@iftex
@unnumbered XEmacs Features

This section describes the difference between Emacs Version 18 and 
XEmacs.

@unnumberedsec General Changes

@itemize @bullet
@ignore
@item 
XEmacs has a new vi emulation mode called evi mode.  To
start evi mode in Emacs, type the command @kbd{M-x evi}.  If you want
Emacs to automatically put you in evi-mode all the time, include this
line in your init file:
@example
(setq term-setup-hook 'evi)
@end example
@xref{evi Mode} for a brief discussion.
@xref{Init File}.
@end ignore

@item 
XEmacs has a new vi emulation mode called ``viper'' mode.  To start
viper mode in XEmacs, type the command @kbd{M-x viper-mode}.  If you
want XEmacs to automatically put you in viper-mode all the time, include
this line in your init file:
@example
(viper-mode)
@end example
@xref{Init File}.

@item
Earlier versions of Emacs only allowed keybindings to ASCII character
sequences.  XEmacs has greatly expanded this by allowing you to
use a vector of key sequences which are in turn composed of a modifier
and a keysym. @xref{Keystrokes} for more information.

@item
The keymap data structure has been reimplemented to allow the use of a
character set larger than ASCII. Keymaps are no longer alists and/or
vectors; they are a new primary data type.  Consequently, code which
manipulated keymaps with list or array manipulation functions will no
longer work.  It must use the functions @code{define-key} or
@code{map-keymap} and @code{set-keymap-parent} (the new keymap
functions).  @xref{Key Bindings} for more information.

@item
Input and display of all ISO-8859-1 characters is supported.

@item
Multiple fonts, including variable-width fonts, and fonts of differing
heights, are supported.

@item
There is a new @file{tags} package and a new UNIX manual browsing
package. They are similar to earlier versions; for more information look
at the source code. 

@item
There is a new implementation of Dired, with many new features. The
online info for Dired, @i{not} the Dired node of Emacs info, provides
more detail. 

@item
GNUS (a network news reader), VM (an alternative mail reader), ILISP (a
package for interacting with inferior Lisp processes), ANGE-FTP (a package
for making FTP-accessible files appear just like files on the local disk,
even to Dired), Calendar (an Emacs-based calendar and appointment-
management tool), and W3 (an interface to the World Wide Web) are a part
of the XEmacs Lisp library.  See the related documentation in the
online info browser.

@item
Emacs now supports floating-point numbers.

@item
When you send mail, mail aliases are now expanded in the buffer. In
earlier versions, they were expanded after the mail-sending command was
executed.

@item
The initial value of @code{load-path} is computed when Emacs starts up,
instead of being hardcoded in when Emacs is compiled. As a result, you
can now move the Emacs executable and Lisp library to a
different location in the file system without having to recompile.

@item
Any existing subdirectories of the Emacs Lisp directory are now added to the
@code{load-path} by default.

@item
On some machines, you can change the audible bell using the
@code{sound-alist} variable. @xref{Audible Bell} for more information. 

@item
You can use multiple X windows to display multiple Emacs frames. 

@item
You can use the X selection mechanism to copy material from other
applications and into other applications.  You can also use all Emacs
region commands on a region selected with the mouse. @xref{Mouse
Selection} for more information.

@item
By default, the variable @code{zmacs-regions} is set to highlight the region
between point and the mark.  This unifies X selection and Emacs selection
behavior.  

@item
XEmacs has a menu bar for mouse-controlled operations in addition to
keystrokes.  @xref{Pull-down Menus}.

@item
You can look in the file @file{/usr/local/lib/xemacs-19.11/etc/Emacs.ad} for 
a list of Emacs X resources.  You can set these resources in your X 
environment to set your preferences for color, fonts, location, and the size 
of XEmacs frames.  Refer to your X documentation for more information 
about resources.

@unnumberedsec New Commands and Variables

There are many new functions in XEmacs, and many existing functions
whose semantics have been expanded.  Most of these are only of interest
to the Emacs-Lisp programmer; see the NEWS file @kbd{C-h n} for a complete
list.  What follows is a partial list of the new interactive commands:

@findex byte-compile-and-load-file
@findex byte-compile-buffer
@item
@code{byte-compile-and-load-file} and @code{byte-compile-buffer}
byte-compile the contents of a file or buffer.

