-*- mode:outline; minor-mode:outl-mouse -*-

* Introduction
==============

This file presents some general information about XEmacs.  It is primarily
about the evolution of XEmacs and its release history.

There are five sections.

    Introduction................(this section) provides an introduction

    Using Outline Mode..........briefly explains how to use outline mode

    The History of XEmacs.......some historical notes

    What's Different?...........new or changed capabilities

    XEmacs Release Notes........details of the changes between releases

New users should look at the next section on "Using Outline Mode".  You will
be more efficient when you can navigate quickly through this file.  Users
interested in some of the details of how XEmacs differs from FSF GNU Emacs
should read the section "What's Different?".  Users who would to know which
capabilities have been introduced in each release should look at the
appropriate subsection of the "XEmacs Release Notes."

    N.B.  The term "FSF GNU Emacs" refers to any release of Emacs Version 19
    from the Free Software Foundation's GNU Project. (We do not say just
    "GNU Emacs" because Richard M. Stallman ["RMS"] thinks that this term
    is too generic; although we sometimes say e.g. "GNU Emacs 19.30" to refer
    to a specific version of FSF GNU Emacs.  We do not say merely "Emacs", as
    RMS prefers, because that is clearly an even more generic term.) The term
    "XEmacs" refers to this program or to its predecessors "Era" and
    "Lucid Emacs".  The predecessor of all these program is called "Emacs 18".
    When no particular version is implied, "Emacs" will be used.


* Using Outline Mode
====================

This file is in outline mode, a major mode for viewing (or editing)
outlines.  It allows you to make parts of the text temporarily invisible so
that you can see just the overall structure of the outline.

There are two ways of using outline mode:  with keys or with menus.  Using
outline mode with menus is the simplest and is just as effective as using
keystrokes.  There are menus for outline mode on the menubar as well as in
popup menus activated by pressing mouse button 3.

Experiment with the menu commands.  Menu items under "Headings" allow
you to navigate from heading to heading.  Menu items under "Show" make
visible portions of the outline while menu items under "Hide" do the
opposite.

A special minor mode called "outl-mouse" has been automatically enabled.  In
this minor mode, glyphs appear which, when clicked on, will alternately hide
or show sections of the outline.

You may at any time press `C-h m' to get a listing of the outline mode key
bindings.  They are reproduced here:

Commands:
C-c C-n   outline-next-visible-heading      move by visible headings
C-c C-p   outline-previous-visible-heading
C-c C-f   outline-forward-same-level        similar but skip subheadings
C-c C-b   outline-backward-same-level
C-c C-u   outline-up-heading		    move from subheading to heading

C-c C-t	make all text invisible (not headings).
M-x show-all	make everything in buffer visible.

The remaining commands are used when point is on a heading line.
They apply to some of the body or subheadings of that heading.
C-c C-d   hide-subtree	make body and subheadings invisible.
C-c C-s   show-subtree	make body and subheadings visible.
C-c tab   show-children	make direct subheadings visible.
		 No effect on body, or subheadings 2 or more levels down.
		 With arg N, affects subheadings N levels down.
C-c C-c	   make immediately following body invisible.
C-c C-e	   make it visible.
C-c C-l	   make body under heading and under its subheadings invisible.
		     The subheadings remain visible.
C-c C-k  make all subheadings at all levels visible.x1


* The History of XEmacs
=======================

This product is an extension of GNU Emacs, previously known to some as
"Lucid Emacs" or "ERA".  It was initially based on an early version of Emacs
Version 19 from the Free Software Foundation and has since been kept
up-to-date with recent versions of that product.  It stems from a
collaboration of Lucid, Inc. with SunSoft DevPro (a division of Sun
Microsystems, Inc.; formerly called SunPro) and the University of Illinois.

NOTE: Lucid, Inc. is currently out of business but development on XEmacs
continues strong.  Recently, Amdahl Corporation and INS Engineering have
both contributed significantly to the development of XEmacs.


** Why Haven't XEmacs and FSF GNU Emacs Merged?
===============================================

This question comes up again and again on comp.emacs.xemacs and other
newsgroups and mailing lists.  Recently in fact there was a long, heated
thread about this issue.

Here is what one XEmacs developer said about this issue.

DISCLAIMER: This is provided for informational purposes only and does
_NOT_ necessarily represent the opinions of any of the other XEmacs
developers or of any of the organizations involved.  Keep in mind
that this is a highly charged issue with differing and strongly-held
opinions held by the various parties involved.

   Subject: Re: elisp code in GNU Emacs/XEmacs
   From: wing@666.com (Ben Wing)
   Message-ID: <wingDqGwLH.K6w@netcom.com>
   Date: Fri, 26 Apr 1996 11:44:05 GMT
   
   In article <9xo91fmordx.fsf@bcarsf26.nortel.ca>, Stephane Boucher
   <sbo@bcarsf26.nortel.ca> wrote:
   
       Well, I don't think the number of volunteers is greater by having 2
       Emacsen. I think your affirmation holds true because of the
       inhability of the various parties involved to work together and
       compromise. If people could all work together, I don't think there
       would be any benifit in having 2 Emacsen. It may seem profitable
       right now, but in the long run, I think everyone looses. The time
       everyone spends porting back and forth, and imitating what the other
       has done is not spent to do new features. I've presonnally
       experienced a project split in the past, and in the end everyone
       lost. 
       
       I don't want to try to blame anybody for the current fiasco. But we do
       have a fiasco. That is unfortunate. There are so many contributors
       out there that if everyone worked together we might be looking
       forward to having, say, threads in Emacs. But instead, as someone
       told me not that long ago, maybe we'll soon see a new editor come out
       based on Java. Threads will be part of it at no extra cost, and those
       people still using Emacs will continue to curse at the fact that they
       can't start GNUS while typing an E-mail, and the various Emacs
       contributors will continue to argue among themselves, nitpicking
       about how to get the perfect solution, rather than try to move
       forward. Meanwhile, people will enjoy using a new state of the art
       editor. 
   
   Don't think we're just being needlessly perverse by continuing to have
   XEmacs. I'm well aware of the problems in having a project split, and
   don't think for a minute that we haven't tried (extremely hard, in
   fact) to come up with a merge.
   
   Unfortunately, as I have said before, the odds of this happening are
   quite low due to severe conflicts (both technical, procedural, and
   philosophical) between RMS and the XEmacs developers. If we were to
   assent to even half of what RMS wants in a merged Emacs, it would take
   years of work to produce the merged Emacs, and the result would be
   less powerful than the existing XEmacs.
   
   Since so many people seem so misinformed about this problem, I'll go
   ahead and state the fundamental dividing issues:
   
    1. RMS does not believe in data abstraction, and cannot be convinced
       of the folly of this. This by itself is such a huge division that
       it makes a merge basically unthinkable. Because of this, FSF Emacs
       is basically unmaintainable by anyone other than RMS. RMS has
       consented to all the data abstraction I want provided that I take
       sole responsibility for writing this code (which basically means
       I'd have to write almost all of the code or rewrite most of his
       code), and provided that he can use this issue as a bargaining
       chip to get concessions of his own.
    2. RMS sees the merge process as a series of mutual concessions
       traded back and forth. IMHO this is reasonable for a peace treaty
       but absurd for a piece of software -- we have to have technical
       agreement on the major issues involved, and the chance of that
       happening is basically nil.
    3. RMS has insisted in full backwards compatibility with all aspects
       of FSF Emacs, no matter how ugly; and furthermore, this backwards
       compatibility must work fast enough to make existing code run
       without problem. This basically means that there would have to be
       parallel C implementations of events, keymaps, and many other data
       structures. This not only will take months or years of extra work
       to implement, but poses some fundamental technical problems due to
       the non-abstractedness of FSF Emacs (e.g. in FSF Emacs keymaps are
       conses or vectors and a lot of code depends on this, and
       reconciling this with XEmacs's primitive keymap type is difficult
       to impossible).
    4. RMS will not even consent to neutral names for the two editors. He
       objects to call his editor FSF Emacs because for some unfathomable
       reason he finds it insulting. He suggests just Emacs, which I find
       not only insulting (XEmacs is just as much Emacs as is FSF Emacs)
       but also quite confusing. He will not even consent to calling his
       editor GNU Emacs without also referring to XEmacs as GNU XEmacs --
       basically a Borg-like assimilation attempt at making XEmacs a GNU
       product, which it is not. (None of the developers of Lucid Emacs
       and XEmacs were or are sanctioned by GNU, and none of us got the
       least bit of assistance or cooperation in doing our work. In fact,
       RMS actively made it harder by choosing to ignore all work
       previously done in XEmacs and adding his own incompatible
       interfaces for functionality already in XEmacs. This makes it
       quite difficult to track FSF Emacs and keep a sane API.) He has
       stated many times, and continues to assert, that most or all of
       the work done on Lucid Emacs and XEmacs was done primarily as a
       testing ground for potential features to be added to FSF Emacs.
       All of the developers of Lucid Emacs and XEmacs assert that this
       is patently false -- so why does RMS continue to insist that this
       is the case?

   ben
   --
   "... then the day came when the risk to remain tight in a bud was
   more painful than the risk it took to blossom." -- Anais Nin


** Why Another Version of Emacs?  (The Lucid, Inc. Point of View)
=================================================================

Lucid's latest product, Energize, is a C/C++ development environment.
Rather than invent (and force our users to learn) a new user-interface, we
chose to build part of our environment on top of the world's best editor,
GNU Emacs.  (Though our product is commercial, the work we did on is
free software, and is useful without having to purchase our product.)

We needed a version of Emacs with mouse-sensitive regions, multiple fonts,
the ability to mark sections of a buffer as read-only, the ability to detect
which parts of a buffer has been modified, and many other features.

*** Why Not Epoch or GNU Emacs?
-------------------------------

For our purposes, the existing version of Epoch was not sufficient; it did
not allow us to put arbitrary pixmaps/icons in buffers, `undo' did not
restore changes to regions, regions did not overlap and merge their
attributes in the way we needed, and several other things.

We could have devoted our time to making Epoch do what we needed (and, in
fact, we spent some time doing that in 1990) but, since the Free Software
Foundation planned to include Epoch-like features in their Version 19, we
decided that our efforts would be better spent improving GNU Emacs
instead of Epoch.

Our original hope was that our changes to GNU Emacs would be
incorporated into the "official" v19.  However, scheduling conflicts arose,
and we found that, given the amount of work still remaining to be done, we
didn't have the time or manpower to do the level of coordination that would
be necessary to get our changes accepted by the Free Software Foundation.
Consequently, we released our work as a forked branch of Emacs, instead of
delaying any longer.

Roughly a year after Lucid Emacs 19.0 was released, a beta version of the
Free Software Foundation branch of Emacs 19 was released.  This version
was better in some areas, and worse in others, as reflects the differing
focus of our development efforts.

We planned to continue developing and supporting Lucid Emacs, and merging in
bug fixes and new features from the Free Software Foundation branch as
appropriate; we did not plan to discard any of the functionality that we
implemented which Richard Stallman of the Free Software Foundation has
chosen not to include in his version.

However, events have overtaken us, and Lucid, Inc. has effectively ceased
doing business and is (September 1994) in the process of being sold.  Our
efforts on Lucid Emacs have also ceased and we've turned over the continued
enhancement of Lucid Emacs to the University of Illinois under Chuck
Thompson, a member of the Lucid Emacs team and a maintainer of Epoch.
At the same time, Lucid Emacs has been renamed XEmacs to reflect the
substantial contribution of the University of Illinois with the support of
Sun Microsystems.

Certain elements of Lucid Emacs, or derivatives of them, have been ported to
the FSF GNU Emacs.  We have not been doing work in this direction, because
we feel that Lucid Emacs has a cleaner and more extensible substrate, and
that any kind of merger between the two branches would be far easier by
merging the Free Software Foundation changes into our version than the other
way around.

We were working closely with the Epoch developers to merge in the
remaining Epoch functionality which Lucid Emacs does not yet have.  Epoch
and Lucid Emacs will soon be one and the same thing.  Work is being done on
a compatibility package which will allow Epoch 4 code to run in XEmacs with
little or no change.  (As of 19.8, Lucid Emacs is running a descendant of
the Epoch redisplay engine.)

** Why Another Version of Emacs?  (The SunPro Point of View)
============================================================

Emacs 18 has been around for a long, long time.  Version 19 was supposed to
be the successor to Emacs 18 with X support.  It was going to be available
"real soon" for a long time (some people remember hearing about v19 as early
as 1984!), but it never came out.  v19 development was going very, very
slowly, and from the outside it seemed that it was not moving at all.  In
the meantime other people gave up waiting for v19 and decided to build their
own X-aware Emacsen.  The most important of these was probably Epoch, which
came from the University of Illinois and was based on v18.

Around three years ago we decided that we wanted an integrated editor.  We
contracted with the University of Illinois to provide a number of basic
enhancements to the functionality in Epoch.  The University of Illinois
initially was planning to deliver this on top of Epoch code.

In the meantime (actually some time before we talked with the University of
Illinois) Lucid had decided that it also wanted to provide an integrated
environment with an integrated editor.  Lucid decided that the Version 19
basis was a better one than Version 18 and thus decided not to use Epoch but
instead work with Richard Stallman, the head of the Free Software Foundation
and principle author of Emacs, on getting Version 19 out.  At some point
Stallman and Lucid parted ways.  Lucid kept working and got a Version 19 out
that they called Lucid Emacs 19.

After Lucid's v19 came out it became clear to us (the University of Illinois
and SunPro) that the right thing to do was to push for an integration of
both Lucid Emacs and Epoch, and to get the deliverables that we were asking
from the University of Illinois on top of this integrated platform.  Through
the last two years, SunPro has been actively supporting this product and has
been investing a comparable amount of effort into it as Lucid has.
Substantial portions of the current code have originated under the support
of SunPro, either directly in SunPro, or in the University of Illinois but
paid for by us.  This code was kept away from Lucid for a while, but later
was made available to them.  Initially Lucid didn't know that we were
supporting UofI, but later we were open about it.

