Applying patch ... ")(sit-for .5)
-     (shell-command-on-region 
-      (point-min) (point-max)
-      (format "%s %s %s"
-             ediff-patch-program ediff-patch-options
-             (expand-file-name file-to-patch))
-      t)
-     (message "Ediff: Applying patch ... Done.")(sit-for .5)
-     ))
-  (switch-to-buffer ediff-patch-diagnostics)
-  (sit-for 0) ;; synchronize
-  
-  (setq startup-hooks (cons 'ediff-toggle-read-only-A startup-hooks))
-  (ediff-files (format "%s.orig" file-to-patch) file-to-patch startup-hooks)
-  
-  (bury-buffer ediff-patch-diagnostics)
-  (message "Patch diagnostics available in buffer %s."
-          (buffer-name ediff-patch-diagnostics)))
+(defun ediff-windows-linewise (dumb-mode &optional wind-A wind-B startup-hooks)
+  "Compare WIND-A and WIND-B, which are selected by clicking, linewise.
+With prefix argument, DUMB-MODE, or on a non-windowing display, works as
+follows:
+If WIND-A is nil, use selected window.
+If WIND-B is nil, use window next to WIND-A."
+  (interactive "P")
+  (ediff-windows dumb-mode wind-A wind-B
+                startup-hooks 'ediff-windows-linewise nil))
+
+;; Compare WIND-A and WIND-B, which are selected by clicking.
+;; With prefix argument, DUMB-MODE, or on a non-windowing display,
+;; works as follows:
+;; If WIND-A is nil, use selected window.
+;; If WIND-B is nil, use window next to WIND-A.
+(defun ediff-windows (dumb-mode wind-A wind-B startup-hooks job-name word-mode)
+  (if (or dumb-mode (not (ediff-window-display-p)))
+      (setq wind-A (ediff-get-next-window wind-A nil)
+           wind-B (ediff-get-next-window wind-B wind-A))
+    (setq wind-A (ediff-get-window-by-clicking wind-A nil 1)
+         wind-B (ediff-get-window-by-clicking wind-B wind-A 2)))
+
+  (let ((buffer-A (window-buffer wind-A))
+       (buffer-B (window-buffer wind-B))
+       beg-A end-A beg-B end-B)
+
+    (save-excursion
+      (save-window-excursion
+       (sit-for 0) ; sync before using window-start/end -- a precaution
+       (select-window wind-A)
+       (setq beg-A (window-start)
+             end-A (window-end))
+       (select-window wind-B)
+       (setq beg-B (window-start)
+             end-B (window-end))))
+    (setq buffer-A
+         (ediff-clone-buffer-for-window-comparison
+          buffer-A wind-A "-Window.A-")
+         buffer-B
+         (ediff-clone-buffer-for-window-comparison
+          buffer-B wind-B "-Window.B-"))
+    (ediff-regions-internal
+     buffer-A beg-A end-A buffer-B beg-B end-B
+     startup-hooks job-name word-mode nil)))
 
-(defalias 'epatch 'ediff-patch-file)
 
-;;; Function to start Ediff on files
+;;;###autoload
+(defun ediff-regions-wordwise (buffer-A buffer-B &optional startup-hooks)
+  "Run Ediff on a pair of regions in specified buffers.
+Regions \(i.e., point and mark\) are assumed to be set in advance except
+for the second region in the case both regions are from the same buffer.
+In such a case the user is asked to interactively establish the second
+region.
+This function is effective only for relatively small regions, up to 200
+lines.  For large regions, use `ediff-regions-linewise'."
+  (interactive
+   (let (bf)
+     (list (setq bf (read-buffer "Region's A buffer: "
+                                (ediff-other-buffer "") t))
+          (read-buffer "Region's B buffer: "
+                       (progn
+                         ;; realign buffers so that two visible bufs will be
+                         ;; at the top
+                         (save-window-excursion (other-window 1))
+                         (ediff-other-buffer bf))
+                       t))))
+  (if (not (ediff-buffer-live-p buffer-A))
+      (error "Buffer %S doesn't exist" buffer-A))
+  (if (not (ediff-buffer-live-p buffer-B))
+      (error "Buffer %S doesn't exist" buffer-B))
+
+
+  (let ((buffer-A
+         (ediff-clone-buffer-for-region-comparison buffer-A "-Region.A-"))
+       (buffer-B
+         (ediff-clone-buffer-for-region-comparison buffer-B "-Region.B-"))
+        reg-A-beg reg-A-end reg-B-beg reg-B-end)
+    (save-excursion
+      (set-buffer buffer-A)
+      (setq reg-A-beg (region-beginning)
+           reg-A-end (region-end))
+      (set-buffer buffer-B)
+      (setq reg-B-beg (region-beginning)
+           reg-B-end (region-end)))
+
+    (ediff-regions-internal
+     (get-buffer buffer-A) reg-A-beg reg-A-end
+     (get-buffer buffer-B) reg-B-beg reg-B-end
+     startup-hooks 'ediff-regions-wordwise 'word-mode nil)))
 
 ;;;###autoload
-(defun ediff-files (file-A file-B &optional startup-hooks)
-  "Run Ediff on a pair files, FILE-A and FILE-B."
+(defun ediff-regions-linewise (buffer-A buffer-B &optional startup-hooks)
+  "Run Ediff on a pair of regions in specified buffers.
+Regions \(i.e., point and mark\) are assumed to be set in advance except
+for the second region in the case both regions are from the same buffer.
+In such a case the user is asked to interactively establish the second
+region.
+Each region is enlarged to contain full lines.
+This function is effective for large regions, over 100-200
+lines.  For small regions, use `ediff-regions-wordwise'."
   (interactive
-   (let (f)
-     (list (setq f (ediff-read-file-name "File A to compare" 
-                                        (if ediff-use-last-dir
-                                            ediff-last-dir-A
-                                          default-directory)
-                                        nil nil))
-          (ediff-read-file-name "File B to compare" 
-                                (if ediff-use-last-dir
-                                    ediff-last-dir-B  nil)
-                                f f)
-          )))
-  (ediff-files-internal file-A file-B startup-hooks))
+   (let (bf)
+     (list (setq bf (read-buffer "Region A's buffer: "
+                                (ediff-other-buffer "") t))
+          (read-buffer "Region B's buffer: "
+                       (progn
+                         ;; realign buffers so that two visible bufs will be
+                         ;; at the top
+                         (save-window-excursion (other-window 1))
+                         (ediff-other-buffer bf))
+                       t))))
+  (if (not (ediff-buffer-live-p buffer-A))
+      (error "Buffer %S doesn't exist" buffer-A))
+  (if (not (ediff-buffer-live-p buffer-B))
+      (error "Buffer %S doesn't exist" buffer-B))
+
+  (let ((buffer-A
+         (ediff-clone-buffer-for-region-comparison buffer-A "-Region.A-"))
+       (buffer-B
+         (ediff-clone-buffer-for-region-comparison buffer-B "-Region.B-"))
+        reg-A-beg reg-A-end reg-B-beg reg-B-end)
+    (save-excursion
+      (set-buffer buffer-A)
+      (setq reg-A-beg (region-beginning)
+           reg-A-end (region-end))
+      ;; enlarge the region to hold full lines
+      (goto-char reg-A-beg)
+      (beginning-of-line)
+      (setq reg-A-beg (point))
+      (goto-char reg-A-end)
+      (end-of-line)
+      (or (eobp) (forward-char)) ; include the newline char
+      (setq reg-A-end (point))
+
+      (set-buffer buffer-B)
+      (setq reg-B-beg (region-beginning)
+           reg-B-end (region-end))
+      ;; enlarge the region to hold full lines
+      (goto-char reg-B-beg)
+      (beginning-of-line)
+      (setq reg-B-beg (point))
+      (goto-char reg-B-end)
+      (end-of-line)
+      (or (eobp) (forward-char)) ; include the newline char
+      (setq reg-B-end (point))
+      ) ; save excursion
+
+    (ediff-regions-internal
+     (get-buffer buffer-A) reg-A-beg reg-A-end
+     (get-buffer buffer-B) reg-B-beg reg-B-end
+     startup-hooks 'ediff-regions-linewise nil nil))) ; no word mode
+
+;; compare region beg-A to end-A of buffer-A
+;; to regions beg-B -- end-B in buffer-B.
+(defun ediff-regions-internal (buffer-A beg-A end-A buffer-B beg-B end-B
+                                       startup-hooks job-name word-mode
+                                       setup-parameters)
+  (let ((tmp-buffer (get-buffer-create ediff-tmp-buffer))
+       overl-A overl-B
+       file-A file-B)
+
+    ;; in case beg/end-A/B aren't markers--make them into markers
+    (ediff-with-current-buffer buffer-A
+      (setq beg-A (move-marker (make-marker) beg-A)
+           end-A (move-marker (make-marker) end-A)))
+    (ediff-with-current-buffer buffer-B
+      (setq beg-B (move-marker (make-marker) beg-B)
+           end-B (move-marker (make-marker) end-B)))
+
+    ;; make file-A
+    (if word-mode
+       (ediff-wordify beg-A end-A buffer-A tmp-buffer)
+      (ediff-copy-to-buffer beg-A end-A buffer-A tmp-buffer))
+    (setq file-A (ediff-make-temp-file tmp-buffer "regA"))
+
+    ;; make file-B
+    (if word-mode
+       (ediff-wordify beg-B end-B buffer-B tmp-buffer)
+      (ediff-copy-to-buffer beg-B end-B buffer-B tmp-buffer))
+    (setq file-B (ediff-make-temp-file tmp-buffer "regB"))
+
+    (setq overl-A (ediff-make-bullet-proof-overlay beg-A end-A buffer-A))
+    (setq overl-B (ediff-make-bullet-proof-overlay beg-B end-B buffer-B))
+    (ediff-setup buffer-A file-A
+                buffer-B file-B
+                nil nil            ; buffer & file C
+                (cons `(lambda ()
+                           (delete-file ,file-A)
+                           (delete-file ,file-B))
+                      startup-hooks)
+                (append
+                 (list (cons 'ediff-word-mode  word-mode)
+                       (cons 'ediff-narrow-bounds (list overl-A overl-B))
+                       (cons 'ediff-job-name job-name))
+                 setup-parameters))
+    ))
 
 
-(defalias 'ediff 'ediff-files)
+;;; Merge files and buffers
 
+;;;###autoload
+(defalias 'ediff-merge 'ediff-merge-files)
+
+(defsubst ediff-merge-on-startup ()
+  (ediff-do-merge 0)
+  ;; Can't remember why this is here, but it may cause the automatically merged
+  ;; buffer to be lost. So, keep the buffer modified.
+  ;;(ediff-with-current-buffer ediff-buffer-C
+  ;;  (set-buffer-modified-p nil))
+  )
 
-;;; Function to start Ediff on buffers
+;;;###autoload
+(defun ediff-merge-files (file-A file-B
+                                ;; MERGE-BUFFER-FILE is the file to be
+                                ;; associated with the merge buffer
+                                &optional startup-hooks merge-buffer-file)
+  "Merge two files without ancestor."
+  (interactive
+   (let ((dir-A (if ediff-use-last-dir
+                   ediff-last-dir-A
+                 default-directory))
+        dir-B f)
+     (list (setq f (ediff-read-file-name
+                   "File A to merge"
+                   dir-A
+                   (ediff-get-default-file-name)
+                   'no-dirs))
+          (ediff-read-file-name "File B to merge"
+                                (setq dir-B
+                                      (if ediff-use-last-dir
+                                          ediff-last-dir-B
+                                        (file-name-directory f)))
+                                (progn
+                                  (setq file-name-history
+                                        (cons (ediff-abbreviate-file-name
+                                               (expand-file-name
+                                                (file-name-nondirectory f)
+                                                dir-B))
+                                              file-name-history))
+                                  (ediff-get-default-file-name f 1)))
+          )))
+  (setq startup-hooks (cons 'ediff-merge-on-startup startup-hooks))
+  (ediff-files-internal file-A
+                       (if (file-directory-p file-B)
+                           (expand-file-name
+                            (file-name-nondirectory file-A) file-B)
+                         file-B)
+                         nil ; file-C
+                         startup-hooks
+                         'ediff-merge-files
+                         merge-buffer-file))
 
