XEmacs 21.4.2 "Developer-Friendly Unix APIs".

[chise/xemacs-chise.git.1] / etc / NEWS

-*- mode:outline -*-
\f
* Introduction
==============

This file presents the changes in recent XEmacs versions.  It
primarily documents user-visible (interface) changes, but also
includes internal changes of possible interest to the users.  When
describing new features, we try to also document ways of reverting to
the old behavior, where applicable.  If you dislike a recent change in
how XEmacs behaves, this file might contain a remedy.

Use `C-c C-f' to move to the next equal level of outline, and
`C-c C-b' to move to previous equal level.  `C-h m' will give more
info about the Outline mode.  Many commands are also available through
the menubar.

Users who would like to know which capabilities have been introduced
in each release should look at the appropriate section of this file.
Starting with version 20.0, XEmacs includes ChangeLogs, which can be
consulted for a more detailed list of changes.

    N.B.  The term "GNU Emacs" refers to any release of Emacs Version
    19 from the Free Software Foundation's GNU Project.  (We do not
    say just "Emacs" as Richard M. Stallman ["RMS"] prefers, because
    it is clearly a more generic term.)  The term "XEmacs" refers to
    this program or sometimes 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.

\f
* Changes in XEmacs 21.4
========================

** Summary of user-visible changes:

  -- The delete key now deletes forward by default.
  -- Shifted motion keys now select text by default.
  -- You can now build XEmacs with support for GTK+ widget set.
  -- ~/.xemacs/init.el is now the preferred location for the init file.
    - XEmacs now supports a `~/.xemacs/init.el' startup file.
    - Custom file will move to ~/.xemacs/custom.el.
  -- Much-improved sample init.el, showing how to use many useful features.
  -- XEmacs support for menu accelerators has been much improved.
  -- Default menubar improvements.
    - Default menubar has many new commands and better organization.
    - The font-menu is now available under MS Windows.
  -- Dialog box improvements, including a real file dialog box.
    - XEmacs now has a proper file dialog box under MS Windows (and GTK)!
    - The old clunky file dialog box is improved.
    - Keyboard traversal now works correctly in MS Windows dialog boxes.
    - There is a Search dialog box available from Edit->Find...
  -- New buffer tabs.
  -- There is a new MS Windows installer, netinstall, ported from Cygwin.
  -- The subprocess quote-handling mechanism under Windows is much improved.
  -- Printing support now available under MS Windows.
  -- Selection improvements.
    - Kill and yank now interact with the clipboard under Windows.
    - MS Windows support for selection is now much more robust.
    - Motif selection support is now more correct (but slower).
  -- Mail spool locking now works correctly.
  -- International support changes.
    - The default coding-priority-list is now safer.
    - International keysyms are now supported under X.
    - MS Windows 1251 code page now supported.
    - Czech, Thai, Cyrillic-KOI8, Vietnamese, Ethiopic now supported.
    - Proper support for words in Latin 3 and Latin 4.
  -- Help buffers contain hyperlinks, and other changes.
  -- The modeline's text is now scrollable.
  -- The mouse wheel under MS Windows now functions correctly.
  -- Interactive searching and matching case improvements.
    - Incremental search will now highlight all visible matches.
    - Interactive searches always respect uppercase characters.
  -- Rectangle functions rewritten to avoid inserting extra spaces.
  -- New command `kill-entire-line' that always kills the entire line.
  -- Default values correctly stored in minibuffer histories.
  -- You can now create "indirect buffers", like in GNU Emacs.
  -- Pixel-based scrolling has been implemented.
  -- Operation progress can be displayed using graphical widgets.
  -- User names following a tilde can now be completed at file name prompts.
  -- XEmacs can now play sound using Enlightenment Sound Daemon (ESD).
  -- X-Face support is now available under MS Windows.
  -- The PostgreSQL Relational Database Management System is now supported.
  -- Indentation no longer indents comments that begin at column zero.
  -- Face and variable settings can have comments in Customize.
  -- New locations for early package hierarchies.
  -- The `auto-save' library has been greatly improved.
  -- New variable `mswindows-alt-by-itself-activates-menu'.
  -- Other init-file-related changes.
    - Init file in your home directory may be called `.emacs.el'.
    - New command-line switches -user-init-file and -user-init-directory.
  -- Etags changes.
    - In DOS, etags looks for file.cgz if it cannot find file.c.
    - New option --ignore-case-regex is an alternative to --regex.
    - New option --declarations, for C-type languages.
    - In C++, tags are created for "operator".
    - Ada now supported.
    - In Fortran, procedure is no longer tagged.
    - In Java, tags are created for "interface".
    - In Lisp, def-type constructs are now tagged.
    - In Perl, the --globals option tags global variables.
    - Python now supported.
    - New file extensions recognized: .ss, .pdb, .psw.

** The delete key now deletes forward by default.

This is regulated by the variable `delete-key-deletes-forward', which
now defaults to t.  `delete-key-deletes-forward' takes effect only on
the systems that offer both a backspace and a delete key.  If set to
nil, the key labeled "Delete" will always delete backward.  If set to
non-nil, the "Delete" key will delete forward, except on keyboards
where a "Backspace" key is not provided (e.g. old DEC keyboards).

Unless our implementation has bugs, the only reason why you would want
to set `delete-key-deletes-forward' to nil is if you want to use the
Delete key to delete backwards, despite the presence (according to
Xlib) of a BackSpace key on the keyboard.