Eventually, all development source trees were synched up.  Currently, there
is basically no difference in the source trees between what is at the
University of Illinois and SunPro.

SunPro originally called the integrated product ERA, for "Emacs Rewritten
Again".  At some point, SunPro and Lucid came to an agreement to find a name
for the product that was not specific to either company.  An additional
constraint that Lucid placed on the name was that it must contain the word
"Emacs" in it -- thus "ERA" was not acceptable.  The agreed-upon name was
"XEmacs", and this is what the product has been called starting with the
19.11 release.


* What's Different?
===================


** Differences between XEmacs and FSF GNU Emacs 19
==================================================

In XEmacs, events are first-class objects.  FSF 19 represents them as
integers, which obscures the differences between a key gesture and the
ancient ASCII code used to represent a particular overlapping subset of them.

In XEmacs, keymaps are first-class opaque objects.  FSF 19 represents them as
complicated combinations of association lists and vectors.  If you use the
advertised functional interface to manipulation of keymaps, the same code
will work in XEmacs, Emacs 18, and FSF GNU Emacs 19; if your code depends
on the underlying implementation of keymaps, it will not.

XEmacs uses "extents" to represent all non-textual aspects of buffers;
FSF 19 uses two distinct objects, "text properties" and "overlays",
which divide up the functionality between them.  Extents are a
superset of the functionality of the two FSF data types.  The full FSF
19 interface to text properties is supported in XEmacs (with extents
being the underlying representation).

Extents can be made to be copied into strings, and thus restored by kill
and yank.  Thus, one can specify this behavior on either "extents" or
"text properties", whereas in FSF 19 text properties always have this
behavior and overlays never do.

Many more packages are provided standard with XEmacs than with FSF 19.

Pixmaps of arbitrary size can be embedded in a buffer.

Variable width fonts work.

The height of a line is the height of the tallest font on that line, instead
of all lines having the same height.

XEmacs uses the MIT "Xt" toolkit instead of raw Xlib calls, which
makes it be a more well-behaved X citizen (and also improves
portability).  A result of this is that it is possible to include
other Xt "Widgets" in the XEmacs window.  Also, XEmacs understands the
standard Xt command-line arguments.

XEmacs provides support for ToolTalk on systems that have it.

XEmacs can ask questions using popup dialog boxes.  Any command executed from
a menu will ask yes/no questions with dialog boxes, while commands executed
via the keyboard will use the minibuffer.

XEmacs has a built-in toolbar.  Four toolbars can actually be configured:
top, bottom, left, and right toolbars.

XEmacs has vertical and horizontal scrollbars.  Unlike in FSF 19 (which
provides a primitive form of vertical scrollbar), these are true toolkit
scrollbars.  A look-alike Motif scrollbar is provided for those who
don't have Motif. (Even for those who do, the look-alike may be preferable
as it is faster.)

If you're running on a machine with audio hardware, you can specify sound 
files for XEmacs to play instead of the default X beep.  See the documentation
of the function load-sound-file and the variable sound-alist.

An XEmacs frame can be placed within an "external client widget" managed by
another application.  This allows an application to use an XEmacs frame as its
text pane rather than the standard Text widget that is provided with Motif or
Athena.  XEmacs supports Motif applications, generic Xt (e.g. Athena)
applications, and raw Xlib applications.

Here are some more specifics about the XEmacs implementation:

*** The Input Model
-------------------

The fundamental unit of input is an "event" instead of a character.  An
event is a new data type that contains several pieces of information.
There are several kinds of event, and corresponding accessor and utility
functions.  We tried to abstract them so that they would apply equally
well to a number of window systems.

NOTE: All timestamps are measured as milliseconds since Emacs started.

 key_press_event	
    event_channel	A token representing which keyboard generated it.
			For this kind of event, this is a frame object.
			(This is for eventual support of multiple displays.)
    timestamp		When it happened
    key			What keysym this is; an integer or a symbol.
			If this is an integer, it will be in the printing
			ASCII range: >32 and <127.
    modifiers		Bucky-bits on that key: control, meta, etc.
			For most keys, Shift is not a bit; that is implicit
			in the keyboard layout.

 button_press_event
 button_release_event
    event_channel	A token representing which mouse generated it.
			For this kind of event, this is a frame object.
    timestamp		When it happened
    button		What button went down or up.
    modifiers		Bucky-bits on that button: shift, control, meta, etc.
    x, y		Where it was at the button-state-change (in pixels).

 pointer_motion_event
    event_channel	A token representing which mouse generated it.
			For this kind of event, this is a frame object.
    timestamp		When it happened
    x, y		Where it was after it moved (in pixels).
    modifiers		Bucky-bits down when the motion was detected.
			(Possibly not all window systems will provide this?)

 process_event
    timestamp		When it happened
    process		the emacs "process" object in question

 timeout_event
    timestamp		Now (really, when the timeout was signaled)
    interval_id		The ID returned when the associated call to
			add_timeout_cb() was made
	------ the rest of the fields are filled in by Emacs -----
    id_number		The Emacs timeout ID for this timeout (more
			than one timeout event can have the same value
			here, since Emacs timeouts, as opposed to
			add_timeout_cb() timeouts, can resignal
			themselves)
    function		An elisp function to call when this timeout is
			processed.
    object		The object passed to that function.

 eval_event
    timestamp		When it happened
    function		An elisp function to call with this event object.
    object		Anything.
			This kind of event is used internally; sometimes the
			window system interface would like to inform emacs of
			some user action (such as focusing on another frame)
			but needs that to happen synchronously with the other
			user input, like keypresses.  This is useful when
			events are reported through callbacks rather
			than in the standard event stream.

 misc_user_event
    timestamp		When it happened
    function		An elisp function to call with this event object.
    object		Anything.
			This is similar to an eval_event, except that it is
			generated by user actions: selections in the
			menubar or scrollbar actions.  It is a "command"
			event, like key and mouse presses (and unlike mouse
			motion, process output, and enter and leave window
			hooks).  In many ways, eval_events are not the same
			as keypresses or misc_user_events.

 magic_event
			No user-serviceable parts within.  This is for things
			like KeymapNotify and ExposeRegion events and so on
			that emacs itself doesn't care about, but which it
			must do something with for proper interaction with
			the window system.

			Magic_events are handled somewhat asynchronously, just
			like subprocess filters.  However, occasionally a 
			magic_event needs to be handled synchronously; in that
			case, the asynchronous handling of the magic_event will
			push an eval_event back onto the queue, which will be 
			handled synchronously later.  This is one of the
			reasons why eval_events exist; I'm not entirely happy
			with this aspect of this event model.


The function `next-event' blocks and returns one of the above-described 
event objects.  The function `dispatch-event' takes an event and processes
it in the appropriate way.

For a process-event, dispatch-event calls the process's handler; for a
mouse-motion event, the mouse-motion-handler hook is called, and so on.
For magic-events, dispatch-event does window-system-dependent things,
including calling some non-window-system-dependent hooks: map-frame-hook,
unmap-frame-hook, mouse-enter-frame-hook, and mouse-leave-frame-hook.

The function `next-command-event' calls `next-event' until it gets a key or
button from the user (that is, not a process, motion, timeout, or magic
event).  If it gets an event that is not a key or button, it calls
`dispatch-event' on it immediately and reads another one.  The
next-command-event function could be implemented in Emacs Lisp, though it
isn't.  Generally one should call `next-command-event' instead of
`next-event'.

read-char calls next-command-event; if it doesn't get an event that can be
converted to an ASCII character, it signals an error.  Otherwise it returns
an integer.

The variable `last-command-char' always contains an integer, or nil (if the
last read event has no ASCII equivalent, as when it is a mouse-click or a
non-ASCII character chord.)

The new variable `last-command-event' holds an event object, that could be
a non-ASCII character, a button click, a menu selection, etc.

The variable `unread-command-char' no longer exists, and has been replaced
by `unread-command-events'.  With the new event model, it is incorrect for
code to do (setq unread-command-char (read-char)), because all user-input
can't be represented as ASCII characters.  *** This is an incompatible 
change.  Code which sets `unread-command-char' must be updated to use the
combination of `next-command-event' and `unread-command-events' instead.

The functions `this-command-keys' and `recent-keys' return a vector of
event objects, instead of a string of ASCII characters.  *** This also
is an incompatible change.

Almost nothing happens at interrupt level; the SIGIO handler simply sets a
flag, and later, the X event queue is scanned for KeyPress events which map
to ^G.  All redisplay happens in the main thread of the process.


*** Keymaps
-----------

Instead of keymaps being alists or obarrays, they are a new primary data
type.  The only user access to the contents of a keymap is through the
existing keymap-manipulation functions, and a new function, map-keymap.
This means that existing code that manipulates keymaps may need to 
be changed.

One of our goals with the new input and keymap code was to make more
character combinations available for binding, besides just ASCII and
function keys.  We want to be able bind different commands to Control-a 
and Control-Shift-a; we also want it to be possible for the keys Control-h
and Backspace (and Control-M and Return, and Control-I and Tab, etc) to
be distinct.

One of the most common complaints that new Emacs users have is that backspace
is help.  The answer is to play around with the keyboard-translate-table, or
be lucky enough to have a system administrator who has done this for you
already; but if it were possible to bind backspace and C-h to different
things, then (under a window manager at least) both backspace and delete
would delete a character, and ^H would be help.  There's no need to deal 
with xmodmap, kbd-translate-table, etc.

Here are some more examples: suppose you want to bind one function to Tab, 
and another to Control-Tab.  This can't be done if Tab and Control-I are the
same thing.  What about control keys that have no ASCII equivalent, like
Control-< ?  One might want that to be bound to set-mark-at-point-min.  We
want M-C-Backspace to be kill-backward-sexp.  But we want M-Backspace to be
kill-backward-word.  Again, this can't be done if Backspace and C-h are
indistinguishable.

The user represents keys as a string of ASCII characters (when possible and
convenient), or as a vector of event objects, or as a vector of "key 
description lists", that looks like (control a), or (control meta delete) 
or (shift f1).  The order of the modifier-names is not significant, so
(meta control x) and (control meta x) are the same.

`define-key' knows how to take any of the above representations and store them
into a keymap.  When Emacs wants to return a key sequence (this-command-keys,
recent-keys, keyboard-macros, and read-key-sequence, for example) it returns
a vector of event objects.  Keyboard macros can also be represented as ASCII
strings or as vectors of key description lists.  

This is an incompatible change: code which calls `this-command-keys',
`recent-keys', `read-key-sequence', or manipulates keyboard-macros probably
needs to be changed so that it no longer assumes that the returned value is a
string.

Control-Shift-a is specified as (control A), not (control shift a), since A
is a two-case character.  But for keys that don't have an upper case
version, like F1, Backspace, and Escape, you use the (shift backspace) syntax.

See the doc string for our version of define-key, reproduced below in the
`Changed Functions' section.  Note that when the KEYS argument is a string,
it has the same semantics as the v18 define-key.


*** Xt Integration
------------------

The heart of the event loop is implemented in terms of the Xt event functions
(specifically XtAppProcessEvent), and uses Xt's concept of timeouts and
file-descriptor callbacks, eliminating a large amount of system-dependent code
(Xt does it for you.)

If Emacs is compiled with support for X, it uses the Xt event loop even when
Emacs is not running on an X display (the Xt event loop supports this).  This
makes it possible to run Emacs on a dumb TTY, and later connect it to one or
more X servers.  It should also be possible to later connect an existing Emacs
process to additional TTY's, although this code is still experimental.  (Our
intent at this point is not to have an Emacs that is being used by multiple
people at the same time: it is to make it possible for someone to go home, log
in on a dialup line, and connect to the same Emacs process that is running
under X in their office without having to recreate their buffer state and so
on.)

If Emacs is not compiled with support for X, then it instead uses more general
code, something like what v18 does; but this way of doing things is a lot more
modular.

(Linking Emacs with Xt seems to only add about 300k to the executable size,
compared with an Emacs linked with Xlib only.)


*** Region Highlighting
-----------------------

If the variable `zmacs-regions' is true, then the region between point and
mark will be highlighted when "active".  Those commands which push a mark
(such as C-SPC, and C-x C-x) make the region become "active" and thus
highlighted.  Most commands (all non-motion commands, basically) cause it to
become non-highlighted (non-"active").  Commands that operate on the region
(such as C-w, C-x C-l, etc.) only work if the region is in the highlighted
state.

zmacs-activate-region-hook and zmacs-deactivate-region-hook are run at the
appropriate times; under X, zmacs-activate-region-hook makes the X selection
be the region between point and mark, thus doing two things at once: making
the region and the X selection be the same; and making the region highlight
in the same way as the X selection.

If `zmacs-regions' is true, then the `mark-marker' command returns nil unless
the region is currently in the active (highlighted) state.  With an argument
of t, this returns the mark (if there is one) regardless of the active-region
state.  You should *generally* not use the mark unless the region is active,
if the user has expressed a preference for the active-region model.  Watch
out!  Moving this marker changes the mark position.  If you set the marker not
to point anywhere, the buffer will have no mark.

In this way, the primary selection is a fairly transitory entity; but
when something is copied to the kill ring, it is made the Clipboard
selection.  It is also stored into CUT_BUFFER0, for compatibility with
X applications that don't understand selections (like Emacs18).

Compatibility note: if you have code which uses (mark) or (mark-marker),
then you need to either: change those calls to (mark t) or (mark-marker t);
or simply bind `zmacs-regions' to nil around the call to mark or mark-marker.
This is probably the best solution, since it will work in Emacs 18 as well.


*** Menubars and Dialog Boxes
-----------------------------

Here is an example of a menubar definition:

(defvar default-menubar
  '(("File"     ["Open File..."         find-file               t]
                ["Save Buffer"          save-buffer             t]
                ["Save Buffer As..."    write-file              t]
                ["Revert Buffer"        revert-buffer           t]
                "-----"
                ["Print Buffer"         lpr-buffer              t]
                "-----"
                ["Delete Frame"         delete-frame            t]
                ["Kill Buffer..."       kill-buffer             t]
                ["Exit Emacs"           save-buffers-kill-emacs t]
                )
    ("Edit"     ["Undo"                 advertised-undo         t]
                ["Cut"                  kill-primary-selection  t]
                ["Copy"                 copy-primary-selection  t]
                ["Paste"                yank-clipboard-selection t]
                ["Clear"                delete-primary-selection t]
                )
    ...))