 ;;;###autoload
-(defun ediff-buffers (buffer-A buffer-B &optional startup-hooks)
-  "Run Ediff on a pair of buffers, BUFFER-A and BUFFER-B."
-  (interactive "bBuffer A to compare: \nbBuffer B to compare: ")
-  (let (ediff-file-A ediff-file-B)
-    (emerge-eval-in-buffer
-     buffer-A
-     (setq ediff-file-A
-          (ediff-make-temp-file
-           (format ".%s." (file-name-nondirectory (buffer-name)))))
-     (write-region (point-min) (point-max) ediff-file-A nil 'no-message))
-    (emerge-eval-in-buffer
-     buffer-B
-     (setq ediff-file-B
-          (ediff-make-temp-file
-           (format ".%s." (file-name-nondirectory (buffer-name)))))
-     (write-region (point-min) (point-max) ediff-file-B nil 'no-message))
-    (ediff-setup (get-buffer buffer-A) ediff-file-A
-                (get-buffer buffer-B) ediff-file-B
-                (cons (` (lambda ()
-                           (delete-file (, ediff-file-A))
-                           (delete-file (, ediff-file-B))))
-                      startup-hooks)
-                )))
-                 
+(defun ediff-merge-files-with-ancestor (file-A file-B file-ancestor
+                                              &optional
+                                              startup-hooks
+                                              ;; MERGE-BUFFER-FILE is the file
+                                              ;; to be associated with the
+                                              ;; merge buffer
+                                              merge-buffer-file)
+  "Merge two files with ancestor."
+  (interactive
+   (let ((dir-A (if ediff-use-last-dir
+                   ediff-last-dir-A
+                 default-directory))
+        dir-B dir-ancestor f ff)
+     (list (setq f (ediff-read-file-name
+                   "File A to merge"
+                   dir-A
+                   (ediff-get-default-file-name)
+                   'no-dirs))
+          (setq ff (ediff-read-file-name "File B to merge"
+                                         (setq dir-B
+                                               (if ediff-use-last-dir
+                                                   ediff-last-dir-B
+                                                 (file-name-directory f)))
+                                         (progn
+                                           (setq file-name-history
+                                                 (cons
+                                                  (ediff-abbreviate-file-name
+                                                   (expand-file-name
+                                                    (file-name-nondirectory f)
+                                                    dir-B))
+                                                  file-name-history))
+                                           (ediff-get-default-file-name f 1))))
+          (ediff-read-file-name "Ancestor file"
+                                (setq dir-ancestor
+                                      (if ediff-use-last-dir
+                                          ediff-last-dir-ancestor
+                                        (file-name-directory ff)))
+                                (progn
+                                  (setq file-name-history
+                                        (cons (ediff-abbreviate-file-name
+                                               (expand-file-name
+                                                (file-name-nondirectory ff)
+                                                dir-ancestor))
+                                              file-name-history))
+                                  (ediff-get-default-file-name ff 2)))
+          )))
+  (setq startup-hooks (cons 'ediff-merge-on-startup startup-hooks))
+  (ediff-files-internal file-A
+                       (if (file-directory-p file-B)
+                           (expand-file-name
+                            (file-name-nondirectory file-A) file-B)
+                         file-B)
+                         file-ancestor
+                         startup-hooks
+                         'ediff-merge-files-with-ancestor
+                         merge-buffer-file))
+
 ;;;###autoload
-(defun ediff-patch-buffer (buffer-name &optional startup-hooks)                  
-  "Run Ediff by patching BUFFER-NAME."
-  (interactive "bBuffer to patch: ")
-  
-  (let* ((file-buffer (get-buffer buffer-name))
-        (file-name (if file-buffer (buffer-file-name  file-buffer))))
-    (if (not file-name)
-       (error "Buffer %s doesn't exist or doesn't visit any file.  Why patch?"
-              file-name))
-    
-    (ediff-patch-file file-name startup-hooks)))
-      
-
-;;; Versions Control functions      
-      
+(defalias 'ediff-merge-with-ancestor 'ediff-merge-files-with-ancestor)
+
 ;;;###autoload
-(defun vc-ediff (rev)
-  "Run ediff on version REV of the current buffer in another window.
-If the current buffer is named `F', the version is named `F.~REV~'.
-If `F.~REV~' already exists, it is used instead of being re-created."
-  (interactive "sVersion to ediff with (default is the latest version): ")
-  (or (featurep 'vc)
-      (if (locate-library "vc") ;; if vc.el is available
-         (progn
-           (require 'vc-hooks) 
-           (define-key vc-prefix-map "=" 'vc-ediff))
-       (error "The VC package is apparently not installed.")))
-  (let ((newvers (current-buffer))
-       (oldvers (vc-version-other-window rev)))
-    (ediff-buffers newvers oldvers)
-    ))
-    
-(defun rcs-ediff-view-revision (&optional rev)
-  "View previous RCS revison of current file.
-With prefix argument, prompts for a revision name." 
-  (interactive (list (if current-prefix-arg 
-                        (read-string "Revision: "))))
-  (let* ((filename (buffer-file-name (current-buffer)))
-        (switches (append '("-p")
-                          (if rev (list (concat "-r" rev)) nil)))
-        (buff (concat (file-name-nondirectory filename) ".~" rev "~")))
-    (message "Working...")
-    (setq filename (expand-file-name filename))
-    (with-output-to-temp-buffer
-       buff
-      (let ((output-buffer (rcs-get-output-buffer filename buff)))
-       (delete-windows-on output-buffer)
-       (save-excursion
-         (set-buffer output-buffer)
-         (apply 'call-process "co" nil t nil
-                ;; -q: quiet (no diagnostics)
-                (append switches rcs-default-co-switches
-                        (list "-q" filename))))) 
-      (message "")
-      buff)))    
+(defun ediff-merge-buffers (buffer-A buffer-B
+                                    &optional
+                                    ;; MERGE-BUFFER-FILE is the file to be
+                                    ;; associated with the merge buffer
+                                    startup-hooks job-name merge-buffer-file)
+  "Merge buffers without ancestor."
+  (interactive
+   (let (bf)
+     (list (setq bf (read-buffer "Buffer A to merge: "
+                                (ediff-other-buffer "") t))
+          (read-buffer "Buffer B to merge: "
+                       (progn
+                         ;; realign buffers so that two visible bufs will be
+                         ;; at the top
+                         (save-window-excursion (other-window 1))
+                         (ediff-other-buffer bf))
+                       t))))
+
+  (setq startup-hooks (cons 'ediff-merge-on-startup startup-hooks))
+  (or job-name (setq job-name 'ediff-merge-buffers))
+  (ediff-buffers-internal
+   buffer-A buffer-B nil startup-hooks job-name merge-buffer-file))
 
 ;;;###autoload
-(defun rcs-ediff (&optional rev)
-  "Run Ediff on the current buffer, comparing it with previous RCS revison.  
-With prefix argument, prompts for revision name." 
-  (interactive (list (if current-prefix-arg 
-                        (read-string "Revision: "))))
-  (or (featurep 'rcs)
-      (if (locate-library "rcs")      
-         (progn
-           (require 'rcs)
-           (global-set-key "\C-cD" 'rcs-ediff))
-       (error "The RCS package is apparently not installed.")))
-  (let ((newvers (current-buffer))
-       (oldvers (rcs-ediff-view-revision rev)))
-    (ediff-buffers newvers oldvers)
-    ))
+(defun ediff-merge-buffers-with-ancestor (buffer-A buffer-B buffer-ancestor
+                                                  &optional
+                                                  startup-hooks
+                                                  job-name
+                                                  ;; MERGE-BUFFER-FILE is the
+                                                  ;; file to be associated
+                                                  ;; with the merge buffer
+                                                  merge-buffer-file)
+  "Merge buffers with ancestor."
+  (interactive
+   (let (bf bff)
+     (list (setq bf (read-buffer "Buffer A to merge: "
+                                (ediff-other-buffer "") t))
+          (setq bff (read-buffer "Buffer B to merge: "
+                                 (progn
+                                   ;; realign buffers so that two visible
+                                   ;; bufs will be at the top
+                                   (save-window-excursion (other-window 1))
+                                   (ediff-other-buffer bf))
+                                 t))
+          (read-buffer "Ancestor buffer: "
+                                 (progn
+                                   ;; realign buffers so that three visible
+                                   ;; bufs will be at the top
+                                   (save-window-excursion (other-window 1))
+                                   (ediff-other-buffer (list bf bff)))
+                                 t)
+          )))
 
+  (setq startup-hooks (cons 'ediff-merge-on-startup startup-hooks))
+  (or job-name (setq job-name 'ediff-merge-buffers-with-ancestor))
+  (ediff-buffers-internal
+   buffer-A buffer-B buffer-ancestor startup-hooks job-name merge-buffer-file))
 