@findex conx
The new @code{conx} function lets you generate random sentences for your
amusement.

@findex compile-defun
@item
@code{compile-defun} compiles and evaluates the current top-level
form.

@findex find-this-file
@findex find-this-file-other-window
@item
@code{find-this-file} and @code{find-this-file-other-window} can be used
interactively with a prefix argument to switch to the filename at point
in the buffer.  @code{find-this-file-other-window} displays the file in
another window.

@findex invert-face
@findex make-face-bold
@findex make-face-bold-italic
@findex make-face-italic
@findex make-face-unbold
@findex make-face-unitalic
@findex set-face-background
@findex set-face-background-pixmap
@findex set-face-font
@findex set-face-foreground
@findex set-face-underline-p
@item
Several new functions have been added that allow you to customize the
color and font attributes of a region of text: @code{invert-face},
@code{make-face-bold}, @code{make-face-bold-italic},
@code{make-face-italic}, @code{make-face-unbold},
@code{make-face-unitalic}, @code{set-face-background},
@code{set-face-background-pixmap}, @code{set-face-font},
@code{set-face-foreground}, and @code{set-face-underline-p}.

@findex load-default-sounds
@findex load-sound-file
@findex play-sound
@item
@code{load-default-sounds} and @code{load-sound-file} allow you to
customize the audible bell sound.  @code{load-default-sounds} loads and
installs sound files.  @code{load-sound-file} reads in audio files and
adds them to the sound alist. @code{play-sound} plays the specified
sound type.

@findex locate-library
@item
@code{locate-library} finds the file that the function
@code{load-library} loads, and it displays the file's full pathname.

@findex make-directory
@findex remove-directory
@item
@code{make-directory} creates a directory, while @code{remove-directory}
removes a directory.

@findex mark-beginning-of-buffer
@findex mark-end-of-buffer
@item
@code{mark-beginning-of-buffer} and @code{mark-end-of-buffer} push the
mark to the beginning or end of a buffer, respectively.

@findex mouse-del-char
@findex mouse-delete-window
@findex mouse-keep-one-window
@findex mouse-kill-line
@findex mouse-line-length
@findex mouse-scroll
@findex mouse-select
@findex mouse-select-and-split
@findex mouse-set-mark
@findex mouse-set-point
@findex mouse-track
@findex mouse-track-adjust
@findex mouse-track-and-copy-to-cutbuffer
@findex mouse-track-delete-and-insert
@findex mouse-track-insert
@findex mouse-window-to-region
Several functions have been added that allow you to perform various
editing, region, and window operations using the mouse:
@code{mouse-del-char}, @code{mouse-delete-window},
@code{mouse-keep-one-window}, @code{mouse-kill-line},
@code{mouse-line-length}, @code{mouse-scroll}, @code{mouse-select},
@code{mouse-select-and-split}, @code{mouse-set-mark},
@code{mouse-set-point}, @code{mouse-track}, @code{mouse-track-adjust},
@code{mouse-track-and-copy-to-cutbuffer},
@code{mouse-track-delete-and-insert}, @code{mouse-track-insert}, and
@code{mouse-window-to-region}.

@findex compare-windows 
@item
@code{compare-windows} takes an argument @var{ignore-whitespace}.
The argument means ignore changes in whitespace.

@end itemize

You can conditionalize your @file{.emacs} file as follows so that XEmacs 
commands are invoked only when you are in XEmacs:

@cindex version number
@example
(cond ((string-match "XEmacs" emacs-version)
       ;;
       ;; Code for any version of XEmacs goes here.
       ;;
       ))

(cond ((not (string-match "XEmacs" emacs-version)))
       ;;
       ;; Code for any version of GNU Emacs goes here.
       ;;
       ))

(cond ((and (string-match "XEmacs" emacs-version)
            (emacs-version>= 21 4))
       ;;
       ;; Code which requires XEmacs version 21.4 or newer goes here
       ;;
       ))