The first element of each menu item is the string to print on the menu.

The second element is the callback function; if it is a symbol, it is
invoked with `call-interactively.'  If it is a list, it is invoked with
`eval'.  

If the second element is a symbol, then the menu also displays the key that
is bound to that command (if any).

The third element of the menu items determines whether the item is selectable.
It may be t, nil, or a form to evaluate.  Also, a hook is run just before a
menu is exposed, which can be used to change the value of these slots. 
For example, there is a hook that makes the "undo" menu item be selectable
only in the cases when `advertised-undo' would not signal an error.  

Menus may have other menus nested within them; they will cascade.

There are utility functions for adding items to menus, deleting items,
disabling them, etc.

The function `popup-menu' takes a menu description and pops it up.  

The function `popup-dialog-box' takes a dialog-box description and pops 
it up.  Dialog box descriptions look a lot like menu descriptions.

The menubar, menu, and dialog-box code is implemented as a library, 
with an interface which hides the toolkit that implements it.  


*** Isearch Changes
-------------------

Isearch has been reimplemented in a different way, adding some new features,
and causing a few incompatible changes.

 -  the old isearch-*-char variables are no longer supported.  In the old
    system, one could make ^A mean "repeat the search" by doing something
    like (setq search-repeat-char ?C-a).  In the new system, this is 
    accomplished with 

       (define-key isearch-mode-map "\C-a" 'isearch-repeat-forward)

 -  The advantage of using the normal keymap mechanism for this is that you
    can bind more than one key to an isearch command: for example, both C-a
    and C-s could do the same thing inside isearch mode.  You can also bind
    multi-key sequences inside of isearch mode, and bind non-ASCII keys.
    For example, to use the F1 key to terminate a search:

       (define-key isearch-mode-map 'f1 'isearch-exit)

    or to make ``C-c C-c'' terminate a search:

       (define-key isearch-mode-map "\C-c\C-c" 'isearch-exit)

 -  If isearch is behaving case-insensitively (the default) and you type an
    upper case character, then the search will become case-sensitive.  This
    can be disabled by setting `search-caps-disable-folding' to nil.

 -  There is a history ring of the strings previously searched for; typing
    M-p or M-n while searching will cycle through this ring.  Typing M-TAB
    will do completion across the set of items in the history ring.

 -  The ESC key is no longer used to terminate an incremental search.  The
    RET key should be used instead.  This change is necessary for it to be
    possible to bind "meta" characters to isearch commands.


*** Startup Code Changes
------------------------

The initial X frame is mapped before the user's .emacs file is executed.
Without this, there is no way for the user to see any error messages
generated by their .emacs file, any windows created by the .emacs file
don't show up, and the copyleft notice isn't shown.

The default values for load-path, exec-path, lock-directory, and
Info-directory-list are not (necessarily) built into Emacs, but are
computed at startup time.  

First, Emacs looks at the directory in which its executable file resides:

  o  If that directory contains subdirectories named "lisp" and "lib-src",
     then those directories are used as the lisp library and exec directory.

  o  If the parent of the directory in which the emacs executable is located
     contains "lisp" and "lib-src" subdirectories, then those are used.

  o  If ../lib/xemacs-<version> (starting from the directory in which the
     emacs executable is located) contains a "lisp" subdirectory and either
     a "lib-src" subdirectory or a <configuration-name> subdirectory, then
     those are used.

  o  If the emacs executable that was run is a symbolic link, then the link
     is chased, and the resultant directory is checked as above.

(Actually, it doesn't just look for "lisp/", it looks for "lisp/prim/",
which reduces the chances of a false positive.)

If the lisp directory contains subdirectories, they are added to the default
load-path as well.  If the site-lisp directory exists and contains
subdirectories, they are then added.  Subdirectories whose names begin with
a dot or a hyphen are not added to the load-path.

These heuristics fail if the Emacs binary was copied from the main Emacs
tree to some other directory, and links for the lisp directory were not put
in.  This isn't much of a restriction: either make there be subdirectories
(or symbolic links) of the directory of the emacs executable, or make the
"installed" emacs executable be a symbolic link to an executable in a more
appropriate directory structure.  For example, this setup works:

    /usr/local/xemacs/xemacs*           ; The executable.
    /usr/local/xemacs/lisp/             ; The associated directories.
    /usr/local/xemacs/etc/              ; Any of the files in this list
    /usr/local/xemacs/lock/             ; could be symbolic links as well.
    /usr/local/xemacs/info/

As does this:

    /usr/local/bin/xemacs -> ../xemacs/src/xemacs-19.14 ; A link...
    /usr/local/xemacs/src/xemacs-19.14*                 ; The executable,
    /usr/local/xemacs/lisp/                             ; and the rest of
    /usr/local/xemacs/etc/                              ; the source tree
    /usr/local/xemacs/lock/
    /usr/local/xemacs/info/

This configuration might be used for a multi-architecture installation; assume
that $LOCAL refers to a directory which contains only files specific to a 
particular architecture (i.e., executables) and $SHARED refers to those files 
which are not machine specific (i.e., lisp code and documentation.)

    $LOCAL/bin/xemacs@ -> $LOCAL/xemacs-19.14/xemacs*
    $LOCAL/xemacs-19.14/lisp@ -> $SHARED/xemacs-19.14/lisp/
    $LOCAL/xemacs-19.14/etc@  -> $SHARED/xemacs-19.14/etc/
    $LOCAL/xemacs-19.14/info@ -> $SHARED/xemacs-19.14/info/

The following would also work, but the above is probably more attractive:

    $LOCAL/bin/xemacs*
    $LOCAL/bin/lisp@ -> $SHARED/xemacs-19.14/lisp/
    $LOCAL/bin/etc@  -> $SHARED/xemacs-19.14/etc/
    $LOCAL/bin/info@ -> $SHARED/xemacs-19.14/info/

If Emacs can't find the requisite directories, it writes a message like this
(or some appropriate subset of it) to stderr:

  WARNING:
  couldn't find an obvious default for load-path, exec-directory, and
  lock-directory, and there were no defaults specified in paths.h when
  Emacs was built.  Perhaps some directories don't exist, or the Emacs
  executable, /cadillac-th/jwz/somewhere/xemacs is in a strange place?

  Without both exec-directory and load-path, Emacs will be very broken.
  Consider making a symbolic link from /cadillac-th/jwz/somewhere/etc
  to wherever the appropriate Emacs etc/ directory is, and from
  /cadillac-th/jwz/somewhere/lisp/ to wherever the appropriate Emacs
  lisp library is.

  Without lock-directory set, file locking won't work.  Consider
  creating /cadillac-th/jwz/somewhere/lock as a directory or symbolic
  link for use as the lock directory.

The default installation tree is the following:

    /usr/local/bin/b2m                          ;
                   ctags                        ; executables that
                   emacsclient                  ; should be in
                   etags                        ; user's path
                   xemacs -> xemacs-<version>   ;
                   xemacs                       ;
    /usr/local/lib/xemacs/site-lisp
    /usr/local/lib/xemacs/lock
    /usr/local/lib/xemacs-<version>/etc         ; architecture ind. files
    /usr/local/lib/xemacs-<version>/info
    /usr/local/lib/xemacs-<version>/lisp
    /usr/local/lib/xemacs-<version>/<configuration>  ; binaries emacs may run


*** X Resources
---------------

(Note: This section is copied verbatim from the XEmacs Reference Manual.)

   The Emacs resources are generally set per-frame. Each Emacs frame
can have its own name or the same name as another, depending on the
name passed to the `make-frame' function.

   You can specify resources for all frames with the syntax:

     Emacs*parameter: value

or

     Emacs*EmacsFrame.parameter:value

You can specify resources for a particular frame with the syntax:

     Emacs*FRAME-NAME.parameter: value


**** Geometry Resources
-----------------------

   To make the default size of all Emacs frames be 80 columns by 55
lines, do this:

     Emacs*EmacsFrame.geometry: 80x55

To set the geometry of a particular frame named `fred', do this:

     Emacs*fred.geometry: 80x55

Important! Do not use the following syntax:

     Emacs*geometry: 80x55

You should never use `*geometry' with any X application. It does not
say "make the geometry of Emacs be 80 columns by 55 lines."  It really
says, "make Emacs and all subwindows thereof be 80x55 in whatever units
they care to measure in."  In particular, that is both telling the
Emacs text pane to be 80x55 in characters, and telling the menubar pane
to be 80x55 pixels, which is surely not what you want.

   As a special case, this geometry specification also works (and sets
the default size of all Emacs frames to 80 columns by 55 lines):

     Emacs.geometry: 80x55

since that is the syntax used with most other applications (since most
other applications have only one top-level window, unlike Emacs).  In
general, however, the top-level shell (the unmapped ApplicationShell
widget named `Emacs' that is the parent of the shell widgets that
actually manage the individual frames) does not have any interesting
resources on it, and you should set the resources on the frames instead.

   The `-geometry' command-line argument sets only the geometry of the
initial frame created by Emacs.

   A more complete explanation of geometry-handling is

   * The `-geometry' command-line option sets the `Emacs.geometry'
     resource, that is, the geometry of the ApplicationShell.

   * For the first frame created, the size of the frame is taken from
     the ApplicationShell if it is specified, otherwise from the
     geometry of the frame.

   * For subsequent frames, the order is reversed: First the frame, and
     then the ApplicationShell.

   * For the first frame created, the position of the frame is taken
     from the ApplicationShell (`Emacs.geometry') if it is specified,
     otherwise from the geometry of the frame.

   * For subsequent frames, the position is taken only from the frame,
     and never from the ApplicationShell.

   This is rather complicated, but it does seem to provide the most
intuitive behavior with respect to the default sizes and positions of
frames created in various ways.


**** Iconic Resources
---------------------

   Analogous to `-geometry', the `-iconic' command-line option sets the
iconic flag of the ApplicationShell (`Emacs.iconic') and always applies
to the first frame created regardless of its name.  However, it is
possible to set the iconic flag on particular frames (by name) by using
the `Emacs*FRAME-NAME.iconic' resource.


**** Resource List
------------------

   Emacs frames accept the following resources:

`geometry' (class `Geometry'): string
     Initial geometry for the frame.  *Note Geometry Resources:: for a
     complete discussion of how this works.

`iconic' (class `Iconic'): boolean
     Whether this frame should appear in the iconified state.

`internalBorderWidth' (class `InternalBorderWidth'): int
     How many blank pixels to leave between the text and the edge of the
     window.

`interline' (class `Interline'): int
     How many pixels to leave between each line (may not be
     implemented).

`menubar' (class `Menubar'): boolean
     Whether newly-created frames should initially have a menubar.  Set
     to true by default.

`initiallyUnmapped' (class `InitiallyUnmapped'): boolean
     Whether XEmacs should leave the initial frame unmapped when it
     starts up.  This is useful if you are starting XEmacs as a server
     (e.g. in conjunction with gnuserv or the external client widget).
     You can also control this with the `-unmapped' command-line option.

`barCursor' (class `BarColor'): boolean
     Whether the cursor should be displayed as a bar, or the
     traditional box.

`textPointer' (class `Cursor'): cursor-name
     The cursor to use when the mouse is over text.  This resource is
     used to initialize the variable `x-pointer-shape'.

`selectionPointer' (class `Cursor'): cursor-name
     The cursor to use when the mouse is over a selectable text region
     (an extent with the `highlight' property; for example, an Info
     cross-reference).  This resource is used to initialize the variable
     `x-selection-pointer-shape'.

`spacePointer' (class `Cursor'): cursor-name
     The cursor to use when the mouse is over a blank space in a buffer
     (that is, after the end of a line or after the end-of-file).  This
     resource is used to initialize the variable
     `x-nontext-pointer-shape'.

`modeLinePointer' (class `Cursor'): cursor-name
     The cursor to use when the mouse is over a mode line.  This
     resource is used to initialize the variable `x-mode-pointer-shape'.

`gcPointer' (class `Cursor'): cursor-name
     The cursor to display when a garbage-collection is in progress.
     This resource is used to initialize the variable
     `x-gc-pointer-shape'.

`scrollbarPointer' (class `Cursor'): cursor-name
     The cursor to use when the mouse is over the scrollbar.  This
     resource is used to initialize the variable
     `x-scrollbar-pointer-shape'.

`pointerColor' (class `Foreground'): color-name
`pointerBackground' (class `Background'): color-name
     The foreground and background colors of the mouse cursor.  These
     resources are used to initialize the variables
     `x-pointer-foreground-color' and `x-pointer-background-color'.

`scrollBarWidth' (class `ScrollBarWidth'): integer
     How wide the vertical scrollbars should be, in pixels; 0 means no
     vertical scrollbars.  You can also use a resource specification of
     the form `*scrollbar.width', or the usual toolkit scrollbar
     resources: `*XmScrollBar.width' (Motif), `*XlwScrollBar.width'
     (Lucid), or `*Scrollbar.thickness' (Athena).  We don't recommend
     that you use the toolkit resources, though, because they're
     dependent on how exactly your particular build of XEmacs was
     configured.

`scrollBarHeight' (class `ScrollBarHeight'): integer
     How high the horizontal scrollbars should be, in pixels; 0 means no
     horizontal scrollbars.  You can also use a resource specification
     of the form `*scrollbar.height', or the usual toolkit scrollbar
     resources: `*XmScrollBar.height' (Motif), `*XlwScrollBar.height'
     (Lucid), or `*Scrollbar.thickness' (Athena).  We don't recommend
     that you use the toolkit resources, though, because they're
     dependent on how exactly your particular build of XEmacs was
     configured.

`scrollBarPlacement' (class `ScrollBarPlacement'): string
     Where the horizontal and vertical scrollbars should be positioned.
     This should be one of the four strings `bottom-left',
     `bottom-right', `top-left', and `top-right'.  Default is
     `bottom-right' for the Motif and Lucid scrollbars and
     `bottom-left' for the Athena scrollbars.