-;;; Functions to start Ediff via remote request
 
 ;;;###autoload
-(defun ediff-files-remote (file-a file-b)
-  "Run Ediff on remote files, FILE-A and FILE-B."
-  (ediff-files-internal file-a file-b nil)
-  (throw 'client-wait nil))
-
-
-(defun ediff-remote-exit (exit-func)
-  "Exit remote Ediff session."
-  (ediff-really-quit)
-  (funcall exit-func))
-
-
-
-;; Select the lowest window on the frame.
-(defun ediff-select-lowest-window ()
-  (let* ((lowest-window (selected-window))
-        (bottom-edge (car (cdr (cdr (cdr (window-edges))))))
-         (last-window (previous-window))
-         (window-search t))
-    (while window-search
-      (let* ((this-window (next-window))
-             (next-bottom-edge (car (cdr (cdr (cdr 
-                                               (window-edges this-window)))))))
-        (if (< bottom-edge next-bottom-edge)
-            (progn
-              (setq bottom-edge next-bottom-edge)
-              (setq lowest-window this-window)))
-
-        (select-window this-window)
-        (if (eq last-window this-window)
-            (progn
-              (select-window lowest-window)
-              (setq window-search nil)))))))
-
-;;; Common setup routines
-
-;; Set up the window configuration.  If POS is given, set the points to
-;; the beginnings of the buffers.
-(defun ediff-setup-windows (buffer-A buffer-B control-buffer &optional pos)
-  ;; Make sure we are not in the minibuffer window when we try to delete
-  ;; all other windows.
-  (if (eq (selected-window) (minibuffer-window))
-      (other-window 1))
-  (delete-other-windows)
-  (switch-to-buffer control-buffer)
-  (ediff-refresh-mode-line)
-  
-  (ediff-arrange-buffer buffer-A buffer-B (current-buffer) pos)
-  (ediff-arrange-buffer buffer-B buffer-A (current-buffer) pos)
-  ;; ediff-arrange-buffer always leaves in ctl buffer
-  ;; setup ctl wind if it is not set.
-  (ediff-setup-control-window)
-  
-  ;; If diff reports errors, display them rather than then compare buffers.
-  (if (/= 0 (emerge-eval-in-buffer ediff-diff-error-buffer (buffer-size)))
-      (let ((diff-output-buf  ediff-diff-buffer))
-       (switch-to-buffer ediff-diff-error-buffer)
-       (ediff-kill-buffer-carefully control-buffer)
-       (error "Errors found in diff output.  Diff output buffer is %s"
-              diff-output-buf))))
-
-
-;; Arranges goal-buf on the screen.
-(defun ediff-arrange-buffer (goal-buf other-buf ctl-buf &optional pos)
-  (let* ((ctl-wind (get-buffer-window ctl-buf t))
-        (goal-wind (get-buffer-window goal-buf t))
-        (other-wind (get-buffer-window other-buf t))
-        (ctl-frame (ediff-window-frame ctl-wind))
-        (goal-frame (if goal-wind (ediff-window-frame goal-wind)))
-        (other-frame (if other-wind (ediff-window-frame other-wind)))
-        (ctl-frame-shared (or (eq ctl-frame goal-frame)
-                              (eq ctl-frame other-frame))))
-                         
-    (cond ((and goal-frame (not (eq goal-wind other-wind)))
-                   ;; goal buffer is visible and we are not comparing file
-                   ;; against itself (by mistake).
-                   ;; Note:  goal-frame != ctl-frame, as we deleted other
-                   ;; windows  on ctl-frame.
-                     (ediff-select-frame goal-frame)
-                     (select-window goal-wind)
-                     (delete-other-windows)) 
-                                             
-         ;; goal-buf invisible, ctl-frame has only ctl-buf
-         ;; then put goal-buf on ctl-frame
-         ((null ctl-frame-shared)
-                     (ediff-select-frame ctl-frame)
-                     (split-window-vertically)
-                     (ediff-select-lowest-window)
-                     (setq ctl-wind (selected-window))
-                     (switch-to-buffer ctl-buf)
-                     (ediff-setup-control-window)
-                     (other-window 1)
-                     (switch-to-buffer goal-buf)) ; goal-buf set
-         ;; goal-buf invisible, ctl-frame has ctl-buf and other-buf
-         ;; So, put everything in one frame
-         (other-frame   ;; share with the other buf
-                      (ediff-select-frame ctl-frame)
-                      (select-window other-wind)
-                      (funcall ediff-split-window-function)
-                      (other-window 1)
-                      (switch-to-buffer goal-buf))
-         (t ;; debug
-          (error "Funny window combination (Ediff bug?)")))
-
-      (if pos
-         (goto-char (point-min)))
-         
-      (ediff-select-frame ctl-frame)
-      (select-window ctl-wind)
-      (switch-to-buffer ctl-buf)))
-      
-;; This function assumes that we are in the window where control buffer is
-;; to reside.
-(defun ediff-setup-control-window ()
-  "Set up window for control buffer."
-  (erase-buffer)
-  (insert ediff-help-message)
-  (shrink-window-if-larger-than-buffer)
-  (setq ediff-control-window (selected-window))
-  (goto-char (point-min))
-  (skip-chars-forward " \t\n"))
-      
-
-;; Set up the keymap in the control buffer
-(defun ediff-set-keys ()
-  "Set up Ediff keymap, if necessary."
-  (if (null ediff-mode-map)
-      (ediff-setup-keymap))
-  (use-local-map ediff-mode-map))
-  
-;; Reload Ediff keymap.  For debugging only.
-(defun ediff-reload-keymap ()
-  (interactive)
-  (setq ediff-mode-map nil)
-  (ediff-set-keys))
-
-(defun ediff-before-change-guard (start end)
-  "If buffer is highlighted with ASCII flags, remove highlighting.
-Arguments, START and END are not used, but are provided
-because this is required by `before-change-function'."
-  (let (notify)
-    (save-window-excursion
-      (mapcar
-       (function
-       (lambda (buf)
-         (if (ediff-buffer-live-p buf)
-             (emerge-eval-in-buffer
-              buf
-              (if (eq ediff-highlighting-style 'ascii)
-                  (progn
-                    (ediff-unselect-and-select-difference
-                     ediff-current-difference 
-                     'unselect-only 'no-recenter)
-                    (setq notify t)
-                    ))))))
-       ediff-this-buffer-control-sessions)
-      (if notify
-         (error "ASCII flags removed. You can edit now. Hit 'c' to rehighlight."))
-     )))
-                  
-
-(defun ediff-remember-buffer-characteristics (&optional arg)
-  "Record certain properties of the buffers being compared.
-Must be called in the control buffer.  Saves `read-only', `modified',
-and `auto-save' properties in buffer local variables.  Turns off
-`auto-save-mode'.  These properties are restored via a call to
-`ediff-restore-buffer-characteristics'."
-
-  ;; remember and alter buffer characteristics
-  (set  (if arg 'ediff-A-buffer-values-setup 'ediff-A-buffer-values)
-       (emerge-eval-in-buffer
-        ediff-A-buffer
-        (prog1
-            (emerge-save-variables ediff-saved-variables)
-          (emerge-restore-variables ediff-saved-variables
-                                    ediff-working-values))))
-  (set  (if arg 'ediff-B-buffer-values-setup 'ediff-B-buffer-values)
-       (emerge-eval-in-buffer
-        ediff-B-buffer
-        (prog1
-            (emerge-save-variables ediff-saved-variables)
-          (emerge-restore-variables ediff-saved-variables
-                                    ediff-working-values)))))
-
-(defun ediff-restore-buffer-characteristics (&optional arg)
-  "Restores properties saved by `ediff-remember-buffer-characteristics'."
-  (let ((A-values (if arg ediff-A-buffer-values-setup ediff-A-buffer-values))
-       (B-values (if arg ediff-B-buffer-values-setup ediff-B-buffer-values)))
-    (emerge-eval-in-buffer ediff-A-buffer
-                          (emerge-restore-variables ediff-saved-variables
-                                                    A-values))
-    (emerge-eval-in-buffer ediff-B-buffer
-                          (emerge-restore-variables ediff-saved-variables
-                                                    B-values))))
-
-
-(defun ediff-extract-diffs (diff-buffer A-buffer B-buffer)
-  (let (diff-list
-       (a-prev 1) ;; this is needed to set the first diff line correctly
-       (b-prev 1))
-    (emerge-eval-in-buffer
-     A-buffer
-     (goto-char (point-min)))
-    (emerge-eval-in-buffer
-     B-buffer
-     (goto-char (point-min)))
-    (emerge-eval-in-buffer
-     diff-buffer
-     (goto-char (point-min))
-     (while (re-search-forward ediff-match-diff-line nil t)
-       (let* ((a-begin (string-to-int (buffer-substring (match-beginning 1)
-                                                       (match-end 1))))
-             (a-end  (let ((b (match-beginning 3))
-                           (e (match-end 3)))
-                       (if b
-                           (string-to-int (buffer-substring b e))
-                         a-begin)))
-             (diff-type (buffer-substring (match-beginning 4) (match-end 4)))
-             (b-begin (string-to-int (buffer-substring (match-beginning 5)
-                                                       (match-end 5))))
-             (b-end (let ((b (match-beginning 7))
-                          (e (match-end 7)))
-                      (if b
-                          (string-to-int (buffer-substring b e))
-                        b-begin)))
-             a-begin-pt a-end-pt b-begin-pt b-end-pt)
-        ;; fix the beginning and end numbers, because diff is somewhat
-        ;; strange about how it numbers lines
-        (if (string-equal diff-type "a")
-            (setq b-end (1+ b-end)
-                  a-begin (1+ a-begin)
-                  a-end a-begin)
-          (if (string-equal diff-type "d")
-              (setq a-end (1+ a-end)
-                    b-begin (1+ b-begin)
-                    b-end b-begin)
-            ;; (string-equal diff-type "c")
-            (setq a-end (1+ a-end)
-                  b-end (1+ b-end))))
-        ;; convert to relative line numbers
-        (emerge-eval-in-buffer
-         A-buffer
-         (forward-line (- a-begin a-prev))
-         (setq a-begin-pt (point))
-         (forward-line (- a-end a-begin))
-         (setq a-end-pt (point)
-               a-prev a-end))
-        (emerge-eval-in-buffer
-         B-buffer
-         (forward-line (- b-begin b-prev))
-         (setq b-begin-pt (point))
-         (forward-line (- b-end b-begin))
-         (setq b-end-pt (point)
-               b-prev b-end))
-        (setq diff-list (nconc diff-list (list (vector a-begin-pt a-end-pt
-                                                       b-begin-pt b-end-pt))))
-        )))
-    diff-list
-    ))
-    
-(defun ediff-convert-diffs-to-overlays (A-buffer B-buffer diff-list)
-  (let* ((current-diff -1)
-        (total-diffs (length diff-list))
-        (control-buffer-suffix ediff-control-buffer-suffix)
-        diff-overlay-list list-element
-        a-begin a-end b-begin b-end
-        a-overlay b-overlay)
-
-    (while diff-list
-      (setq current-diff (1+ current-diff)
-           list-element (car diff-list)
-           a-begin      (aref list-element 0)
-           a-end        (aref list-element 1)
-           b-begin      (aref list-element 2)
-           b-end        (aref list-element 3))
-           
-      ;; place overlays at the appropriate places in the buffers
-      (setq a-overlay (ediff-make-overlay a-begin a-end A-buffer))
-      ;; priority of a-overlay and b-overlay should be equal. otherwise it
-      ;; won't work due to Emacs bug---insert-in-front-hooks will be called
-      ;; only on behalf of the buffer with higher priority.
-      (ediff-overlay-put a-overlay 'priority ediff-shaded-overlay-priority)
-      (ediff-overlay-put a-overlay 'ediff-diff-num current-diff)
-      (ediff-overlay-put a-overlay
-                        'insert-in-front-hooks '(ediff-insert-in-front))
-      (ediff-overlay-put a-overlay
-                        'ediff-control-buffer control-buffer-suffix)
-      (ediff-overlay-put a-overlay 
-                        'face (if (ediff-odd-p current-diff) ;; odd diff
-                                  'ediff-odd-diff-face-A-var
-                                'ediff-even-diff-face-A-var))
-                        
-      (setq b-overlay (ediff-make-overlay b-begin b-end B-buffer))
-      (ediff-overlay-put b-overlay 'priority ediff-shaded-overlay-priority)
-      (ediff-overlay-put b-overlay 'ediff-diff-num current-diff)
-      (ediff-overlay-put b-overlay
-                        'insert-in-front-hooks '(ediff-insert-in-front))
-      (ediff-overlay-put b-overlay
-                        'ediff-control-buffer control-buffer-suffix)
-      (ediff-overlay-put b-overlay 
-                        'face (if (ediff-odd-p current-diff) ;; odd diff
-                                  'ediff-odd-diff-face-B-var
-                                'ediff-even-diff-face-B-var))
-                                
-      (if (ediff-if-lucid) ;; chars inserted at end will be inside extent
-         (progn
-           (ediff-overlay-put a-overlay
-                              'ediff-marker 
-                              (move-marker (make-marker) a-begin A-buffer))
-           (ediff-overlay-put b-overlay
-                              'ediff-marker 
-                              (move-marker (make-marker) b-begin B-buffer))
-           (ediff-overlay-put a-overlay 'end-open nil)
-           (ediff-overlay-put b-overlay 'end-open nil)))
-                        
-      ;; record all overlays for this difference
-      (setq diff-overlay-list
-           (nconc diff-overlay-list (list (vector a-overlay b-overlay)))
-           diff-list (cdr diff-list))
-      (message "Ediff: Processing diff region %d of %d"
-              current-diff total-diffs)
-      ) ;; while