(cond ((and (string-match "XEmacs" emacs-version)
            (emacs-version>= 21 4 12)
            (not (emacs-version>= 21 4 15)))
       ;;
       ;; Code which requires exactly XEmacs version 21.4.12 through
       ;; 21.4.14, inclusive, goes here. (e.g. A bug was introduced in
       ;; 21.4.12 and fixed in 21.4.15 but many of the versions of
       ;; XEmacs around in the computer laboratory run those versions,
       ;; so I need to introduce a workaround.  In such a case, you
       ;; should ideally try to conditionalize on something else,
       ;; e.g. a feature symbol or a simple test that can be run to
       ;; smoke out the bug.)
       ;;
       ))

(cond ((and (not (string-match "XEmacs" emacs-version)
            (emacs-version>= 20 2))
       ;;
       ;; Code which requires GNU Emacs version 20.2 or newer, but not XEmacs,
       ;; goes here
       ;;
       ))

@end example

@emph{NOTE}: @strong{DO} use @code{(emacs-version>= ...)}.  @strong{DO NOT}
try to do this yourself using @code{emacs-major-version} and
@code{emacs-minor-version}.  You will, with high probability, get it
wrong.  Typical attempts to replace @code{(emacs-version>= 21 4)} use

@example
(and (>= emacs-major-version 21)
     (>= emacs-minor-version 4))
@end example

which correctly excludes 21.3 and all previous versions,
but also excludes 22.0 through 22.3, 23.0 through 23.3, etc.

A "more clever" version, as advocated in earlier versions
of this very manual, was like this:

@example
(or (> emacs-major-version 21)
    (>= emacs-minor-version 4))
@end example

which correctly includes 21.4 and all following versions,
but also includes 20.4 through 20.99999, 19.4 through
19.99999, etc.

Alternatively, use @file{.xemacs/init.el} for an init file.  @xref{Init File}.

Of particular interest for use in  files are:

@itemize @bullet
@findex add-menu
@findex add-menu-item
@findex delete-menu-item
@findex disable-menu-item
@findex enable-menu-item
@findex relabel-menu-item
@item
@code{add-menu} lets you add a new menu to the menubar or a submenu to a
pull-down menu.  @code{add-menu-item}, @code{disable-menu-item},
@code{delete-menu-item}, @code{enable-menu-item}, and
@code{relabel-menu-item} allow you to customize the XEmacs
pull-down menus.

@findex make-frame
@item
@code{make-frame} creates a new Emacs frame (X window).

@end itemize

These new variables are only present in XEmacs:

@itemize @bullet

@vindex minibuffer-confirm-incomplete
@item
@code{minibuffer-confirm-incomplete} prompts for confirmation in 
contexts where @code{completing-read} allows answers that are not valid
completions.

@vindex x-mode-pointer-shape
@vindex x-nontext-pointer-shape
@vindex x-pointer-background-color
@vindex x-pointer-foreground-color
@vindex x-pointer-shape
@item
Several variables have been added that allow you to customize the color
and shape of the mouse pointer: @code{x-pointer-background-color},
@code{x-pointer-foreground-color}, @code{x-mode-pointer-shape},
@code{x-pointer-shape}, and @* @code{x-nontext-pointer-shape}.

@vindex zmacs-regions
@item
@code{zmacs-regions} determines whether LISPM-style active regions
should be used.
@end itemize

@unnumberedsec Changes in Key Bindings

XEmacs has the following new default function keybindings:

@table @kbd
@item @key{HELP}
Same as @kbd{C-h}.

@item @key{UNDO}
Same as @kbd{M-x undo}.

@item @key{CUT}
Same as the Cut menu item; that is, it copies the selected text to
the X Clipboard selection.

@item @key{COPY}
Same as the Copy menu item.

@item @key{PASTE}
Same as the Paste menu item.

@item @key{PGUP}
Same as @kbd{M-v}.

@item @key{PGDN}
Same as @kbd{C-v}.

@item @key{HOME}
Same as @kbd{M-<}.

@item @key{END}
Same as @kbd{M->}.

@item @key{LEFT-ARROW}
Same as the function @code{backward-char}.

@item @key{RIGHT-ARROW}
Same as the function @code{forward-char}.

@item @key{UP-ARROW}
Same as the function @code{previous-line}.

@item @key{DOWN-ARROW}
Same as the function @code{next-line}.

@end table


@end iftex