`topToolBarHeight' (class `TopToolBarHeight'): integer
`bottomToolBarHeight' (class `BottomToolBarHeight'): integer
`leftToolBarWidth' (class `LeftToolBarWidth'): integer
`rightToolBarWidth' (class `RightToolBarWidth'): integer
     Height and width of the four possible toolbars.

`topToolBarShadowColor' (class `TopToolBarShadowColor'): color-name
`bottomToolBarShadowColor' (class `BottomToolBarShadowColor'): color-name
     Color of the top and bottom shadows for the toolbars.  NOTE: These
     resources do *not* have anything to do with the top and bottom
     toolbars (i.e. the toolbars at the top and bottom of the frame)!
     Rather, they affect the top and bottom shadows around the edges of
     all four kinds of toolbars.

`topToolBarShadowPixmap' (class `TopToolBarShadowPixmap'): pixmap-name
`bottomToolBarShadowPixmap' (class `BottomToolBarShadowPixmap'): pixmap-name
     Pixmap of the top and bottom shadows for the toolbars.  If set,
     these resources override the corresponding color resources. NOTE:
     These resources do *not* have anything to do with the top and
     bottom toolbars (i.e. the toolbars at the top and bottom of the
     frame)!  Rather, they affect the top and bottom shadows around the
     edges of all four kinds of toolbars.

`toolBarShadowThickness' (class `ToolBarShadowThickness'): integer
     Thickness of the shadows around the toolbars, in pixels.

`visualBell' (class `VisualBell'): boolean
     Whether XEmacs should flash the screen rather than making an
     audible beep.

`bellVolume' (class `BellVolume'): integer
     Volume of the audible beep.

`useBackingStore' (class `UseBackingStore'): boolean
     Whether XEmacs should set the backing-store attribute of the X
     windows it creates.  This increases the memory usage of the X
     server but decreases the amount of X traffic necessary to update
     the screen, and is useful when the connection to the X server goes
     over a low-bandwidth line such as a modem connection.


**** Face Resources
-------------------

   The attributes of faces are also per-frame. They can be specified as:

     Emacs.FACE_NAME.parameter: value

     (*do not* use `Emacs*FACE_NAME...')

or

     Emacs*FRAME_NAME.FACE_NAME.parameter: value

Faces accept the following resources:

`attributeFont' (class `AttributeFont'): font-name
     The font of this face.

`attributeForeground' (class `AttributeForeground'): color-name
`attributeBackground' (class `AttributeBackground'): color-name
     The foreground and background colors of this face.

`attributeBackgroundPixmap' (class `AttributeBackgroundPixmap'): file-name
     The name of an XBM file (or XPM file, if your version of Emacs
     supports XPM), to use as a background stipple.

`attributeUnderline' (class `AttributeUnderline'): boolean
     Whether text in this face should be underlined.

   All text is displayed in some face, defaulting to the face named
`default'.  To set the font of normal text, use
`Emacs*default.attributeFont'. To set it in the frame named `fred', use
`Emacs*fred.default.attributeFont'.

   These are the names of the predefined faces:

`default'
     Everything inherits from this.

`bold'
     If this is not specified in the resource database, Emacs tries to
     find a bold version of the font of the default face.

`italic'
     If this is not specified in the resource database, Emacs tries to
     find an italic version of the font of the default face.

`bold-italic'
     If this is not specified in the resource database, Emacs tries to
     find a bold-italic version of the font of the default face.

`modeline'
     This is the face that the modeline is displayed in.  If not
     specified in the resource database, it is determined from the
     default face by reversing the foreground and background colors.

`highlight'
     This is the face that highlighted extents (for example, Info
     cross-references and possible completions, when the mouse passes
     over them) are displayed in.

`left-margin'
`right-margin'
     These are the faces that the left and right annotation margins are
     displayed in.

`zmacs-region'
     This is the face that mouse selections are displayed in.

`text-cursor'
     This is the face that the cursor is displayed in.

`isearch'
     This is the face that the matched text being searched for is
     displayed in.

`info-node'
     This is the face of info menu items.  If unspecified, it is copied
     from `bold-italic'.

`info-xref'
     This is the face of info cross-references.  If unspecified, it is
     copied from `bold'. (Note that, when the mouse passes over a
     cross-reference, the cross-reference's face is determined from a
     combination of the `info-xref' and `highlight' faces.)

   Other packages might define their own faces; to see a list of all
faces, use any of the interactive face-manipulation commands such as
`set-face-font' and type `?' when you are prompted for the name of a
face.

   If the `bold', `italic', and `bold-italic' faces are not specified
in the resource database, then XEmacs attempts to derive them from the
font of the default face.  It can only succeed at this if you have
specified the default font using the XLFD (X Logical Font Description)
format, which looks like

     *-courier-medium-r-*-*-*-120-*-*-*-*-*-*

If you use any of the other, less strict font name formats, some of
which look like

     lucidasanstypewriter-12
     fixed
     9x13

   then XEmacs won't be able to guess the names of the bold and italic
versions.  All X fonts can be referred to via XLFD-style names, so you
should use those forms.  See the man pages for `X(1)', `xlsfonts(1)',
and `xfontsel(1)'.


**** Widgets
------------

   There are several structural widgets between the terminal EmacsFrame
widget and the top level ApplicationShell; the exact names and types of
these widgets change from release to release (for example, they changed
in 19.9, 19.10, 19.12, and 19.13) and are subject to further change in
the future, so you should avoid mentioning them in your resource database.
The above-mentioned syntaxes should be forward-compatible.  As of 19.14,
the exact widget hierarchy is as follows:

    INVOCATION-NAME           "shell"              "container"     FRAME-NAME
    x-emacs-application-class "TopLevelEmacsShell" "EmacsManager" "EmacsFrame"

(for normal frames)

or

    INVOCATION-NAME           "shell"               "container"     FRAME-NAME
    x-emacs-application-class "TransientEmacsShell" "EmacsManager" "EmacsFrame"

(for popup/dialog-box frames)

where INVOCATION-NAME is the terminal component of the name of the
XEmacs executable (usually `xemacs'), and `x-emacs-application-class'
is generally `Emacs'.


**** Menubar Resources
----------------------

   As the menubar is implemented as a widget which is not a part of
XEmacs proper, it does not use the face mechanism for specifying fonts
and colors: It uses whatever resources are appropriate to the type of
widget which is used to implement it.

   If Emacs was compiled to use only the Motif-lookalike menu widgets,
then one way to specify the font of the menubar would be

     Emacs*menubar*font: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*

   If the Motif library is being used, then one would have to use

     Emacs*menubar*fontList: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*

   because the Motif library uses the `fontList' resource name instead
of `font', which has subtly different semantics.

   The same is true of the scrollbars: They accept whichever resources
are appropriate for the toolkit in use.


*** Source Code Highlighting
----------------------------

It's possible to have your buffers "decorated" with fonts or colors
indicating syntactic structures (such as strings, comments, function names,
"reserved words", etc.).  In XEmacs, the preferred way to do this is with
font-lock-mode; activate it by adding the following code to your .emacs file:

        (add-hook 'emacs-lisp-mode-hook 'turn-on-font-lock)
        (add-hook 'c-mode-hook          'turn-on-font-lock)
        (add-hook 'c++-mode-hook        'turn-on-font-lock)
        (add-hook 'dired-mode-hook      'turn-on-font-lock)
        ...etc...

To customize it, see the descriptions of the function `font-lock-mode' and
the variables `font-lock-keywords', `c-font-lock-keywords', etc.

There exist several other source code highlighting packages, but font-lock
does one thing that most others don't do: highlights as you type new text;
and one thing that no others do: bases part of its decoration on the
syntax table of the major mode.  Font-lock has C-level support to do this
efficiently, so it should also be significantly faster than the others.

If there's something that another highlighting package does that you can't
make font-lock do, let us know.  We would prefer to consolidate all of the
desired functionality into one package rather than ship several different
packages which do essentially the same thing in different ways.


** Differences Between XEmacs and Emacs 18
==========================================

Auto-configure support has been added, so it should be fairly easy to compile
XEmacs on different systems.  If you have any problems or feedback about
compiling on your system, please let us know.

We have reimplemented the basic input model in a more general way; instead of
X input being a special-case of the normal ASCII input stream, XEmacs has a
concept of "input events", and ASCII characters are a subset of that.  The
events that XEmacs knows about are not X events, but are a generalization of
them, so that XEmacs can eventually be ported to different window systems.

We have reimplemented keymaps so that sequences of events can be stored into
them instead of just ASCII codes; it is possible to, for example, bind
different commands to each of the chords Control-h, Control-H, Backspace,
Control-Backspace, and Super-Shift-Backspace.  Key bindings, function key
bindings, and mouse bindings live in the same keymaps.

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

You can have multiple X windows ("frames" in XEmacs terminology).

XEmacs has objects called "extents" and "faces", which are roughly
analogous to Epoch's "buttons," "zones," and "styles."  An extent is a
region of text (a start position and an end position) and a face is a
collection of textual attributes like fonts and colors.  Every extent
is displayed in some "face", so changing the properties of a face
immediately updates the display of all associated extents.  Faces can
be frame-local: you can have a region of text which displays with
completely different attributes when its buffer is viewed from a
different X window.

The display attributes of faces may be specified either in lisp or through
the X resource manager.

Pixmaps of arbitrary size can be embedded in a buffer.

Variable width fonts work.

The height of a line is the height of the tallest font on that line, instead
of all lines having the same height.

XEmacs uses the MIT "Xt" toolkit instead of raw Xlib calls, which
makes it be a more well-behaved X citizen (and also improves
portability).  A result of this is that it is possible to include
other Xt "Widgets" in the XEmacs window.  Also, XEmacs understands the
standard Xt command-line arguments.

XEmacs understands the X11 "Selection" mechanism; it's possible to define
and customize selection converter functions and new selection types from 
Emacs Lisp, without having to recompile XEmacs.

XEmacs provides support for ToolTalk on systems that have it.

XEmacs supports the Zmacs/Lispm style of region highlighting, where the
region between the point and mark is highlighted when in its "active" state.

XEmacs has a menubar, whose contents are customizable from emacs-lisp.
This menubar looks Motif-ish, but does not require Motif.  If you already
own Motif, however, you can configure XEmacs to use a *real* Motif menubar
instead.

XEmacs can ask questions using popup dialog boxes.  Any command executed from
a menu will ask yes/no questions with dialog boxes, while commands executed
via the keyboard will use the minibuffer.

XEmacs has vertical and horizontal scrollbars.

The initial load-path is computed at run-time, instead of at compile-time.
This means that if you move the XEmacs executable and associated directories
to somewhere else, you don't have to recompile anything.

You can specify what the title of the XEmacs windows and icons should be
with the variables `frame-title-format' and `frame-icon-title-format',
which have the same syntax as `mode-line-format'.

XEmacs now supports floating-point numbers.

XEmacs now knows about timers directly, instead of them being simulated by
a subprocess.

XEmacs understands truenames, and can be configured to notice when you are
visiting two names of the same file.  See the variables find-file-use-truenames
and find-file-compare-truenames.

If you're running on a machine with audio hardware, you can specify sound 
files for XEmacs to play instead of the default X beep.  See the documentation
of the function load-sound-file and the variable sound-alist.

An XEmacs frame can be placed within an "external client widget" managed by
another application.  This allows an application to use an XEmacs frame as its
text pane rather than the standard Text widget that is provided with Motif or
Athena.  XEmacs supports Motif applications, generic Xt (e.g. Athena)
applications, and raw Xlib applications.

Random changes to the emacs-lisp library: (some of this was not written by
us, but is included because it's free software and we think it's good stuff)

  - there is a new optimizing byte-compiler
  - there is a new abbrev-based mail-alias mechanism
  - the -*- line can contain local-variable settings
  - there is a new TAGS package
  - there is a new VI-emulation mode (viper)
  - there is a new implementation of Dired
  - there is a new implementation of Isearch
  - the VM package for reading mail is provided
  - the W3 package for browsing the World Wide Web hypertext information
    system is provided
  - the Hyperbole package, a programmable information management and
    hypertext system
  - the OO-Browser package, a multi-language object-oriented browser

There are many more specifics in the "Miscellaneous Changes" section, below.

The online Emacs Manual and Emacs-Lisp Manual are now both relatively
up-to-date.

* XEmacs Release Notes
======================

** Future Plans for XEmacs
==========================

For the curious, the biggest changes in 19.15 will include integration
of TM (a MIME package for VM and GNUS), EFS (the next generation of
ange-ftp), and Auc-TeX, and a "lite" distribution that includes a
minimal base and a set of optional packages (which will include TM,
EFS, and Auc-TeX, as well as all of the large packages currently
distributed with XEmacs).  There will also still be a full distribution
that includes all the optional packages.

In the longer term, we are also working on a separate branch of XEmacs that
includes full Asian-language ("MULE") support.  This work is currently in
beta and is being supported by Sun Microsystems.


** Major Differences Between 19.13 and 19.14
============================================

XEmacs has a new address!  The canonical ftp site is now
ftp.xemacs.org:/pub/xemacs and the Web page is now at
http://www.xemacs.org/.  All mailing lists now have @xemacs.org
addresses.  For the time being the @cs.uiuc.edu addresses will
continue to function.

This is a major new release.  Many features have been added, as well
as many bugs fixed.  The Motif menubar has still _NOT_ been fixed for
19.14.  You should use the Lucid menubar instead.



Major user-visible changes:
---------------------------

-- Color support in TTY mode is provided.  You have to have a TTY capable
   of displaying them, such as color xterm or the console under Linux.
   If your terminal type supports colors (e.g. `xterm-color'), XEmacs
   will automatically notice this and start using color.

-- blink-cursor-mode enables a blinking text cursor.  There is a
   menubar option for this also.

-- auto-show-mode is turned on by default; this means that XEmacs
   will automatically scroll a window horizontally as necessary to
   keep point in view.