-    ;; this is just to avoid confusing the user with diff num < total-diffs
-    (message "Ediff: Processing diff region %d of %d"
-              (1+ current-diff) total-diffs)
-    ;; convert the list of difference information into a vector for
-    ;; fast access
-    (setq ediff-difference-vector
-         (apply 'vector diff-overlay-list))))
-
-
-
-;;; Commands
-
-(defun ediff-recenter (&optional no-rehighlight)
-  "Bring the highlighted region of all buffers A and B into view.
-Reestablish the default three-window display."
-  (interactive)
-  (setq ediff-disturbed-overlays nil) ;; clear after use
-  (let (buffer-read-only)
-    (ediff-setup-windows ediff-A-buffer ediff-B-buffer ediff-control-buffer))
-  ;; Redisplay whatever buffers are showing, if there is a selected difference
-  (if (and (>= ediff-current-difference 0)
-          (< ediff-current-difference ediff-number-of-differences))
-      (let* ( ;; context must be saved before switching to windows A/B
-            (buffer-A ediff-A-buffer)
-            (buffer-B ediff-B-buffer)
-            (wind (selected-window))
-            (control-buf ediff-control-buffer)
-            (before-flag-shift-A (if (eq ediff-highlighting-style 'ascii)
-                                     (1- (length ediff-before-flag-A))
-                                   0))
-            (after-flag-shift-A (if (eq ediff-highlighting-style 'ascii)
-                                    (1- (length ediff-after-flag-A))
-                                  0))
-            (before-flag-shift-B (if (eq ediff-highlighting-style 'ascii)
-                                     (1- (length ediff-before-flag-B))
-                                   0))
-            (after-flag-shift-B (if (eq ediff-highlighting-style 'ascii)
-                                    (1- (length ediff-after-flag-B))
-                                  0))
-            (window-A (get-buffer-window buffer-A t))
-            (window-B (get-buffer-window buffer-B t)))
-       
-       (or no-rehighlight
-           (ediff-operate-on-flags 'insert))
-           
-       (if window-A (progn
-                      (select-window window-A)
-                      (ediff-position-region
-                       (- (ediff-get-diff-posn 'A 'beg nil control-buf)
-                          before-flag-shift-A)
-                       (+ (ediff-get-diff-posn 'A 'end nil control-buf)
-                          after-flag-shift-A)
-                       (ediff-get-diff-posn 'A 'beg nil control-buf))))
-       (if window-B (progn
-                      (select-window window-B)
-                      (ediff-position-region
-                       (- (ediff-get-diff-posn 'B 'beg nil control-buf)
-                          before-flag-shift-B)
-                       (+ (ediff-get-diff-posn 'B 'end nil control-buf)
-                          after-flag-shift-B)
-                       (ediff-get-diff-posn 'B 'beg nil control-buf))))
-       (select-window wind))))
-       
-(defun ediff-toggle-split ()
-  "Toggle vertical/horizontal window split. 
-Does nothing if file-A and file-B are in different frames."
-  (interactive)
-  (let* ((wind-A (get-buffer-window ediff-A-buffer t))
-        (wind-B (get-buffer-window ediff-B-buffer t))
-        (frame-A (if wind-A (ediff-window-frame wind-A)))
-        (frame-B (if wind-B (ediff-window-frame wind-B))))
-    (if (eq frame-A frame-B)
-       (setq ediff-split-window-function
-             (if (eq ediff-split-window-function 'split-window-vertically)
-                 'split-window-horizontally
-               'split-window-vertically))
-      (message "Buffers A and B are residing in different frames. Why split?"))
-    (ediff-recenter 'no-rehighlight)))
-  
-(defun ediff-toggle-hilit ()
-  "Switch between highlighting using ASCII flags and highlighting using faces.
-On a dumb terminal, switches between ASCII highlighting and no highlighting." 
-  (interactive)
-  (if (not window-system)
-      (if (eq ediff-highlighting-style 'ascii)
-         (progn
-           (message "ASCII highlighting flags removed.")
-           (ediff-unselect-and-select-difference ediff-current-difference
-                                                 'unselect-only)
-           (setq ediff-highlighting-style 'off))
-       (ediff-unselect-and-select-difference ediff-current-difference
-                                             'select-only))
-    (ediff-unselect-and-select-difference ediff-current-difference
-                                         'unselect-only)
-    ;; cycle through highlighting
-    (cond ((and ediff-want-faces (null ediff-highlight-selected-only))
-          (message "Ediff: Unhighlighted unselected difference regions.")
-          (setq ediff-highlight-selected-only t))
-         (ediff-want-faces
-          (message "Ediff: Now using ASCII flags only.")
-          (setq ediff-want-faces nil))
-         (t
-          (message "Ediff: Re-highlighted all difference regions.")
-          (setq ediff-want-faces t
-                ediff-highlight-selected-only nil)))
-                
-    (if (and ediff-want-faces (null ediff-highlight-selected-only))
-       (if (not (face-differs-from-default-p 'ediff-odd-diff-face-A-var))
-           (progn
-             (copy-face ediff-odd-diff-face-A 'ediff-odd-diff-face-A-var)
-             (copy-face ediff-odd-diff-face-B 'ediff-odd-diff-face-B-var)
-             (copy-face ediff-even-diff-face-A 'ediff-even-diff-face-A-var)
-             (copy-face ediff-even-diff-face-B 'ediff-even-diff-face-B-var)))
-      (copy-face 'default 'ediff-odd-diff-face-A-var)
-      (copy-face 'default 'ediff-odd-diff-face-B-var)
-      (copy-face 'default 'ediff-even-diff-face-A-var)
-      (copy-face 'default 'ediff-even-diff-face-B-var))
-    
-    (ediff-unselect-and-select-difference
-     ediff-current-difference 'select-only))
-  (ediff-operate-on-flags 'insert)
-  )
-  
-(defun ediff-toggle-help ()
-  "Toggle short/long help message."
-  (interactive)
-  (let (buffer-read-only)
-    (erase-buffer)
-    (if (string= ediff-help-message ediff-help-message-long)
-       (setq ediff-help-message ediff-help-message-short)
-      (setq ediff-help-message ediff-help-message-long)))
-  (ediff-recenter 'no-rehighlight))
-  
-  
-(defun ediff-toggle-read-only-A ()
-  "Used as a startup hook to set `.orig' patch file read-only."
-  (let ((last-command-char ?A))
-    (ediff-toggle-read-only)))
-  
-(defun ediff-toggle-read-only ()
-  "Toggles buffer-read-only for buffer buffers A and B."
+(defun ediff-merge-revisions (&optional file startup-hooks merge-buffer-file)
+  ;; MERGE-BUFFER-FILE is the file to be associated with the merge buffer
+  "Run Ediff by merging two revisions of a file.
+The file is the optional FILE argument or the file visited by the current
+buffer."
   (interactive)
-  (emerge-eval-in-buffer
-   (if (eq last-command-char ?A) ediff-A-buffer ediff-B-buffer)
-   (setq buffer-read-only (null buffer-read-only))))
-
-;;; Window scrolling operations
-;; These operations are designed to scroll all three windows the same amount,
-;; so as to keep the text in them aligned.
-
-;; Perform some operation on two file windows (if they are showing).
-;; Catches all errors on the operation in the A and B windows.
-;; Usually, errors come from scrolling off the
-;; beginning or end of the buffer, and this gives nice nice error messages.
-(defun ediff-operate-on-windows (operation arg)
-  (let* ((buffer-A ediff-A-buffer)
-        (buffer-B ediff-B-buffer)
-        (wind (selected-window))
-        (window-A (get-buffer-window buffer-A t))
-        (window-B (get-buffer-window buffer-B t)))
-      (if window-A (progn
-                    (select-window window-A)
-                    (condition-case nil
-                        (funcall operation arg)
-                      (error))))
-      (if window-B (progn
-                    (select-window window-B)
-                    (condition-case nil
-                        (funcall operation arg)
-                      (error))))
-      (select-window wind)
-                      ))
-
-(defun ediff-scroll-up (&optional arg)
-  "Scroll up buffers A and B, if they are in windows.
-With optional argument ARG, scroll ARG lines; otherwise scroll by nearly
-the height of window-A."
-  (interactive "P")
-  (ediff-operate-on-windows
-   'scroll-up 
-   ;; calculate argument to scroll-up
-   ;; if there is an explicit argument
-   (if (and arg (not (equal arg '-)))
-       ;; use it
-       (prefix-numeric-value arg)
-     ;; if not, see if we can determine a default amount (the window height)
-     (let* ((window-A (get-buffer-window ediff-A-buffer t))
-           (window-B (get-buffer-window ediff-B-buffer t))
-           default-amount)
-       (if (or (null window-A) (null window-B))
-          (setq default-amount 0)
-        (setq default-amount 
-              (- (min (window-height window-A) (window-height window-B))
-                 1 next-screen-context-lines)))
-       ;; the window was found
-       (if arg
-          ;; C-u as argument means half of default amount
-          (/ default-amount 2)
-        ;; no argument means default amount
-        default-amount)))))
-
-(defun ediff-scroll-down (&optional arg)
-  "Scroll down buffers A and B, if they are in windows.
-With optional argument ARG, scroll ARG lines; otherwise scroll by nearly
-the height of window-A."
-  (interactive "P")
-  (ediff-operate-on-windows
-   'scroll-down
-   ;; calculate argument to scroll-down
-   ;; if there is an explicit argument
-   (if (and arg (not (equal arg '-)))
-       ;; use it
-       (prefix-numeric-value arg)
-     ;; if not, see if we can determine a default amount (the window height)
-     (let* ((window-A (get-buffer-window ediff-A-buffer t))
-           (window-B (get-buffer-window ediff-B-buffer t))
-           default-amount)
-       (if (or (null window-A) (null window-B))
-          (setq default-amount 0)
-        (setq default-amount 
-              (- (min (window-height window-A) (window-height window-B))
-                 1 next-screen-context-lines)))
-       ;; the window was found
-       (if arg
-          ;; C-u as argument means half of default amount
-          (/ default-amount 2)
-        ;; no argument means default amount
-        default-amount)))))
-
-(defun ediff-scroll-left (&optional arg)
-  "Scroll left buffer-A and buffer-B, if they are in windows.
-If an argument is given, that is how many columns are scrolled, else nearly
-the width of the A and B windows."
-  (interactive "P")
-  (ediff-operate-on-windows
-   'scroll-left
-   ;; calculate argument to scroll-left
-   ;; if there is an explicit argument
-   (if (and arg (not (equal arg '-)))
-       ;; use it
-       (prefix-numeric-value arg)
-     ;; if not, see if we can determine a default amount
-     ;; (half the window width)
-     (if (null ediff-control-window)
-        ;; no control window, use nil
-        nil
-       (let ((default-amount
-              (- (/ (window-width ediff-control-window) 2) 3)))
-        ;; the window was found
-        (if arg
-            ;; C-u as argument means half of default amount
-            (/ default-amount 2)
-          ;; no argument means default amount
-          default-amount))))))
-
-(defun ediff-scroll-right (&optional arg)
-  "Scroll right buffer-A and buffer-B, if they are in windows.
-If an argument is given, that is how many columns are scrolled, else nearly
-the width of the A and B windows."
-  (interactive "P")
-  (ediff-operate-on-windows
-   'scroll-right
-   ;; calculate argument to scroll-right
-   ;; if there is an explicit argument
-   (if (and arg (not (equal arg '-)))
-       ;; use it
-       (prefix-numeric-value arg)
-     ;; if not, see if we can determine a default amount
-     ;; (half the window width)
-     (if (null ediff-control-window)
-        ;; no control window, use nil
-        nil
-       (let ((default-amount
-              (- (/ (window-width ediff-control-window) 2) 3)))
-        ;; the window was found
-        (if arg
-            ;; C-u as argument means half of default amount
-            (/ default-amount 2)
-          ;; no argument means default amount
-          default-amount))))))
-
-(defun ediff-position-region (beg end pos)
-  "This is a variation on `emerge-position-region'.
-The difference is that it always tries to align difference regions in
-buffer-A and buffer-B, so that it will be easier to compare them."
-  (set-window-start (selected-window) beg)
-  (if (pos-visible-in-window-p end)
-      ;; Determine the number of lines that the region occupies
-      (let ((lines 0))
-       (while (> end (progn
-                       (move-to-window-line lines)
-                       (point)))
-         (setq lines (1+ lines)))
-       ;; And position the beginning on the right line
-       (goto-char beg)
-       (recenter (/ (1+ (max (- (1- (window-height (selected-window)))
-                                lines)
-                             1)
-                        )
-                    2))))
-  (goto-char pos)
-  )
+  (if (stringp file) (find-file file))
+  (let (rev1 rev2)
+    (setq rev1
+         (read-string
+          (format
+           "Version 1 to merge (default %s's working version): "
+           (if (stringp file)
+               (file-name-nondirectory file) "current buffer")))
+         rev2
+         (read-string
+          (format
+           "Version 2 to merge (default %s): "
+           (if (stringp file)
+               (file-name-nondirectory file) "current buffer"))))
+    (ediff-load-version-control)
+    ;; ancestor-revision=nil
+    (funcall
+     (intern (format "ediff-%S-merge-internal" ediff-version-control-package))
+     rev1 rev2 nil startup-hooks merge-buffer-file)))
 
 
-(defun ediff-next-difference (arg)
-  "Advance to the next difference. 
-With a prefix argument, go back that many differences."
-  (interactive "P")
-  (if (< ediff-current-difference ediff-number-of-differences)
-      (let ((n (min ediff-number-of-differences
-                   (+ ediff-current-difference (if arg arg 1))))
-           (buffer-read-only nil))
-       (ediff-unselect-and-select-difference n))
-    (error "At end of the difference list.")))
-
-(defun ediff-previous-difference (arg)
-  "Go to the previous difference. 
-With a prefix argument, go back that many differences."
-  (interactive "P")
-  (if (> ediff-current-difference -1)
-      (let ((n (max -1 (- ediff-current-difference (if arg arg 1))))
-           (buffer-read-only nil))
-         (ediff-unselect-and-select-difference n))
-    (error "At beginning of the difference list.")))
-
-(defun ediff-jump-to-difference (difference-number)
-  "Go to the difference specified as a prefix argument."
-  (interactive "p")
-  (let ((buffer-read-only nil))
-    (setq difference-number (1- difference-number))
-    (if (and (>= difference-number -1)
-            (< difference-number (1+ ediff-number-of-differences)))
-       (ediff-unselect-and-select-difference difference-number)
-      (error "Bad difference number"))))
-      
-(defun ediff-jump-to-difference-at-point ()
-  "Go to the difference closest to the point in buffer A or B.
-If this command is invoked via `ja' or `ga' then the point in buffer A is
-used.  Otherwise, buffer B is used."
+;;;###autoload
+(defun ediff-merge-revisions-with-ancestor (&optional
+                                           file startup-hooks
+                                           ;; MERGE-BUFFER-FILE is the file to
+                                           ;; be associated with the merge
+                                           ;; buffer
+                                           merge-buffer-file)
+  "Run Ediff by merging two revisions of a file with a common ancestor.
+The file is the optional FILE argument or the file visited by the current
+buffer."
   (interactive)
-  (let ((buffer-read-only nil)
-       (buf-type (if (eq last-command-char ?a) 'A  'B)))
-    
-    (ediff-jump-to-difference (ediff-diff-at-point buf-type))))
-       
-      
-;; find region "most related to the current point position      
-
-(defun ediff-diff-at-point (buf-type)
-  (let ((buffer (if (eq buf-type 'A) ediff-A-buffer ediff-B-buffer))
-       (ctl-buffer ediff-control-buffer)
-       (diff-no -1)
-       (prev-beg 0)
-       (beg 0))
-       
-    (emerge-eval-in-buffer
-     buffer
-     (while (or (< (point) prev-beg) (> (point) beg))
-       (setq diff-no (1+ diff-no))
-       (setq prev-beg beg)
-       (setq beg (ediff-get-diff-posn buf-type 'beg diff-no ctl-buffer)))
-      
-     (if (< (abs (- (point) prev-beg))
-           (abs (- (point) beg)))
-        diff-no
-       (1+ diff-no))  ;; jump-to-diff works with diff nums higher by 1
-     )))
-
-;;; Copying diffs.
-
-(defun ediff-diff-to-diff (arg)
-  "Copy buffer-A'th diff to buffer B.
-If numerical prefix argument, copy this diff specified in the arg.
-Otherwise, copy the difference given by `ediff-current-difference'." 
+  (if (stringp file) (find-file file))
+  (let (rev1 rev2 ancestor-rev)
+    (setq rev1
+         (read-string
+          (format
+           "Version 1 to merge (default %s's working version): "
+           (if (stringp file)
+               (file-name-nondirectory file) "current buffer")))
+         rev2
+         (read-string
+          (format
+           "Version 2 to merge (default %s): "
+           (if (stringp file)
+               (file-name-nondirectory file) "current buffer")))
+         ancestor-rev
+         (read-string
+          (format
+           "Ancestor version (default %s's base revision): "
+           (if (stringp file)
+               (file-name-nondirectory file) "current buffer"))))
+    (ediff-load-version-control)
+    (funcall
+     (intern (format "ediff-%S-merge-internal" ediff-version-control-package))
+     rev1 rev2 ancestor-rev startup-hooks merge-buffer-file)))
+
+;; MK: Check. This function doesn't seem to be used any more by pcvs or pcl-cvs
+;;;###autoload
+(defun run-ediff-from-cvs-buffer (pos)
+  "Run Ediff-merge on appropriate revisions of the selected file.
+First run after `M-x cvs-update'.  Then place the cursor on a line describing a
+file and then run `run-ediff-from-cvs-buffer'."
+  (interactive "d")
+  (ediff-load-version-control)
+  (let ((tin (tin-locate cvs-cookie-handle pos)))
+    (if tin
+       (cvs-run-ediff-on-file-descriptor tin)
+      (error "There is no file to merge"))))
+
+
+;;; Apply patch
+
+;;;###autoload
+(defun ediff-patch-file (&optional arg patch-buf)
+  "Run Ediff by patching SOURCE-FILENAME.
+If optional PATCH-BUF is given, use the patch in that buffer
+and don't ask the user.
+If prefix argument, then: if even argument, assume that the patch is in a
+buffer. If odd -- assume it is in a file."
   (interactive "P")
-  (if arg
-      (ediff-jump-to-difference arg))
-  (ediff-copy-diff ediff-current-difference
-                  (if (eq last-command-char ?a) 'B  'A))
-  (ediff-recenter 'no-rehighlight))
-
-
-(defun ediff-copy-diff (n buf-type)
-  "Copy diff N from BUF-TYPE \(given as `A' or `B'\)."
-  (let* ((other-buf (if (eq buf-type 'A) 
-                       ediff-B-buffer ediff-A-buffer))
-        (buf (if (eq buf-type 'A) 
-                 ediff-A-buffer ediff-B-buffer))
-        (other-buf-type (if (eq buf-type 'A) 'B 'A))
-        (ctrl-buf ediff-control-buffer)
-        reg-to-copy reg-to-delete
-        reg-to-delete-beg reg-to-delete-end)
-       
-    (ediff-operate-on-flags 'remove)
-    (setq reg-to-delete-beg
-         (ediff-get-diff-posn other-buf-type 'beg n ctrl-buf))
-    (setq reg-to-delete-end
-         (ediff-get-diff-posn other-buf-type 'end n ctrl-buf))
-    (setq reg-to-copy (emerge-eval-in-buffer
-                      buf
-                      (buffer-substring (ediff-get-diff-posn
-                                         buf-type 'beg n ctrl-buf)
-                                        (ediff-get-diff-posn
-                                         buf-type 'end n ctrl-buf))))
-    (setq reg-to-delete (emerge-eval-in-buffer
-                        other-buf
-                        (buffer-substring reg-to-delete-beg
-                                          reg-to-delete-end)))
-    (setq ediff-disturbed-overlays nil) ;; clear before use
-    
-    (if (string= reg-to-delete reg-to-copy)
-       (progn
-         (ding)
-         (message
-          "Diff regions %d are identical in buffers A and B. Nothing copied." 
-          (1+ n)))
-       
-      ;; seems ok to copy
-      (if (ediff-test-save-region n other-buf-type)
-           (condition-case conds
-               (let (inhibit-read-only)
-                 (emerge-eval-in-buffer
-                  other-buf
-                  ;; to prevent flags from interfering if buffer is writable
-                  (setq inhibit-read-only (null buffer-read-only))
-                  (let ((before-change-function nil))
-                    (goto-char reg-to-delete-end)
-                    (insert-before-markers reg-to-copy)
-                    (if (ediff-if-lucid)
-                        (progn
-                          (ediff-collect-extents-lucid reg-to-delete-beg)
-                          (if (> reg-to-delete-end reg-to-delete-beg)
-                              (progn
-                                (kill-region reg-to-delete-beg
-                                             reg-to-delete-end) 
-                                (if (string= reg-to-copy "")
-                                    (ediff-adjust-disturbed-extents-lucid
-                                     reg-to-delete-beg)))))
-                      (if (> reg-to-delete-end reg-to-delete-beg)
-                          (kill-region reg-to-delete-beg reg-to-delete-end)
-                        (ediff-move-disturbed-overlays reg-to-delete-beg)))
-                    ))
-                 (ediff-save-diff-region n other-buf-type reg-to-delete))
-             (error (message "%s %s"
-                             (car conds)
-                             (mapconcat 'prin1-to-string (cdr conds) " "))
-                    (beep 1))))
-      )
-    (ediff-operate-on-flags 'insert)
-    ))
-     
-(defun ediff-save-diff-region (n buf-type reg)
-  "Save Nth diff of buffer BUF-TYPE \(`A' or `B'\).
-That is to say, the Nth diff on the `ediff-killed-diffs-alist'.  REG
-is the region to save.  It is redundant here,but is passed anyway, for
-convenience."
-
-  (let* ((n-th-diff-saved (assoc n ediff-killed-diffs-alist))
-        (this-buf-n-th-diff-saved (assoc buf-type (cdr n-th-diff-saved))))
-        
-    (if this-buf-n-th-diff-saved
-       ;; either nothing saved for n-th diff and buffer or we OK'ed
-       ;; overriding
-       (setcdr this-buf-n-th-diff-saved reg)
-      (if n-th-diff-saved ;; n-th diff saved, but for another buffer
-         (nconc n-th-diff-saved  (list (cons buf-type reg)))
-       (setq ediff-killed-diffs-alist  ;; create record for n-th diff
-             (cons (list n (cons buf-type reg))
-                   ediff-killed-diffs-alist))))
-    (message "Saved diff region #%d for buffer %S. To recover hit '%s'."
-            (1+ n) buf-type (if (eq buf-type 'A) "ra" "rb"))))
-    
-(defun ediff-test-save-region (n buf-type)
-  "Test if saving Nth difference region of buffer BUF-TYPE is possible."
-  (let* ((n-th-diff-saved (assoc n ediff-killed-diffs-alist))
-        (this-buf-n-th-diff-saved (assoc buf-type (cdr n-th-diff-saved))))
-        
-    (if this-buf-n-th-diff-saved
-       (if (yes-or-no-p
-            (format 
-             "You've previously copied diff %d from %S to %S. Confirm. "
-             (1+ n) (if (eq buf-type 'A) 'B 'A) buf-type))
-           t
-         (error "Quit."))
-      t)))
-         
-(defun ediff-pop-diff (n buf-type)
-  "Pop last killed Nth diff region from buffer BUF-TYPE."
-  (let* ((n-th-record (assoc n ediff-killed-diffs-alist))
-        (saved-rec (assoc buf-type (cdr n-th-record)))
-        (buf (if (eq buf-type 'A) ediff-A-buffer ediff-B-buffer))
-        saved-diff reg-beg reg-end recovered)
-       
-    (if (cdr saved-rec)
-       (setq saved-diff (cdr saved-rec))
-      (error "Nothing saved for diff %d in buffer %S." (1+ n) buf-type))
-    
-    (ediff-operate-on-flags 'remove)
-       
-    (setq reg-beg (ediff-get-diff-posn buf-type 'beg n ediff-control-buffer))
-    (setq reg-end (ediff-get-diff-posn buf-type 'end n ediff-control-buffer))
-    (setq ediff-disturbed-overlays nil) ;; clear before use
-    
-    (condition-case conds
-       (emerge-eval-in-buffer
-        buf
-        (let ((inhibit-read-only (null buffer-read-only))
-              (before-change-function nil))
-          (goto-char reg-end)
-          (insert-before-markers saved-diff)
-          
-          (if (ediff-if-lucid)
-              (progn
-                (ediff-collect-extents-lucid reg-beg)
-                (if (> reg-end reg-beg)
-                    (progn
-                      (kill-region reg-beg reg-end)
-                      (if (string= saved-diff "")
-                          (ediff-adjust-disturbed-extents-lucid reg-beg)))))
-            (if (> reg-end reg-beg)
-                (kill-region reg-beg reg-end)
-              (ediff-move-disturbed-overlays reg-beg)))
-            
-          (setq recovered t)
-          ))
-      (error (message "%s %s"
-                     (car conds)
-                     (mapconcat 'prin1-to-string (cdr conds) " "))
-            (beep 1)))
-    
-    (ediff-operate-on-flags 'insert)
-    (if recovered
-       (progn
-         (setq  n-th-record (delq saved-rec n-th-record))
-         (message "Diff region %d restored for buffer %S." (1+ n) buf-type)))
-    ))
-      
-(defun ediff-restore-diff  (arg)
-  "Restore ARGth diff from `ediff-killed-diffs-alist'.
-ARG is a prefix argument.  If ARG is nil, restore current-difference."
+  (let (source-dir source-file)
+    (require 'ediff-ptch)
+    (setq patch-buf
+         (ediff-get-patch-buffer
+          (if arg (prefix-numeric-value arg)) patch-buf))
+    (setq source-dir (cond (ediff-use-last-dir ediff-last-dir-patch)
+                          ((and (not ediff-patch-default-directory)
+                                (buffer-file-name patch-buf))
+                           (file-name-directory
+                            (expand-file-name
+                             (buffer-file-name patch-buf))))
+                          (t default-directory)))
+    (setq source-file
+         (read-file-name
+          "File to patch (directory, if multifile patch): "
+          ;; use an explicit initial file
+          source-dir nil nil (ediff-get-default-file-name)))
+    (ediff-dispatch-file-patching-job patch-buf source-file)))
+
+;;;###autoload
+(defun ediff-patch-buffer (&optional arg patch-buf)
+  "Run Ediff by patching the buffer specified at prompt.
+Without the optional prefix ARG, asks if the patch is in some buffer and
+prompts for the buffer or a file, depending on the answer.
+With ARG=1, assumes the patch is in a file and prompts for the file.
+With ARG=2, assumes the patch is in a buffer and prompts for the buffer.
+PATCH-BUF is an optional argument, which specifies the buffer that contains the
+patch. If not given, the user is prompted according to the prefix argument."
   (interactive "P")
-  (if arg
-      (ediff-jump-to-difference arg))
-  (ediff-pop-diff ediff-current-difference 
-                 (if (eq last-command-char ?a) 'A   'B))
-  (ediff-recenter 'no-rehighlight))
-    
-
-;;; Quitting, suspending, etc.
-(defun ediff-quit ()
-  "Finish an Ediff session and exit Ediff.
-Unselects the selected difference, if any, restores the read-only and modified
-flags of the compared file buffers, kills Ediff buffers for this session
-\(but not file-A and file-B\)."
-  (interactive)
-  (if (prog1
-         (y-or-n-p "Do you really want to exit Ediff? ")
-       (message ""))
-      (ediff-really-quit)))
-
-;; Perform the quit operations.
-(defun ediff-really-quit ()
-  (setq buffer-read-only nil)
-  (ediff-unselect-and-select-difference -1)
-  ;; null out the difference overlays so they won't slow down future editing
-  ;; operations
-  (mapcar (function (lambda (d)
-                     (ediff-delete-overlay (aref d 0))
-                     (ediff-delete-overlay (aref d 1))))
-         ediff-difference-vector)
-  ;; allow them to be garbage collected
-  (setq ediff-difference-vector nil)
-  (setq ediff-help-message ediff-help-message-long)
-  (ediff-restore-buffer-characteristics t) ;; restore as they were at setup
-  (ediff-unhighlight-diffs-totally)
-  
-  ;; restore buffer mode line id's in buffer-A/B
-  (let ((control-buffer ediff-control-buffer))
-    (emerge-eval-in-buffer
-     ediff-A-buffer
-     (setq before-change-function nil)
-     (setq ediff-this-buffer-control-sessions 
-          (delq control-buffer ediff-this-buffer-control-sessions))
-     (if (null ediff-this-buffer-control-sessions)
-        (setq local-write-file-hooks 
-              (delq 'ediff-block-write-file local-write-file-hooks)))
-     (kill-local-variable 'mode-line-buffer-identification))
-    (emerge-eval-in-buffer
-     ediff-B-buffer
-     (setq ediff-this-buffer-control-sessions 
-          (delq control-buffer ediff-this-buffer-control-sessions))
-     (if (null ediff-this-buffer-control-sessions)
-        (setq local-write-file-hooks 
-              (delq 'ediff-block-write-file local-write-file-hooks)))
-     (setq before-change-function nil)
-     (kill-local-variable 'mode-line-buffer-identification)))
-   
-  (run-hooks 'ediff-quit-hooks))
-  
-(defun ediff-kill-buffer-carefully (buf)
-  "Kill buffer BUF if it exists."
-  (if (ediff-buffer-live-p buf)
-      (kill-buffer (get-buffer buf))))
-
-;; The default way of quitting Ediff.
-;; Kills control buffers and leaves the
-;; frame split between the two diff'ed files.
-(defun ediff-default-quit-hook ()
-  (let ((buff-A ediff-A-buffer)
-       (buff-B ediff-B-buffer))
-    (ediff-kill-buffer-carefully ediff-diff-buffer)
-    (ediff-kill-buffer-carefully ediff-diff-error-buffer)
-    (ediff-kill-buffer-carefully ediff-control-buffer)
-    (ediff-kill-buffer-carefully ediff-patch-diagnostics)
-    (delete-other-windows)
-    (switch-to-buffer buff-B)
-    (split-window-vertically)
-    (switch-to-buffer buff-A)))
-    
-;; The default way of suspending Ediff.
-;; Buries Ediff buffers, kills all windows.
-(defun ediff-default-suspend-hook ()
-  (let ((buf-A ediff-A-buffer)
-       (buf-B ediff-B-buffer)
-       (buf-patch ediff-patch-buf)
-       (buf-patch-diag ediff-patch-diagnostics)
-       (buf-err  ediff-diff-error-buffer)
-       (buf-diff ediff-diff-buffer))
-    (bury-buffer) ;; ediff-control-buffer
-    (delete-other-windows)
-    (bury-buffer buf-err)
-    (bury-buffer buf-diff)
-    (bury-buffer buf-patch)
-    (bury-buffer buf-patch-diag)
-    (bury-buffer buf-A)
-    (bury-buffer buf-B)))
-     
-     
-(defun ediff-suspend ()
-  "Suspend Ediff.
-To resume, switch to the appropriate `*ediff-control*'
-buffer and then type \\[ediff-recenter].  Ediff will automatically set
-up an appropriate window config."
-  (interactive)
-  (run-hooks 'ediff-suspend-hooks)
-  (message
-   "To resume, switch to *ediff-control* and hit 'c' (ediff-recenter)."))
+  (require 'ediff-ptch)
+  (setq patch-buf
+       (ediff-get-patch-buffer
+        (if arg (prefix-numeric-value arg)) patch-buf))
+  (ediff-patch-buffer-internal
+   patch-buf
+   (read-buffer
+    "Which buffer to patch? "
+    (ediff-other-buffer patch-buf))))
 