-- a file dialog box is provided and will be used whenever you
   are prompted for a filename as a result of a menubar selection.

-- XEmacs can be compiled with built-in GIF, JPEG, and PNG support.
   The GIF libraries are supplied with XEmacs; for JPEG and PNG,
   you have to obtain the appropriate libraries (this is well-
   documented).  This makes image display much easier and faster under
   W3 (the web browser) and TM (adds MIME support to VM and GNUS;
   not yet included with XEmacs but will be in 19.15).

-- XEmacs provides a really nice mode (PSGML with "Wing improvements")
   for editing HTML and other SGML documents.  It parses the document,
   and as a result it does proper indentation, can show you the context
   you're in, the allowed tags at a particular position, etc.

-- XEmacs comes standard with modes for editing Java and VRML code,
   including font-lock support.

-- GNUS 5.2 comes standard with XEmacs.

-- You can now embed colors in the modeline, with different sections
   of the modeline responding appropriately to various mouse gestures:
   For example, clicking on the "read-only" indicator toggles the
   read-only status of a buffer, and clicking on the buffer name
   cycles to the next buffer.  Pressing button3 on these areas brings
   up a popup menu of appropriate commands.

-- There is a much nicer mode for completion lists and such.
   At the minibuffer prompt, if you hit page-up or Meta-V, the completion
   buffer will be displayed (if it wasn't already), you're moved into
   it, and can move around and select filenames using the arrow keys
   and the return key.  Rather than a cursor, a filename is highlighted,
   and the arrow keys change which filename is highlighted.

-- The edit-faces subsystem has also been much improved, in somewhat
   similar ways to the completion list improvements.

-- Many improvements were made to the multi-device support.
   We now provide an auxiliary utility called "gnuattach" that
   lets you connect to an existing XEmacs process and display
   a TTY frame on the current TTY connection, and commands
   `make-frame-on-display' (with a corresponding menubar entry)
   and `make-frame-on-tty' for more easily creating frames on
   new TTY or X connections.

-- We have incorporated nearly all of the functionality of GNU Emacs
   19.30 into XEmacs.  This includes support for lazy-loaded
   byte code and documentation strings, improved paragraph filling,
   better support for margins within documents, v19 regular expression
   routines (including caching of compiled regexps), etc.

-- In accordance with GNU Emacs 19.30, the following key binding
   changes have been made:

   C-x ESC -> C-x ESC ESC
   ESC ESC -> ESC :
   ESC ESC ESC is "abort anything" (keyboard-escape-quit).

-- All major packages have been updated to their latest-released
   versions.

-- XEmacs now gracefully handles a full colormap (such as typically
   results when running Netscape).  The nearest available color
   is automatically substituted.

-- Many bug fixes to the subprocess/PTY code, ps-print, menubar
   functions, `set-text-properties', DEC Alpha support, toolbar
   resizing (the "phantom VM toolbar" bug), and lots and lots
   of other things were made.

-- The ncurses library (a replacement for curses, found especially
   under Linux) is supported, and will be automatically used
   if it can be found.

-- You can now undo in the minibuffer.

-- Surrogate minibuffers now work.  These are also sometimes referred
   to as "global" minibuffers.

-- font-lock has been merged with GNU Emacs 19.30, improved defaults
   have been added, and changes have been made to the way it is
   configured.

-- Many, many modes have menubar entries for them.

-- `recover-session' lets you recover whatever files can be recovered
   after your XEmacs process has died unexpectedly.

-- C-h k followed by a toolbar button press correctly reports
   the binding of the toolbar button.

-- `function-key-map', `key-translation-map', and `keyboard-translate-table'
   are now correctly implemented.

-- `show-message-log' (and its menubar entry under Edit) have been
   removed; instead use `view-lossage' (and its menubar entry under
   Help).

-- There is a standard menubar entry for specifying which browser
   (Netscape, W3, Mosaic, etc.) to use when dispatching URL's
   in mail, Usenet news, etc.

-- Improved native sound support under Linux.

-- Lots of other things we forgot to mention.



Significant Lisp-level changes:
-------------------------------

-- Many improvements to the E-Lisp documentation have been made;
   it should now be up-to-date and complete in nearly all cases.

-- XEmacs has extensive documentation on its internals, for
   would-be C hackers.

-- Common-Lisp support (the CL package) is now dumped standard
   into XEmacs.  No more need for (require 'cl) or anything
   like that.

-- Full support for extents and text properties over strings is
   provided.

-- The extent properties `start-open', `end-open', `start-closed',
   and `end-closed' now work correctly w.r.t. text properties.

-- The `face' property of extents and text properties can now
   be a list.

-- The `mouse-face' property from FSF GNU Emacs is now supported.
   It supersedes the `highlight' property.

-- `enriched' and `facemenu' packages from FSF GNU Emacs have been ported.

-- New functions for easier creation of dialog boxes:
   `get-dialog-box-response', `message-box', and `message-or-box'.

-- `function-min-args' and `function-max-args' allow you to determine
   the minimum and maximum allowed arguments for any type of
   function (i.e. subr, lambda expression, byte-compiled function, etc.).

-- Some C-level support for doing E-Lisp profiling is provided.
   See `start-profiling', `stop-profiling', and
   `pretty-print-profiling-info'.

-- `current-process-time' reports the user, system, and real times
   for the currently running XEmacs process.

-- `next-window', `previous-window', `next-frame', `previous-frame',
   `other-window', `get-lru-window', etc. have an extra device
   argument that allows you to restrict which devices it includes
   (normally all devices).  Some functions that incorrectly ignored
   frames on different devices (e.g. C-x 0) are fixed.

-- new functions `run-hook-with-args-until-success',
   `run-hook-with-args-until-failure'.

-- generalized facility for local vs. global hooks.  See `make-local-hook',
   `add-hook'.

-- New functions for querying the window tree: `frame-leftmost-window',
   `frame-rightmost-window', `window-first-hchild', `window-first-vchild',
   `window-next-child', `window-previous-child', and `window-parent'.

-- Epoch support works.  This gets you direct access to some X events
   and objects (e.g. properties and property-notify events).

-- The multi-device support has been majorly revamped.  There is now
   a new concept of "consoles" (devices grouped together under a
   common keyboard/mouse), console-local variables, and a generalized
   concept of device/console connection.

-- `display-buffer' synched with GNU Emacs 19.30, giving you lots of
   wondrous cruft such as
     -- unsplittable frames
     -- pop-up-frames, pop-up-frame-function
     -- special-display-buffer-names, special-display-regexps,
        special-display-function
     -- same-window-buffer-names, same-window-regexps

-- XEmacs has support for accessing DBM- and/or DB-format databases,
   provided that you have the appropriate libraries on your system.

-- There is a new font style: "strikethru" fonts.

-- New data type "weak list", which is a list with special
   garbage-collection properties, similar to weak hash tables.

-- `set-face-parent' makes one face inherit all properties from another.

-- The junky frame parameters mechanism has been revamped as
   frame properties, which a standard property-list interface.

-- Lots and lots of functions for working with property lists have
   been added.

-- New functions `push-window-configuration', `pop-window-configuration',
   `unpop-window-configuration' for maintain a stack of window
   configurations.

-- Many fixups to the glyph code; icons and mouse pointers are now
   properly merged into the glyph mechanism.

-- `set-specifier' works more sensibly, like `set-face-property'.

-- Many new specifiers for individually controlling toolbar height/width
   and visibility and text cursor visibility.

-- New face `text-cursor' controls the colors of the text cursor.

-- Many new variables for turning on debug information about the
   inner workings of XEmacs.

-- Hash tables can now compare their keys using `equal' or `eql'
   as well as `eq'.

-- Other things too numerous to mention.



Significant configuration/build changes:
----------------------------------------

-- You can disable TTY support, toolbar support, scrollbar support,
   menubar support, and/or dialog box support at configure time
   to save memory.

-- New configure option `--extra-verbose' shows the diagnostic
   output from feature testing; this should help track down
   problems with incorrect feature detection.

-- `dont-have-xmu' is now `with-xmu', with the reversed sense.
   (It defaults to `yes'.)

-- `with-mocklisp' lets you add Mocklisp support if you really
   need this.

-- `with-term' for adding TERM support for Linux users.



** Major Differences Between 19.12 and 19.13
============================================

This is primarily a bug-fix release.  Lots of bugs have been fixed.
Hopefully only a few have been introduced.  The most noteworthy bug
fixes are:

 -- There should be no more problems connecting XEmacs to an X
    server over SLIP or other slow connections.
 -- Periodic crashes when using the Buffers menu should be gone.
 -- etags would sometimes erase the current buffer; it doesn't
    any more.
 -- XEmacs will correctly exit if the X server dies.
 -- uniconified frames are displayed properly under TVTWM.
 -- Breakage in `add-menu-item' / `add-menu-button' is fixed.

The Motif menubar has _NOT_ been fixed for 19.13.  You should use the
Lucid menubar instead.

Multi-device support should now be working properly.  You can now open
an X device after having started out on a TTY device.

Background pixmaps now work.  See `set-face-background-pixmap'.

Echo area messages are now saved to a buffer, " *Message Log*".  To
see this buffer, use the command `show-message-log'.  It is possible
to filter the message which are actually included by modifying the
variables `log-message-ignore-regexps' and `log-message-ignore-labels'.

You can now control which warnings you want to see.  See
`display-warning-suppressed-classes' and friends.

You can now set the default location of an "other window" from the
Options menu.

"Save Options" now saves the state of all faces.

You can choose which file "Save Options" writes into; see
`save-options-file'.

XPM support is no longer required for the toolbar.

The relocating allocator is now enabled by default whenever possible.
This allows buffer memory to be returned to the system when no longer
in use which helps keep XEmacs process size down.

The ability to have captioned toolbars has been added.  Currently only
the default toolbar actually has a captioned version provided.  A new
specifier variable, `toolbar-buttons-captioned-p' controls whether the
toolbar is captioned.

A copy of the XEmacs FAQ is now included and is available through info.

The on-line E-Lisp reference manual has been significantly updated.

There is now audio support under Linux.

Modifier keys can now be sticky.  This is controlled by the variable
`modifier-keys-are-sticky'.

manual-entry should now work correctly under Irix with the penalty of
a longer startup time the first time it is invoked.  If you are having
problems with this on another system try setting
`Manual-use-subdirectory-list' to t.

make-tty-device no longer automatically creates the first frame.

Rectangular regions now work correctly.

ediff no longer sets synchronize-minibuffers to t unless you first set
ediff-synchronize-minibuffers

keyboard-translate-table has been implemented.  This means that the
`enable-flow-control' command for dealing with TTY connections that
filter out ^S and ^Q now works.

You can now create frames that are initially unmapped and frames that
are "transient for another frame", meaning that they behave more like
dialog-box frames.

Other E-Lisp changes:

-- Specifier `menubar-visible-p' for controlling menubar visibility
-- Local command hooks should be set using `local-pre-command-hook'
   and `local-post-command-hook' instead of making the global
   equivalents be buffer-local.
-- `quit-char', `help-char', `meta-prefix-char' can be any key specifier
   instead of just an integer.
-- new functions `add-async-timeout' and `disable-async-timeout'.
   These let you create asynchronous timeouts, which are like
   normal timeouts except that they're executed even during
   running Lisp code.  Use this with care!
-- `debug-on-error' and `stack-trace-on-error' now enter the debugger
   only when an *unhandled* error occurs.  If you want the old
   behavior, use `debug-on-signal' and `stack-trace-on-signal'.
-- \U, \L, \u, \l, \E recognized specially in `replace-match'.
   These are standard ex/perl commands for changing the case of
   replaced text.
-- New function event-matches-key-specifier-p.  This provides
   a clean way of comparing keypress events with key specifiers
   such as 65, (shift home), etc. without having to resort
   to ugly `character-to-event' / `event-to-character' hacks.
-- New function `add-to-list'
-- New Common-Lisp functions `some', `every', `notevery', `notany',
   `adjoin', `union', `intersection', `set-difference',
   `set-exclusive-or', `subsetp'
-- `remove-face-property' provides a clean way of removing a
   face property.

Many of the Emacs Lisp packages have been updated.  Some of the new
Emacs Lisp packages ---

ada-mode:  major mode for editing Ada source

arc-mode:  simple editing of archives

auto-show-mode:  automatically scrolls horizontally to keep point on-screen 

completion:  dynamic word completion mode

dabbrev:  the dynamic abbrev package has been rewritten and is much
          more powerful -- e.g. it searches in other buffers as well
          as the current one

easymenu:  menu support package

live-icon:  makes frame icons represent the current frame contents

mailcrypt 3.2:  mail encryption with PGP; included but v2.4 is still
		the default

two-column:  for editing two-column text 


** Major Differences Between 19.11 and 19.12
============================================

This is a huge new release.  Almost every aspect of XEmacs has been changed
at least somewhat.  The highlights are:

-- TTY support (includes face support)
-- new redisplay engine; should be faster, less buggy, and more powerful
-- terminology change from "screen" to "frame"
-- built-in toolbar
-- toolbar support added to many packages
-- multiple device support (still in beta; improvements to come in
   19.13)
-- Purify used to ensure that there are no memory leaks or memory corruption
   problems
-- horizontal and vertical scrollbars in all windows
-- new Lucid (i.e. look-alike Motif) scrollbar widget
-- stay-up menus in the Lucid (look-alike Motif) menubar widget
-- 3-d modeline
-- new extents engine; should be faster, less buggy, and more powerful
-- much more powerful control over faces
-- expanded menubar
-- more work on synching with GNU Emacs 19.28
-- new packages: Hyperbole, OOBR (object browser), hm--html-menus, viper,
   lazy-lock.el, ksh-mode.el, rsz-minibuf.el
-- package updates for all major packages
-- dynodump package for Solaris: provides proper undumping and portable
   binaries across different OS versions and machine types
-- Greatly expanded concept of "glyphs" (pixmaps etc. in a buffer)
-- built-in support for displaying X-Faces, if the X-Face library is
   available
-- built-in support for SOCKS if the SOCKS library is available
-- graceful behavior when the colormap is full (e.g. Netscape ate
   all the colors)
-- built-in MD5 (secure hashing function) support


More specific information:

*** TTY Support
---------------

The long-awaited TTY support is now available.  XEmacs will start up
in TTY mode (using the tty you started XEmacs from) if the DISPLAY
environment variable is not set or if you use the `-nw' option.