 
-(defun ediff-file-names ()
-  "Show the names of the buffers or files being operated on by Ediff.
-Hit \\[ediff-recenter] to reset the windows afterward."
-  (interactive)
-  (with-output-to-temp-buffer "*Help*"
-    (emerge-eval-in-buffer ediff-A-buffer
-                          (if buffer-file-name
-                              (progn
-                                (princ "File A is: ")
-                                (princ buffer-file-name))
-                            (progn
-                              (princ "Buffer A is: ")
-                              (princ (buffer-name))))
-                          (princ "\n"))
-    (emerge-eval-in-buffer ediff-B-buffer
-                          (if buffer-file-name
-                              (progn
-                                (princ "File B is: ")
-                                (princ buffer-file-name))
-                            (progn
-                              (princ "Buffer B is: ")
-                              (princ (buffer-name))))
-                          (princ "\n"))
+;;;###autoload
+(defalias 'epatch 'ediff-patch-file)
+;;;###autoload
+(defalias 'epatch-buffer 'ediff-patch-buffer)
+
+
+
+\f
+;;; Versions Control functions
+
+;;;###autoload
+(defun ediff-revision (&optional file startup-hooks)
+  "Run Ediff by comparing versions of a file.
+The file is an optional FILE argument or the file entered at the prompt.
+Default: the file visited by the current buffer.
+Uses `vc.el' or `rcs.el' depending on `ediff-version-control-package'."
+  ;; if buffer is non-nil, use that buffer instead of the current buffer
+  (interactive "P")
+  (if (not (stringp file))
+    (setq file
+         (ediff-read-file-name "Compare revisions for file"
+                               (if ediff-use-last-dir
+                                   ediff-last-dir-A
+                                 default-directory)
+                               (ediff-get-default-file-name)
+                               'no-dirs)))
+  (find-file file)
+  (if (and (buffer-modified-p)
+          (y-or-n-p (message "Buffer %s is modified. Save buffer? "
+                             (buffer-name))))
+      (save-buffer (current-buffer)))
+  (let (rev1 rev2)
+    (setq rev1
+         (read-string
+          (format "Revision 1 to compare (default %s's latest revision): "
+                  (file-name-nondirectory file)))
+         rev2
+         (read-string
+          (format "Revision 2 to compare (default %s's current state): "
+                  (file-name-nondirectory file))))
+    (ediff-load-version-control)
+    (funcall
+     (intern (format "ediff-%S-internal" ediff-version-control-package))
+     rev1 rev2 startup-hooks)
     ))
 