Faces are available on TTY's.  For a demonstration, try editing a C
file and turning on font-lock-mode.

You can also connect to additional TTY's using `make-tty-device',
whether your first frame was a TTY or an X window.  This ability is
not yet completely finished.

The full event-loop capabilities (processes, timeouts, etc.) are
available on TTY's.



*** New Redisplay Engine
------------------------

The redisplay engine has been rewritten to improve its efficiency and
to increase its functionality.  It should also be significantly more
bug-free than the previous redisplay engine.

A line that is not big enough to display at the bottom of the window
will normally be clipped (so that it is partially visible) rather than
not displayed at all.  The variable `pixel-vertical-clip-threshold'
can be used to control the minimum space that must be available for a
line to be clipped rather than not displayed at all.

Tabs are displayed in such a way that things line up fairly well even
in the presence of variable-width fonts and/or lines with
multiply-sized fonts.

Display tables are implemented, through the specifier variable
`current-display-table'.  They can be buffer-local, window-local,
frame-local, or device-local.  See below for info about specifiers.



*** Toolbar
-----------

There is now built-in support for a toolbar.  A sample toolbar is
visible by default at the top of the frame.  Four separate toolbars
can be configured (at the top, bottom, left, and right of the frame).
The toolbar specification is similar to the menubar specification.
The up, down, and disabled glyphs of a toolbar button can be
separately controlled.  Explanatory text can be echoed in the echo
area when the mouse passes over a toolbar button.  The size, contents,
and visibility of the various toolbars can be controlled on a
per-buffer, per-window, per-frame, and per-device basis through the
use of specifiers.  See the chapter on toolbars in the Lisp Reference
Manual (included with XEmacs) for more information.

The toolbar color and shadow thicknesses are currently controlled only
through `modify-frame-parameters' and through X resources.  We are
planning on making these controllable through specifiers as well. (Our
hope is to make `modify-frame-parameters' obsolete, as it is a clunky
and not very powerful mechanism.)

Info, GNUS, VM, W3, and various other packages include custom toolbars
with them.



*** Menubar
-----------

Stay-up menus are implemented in the look-alike Motif menubar.

The default menubar has been expanded to include most commonly-used
functions in XEmacs.

The options menu has been greatly expanded to include many more
options.

The menubar specification format has been greatly expanded.  Per-menu
activation hooks can be specified through the :filter keyword (thus
obsoleting `activate-menubar-hook'); this allows for fast response
time when you have a large and complex menu.  You can dynamically
control whether menu items are present through the :included and
:config keywords. (The latter keyword implements a simple menubar
configuration scheme, in conjunction with the variable
`menubar-configuration'.) Many different menu-item separators (single
or double line; solid or dashed; flat, etched-in, or etched-out) are
available.  See the chapter on menus in the Lisp Reference Manual for
more information about all of this.

New functions `add-submenu' and `add-menu-button' are available.
These supersede the older `add-menu' and `add-menu-item' functions,
and provide a more powerful and consistent interface.

New convenience functions for popping up the part or all of the
menubar in a pop-up menu are available: `popup-menubar-menu' and
`popup-buffer-menu'.

Menus are now incrementally constructed greatly improving menubar
response time.



*** Scrollbars
--------------

A look-alike Motif scrollbar is now included with XEmacs.  No longer
will you have to suffer with ugly Athena scrollbars.

Windows can now have horizontal scrollbars.  Normally they are visible
when the window's buffer is set to truncate lines rather than wrap
them (e.g. `(setq truncate-lines t)').

All windows, not only the right-most ones, can have vertical
scrollbars.

The functions to change a scrollbar's width have been superseded by
the specifier variables `scrollbar-width' and `scrollbar-height'.
This allows their values to be controlled on a buffer-local,
window-local, frame-local, and device-local basis.  See below.

The scrollbars interact better with the event loop (for example, you
can type `C-h k', do a scrollbar action, and see a description of this
scrollbar action printed as if you had pressed a key sequence or
selected a menu item).

The scrollbar behavior can be reprogrammed, by advising the
`scrollbar-*' functions.



*** Key Bindings
----------------

The oft-used function `goto-line' now has its own binding: M-g.

New bindings are available for scrolling the "other" window: M-next,
M-prior, M-home, M-end. (On many keyboards, `next' and `prior'
labelled `PgUp' and `PgDn'.)

You can reactivate a deactivated Zmacs region, without having any
other effects, with the binding M-C-z.

The bindings `M-u', `M-l', and `M-c' now work on the region (if a
region is active) or work on a word, as before.

Shift-Control-G forces a "critical quit", which drops immediately into
the debugger; see below.



*** Modeline
------------

The modeline can now have a 3-d look; this is enabled by default.  The
specifier variable `modeline-shadow-thickness' controls the size.

The modeline can now be turned off on a per-buffer, per-window,
per-frame, or per-device basis.  The specifier variable
`has-modeline-p' controls whether the modeline is visible.  See below
for details about the vastly powerful specifier mechanism.

The modeline functions and variables have been renamed to be
`*-modeline-*' rather than `*-mode-line-*'.  Aliases are provided for
all the old names.

Variable width fonts now work correctly when used in the modeline.



*** Minibuffer, Echo Area
-------------------------

The minibuffer is no longer constrained to be one line high.  The
package rsz-minibuf.el is included to automatically resize the
minibuffer when its contents are too big; enable this with
`resize-minibuffer-mode'.

The echo area is now a true buffer, called " *Echo Area*".  This
allows you to customize the echo area behavior through
before-change-functions and after-change-functions.



*** Specifiers
--------------

XEmacs has a new concept called "specifiers", used to configure most
display options (toolbar size and contents, scrollbar size, face
properties, modeline visibility and shadow-thickness, glyphs, display
tables, etc.).  We are planning on converting all display
characteristics to use specifiers, and obsoleting the clunky functions
`frame-parameters' and `modify-frame-parameters'.  Specifically:

-- You can specify values (called "instantiators") for particular
   "locales" (i.e. buffers, windows, frames, devices, or a global value).
   When determining what the actual value (or "instance") of a specifier
   is, the specifications that are provided are searched from most
   specific (i.e. buffer-local) to most general (i.e. global), looking
   for a matching one.

-- You can specify multiple instantiators for a particular locale.
   For example, when specifying what the foreground color of a face
   is in a particular buffer, you could specify two instantiators:
   "dark sea green" and "green".  The color would then be dark sea
   green on devices that recognize that color, and green on other
   devices.  You have effectively provided a fallback value to make
   sure you get reasonable behavior on all devices.

-- You can add one or more tags to an instantiator, where a tag
   is a symbol that has been previously registered with XEmacs.
   This allows you to identify your instantiators for later
   removal in a way that won't interfere with other applications
   using the same specifier.  Furthermore, particular tags can
   be restricted to match only particular sorts of devices.
   Any tagged instantiator will be ignored if the device over which
   it is being instanced does not match any of its tags.  This
   allows you, for example, to restrict an instantiator to a
   particular device type (X or TTY) and/or class (color, grayscale,
   or mono). (You might want to specify, for example, that a
   particular face is displayed in green on color devices and is
   underlined on mono devices.)

-- A full API is provided for manipulating specifiers, and full
   documentation is provided in the Lisp Reference Manual.



*** Basic Lisp Stuff
--------------------

Common-Lisp backquote syntax is recognized.  For example, the old
expression

(` (a b (, c)))

can now be written

`(a b ,c)

The old backquote syntax is still accepted.

The new function `type-of' returns a symbol describing the type of a
Lisp object (`integer', `string', `symbol', etc.)

Symbols beginning with a colon (called "keywords") are treated
specially in that they are automatically made self-evaluating when
they are interned into `obarray'.  The new function `keywordp' returns
whether a symbol begins with a colon.

`get', `put', and `remprop' have been generalized to allow you to set
and retrieve properties on many different kinds of objects: symbols,
strings, faces, glyphs, and extents (for extents, however, this is not
yet implemented).  They are joined by a new function `object-props'
that returns all of the properties that have been set on an object.

New functions `plists-eq' and `plists-equal' are provided for
comparing property lists (a property list is an alternating list
of keys and values).

The Common-Lisp functions `caar', `cadr', `cdar', `cddr', `caaar', etc.
(up to four a's and/or d's), `first', `second', `third', etc. (up to
`tenth'), `last', `rest', and `endp' have been added, for more
convenient manipulation of lists.

New function `mapvector' maps over a sequence and returns a vector
of the results, analogous to `mapcar'.

New functions `rassoc', `remassoc', `remassq', `remrassoc', and
`remrassq' are provided for working with alists.

New functions `defvaralias', `variable-alias' and `indirect-variable'
are provided for creating variable aliases.

Strings have a modified-tick that is bumped every time a string
is modified in-place with `aset' or `fillarray'.  This is retrieved
with the new function `string-modified-tick'.

New macro `push' destructively adds an element to the beginning of a
list.  New macro `pop' destructively removes and returns the first
element of a list.



*** Buffers
-----------

Most functions that operate on buffer text now take an optional BUFFER
argument, specifying which buffer they operate on.  (Previously, they
always operated on the current buffer.)

The new function `transpose-regions' is provided, ported from GNU
Emacs.

The new function `save-current-buffer' works like `save-excursion'
but only saves the current buffer, not the location of point in
that buffer.



*** Devices
-----------

XEmacs has a new concept of "device", which is represents a particular
X display or TTY connection.  `make-frame' has a new, optional device
parameter that allows you to specify which device the frame is to be
created on.

Multiple simultaneous TTY and/or X connections may be made.  The
specifier mechanism provides reasonable behavior of glyphs, faces,
etc. over heterogeneous device types and over devices whose individual
capabilities may vary.

There is also a device type called "stream" that represents a STDIO
device that has no redisplay or cursor-motion capabilities, such as
the "glass terminal" that XEmacs uses when it is run noninteractively.
There is not all that much you can do with stream devices currently;
please let us know if there are good uses you can think of for this
capability. (For example, log files?)

A new device API is provided.  Functions are provided such as
`device-name' (the name of the device, which generally is based on the
X display or TTY file name), `device-type' (X, TTY, or stream),
`device-class' (color, grayscale, or mono), etc.  See the Lisp
Reference Manual.

Many functions have been extended to contain an additional, optional
device argument, where such an extension makes sense.  In general, if
the argument is omitted, it is equivalent to specifying
`(selected-device)'.

Many previous functions and variables are obsoleted in favor of the
device API.  For example, `window-system' is obsoleted by
`device-type', and `x-color-display-p' and friends are obsoleted by
`device-class'.

** NOTE **: The obsolete variable `window-system' is going
to be deleted soon, probably in 19.14.  Please correct all
your code to use `device-type'.

** INCOMPATIBLE CHANGE **: The function `x-display-visual-class'
returns different values from previous versions of XEmacs.



*** Errors, Warnings, C-g
-------------------------

There is a new warnings system implemented.  Many warnings that were
formerly displayed in various ad-hoc ways (e.g. warnings about screwy
modifier mappings, messages about failures handling the mouse cursor
and errors in a gc-hook) have been regularized through this system.
The new function `warn' displays a warning before the next redisplay
(the actually display of the warning messages is accomplished through
`display-warning-buffer').  Both `warn' and `display-warning-buffer'
are Lisp functions (the C code calls out to them as necessary), and
thus you can customize the warning system.

Under an X display, you can press Shift-Control-G to force a "critical
quit".  This will immediately display a backtrace and pop you into the
debugger, regardless of the settings of `inhibit-quit' and
`debug-on-quit'.

C-g now works properly even on systems that don't implement SIGIO or
for which SIGIO is broken (e.g. IRIX 5.3 and older versions of Linux).
In addition, the SIGIO support has been fixed for many systems on
which it didn't always work properly before (e.g. HPUX and Solaris).

   

*** Events
----------

** INCOMPATIBLE CHANGE **: Many event functions have been changed to
accept and return windows instead of frames.

New function: `event-live-p', specifying whether `deallocate-event'
has been called on an event.

The "menu event" type has been renamed to "misc-user event", and
encompasses scrollbar events as well as menu events.  We are planning
on making it also encompass toolbar events in a future release.

New functions are provided for determining whether an particular
sections of a frame: `event-over-border-p', `event-over-glyph-p',
`event-over-modeline-p', `event-over-text-area-p', and
`event-over-toolbar-p'.  The old, kludgey methods of checking the
window-height, the internal-border-width, etc. are unreliable and
should not be used.

New functions `event-window-x-pixel' and `event-window-y-pixel' are
provided for determining where in a particular window an event
happened.

New functions `event-glyph-x-pixel' and `event-glyph-y-pixel' are
provided for determining where in a particular glyph an event
happened.

New function `event-closest-point', which returns the closest buffer
position to the event even if the event did not occur over any text.

New variable `unread-command-events', superseding the older
`unread-command-event'.

Many event-loop bugs have been fixed.



*** Extents
-----------

The extent code has been largely rewritten.  It should be faster and
more reliable.

The text-property implementation has been greatly improved.

Some new extent primitives are provided to return the position of the
next or previous property change in a buffer.

Extents can now have a parent specified; then all of its properties
(except for the buffer it's in and its position in that buffer) come
from that extent.  Hierarchies of such extents can be created.

Extents now have a `detachable' property that controls what happens
(they either get detached or shrink down to zero-length) when their
text is deleted.  Previously, such extents would always be detached.

The `invisible' property on extents now works.

`map-extents' has three additional parameters that provide more
control over which extents are mapped.

`map-extents' deals better with changes made to extents in the
buffer being mapped over.

A new function `mapcar-extents' (an alternative to `map-extents') has
been provided and should be easier to use than `map-extents'.