 
+;;;###autoload
+(defalias 'erevision 'ediff-revision)
 
-(defun ediff-line-numbers ()
-  "Display the current line numbers.
-This function displays the line numbers of the points in the A, B."
-  (interactive)
-  (let* ((A-line (emerge-eval-in-buffer ediff-A-buffer
-                                      (count-lines (point-min) (point))))
-        (B-line (emerge-eval-in-buffer ediff-B-buffer
-                                      (count-lines (point-min) (point)))))
-    (message "At lines:  A = %d, B = %d" A-line B-line)))
-
-
-;;; Support routines
-
-;; Select a difference by placing the ASCII flags around the appropriate
-;; group of lines in the A, B buffers
-(defun ediff-select-difference (n)
-  (if (and (>= n 0) (< n ediff-number-of-differences))
-      (progn
-       (ediff-remember-buffer-characteristics)
-       (if (and window-system ediff-want-faces)
-           (progn
-             (ediff-highlight-diff n)
-             (setq ediff-highlighting-style 'face))
-         (setq ediff-highlighting-style 'ascii)
-         (ediff-place-flags-in-buffer 'A ediff-A-buffer
-                                      ediff-control-buffer n)
-         (ediff-place-flags-in-buffer 'B ediff-B-buffer
-                                      ediff-control-buffer n)) 
-         
-       (ediff-restore-buffer-characteristics)
-       (run-hooks 'ediff-select-hooks))))
-       
-
-;; Unselect a difference by removing the ASCII flags in the buffers.
-(defun ediff-unselect-difference (n)
-  (if (and (>= n 0) (< n ediff-number-of-differences))
-      (progn 
-       (ediff-remember-buffer-characteristics)
-       
-       (cond ((and window-system ediff-want-faces)
-              (ediff-unhighlight-diff))
-             ((eq ediff-highlighting-style 'ascii)
-              (ediff-remove-flags-from-buffer
-               ediff-A-buffer
-               (ediff-get-diff-posn 'A 'beg n)
-               (ediff-get-diff-posn 'A 'end n)
-               ediff-before-flag-A ediff-after-flag-A)
-              (ediff-remove-flags-from-buffer
-               ediff-B-buffer
-               (ediff-get-diff-posn 'B 'beg n)
-               (ediff-get-diff-posn 'B 'end n)
-               ediff-before-flag-B ediff-after-flag-B)))
-               
-       (ediff-restore-buffer-characteristics)
-       (setq ediff-highlighting-style nil)
-       (run-hooks 'ediff-unselect-hooks))))
-  
-
-;; Unselects prev diff and selects a new one, if FLAG has value other than
-;; 'select-only or 'unselect-only.  If FLAG is 'select-only, the
-;; next difference is selected, but the current selection is not
-;; unselected.  If FLAG is 'unselect-only then the current selection is
-;; unselected, but the next one is not selected.  If NO-RECENTER is non-nil,
-;; don't recenter buffers after selecting/unselecting.
-;; 
-;; Don't use `ediff-select-difference' and `ediff-unselect-difference'
-;; directly,;; since this will screw up the undo info in the presence of
-;; ASCII flags. 
-;; Instead, use `ediff-unselect-and-select-difference' with appropriate
-;; flags.
-
-(defun ediff-unselect-and-select-difference (n &optional flag no-recenter)
-  (let ((wind (selected-window))
-       ;; save buf modified info
-       (buf-A-modified (buffer-modified-p ediff-A-buffer))
-       (buf-B-modified (buffer-modified-p ediff-B-buffer))
-       ;; temporarily disable undo so highlighting won't confuse the user
-       buf-A-undo buf-B-undo)
-       
-      (emerge-eval-in-buffer
-       ediff-A-buffer
-       (setq buf-A-undo buffer-undo-list))
-      (emerge-eval-in-buffer
-       ediff-B-buffer
-       (setq buf-B-undo buffer-undo-list))
-       
-      (buffer-disable-undo ediff-A-buffer)
-      (buffer-disable-undo ediff-B-buffer)
-    
-      (unwind-protect    ;; we don't want to lose undo info due to error
+
+;; Test if version control package is loaded and load if not
+;; Is SILENT is non-nil, don't report error if package is not found.
+(defun ediff-load-version-control (&optional silent)
+  (require 'ediff-vers)
+  (or (featurep ediff-version-control-package)
+      (if (locate-library (symbol-name ediff-version-control-package))
          (progn
-           (or (eq flag 'select-only)
-               (ediff-unselect-difference ediff-current-difference))
-               
-           ;; Auto-save buffers while Ediff flags are temporarily removed.
-           (emerge-eval-in-buffer
-            ediff-A-buffer
-            (if buf-A-modified
-                (do-auto-save)))
-           (emerge-eval-in-buffer
-            ediff-B-buffer
-            (if buf-B-modified
-                (do-auto-save)))
-    
-           (or (eq flag 'unselect-only)
-               (ediff-select-difference n))
-           (setq ediff-current-difference n)
-           ) ;; end protected section
-      
-       (select-window wind) ;; must be before recenter!
-       (ediff-refresh-mode-line)
-       (or no-recenter
-           (ediff-recenter 'no-rehighlight))
-         
-       ;; restore undo and buffer-modified info
-       (emerge-eval-in-buffer
-        ediff-A-buffer
-        (set-buffer-modified-p buf-A-modified)
-        (setq buffer-undo-list buf-A-undo))
-       (emerge-eval-in-buffer
-        ediff-B-buffer
-        (set-buffer-modified-p buf-B-modified)
-        (setq buffer-undo-list buf-B-undo))
-       )))
-
-;; Revise the mode line to display which difference we have selected
-
-(defun ediff-refresh-mode-line ()
-  (setq mode-line-buffer-identification
-       (list (format "Ediff: %%b   diff %d of %d"
-                     (1+ ediff-current-difference)
-                     ediff-number-of-differences)))
-  ;; Force mode-line redisplay
-  (set-buffer-modified-p (buffer-modified-p)))
-
-
-
-;; Verify that we have a difference selected.
-(defun ediff-validate-difference ()
-  (if (not (and (>= ediff-current-difference 0)
-               (< ediff-current-difference ediff-number-of-differences)))
-      (error "No difference selected")))
-
-;; The following is added to take care of Lemacs.
-
-        
-(defun ediff-read-file-name (prompt default-dir default-file A-file)
-; This is a modified version of a similar function in `emerge.el'.
-; PROMPT should not have trailing ': ', so that it can be modified
-; according to context.
-; If both A-FILE and default-dir are set, the file constructed our of
-; default-dir and the non-directory part of A-FILE is used as default and as
-; initial input.
-; If A-FILE is set (but default-dir is not), it is used as default and
-; initial input. 
-; If default-file is set, it should be used as the default value.
-; If default-dir is non-nil, use it as the default directory.
-; Otherwise, use the value in Emacs's var default-directory.
-  (cond
-   ((and A-file default-dir)
-    (read-file-name (format "%s (default %s%s): "
-                           prompt
-                           (abbreviate-file-name
-                            (expand-file-name default-dir))
-                           (file-name-nondirectory A-file))
-                   (expand-file-name default-dir)
-                   (concat (expand-file-name default-dir)
-                           (file-name-nondirectory A-file))
-                   'confirm (file-name-nondirectory A-file)))
-   (A-file
-    (read-file-name (format "%s (default %s): "
-                           prompt (file-name-nondirectory A-file))
-                   (expand-file-name (file-name-directory A-file))
-                   A-file
-                   'confirm (file-name-nondirectory A-file)))
-   ;; If there is a default file, but no A-file, use it.
-   (default-file
-     (read-file-name (format "%s (default %s): " prompt default-file)
-                    default-dir ;; if nil then default-directory.
-                    nil 'confirm))
-   (t
-    (read-file-name (concat prompt ": ")
-                   default-dir ;; if nil then default-directory.
-                   nil 'confirm))))
-
-  
-(defun ediff-make-temp-file (prefix)
-  (let ((f (make-temp-name (concat ediff-temp-file-prefix prefix))))
-    ;; create the file
-    (write-region (point-min) (point-min) f nil 'no-message)
-    (set-file-modes f ediff-temp-file-mode)
-    f))
-    
-(defun ediff-block-write-file ()    
-  "Prevent writing files A and B directly."
-  (if (ediff-check-for-ascii-flags)
-      (error "Use 'wa' and 'wb' to save buffs A/B (first switch back to *ediff-control*.")))
-
-(defun ediff-check-for-ascii-flags ()
-  (eval
-   (cons 'or
-        (mapcar (function (lambda (buf)
-                            (emerge-eval-in-buffer
-                             buf
-                             (eq ediff-highlighting-style 'ascii))))
-                ediff-this-buffer-control-sessions))))
-
-(defun ediff-insert-in-front (overl beg end)
-  "Capture overlays that had insertions in the front.
-Called when overlay OVERL gets insertion in front."
-  (if (ediff-overlay-get overl 'ediff-diff-num)
-      (setq ediff-disturbed-overlays
-           (cons overl ediff-disturbed-overlays)))
-  )
-  
-(defun ediff-collect-extents-lucid (pos)
-  "Collects all extents at POS having property `ediff-diff-num'.
-Lucid Emacs causes headache by detaching empty extents, so I have to save
-them before they disappear."
-  (let (lis elt)
-    (while (setq elt (extent-at pos nil 'ediff-diff-num elt))
-      (setq lis (cons elt lis)))
-    (setq ediff-disturbed-overlays lis)))
-  
-(defun ediff-move-disturbed-overlays (posn)  
-  (mapcar (function (lambda (overl)
-                      (ediff-move-overlay overl
-                                          posn
-                                          (ediff-overlay-end overl))
-                      ))
-         ediff-disturbed-overlays)
-  (setq ediff-disturbed-overlays nil))
-  
-(defun ediff-adjust-disturbed-extents-lucid (posn &optional posn-type)
-;; POSN-TYPE tells if POSN should become a new start of the extents
-;; (if 'new-start) or a new end (if 'new-end). If POSN-TYPE is nil, then
-;; POSN is both the new start and the new end.
-  (mapcar (function (lambda (overl)
-                      (cond ((and (null posn-type)
-                                  (equal (ediff-overlay-start overl)
-                                         (ediff-overlay-end overl)))
-                             (ediff-move-overlay overl posn posn))
-                          
-                            (posn-type
-                             (ediff-move-overlay
-                              overl
-                              (if (eq posn-type 'new-start)
-                                  posn
-                                (ediff-overlay-start overl))
-                              (if (eq posn-type 'new-end)
-                                  posn
-                                (ediff-overlay-end overl)))))))
-         ediff-disturbed-overlays)
-    (setq ediff-disturbed-overlays nil))
-  
-(defun ediff-save-buffer ()
-  "Safe way of saving buffers A and B."
-  (interactive)
-  (let ((hooks local-write-file-hooks))
-    (ediff-unselect-and-select-difference ediff-current-difference
-                                         'unselect-only)
-    (unwind-protect
-       (emerge-eval-in-buffer
-        (if (eq last-command-char ?a) ediff-A-buffer ediff-B-buffer)
-        ;; temporarily remove writing block 
-        (setq hooks (delq 'ediff-block-write-file hooks))
-        (let ((local-write-file-hooks hooks))
-          (save-buffer)))
-      (ediff-unselect-and-select-difference ediff-current-difference
-                                           'select-only)
-      )))
-    
-
-       
-;; Essentially `emerge-remove-flags-in-buffer', modified to allow deletion
-;; of read-only flags.
-(defun ediff-remove-flags-from-buffer (buffer before-posn after-posn
-                                             before-flag after-flag)
-  (emerge-eval-in-buffer
-   buffer
-   (let ((buffer-read-only nil)
-        (before-change-function nil)
-        (inhibit-read-only t)
-        (before-flag-length (length before-flag))
-        (after-flag-length (length after-flag))
-        )
-     (goto-char after-posn)
-     (setq after-posn (point-marker)) ;; after-posn is now a marker
-     ;; remove the flags, if they're there
-     (goto-char (- before-posn before-flag-length))
-     (if (ediff-if-lucid)
-        (ediff-collect-extents-lucid (+ (point) before-flag-length)))
-     (if (looking-at (regexp-quote before-flag))
-        (delete-region (point) (+ (point) before-flag-length))
-       ;; the flag isn't there
-       (ding)
-       (message "Trouble removing ASCII flag"))
-     (if (ediff-if-lucid)
-        (ediff-adjust-disturbed-extents-lucid (point)))
-        
-     (if (ediff-if-lucid)
-        (ediff-collect-extents-lucid (point)))
-     (goto-char after-posn)
-     (if (looking-at (regexp-quote after-flag))
-        (delete-region (point) (+ (point) after-flag-length))
-       ;; the flag isn't there
-       (ding)
-       (message "Trouble removing ASCII flag"))
-     (if (ediff-if-lucid)
-        (ediff-adjust-disturbed-extents-lucid (point)))
-     (setq after-posn nil) ;; after has become a marker--garbage-collect
-     )))
-
-
-;; This is a modified `emerge-place-flags-in-buffer'.
-(defun ediff-place-flags-in-buffer (buf-type buffer ctl-buffer difference)
-  (emerge-eval-in-buffer
-   buffer
-   (ediff-place-flags-in-buffer1 buf-type ctl-buffer difference)))
-
-;; Modified `emerge-place-flags-in-buffer1'.
-(defun ediff-place-flags-in-buffer1 (buf-type ctl-buffer difference)
-  (let ((buffer-read-only nil)
-       (inhibit-read-only t)
-       (before-change-function nil)
-       (before-flag-name (if (eq buf-type 'A)
-                              'ediff-before-flag-A
-                           'ediff-before-flag-B))
-       (after-flag-name (if (eq buf-type 'A)
-                              'ediff-after-flag-A
-                            'ediff-after-flag-B))
-       beg-of-line flag)
-       
-    ;; insert the flag before the difference
-    (let ((before (ediff-get-diff-posn buf-type 'beg difference ctl-buffer)))
-      (goto-char before)
-      (setq beg-of-line (bolp))
-      
-      (setq flag (emerge-eval-in-buffer
-                 ctl-buffer
-                 (if beg-of-line
-                     (set before-flag-name ediff-before-flag-bol)
-                   (set before-flag-name ediff-before-flag-mol))))
-        
-      ;; insert the flag itself
-      (if (ediff-if-lucid)
-         (ediff-collect-extents-lucid (point)))
-      (insert-before-markers flag)
-      (if (ediff-if-lucid)
-         ;; Lucid's extent end-points behave strangely; they won't
-         ;; respect insert-before-markers
-         (ediff-adjust-disturbed-extents-lucid (point) 'new-start))
-      )
-    ;; insert the flag after the difference
-    (let* ((after (ediff-get-diff-posn buf-type 'end difference ctl-buffer)))
-      (goto-char after)
-      (setq beg-of-line (bolp))
-
-      (setq flag (emerge-eval-in-buffer
-                 ctl-buffer
-                 (if beg-of-line
-                     (set after-flag-name ediff-after-flag-bol)
-                   (set after-flag-name ediff-after-flag-mol))))
-
-      ;; insert the flag itself
-      (if (ediff-if-lucid)
-         (ediff-collect-extents-lucid (point)))
-      (insert flag)
-      (if (ediff-if-lucid)
-         (ediff-adjust-disturbed-extents-lucid after 'new-end))
-      )))
-
-  
-(defun ediff-get-diff-posn (buf-type pos &optional n control-buf)
-  "Returns positions of difference sectors in the BUF-TYPE buffer.
-BUF-TYPE should be a symbol--either `A' or `B'. 
-POS is either `beg' or `end'--it specifies whether you want the position at the
-beginning of a difference of at the end.
-
-The optional argument N says which difference \(default:
-`ediff-current-difference'\).  The optional argument CONTROL-BUF says
-which control buffer is in effect in case it is not the current
-buffer."
-  (let (diff-overlay)
-    (or control-buf
-       (setq control-buf (current-buffer)))
-
-    (emerge-eval-in-buffer
-     control-buf
-     (or n  (setq n ediff-current-difference))
-     (if (or (< n 0) (>= n ediff-number-of-differences))
-        (error "There is no diff %d in this session. Valid diffs are 1 to %d."
-               (1+ n) ediff-number-of-differences))
-     (setq diff-overlay (aref (aref ediff-difference-vector n)
-                             (if (eq buf-type 'A) 0 1))))
-    
-    (if (ediff-overlay-get diff-overlay 'detached)
-       (ediff-move-overlay diff-overlay
-                           (ediff-overlay-get diff-overlay 'ediff-marker)
-                           (ediff-overlay-get diff-overlay 'ediff-marker)))
-    (if (eq pos 'beg)
-       (ediff-overlay-start diff-overlay)
-      (ediff-overlay-end diff-overlay))
-    ))
-    
-
-
-;; These would highlight differences under X
-(defun ediff-highlight-diff (n)
-  "Put face on diff N.  Invoked for X displays only."
-  (let* ((last-A (emerge-eval-in-buffer ediff-A-buffer (point-max)))
-        (last-B (emerge-eval-in-buffer ediff-B-buffer (point-max)))
-        (begin-A (ediff-get-diff-posn 'A 'beg n))
-        (end-A (ediff-get-diff-posn 'A 'end n))
-        (xtraA (if (equal begin-A end-A) 1 0))
-        (end-A-hilit (min last-A (+ end-A xtraA)))
-        
-        (begin-B (ediff-get-diff-posn 'B 'beg n))
-        (end-B (ediff-get-diff-posn 'B 'end n))
-        (xtraB (if (equal begin-B end-B) 1 0))
-        (end-B-hilit (min last-B (+ end-B xtraB))))
-         
-    (if (ediff-if-lucid)
-       (progn 
-         (ediff-move-overlay
-          ediff-current-diff-overlay-A begin-A end-A-hilit)
-         (ediff-move-overlay
-          ediff-current-diff-overlay-B begin-B end-B-hilit))
-      ;; Emacs 19.22 has a bug, which requires that ediff-move-overlay will
-      ;; have the buffer as a parameter.  Believed fixed in 19.23.
-      (ediff-move-overlay ediff-current-diff-overlay-A
-                         begin-A end-A-hilit ediff-A-buffer)
-      (ediff-move-overlay ediff-current-diff-overlay-B
-                         begin-B end-B-hilit ediff-B-buffer))
-    ;; giving priority of 0 and then changing it may look funny, but
-    ;; this is intended to overcome an Emacs bug.
-    (ediff-overlay-put ediff-current-diff-overlay-A 'priority  0)
-    (ediff-overlay-put ediff-current-diff-overlay-B 'priority  0)
-    (ediff-overlay-put ediff-current-diff-overlay-A 'priority  
-                (ediff-highest-priority begin-A end-A-hilit ediff-A-buffer))
-    (ediff-overlay-put ediff-current-diff-overlay-B 'priority 
-                (ediff-highest-priority begin-B end-B-hilit ediff-B-buffer))
-                
-    (if (and (not (face-differs-from-default-p 'ediff-odd-diff-face-A-var))
-            (null ediff-highlight-selected-only))
-       (progn
-         (copy-face ediff-odd-diff-face-A 'ediff-odd-diff-face-A-var)
-         (copy-face ediff-odd-diff-face-B 'ediff-odd-diff-face-B-var)
-         (copy-face ediff-even-diff-face-A 'ediff-even-diff-face-A-var)
-         (copy-face ediff-even-diff-face-B 'ediff-even-diff-face-B-var)))
-         
-    ;; unhighlight the background overlay for the diff n so they won't
-    ;; interfere with the current diff overlay
-    (ediff-overlay-put (aref (aref ediff-difference-vector n) 0) 'face nil)
-    (ediff-overlay-put (aref (aref ediff-difference-vector n) 1) 'face nil)
-    
-    (sit-for 0) ;; needs to synch for some reason
-    ))
+           (message "") ; kill the message from `locate-library'
+           (require ediff-version-control-package))
+       (or silent
+           (error "Version control package %S.el not found.  Use vc.el instead"
+                  ediff-version-control-package)))))
 
 
-(defun ediff-unhighlight-diff ()
-  "Remove overlays from buffers A and B."
-    
-  (ediff-move-overlay ediff-current-diff-overlay-A 1 1)
-  (ediff-move-overlay ediff-current-diff-overlay-B 1 1)
-  
-  ;; rehighlight the overlay in the background of the
-  ;; current difference region
-  (ediff-overlay-put (aref (aref ediff-difference-vector
-                                ediff-current-difference) 
-                          0)
-                    'face (if (ediff-odd-p ediff-current-difference)
-                              'ediff-odd-diff-face-A-var
-                            'ediff-even-diff-face-A-var))
-  (ediff-overlay-put (aref (aref ediff-difference-vector
-                                ediff-current-difference) 
-                          1)
-                    'face (if (ediff-odd-p ediff-current-difference)
-                              'ediff-odd-diff-face-B-var
-                            'ediff-even-diff-face-B-var))
-  )
+;;;###autoload
+(defun ediff-version ()
+  "Return string describing the version of Ediff.
+When called interactively, displays the version."
+  (interactive)
+  (if (interactive-p)
+      (message (ediff-version))
+    (format "Ediff %s of %s" ediff-version ediff-date)))
 
 
-(defun ediff-unhighlight-diffs-totally ()
-    (if (and window-system ediff-want-faces)
-       (let ((inhibit-quit t))
-         (if (face-differs-from-default-p 'ediff-odd-diff-face-A-var)
-             (progn
-               (copy-face 'default 'ediff-odd-diff-face-A-var)
-               (copy-face 'default 'ediff-odd-diff-face-B-var)
-               (copy-face 'default 'ediff-even-diff-face-A-var)
-               (copy-face 'default 'ediff-even-diff-face-B-var)))
-         (if (ediff-overlayp ediff-current-diff-overlay-A)
-             (ediff-delete-overlay ediff-current-diff-overlay-A))
-         (setq ediff-current-diff-overlay-A nil)
-         (if (ediff-overlayp ediff-current-diff-overlay-B)
-             (ediff-delete-overlay ediff-current-diff-overlay-B))
-         (setq ediff-current-diff-overlay-B nil))))
-
-         
-(defun ediff-operate-on-flags (action)
-  "Re/unhighlights buffers A and B with all flags from all Ediff sessions.
-This is usually needed only when a
-buffer is involved in multiple Ediff sessions."
-  (let* ((A-sessions (emerge-eval-in-buffer
-                     ediff-A-buffer
-                     ediff-this-buffer-control-sessions))
-        (B-sessions (emerge-eval-in-buffer
-                     ediff-B-buffer
-                     ediff-this-buffer-control-sessions))
-        (sessions (ediff-union A-sessions B-sessions))
-        (flag (if (eq action 'remove) 'unselect-only 'select-only)))
-        
-    (mapcar (function (lambda (buf)
-                       (emerge-eval-in-buffer
-                        buf
-                        (or (if (eq action 'insert)
-                                (memq ediff-highlighting-style '(ascii off))
-                              (not (eq ediff-highlighting-style 'ascii)))
-                            (ediff-unselect-and-select-difference
-                             ediff-current-difference 
-                             flag 'no-recenter))
-                        )))
-           sessions)))
-     
-(defun ediff-union (list1 list2)
-  "Combine LIST1 and LIST2 using a set-union operation.
-The result list contains all items that appear in either LIST1 or LIST2.
-This is a non-destructive function; it makes a copy of the data if necessary
-to avoid corrupting the original LIST1 and LIST2.
-This is a slightly simplified version from `cl-seq.el'.  Added here to
-avoid loading cl-*."
-  (cond ((null list1) list2) ((null list2) list1)
-       ((equal list1 list2) list1)
-       (t
-        (or (>= (length list1) (length list2))
-            (setq list1 (prog1 list2 (setq list2 list1))))
-        (while list2
-          (or (memq (car list2) list1)
-              (setq list1 (cons (car list2) list1)))
-          (setq list2 (cdr list2)))
-        list1)))
-        
-(defun ediff-debug ()
+;;;###autoload
+(defun ediff-documentation (&optional node)
+  "Display Ediff's manual.
+With optional NODE, goes to that node."
   (interactive)
-  (with-output-to-temp-buffer "*ediff-debug*"
-    (princ 
-     (format "Ctl buffer: %S\n\nediff-difference-vector:\n"
-            ediff-control-buffer))
-    (mapcar (function
-            (lambda (overl-vec)
-              (princ (format "Diff %d:  %S %S %S\n\t %S %S %S\n" 
-                             (1+ (ediff-overlay-get (aref overl-vec 0)
-                                                    'ediff-diff-num))
-                             (ediff-overlay-get (aref overl-vec 0)
-                                                'ediff-control-buffer) 
-                             (ediff-overlay-get (aref overl-vec 0)
-                                                'insert-in-front-hooks)
-                             (aref overl-vec 0)
-                             (ediff-overlay-get (aref overl-vec 1)
-                                                'ediff-control-buffer) 
-                             (ediff-overlay-get (aref overl-vec 0)
-                                                'insert-in-front-hooks)
-                             (aref overl-vec 1)
-                             ))))
-           ediff-difference-vector)
-    (princ "\nediff-disturbed-overlays:\n")
-    (mapcar (function
-            (lambda (overl)
-              (princ (format "%S  %S\n"
-                             (ediff-overlay-get overl 'ediff-control-buffer)
-                             overl
-                             ))))
-           ediff-disturbed-overlays)))
-
-  
-(run-hooks 'ediff-load-hooks)
-  
+  (let ((ctl-window ediff-control-window)
+       (ctl-buf ediff-control-buffer))
+
+    (ediff-skip-unsuitable-frames)
+    (condition-case nil
+       (progn
+         (pop-to-buffer (get-buffer-create "*info*"))
+         (info (if ediff-xemacs-p "ediff.info" "ediff"))
+         (if node
+             (Info-goto-node node)
+           (message "Type `i' to search for a specific topic"))
+         (raise-frame (selected-frame)))
+      (error (beep 1)
+            (with-output-to-temp-buffer ediff-msg-buffer
+              (ediff-with-current-buffer standard-output
+                (fundamental-mode))
+              (princ ediff-BAD-INFO))
+            (if (window-live-p ctl-window)
+                (progn
+                  (select-window ctl-window)
+                  (set-window-buffer ctl-window ctl-buf)))))))
+
+
+(dolist (mess '("^Errors in diff output. Diff output is in "
+                "^Hmm... I don't see an Ediff command around here...$"
+                "^Undocumented command! Type `G' in Ediff Control Panel to drop a note to the Ediff maintainer$"
+                ": This command runs in Ediff Control Buffer only!$"
+                ": Invalid op in ediff-check-version$"
+                "^ediff-shrink-window-C can be used only for merging jobs$"
+                "^Lost difference info on these directories$"
+                "^This command is inapplicable in the present context$"
+                "^This session group has no parent$"
+                "^Can't hide active session, $"
+                "^Ediff: something wrong--no multiple diffs buffer$"
+                "^Can't make context diff for Session $"
+                "^The patch buffer wasn't found$"
+                "^Aborted$"
+                "^This Ediff session is not part of a session group$"
+                "^No active Ediff sessions or corrupted session registry$"
+                "^No session info in this line$"
+                "^`.*' is not an ordinary file$"
+                "^Patch appears to have failed$"
+                "^Recomputation of differences cancelled$"
+                "^No fine differences in this mode$"
+                "^Lost connection to ancestor buffer...sorry$"
+                "^Not merging with ancestor$"
+                "^Don't know how to toggle read-only in buffer "
+                "Emacs is not running as a window application$"
+                "^This command makes sense only when merging with an ancestor$"
+                "^At end of the difference list$"
+                "^At beginning of the difference list$"
+                "^Nothing saved for diff .* in buffer "
+                "^Buffer is out of sync for file "
+                "^Buffer out of sync for file "
+                "^Output from `diff' not found$"
+                "^You forgot to specify a region in buffer "
+                "^All right. Make up your mind and come back...$"
+                "^Current buffer is not visiting any file$"
+                "^Failed to retrieve revision: $"
+                "^Can't determine display width.$"
+                "^File `.*' does not exist or is not readable$"
+                "^File `.*' is a directory$"
+                "^Buffer .* doesn't exist$"
+                "^Directories . and . are the same: "
+                "^Directory merge aborted$"
+                "^Merge of directory revisions aborted$"
+                "^Buffer .* doesn't exist$"
+                "^There is no file to merge$"
+                "^Version control package .*.el not found. Use vc.el instead$"))
+  (add-to-list 'debug-ignored-errors mess))
+
+
+(require 'ediff-util)
+
+(run-hooks 'ediff-load-hook)
 
 (provide 'ediff)
 
+
+;;; Local Variables:
+;;; eval: (put 'ediff-defvar-local 'lisp-indent-hook 'defun)
+;;; eval: (put 'ediff-with-current-buffer 'lisp-indent-hook 1)
+;;; eval: (put 'ediff-with-current-buffer 'edebug-form-spec '(form body))
+;;; End:
+
+;;; arch-tag: 97c71396-db02-4f41-8b48-6a51c3348fcc
 ;;; ediff.el ends here