*** Faces
---------

Faces can now be buffer-local, window-local, and device-local as well
as frame-local, and can be further restricted to a particular device
type or class.  The way in which faces can be controlled is now based
on the general and powerful specifier mechanism; see above.

The new function `set-face-property' generalizes `set-face-font',
`set-face-foreground', etc. and takes many new optional arguments, in
accordance with the new specifier mechanism.

The new functions `face-property' and `face-property-instance'
generalize `face-font', `face-foreground', etc. and take many new
optional arguments, in accordance with the new specifier mechanism.
(`face-property' returns the value, if any, that was specified for a
particular locale, and `face-property-instance' returns the actual
value that will be used for display.  See the section on specifiers.)

The functions `face-font', `face-foreground', `face-background',
`set-face-font', `set-face-foreground', `set-face-background',
etc. are now convenience functions, trivially implemented using
`face-property' and `set-face-property' and take new optioanl
arguments in accordance with those functions.  New convenience
functions `face-font-instance', `face-foreground-instance',
`face-background-instance', etc. are provided and are trivially
implemented using `face-property-instance'.

Inheritance of face properties can now be specified.  Each individual
face property can inherit differently from other properties, or not
inherit at all.

You can set user-defined properties on faces using
`set-face-property'.

You can create "temporary" faces, which are faces that disappear
when they are no longer in use.  This is as opposed to normal
faces, which stay around forever.

The function `make-face' takes a new optional argument specifying
whether a face should be permanent or temporary, and returns the
actual face object rather than the face symbol, as in previous
versions of XEmacs.

The function `face-list' takes a new optional argument specifying
whether permanent, temporary, or both kinds of faces should be
returned.

Faces have new TTY-specific properties: `highlight', `reverse',
`alternate', `blinking', and `dim'.

Redisplay is smarter about dealing with face changes: changes to a
particular face no longer cause all frames to be cleared and
redisplayed.

The Edit-Faces package is provided for interactively changing faces.
A menu item on the options menu is provided for this.

New functions are provided for retrieving the ascent, descent, height,
and width of a character in a particular face.



*** Fonts, Colors
-----------------

** INCOMPATIBLE CHANGE **: The old "font" and "pixel" objects are gone.
In place are new objects "font specifier", "font instance", "color
specifier", and "color instance".  Functions `font-name', `pixel-name'
(an obsolete alias for `color-name'), etc. are now convenience
functions for working with font and color specifiers.  Old code that
is not too sophisticated about working with font and pixel objects may
still work, though.  (For example, the idiom `(font-name (face-font
'default))' still works.)

You can now extract the RGB components of a color-instance object
(similar to the old pixel object) with the function
`color-instance-rgb-components'.  There is also a convenience function
`color-rgb-components' for working with color specifiers.

If there are no more colors available in the colormap, the nearest
existing color will be used when allocating a new color.



*** Frames
----------

What used to be called "screens" are now called "frames", for clarity
and consistency with GNU Emacs.  Aliases are provided for all the old
screen functions and variables, to avoid introducing a huge E-Lisp
incompatibility.

The frame code has been merged with GNU Emacs 19.28, providing
improved functionality for many functions.



*** Glyphs, Images, and Pixmaps
-------------------------------

Glyphs (used in various places, i.e. as begin-glyphs and end-glyphs
attached to extents and appearing in a buffer or in marginal
annotations; as the truncator and continuor glyphs marking line wrap
or truncation; as an overlay at the beginning of a line; as the
displayable element in a toolbar button; etc.) can now be
buffer-local, window-local, frame-local, and device-local, and can be
further restricted to a particular device type or class.  The way in
which faces can be controlled is now based on the general and powerful
specifier mechanism; see above.

** INCOMPATIBLE CHANGE **: The glyph and pixmap API has been completely
overhauled.  A new Lisp object "glyph" is provided and should be used
where the old "pixmap" object would have been used.  The pixmap object
exists no longer.  There are also new Lisp objects "image specifier"
and "image instance" (an image-instance is the closest equivalent to
what a pixmap object was).  More work on glyphs and images is slated
for 19.13.  The glyph and image docs in the Lisp Reference Manual are
incomplete and will be finished in 19.13.

The new function `set-glyph-property' allows setting of all the
glyph properties (`baseline', `contrib-p', etc.).  Convenience
functions for particular properties are also provided, just like
for faces.

You can set user-defined properties on glyphs using the new function
`set-glyph-property'.

When displaying pixmaps, existing, closest-matching colors will be
used if the colormap is full.

If the compface library is compiled into XEmacs, there is built-in
support for displaying X-Face bitmaps. (These are typically small
pictures of people's faces, included in a mail message through the
X-Face: header.) VM and highlight-headers will automatically use the
built-in X-Face support if it is available.

Annotations in the right margin (as well as the left margin) are now
implemented.  The left and right margin width functions have been
superseded by the specifier variables `left-margin-width' and
`right-margin-width', allowing much more flexible control through the
specifier mechanism.

** INCOMPATIBLE CHANGE **: The variable `use-left-overflow',
for controlling annotations in the left margin, is now a specifier
variable instead of a buffer-local variable.  (There is also a new
variable `use-right-overflow', that is complementary.)



*** Hashing
-----------

Two new types of weak hashtables can be created: key-weak and
value-weak.  In a key-weak hashtable, an entry remains around
if its key is referenced elsewhere, regardless of whether this
is also the case for the value.  Value-weak hashtables are
complementary. (This is as opposed to the traditional weak
hashtables, where an entry remains around only if both the
key and value are referenced elsewhere.) New functions
`make-key-weak-hashtable' and `make-value-weak-hashtable'
are provided for creating these hashtables.

The new function `md5' is provided for performing an MD5
hash of an object.  MD5 is a secure message digest algorithm
developed by RSA, inc.



*** Keymaps
-----------

The FSF GNU Emacs concept of `function-key-map' is now partially
implemented.  This allows conversion of function-key escape sequences
such as `ESC [ 1 1 ~' into an equivalent human-readable keysym such as
`F1'.  This work will be completed in 19.14.  The function-key map is
device-local and controllable through the functions
`device-function-key-map' and `set-device-function-key-map'.

`where-is-internal' now correctly searches minor-mode keymaps,
extent-local keymaps, etc.  As a side effect of this, menu items will
now correctly show the keyboard equivalent for commands that are
available through a minor-mode keymap, extent-local keymap, etc.

** INCOMPATIBLE CHANGE **: The modifier key "Symbol" has
been renamed to "Alt", for compatibility with the rest of the world.
Keep in mind that on many keyboards, the key labelled "Alt" actually
generates the "Meta" modifier.  (On Sun keyboards, however, the key
labelled "Alt" does indeed generate the "Alt" modifier, and the key
labelled with a diamond generates the "Meta" modifier.)



*** Mouse, Active Region
------------------------

The mouse internals in mouse.el have been rewritten.  Hooks have been
provided for easier customization of mouse behavior.  For example, you
can now easily specify an action to be invoked on single-click
(i.e. down-up without appreciable motion), double-click, drag-up, etc.

Some code from FSF GNU Emacs has been ported over, generalizing some of
the X-specific mouse stuff.

** INCOMPATIBLE CHANGE **: The function `set-mouse-position' accepts
a window instead of a frame.

New function `mouse-position' that obsoletes and is more powerful than
`read-mouse-position'.

New functions `mouse-pixel-positon' and `set-mouse-pixel-position' for
working with pixels instead of characters.

The active (Zmacs) region is now highlighted using the `zmacs-region-face'
instead of the `primary-selection-face'; this generalizes what used
to be X-specific.

New functions `region-active-p', `region-exists-p', and `activate-region'
provide a uniform API for dealing with the region irrespective of
whether the variable `zmacs-regions' is set.

XEmacs is now a better X citizen with respect to the primary selection:
it does not stomp on the primary selection quite so much.  This makes
things more manageable if you set `zmacs-regions' to nil.



*** Processes
-------------

Various process race conditions and bugs have been fixed.  Problems
with process termination not getting noticed until much later (if at
all) should be gone now, as well as problems with zombie processes
under some systems.

SOCKS support is now included.  SOCKS is a package that allows hosts
behind a firewall to gain full access to the Internet without
requiring direct IP reachability.



*** Windows
-----------

Windows 95 is still not out yet.

** INCOMPATIBLE CHANGE **: The functions `locate-window-from-coordinates'
and `window-edges' have been eliminated.  It no longer makes sense to
work with windows in terms of character positions, because windows can
(and often do) have many differently-sized fonts in them, because the
3-D modeline is not exactly one line high, etc.

The new functions `window-pixel-edges', `window-highest-p',
`window-lowest-p', `frame-highest-window', and `frame-lowest-window'
are provided as substitutes for the above-mentioned, deleted
functions.

The function `window-end' now takes an optional GUARANTEE argument
that will ensure that the value is actually correct as of the next
redisplay.

The window code has been merged with GNU Emacs 19.28, providing
improved functionality for many functions.



*** System-Specific Information
-------------------------------

Georg Nikodym's dynodump package is provided, for proper unexec()ing
on Solaris systems.  Executables built on Solaris 2.3 can now run on
Solaris 2.4 without crashing; similarly with executables built on one
type of Sun machine and run on another.

AIX 4.x is supported.

The NeXTstep operating system is supported in TTY mode (this is still
in beta).  There are plans to port XEmacs to the NeXTstep window
system, but it may be awhile before this is complete.

Problems with the `round' function causing arithmetic errors on HPUX 9
have been fixed.

You can now build XEmacs as an ELF executable on Linux systems that
support ELF.

Various other new system configurations are supported.



*** Packages
------------

Most packages have been updated to the latest available versions.


Some of the new Emacs Lisp packages ---

Hyperbole: the everyday information manager.  Provides a Rolodex,
	   allows links to be embedded in text, etc.

OOBR: a sophisticated class browser for object-oriented languages.

viper: a better VI emulator that allows Emacs and VI features
       to coexist happily.

hm--html-menus: a sophisticated package for editing HTML code,
		from Heiko Muenkel.

ksh-mode.el: for editing shell scripts.

lazy-lock.el: a lazy, on-the-fly fontifier.

paren.el: an improved matching paren highlighter



Major changes to existing packages --

VM: has a toolbar, many other nice features.

w3: has a toolbar, many other nice features.

ediff: provides three-way merging, has a better user interface.

info: has a toolbar.

highlight-headers.el: now highlights URL's and makes them active so
		      that when clicked either Netscape 1.1 is called
		      or Emacs W3 is run.


** Major Differences Between 19.10 and 19.11
============================================
  
The name has changed from "Lucid Emacs" to "XEmacs".  Along with this is a
new canonical ftp site: cs.uiuc.edu:/pub/xemacs.

XEmacs now has its very own World Wide Web page!  It contains a
complete list of the FTP distribution sites, the most recent FAQ,
pointers to Emacs Lisp packages not included with the distribution, and
other useful stuff.  Check it out at http://xemacs.cs.uiuc.edu/.

A preliminary New Users Guide.

cc-mode.el now provides the default C, C++ and Objective-C modes.

The primary goal of this release is stability.  Very few new features have
been introduced but lots of bugs have been fixed.  Many of the Emacs Lisp
packages have been updated.

Some of the new Emacs Lisp packages ---

tcl-mode.el:  major mode for editing TCL code

fast-lock.el: saves and restores font-lock highlighting, greatly
            reducing the time necessary for loading a font-lock'ed
            file

ps-print.el: prints buffers to Postscript printers preserving the
           buffer's bold and italic text attributes

toolbar.el: provides a "fake" toolbar for use with XEmacs (an
          integrated one will be included with 19.12)


** Major Differences Between 19.9 and 19.10
===========================================

The GNU `configure' system is now used to build lemacs.

The Emacs Manual and Emacs Lisp Reference Manual now document version 19.10.
If you notice any errors, please let us know.

When pixmaps are displayed in a buffer, they contribute to the line height -
that is, if the glyph is taller than the rest of the text on the line, the
line will be as tall as necessary to display the glyph.

In addition to using arbitrary sound files as emacs beeps, one can control
the pitch and duration of the standard X beep, on X servers which allow that
(Note: most don't.)

There is support for playing sounds on systems with NetAudio servers.

Minor modes may have mode-specific key bindings; keymaps may have an arbitrary
number of parent maps.

Menus can have toggle and radio buttons in them.

There is a font selection menu.

Some default key bindings have changed to match FSF19; the new bindings are

  Screen-related commands:
        C-x 5 2                 make-screen
        C-x 5 0                 delete-screen
        C-x 5 b                 switch-to-buffer-other-screen
        C-x 5 f                 find-file-other-screen
        C-x 5 C-f               find-file-other-screen
        C-x 5 m                 mail-other-screen
        C-x 5 o                 other-screen
        C-x 5 r                 find-file-read-only-other-screen
  Abbrev-related commands:
        C-x a l                 add-mode-abbrev
        C-x a C-a               add-mode-abbrev
        C-x a g                 add-global-abbrev
        C-x a +                 add-mode-abbrev
        C-x a i g               inverse-add-global-abbrev
        C-x a i l               inverse-add-mode-abbrev
        C-x a -                 inverse-add-global-abbrev
        C-x a e                 expand-abbrev
        C-x a '                 expand-abbrev
  Register-related commands:
        C-x r C-SPC             point-to-register
        C-x r SPC               point-to-register
        C-x r j                 jump-to-register
        C-x r s                 copy-to-register
        C-x r x                 copy-to-register
        C-x r i                 insert-register
        C-x r g                 insert-register
        C-x r r                 copy-rectangle-to-register
        C-x r c                 clear-rectangle
        C-x r k                 kill-rectangle
        C-x r y                 yank-rectangle
        C-x r o                 open-rectangle
        C-x r t                 string-rectangle
        C-x r w                 window-configuration-to-register
  Narrowing-related commands:
        C-x n n                 narrow-to-region
        C-x n w                 widen
  Other changes:
        C-x 3                   split-window-horizontally (was undefined)
        C-x -                   shrink-window-if-larger-than-buffer
        C-x +                   balance-windows

The variable allow-deletion-of-last-visible-screen has been removed, since 
it was widely hated.  You can now always delete the last visible screen if
there are other iconified screens in existence.

ToolTalk support is provided.

An Emacs screen can be placed within an "external client widget" managed
by another application.  This allows an application to use an Emacs screen
as its text pane rather than the standard Text widget that is provided
with Motif or Athena.

Additional compatibility with Epoch is provided (though this is not yet
complete.)


** Major Differences Between 19.8 and 19.9
==========================================

Scrollbars!  If you have Motif, these are real Motif scrollbars; otherwise,
Athena scrollbars are used.  They obey all the usual resources of their
respective toolkits.

There is now an implementation of dialog boxes based on the Athena
widgets, as well as the existing Motif implementation.

This release works with Motif 1.2 as well as 1.1.  If you link with Motif, 
you do not also need to link with Athena.

If you compile lwlib with both USE_MOTIF and USE_LUCID defined (which is the
recommended configuration) then the Lucid menus will draw text using the Motif
string-drawing library, instead of the Xlib one.  The reason for this is that
one can take advantage of the XmString facilities for including non-Latin1
characters in resource specifications.  However, this is a user-visible change
in that, in this configuration, the menubar will use the "*fontList" resource 
in preference to the "*font" resource, if it is set.

It's possible to make extents which are copied/pasted by kill and undo.
There is an implementation of FSF19-style text properties based on this.

There is a new variable, minibuffer-max-depth, which is intended to circumvent
a common source of confusion among new Emacs users.  Since, under a window
system, it's easy to jump out of the minibuffer (by doing M-x, then getting
distracted, and clicking elsewhere) many, many novice users have had the
problem of having multiple minibuffers build up, even to the point of
exhausting the lisp stack.  So the default behavior is to disallow the
minibuffer to ever be reinvoked while active; if you attempt to do so, you
will be prompted about it.

There is a new variable, teach-extended-commands-p, which if set, will cause
`M-x' to remind you of any key bindings of the command you just invoked the
"long way."

There are menus in Dired, Tar, Comint, Compile, and Grep modes.

There is a menu of window management commands on the right mouse button over
the modelines.

Popup menus now have titles at the top; this is controlled by the new 
variable `popup-menu-titles'.

The `Find' key on Sun keyboards will search for the next (or previous)
occurrence of the selected text, as in OpenWindows programs.

The `timer' package has been renamed to `itimer' to avoid a conflict with
a different package called `timer'.

VM 5.40 is included.

W3, the emacs interface to the World Wide Web, is included.

Felix Lee's GNUS speedups have been installed, including his new version of
nntp.el which makes GNUS efficiently utilize the NNTP XOVER command if
available (which is much faster.)  

GNUS should also be much friendlier to new users: it starts up much faster,
and doesn't (necessarily) subscribe you to every single newsgroup.

The byte-compiler issues a new class of warnings: variables which are
bound but not used.  This is merely an advisory, and does not mean the
code is incorrect; you can disable these warnings in the usual way with
the `byte-compiler-options' macro.

the `start-open' and `end-open' extent properties, for specifying whether
characters inserted exactly at a boundary of an extent should go into the
extent or out of it, now work correctly.

The `extent-data' slot has been generalized/replaced with a property list,
so it's easier to attach arbitrary data to extent objects.

The `event-modifiers' and `event-modifier-bits' functions work on motion
events as well as other mouse and keyboard events.

Forms-mode uses fonts and read-only regions.

The behavior of the -geometry command line option should be correct now.

The `iconic' screen parameter works when passed to x-create-screen.

The user's manual now documents Lucid Emacs 19.9.

The relocating buffer allocator is turned on by default; this means that when
buffers are killed, their storage will be returned to the operating system, 
and the size of the emacs process will shrink.

CAVEAT: code which contains calls to certain `face' accessor functions will
need to be recompiled by version 19.9 before it will work.  The functions
whose callers must be recompiled are: face-font, face-foreground,
face-background, face-background-pixmap, and face-underline-p.  The symptom
of this problem is the error "Wrong type argument, arrayp, #<face ... >".
The .elc files generated by version 19.9 will work in 19.6 and 19.8, but
older .elc files which contain calls to these functions will not work in 19.9.

Work In Progress:

 - We have been in the process of internationalizing Lucid Emacs.  This code is
   ***not*** ready for general use yet.  However, the code is included (and
   turned off by default) in this release.

   - If you define I18N2 at compile-time, then sorting/collation will be done
     according to the locale returned by setlocale().

   - If you define I18N3 at compile-time, then all messages printed by lemacs
     will be filtered through the gettext() library routine, to enable the use
     of locale-specific translation catalogues.  The current implementation of
     this is quite dependent on Solaris 2, and has a very large impact on 
     existing code, therefore we are going to be making major changes soon.
     (You'll notice calls to `gettext' and `GETTEXT' scattered around much of
     the lisp and C code; ignore it, this will be going away.)

   - If you define I18N4 at compile-time, then lemacs will internally use a
     wide representation of characters, enabling the use of large character
     sets such as Kanji.  This code is very OS dependent: it requires X11R5, 
     and several OS-supplied library routines for reading and writing wide
     characters (getwc(), putwc(), and a few others.)  Performance is also a
     problem.  This code is also scheduled for a major overhaul, with the
     intent of improving performance and portability.  

     Our eventual goal is to merge with MULE, or at least provide the same base
     level of functionality.  If you would like to help out with this, let us 
     know.

 - Other work-in-progress includes Motif drag-and-drop support, ToolTalk 
   support, and support for embedding an Emacs widget inside another 
   application (where it can function as that other application's text-entry
   area).  This code has not been extensively tested, and may (or may not)
   have portability problems, but it's there for the adventurous.  Comments, 
   suggestions, bug reports, and especially fixes are welcome.  But have no
   expectations that this experimental code will work at all.


** Major Differences Between 19.6 and 19.8
==========================================

There were almost no differences between versions 19.6 and 19.7; version 19.7
was a bug-fix release that was distributed with Energize 2.1.

Lucid Emacs 19.8 represents the first stage of the Lucid Emacs/Epoch merger.
The redisplay engine now in lemacs is an improved descendant of the Epoch
redisplay.  As a result, many bugs have been eliminated, and several disabled
features have been re-enabled.  Notably:

Selective display (and outline-mode) work.

Horizontally split windows work.

The height of a line is the height of the tallest font displayed on that line;
it is possible for a screen to display lines of differing heights. (Previously,
the height of all lines was the height of the tallest font loaded.)

There is lisp code to scale fonts up and down, for example, to load the next-
taller version of a font.

There is a new internal representation for lisp objects, giving emacs-lisp 28
bit integers and a 28 bit address space, up from the previous maximum of 26.
We expect eventually to increase this to 30 bit integers and a 32 bit address
space, eliminating the need for DATA_SEG_BITS on some architectures.  (On 64
bit machines, add 32 to all of these numbers.)

GC performance is improved.

Various X objects (fonts, colors, cursors, pixmaps) are accessible as first-
class lisp objects, with finalization.

An alternate interface to embedding images in the text is provided, called
"annotations."  You may create an "annotation margin" which is whitespace at
the left side of the screen that contains only annotations, not buffer text.

When using XPM files, one can specify the values of logical color names to be
used when loading the files.

It is possible to resize windows by dragging their modelines up and down.  More
generally, it is possible to add bindings for mouse gestures on the modelines.

There is support for playing sound files on HP machines.

ILISP version 5.5 is included.

The Common Lisp #' read syntax is supported (#' is to "function" as ' is to
"quote".)

The `active-p' slot of menu items is now evaluated, so one can put arbitrary
lisp code in a menu to decide whether that item should be selectable, rather
than doing this with an `activate-menubar-hook'.

The X resource hierarchy has changed slightly, to be more consistent.  It used
to be
        argv[0]                 SCREEN-NAME     pane    screen
        ApplicationShell        EmacsShell      Paned   EmacsFrame

   now it is

        argv[0]                 shell           pane    SCREEN-NAME
        ApplicationShell        EmacsShell      Paned   EmacsFrame

The Lucid Emacs sources have been largely merged with FSF version 19; this
means that the lisp library contains the most recent releases of various
packages, and many new features of FSF 19 have been incorporated.

Because of this, the lemacs sources should also be substantially more portable.


** Major Differences Between 19.4 and 19.6
==========================================

There were almost no differences between versions 19.4 and 19.5; we fixed
a few minor bugs and repacked 19.4 as 19.5 for a CD-ROM that we gave away
as a trade show promotion.

The primary goal of the 19.6 release is stability, rather than improved
functionality, so there aren't many user-visible changes.  The most notable
changes are:

 - The -geometry command-line option now correctly overrides geometry
   specifications in the resource database.
 - The `width' and `height' screen-parameters work.
 - Font-lock-mode considers the comment start and end characters to be
   a part of the comment.
 - The lhilit package has been removed.  Use font-lock-mode instead.
 - vm-isearch has been fixed to work with isearch-mode.
 - new versions of ispell and calendar.
 - sccs.el has menus.

Lots of bugs were fixed, including the problem that lemacs occasionally
grabbed the keyboard focus.

Also, as of Lucid Emacs 19.6 and Energize 2.0 (shipping now) it is possible
to compile the public release of Lucid Emacs with support for Energize; so
now Energize users will be able to build their own Energize-aware versions
of lemacs, and will be able to use newer versions of lemacs as they are
released to the net.  (Of course, this is not behavior covered by your
Energize support contract; you do it at your own risk.)

I have not incorporated all portability patches that I have been sent since
19.4; I will try to get to them soon.  However, if you need to make any
changes to lemacs to get it to compile on your system, it would be quite
helpful if you would send me context diffs (diff -c) against version 19.6.


** Major Differences Between 19.3 and 19.4
==========================================

Prototypes have been added for all functions.  Emacs compiles in the strict
ANSI modes of lcc and gcc, so portability should be vastly improved.

Many many many many core leaks have been plugged, especially in screen 
creation and deletion.

The float support reworked to be more portable and ANSI conformant.  This
resulted in these new configuration parameters: HAVE_INVERSE_HYPERBOLIC, 
HAVE_CBRT, HAVE_RINT, FLOAT_CHECK_ERRNO, FLOAT_CATCH_SIGILL, 
FLOAT_CHECK_DOMAIN.  Let us know if you had to change the defaults on your
architecture.

The SunOS unexec has been rewritten, and now works with either static or 
dynamic libraries, depending on whether -Bstatic or -Bdynamic were specified
at link-time.

Small (character-sized) bitmaps can be mixed in with buffer text via the new
functions set-extent-begin-glyph and set-extent-end-glyph.  (This is actually
a piece of functionality that Energize has been using for a while, but we've
just gotten around to making it possible to use it without Energize.  See how
nice we are?  Go buy our product.)

If compiled with Motif support, one can pop up dialog boxes from emacs lisp.
We encourage someone to contribute Athena an version of this code; it
shouldn't be much work.  

If dialog boxes are available, then y-or-n-p and yes-or-no-p use dialog boxes
instead of the minibuffer if invoked as a result of a command that was 
executed from a menu instead of from the keyboard.

Multiple screen support works better; check out doc of get-screen-for-buffer.

The default binding of backspace is the same as delete.  (C-h is still help.)

A middle click while the minibuffer is active does completion if you click on 
a highlighted completion, otherwise it executes the global binding of button2.

New versions of Barry Warsaw's c++-mode and syntax.c.  Font-lock-mode works
with C++ mode now.

The semantics of activate-menubar-hook has changed; the functions are called
with no arguments now.

`truename' no longer hacks the automounter; use directory-abbrev-alist instead.

Most minibuffer handling has been reimplemented in emacs-lisp.

There is now a builtin minibuffer history mechanism which replaces gmhist.


** Major Differences Between 19.2 and 19.3
==========================================

The ISO characters have correct case and syntax tables now, so the word-motion
and case-converting commands work sensibly on them.

If you set ctl-arrow to an integer, you can control exactly which characters
are printable.  (There will be a less crufty way to do this eventually.)

Menubars can now be buffer local; the function set-screen-menubar no longer
exists.  Look at GNUS and VM for examples of how to do this, or read 
menubar.el.

When emacs is reading from the minibuffer with completions, any completions
which are visible on the screen will highlight when the mouse moves over them;
clicking middle on a completion is the same as typing it at the minibuffer.
Some implications of this:  The *Completions* buffer is always mousable.  If
you're using the completion feature of find-tag, your source code will be
mousable when you type M-.  Dired buffers will be mousable as soon as you 
type ^X^F.  And so on.

The old isearch code has been replaced with a descendant of Dan LaLiberte's
excellent isearch-mode; it is more customizable, and generally less bogus.
You can search for "composed" characters.  There are new commands, too; see
the doc for ^S, or the NEWS file.

A patched GNUS 3.14 is included.

The user's manual now documents Lucid Emacs 19.3.

A few more modes have mouse and menu support.

The startup code should be a little more robust, and give you more reasonable
error messages when things aren't installed quite right (instead of the
ubiquitous "cannot open DISPLAY"...)

Subdirectories of the lisp directory whose names begin with a hyphen or dot
are not automatically added to the load-path, so you can use this to avoid
accidentally inflicting experimental software on your users.

I've tried to incorporate all of the portability patches that were sent to
me; I tried to solve some of the problems in different ways than the 
patches did, so let me know if I missed something.

Some systems will need to define NEED_STRDUP, NEED_REALPATH, HAVE_DREM, or
HAVE_REMAINDER in config.h.  Really this should be done in the appropriate
s- or m- files, but I don't know which systems need these and which don't.
If yours does, let me know which file it should be in.

Check out these new packages:

blink-paren.el: causes the matching parenthesis to flash on and off whenever
                the cursor is sitting on a paren-syntax character.

pending-del.el: Certain commands implicitly delete the highlighted region:
                Typing a character when there is a highlighted region replaces
                that region with the typed character.

font-lock.el:   A code-highlighting package, driven off of syntax tables, so
                that it understands block comments, strings, etc.  The 
                insertion hook is used to fontify text as you type it in.

shell-font.el:  Displays your shell-buffer prompt in boldface.