** Shifted motion keys now select text by default.

You can turn this off by setting `shifted-motion-keys-select-region'
to nil.  This works based off of particular keys, not particular
commands: Thus, the arrow keys will normally trigger selection when
the Shift key is held down regardless of their bindings, and non-arrow
keys with the same bindings (e.g. C-f) will not work this way.  You
can control which keys trigger shifted motion using
`motion-keys-for-shifted-motion'.  See also
`unshifted-motion-keys-deselect-region'.

** You can now build XEmacs with support for GTK+ widget set.

XEmacs built that way uses GTK+ to draw menubars, scrollbars, and
other GUI components, as well GDK for drawing text, choosing fonts,
allocating colors, etc.  Additionally, GTK-XEmacs supports Lisp
functions for writing your own GTK programs in Emacs Lisp!

To use this, build XEmacs with the `--with-gtk' configure flag.  (Of
course, you'll need to have the GTK+ libraries and header files on the
system.)  Gnome widgets and functionality are supported where
available, and can be turned off.

** ~/.xemacs/init.el is now the preferred location for the init file.

*** XEmacs now supports a `~/.xemacs/init.el' startup file.
If it exists, XEmacs will prefer it over `.emacs' and `.emacs.el'.
The file may be byte-compiled as `~/.xemacs/init.elc'.

If present, the `~/.xemacs/' directory may contain startup files for
XEmacs packages that support it.

The first time you start up XEmacs, it will ask you if you would like
to migrate your `.emacs' to the new location. (Your custom settings
will also be moved, to `~/.xemacs/custom.el' -- see below.) If so, you
will also be asked whether you would like to create a compatibility
`.emacs' for backward compatibility with previous versions of XEmacs
and with GNU Emacs. (This compatibility `.emacs' simply loads the new
init and custom files.) Doing this is generally a good idea -- new
versions of XEmacs will prefer `~/.xemacs/init.el' over `~/.emacs' in
any case.

You can manually migrate at any time with `migrate-user-init-file',
and undo any migration with `unmigrate-user-init-file'.  The function
`create-compatibility-dot-emacs' also lets you manually create a
compatibility `.emacs'.

NOTE: Under MS Windows, your home directory (i.e. the directory named
`~') is specified by the HOME environment variable, and defaults to
C:\.  To set this variable, modify AUTOEXEC.BAT under Windows 95/98,
or select Control Panel->System->Advanced->Environment Variables...
under Windows NT/2000.

*** Custom file will move to ~/.xemacs/custom.el.

Whereas customize settings were formerly stored in the regular init
file, XEmacs now prefers them to be in a separate file
`~/.xemacs/custom.el', completely under automatic control.  This
change goes with the migration of the init file, and XEmacs offers
automatic migration upon startup.

** Much-improved sample init.el, showing how to use many useful features.

The sample init file, located in the `etc/' directory of the XEmacs
installation, has been renamed from `sample.emacs' to `sample.init.el',
and pretty much rewritten from scratch. (You can view it by selecting
the menu item Help->Samples->Sample init.el.)  Many of the most-useful
optional features in XEmacs have been enabled, and other features that
are useful but may be annoying to some are present but commented out.
There is also extensive documentation on how to add your own
improvements to the init file and where to find more documentation
elsewhere in XEmacs.  The file has been specifically designed so that
most people can simply make it their own init file by copying it to
~/.xemacs/init.el, and they will be satisfied with the results.

** XEmacs support for menu accelerators has been much improved.

It now works properly under MS Windows, for example.  To enable
accelerators, set `menu-accelerator-enabled' to `menu-force'.  Menus
now have accelerators by default, currently on the first letter of the
menu item unless another letter was indicated as the accelerator using
%_ in the menu string.  These %_ specifications are automatically
removed when displaying the menu item, and are handled correctly in
functions such as `normalize-menu-item-name'.  Some auto-generated
menus will have accelerators added dynamically, using numbers 1-9 and
letters; to add this feature yourself, use the Lisp command
`submenu-generate-accelerator-spec' in a menu filter.  The feature
`menu-accelerator-support' has been added so that packages can check
whether this support exists.

** Default menubar improvements.

*** Default menubar has many new commands and better organization.

The default menubar has been extensively reorganized.  Many more
commands are available, and they are more logically organized.  The
Options menu, in particular, has been significantly expanded, and almost
everything on the new Cmds menu is new. (Much of the useful
functionality from the `big-menubar' package has been imported.)

*** The font-menu is now available under MS Windows.

** Dialog box improvements, including a real file dialog box.

*** XEmacs now has a proper file dialog box under MS Windows (and GTK)!
This will appear whenever you select a menu item that requires a file
as an argument.

*** The old clunky file dialog box is improved.
The in-buffer file dialog box (visible on non-MS-Windows, non-GTK
systems) is still clunky but has had many improvements to make it work
significantly better.

*** Keyboard traversal now works correctly in MS Windows dialog boxes.

*** There is a Search dialog box available from Edit->Find...
However, it's very experimental and needs a lot of work.

** New buffer tabs.

You can now use buffer tabs to switch between buffers.

The tabs are located between the toolbar and the uppermost window, in
a location called the "gutter".  If you dislike the buffer tabs, you can
disable them using the menu item `Options->Display->Buffers Tab Visible'
by customizing `gutter-buffers-tab-visible-p', or by placing this in
your .xemacs/init.el:

   (custom-set-variables '(gutter-buffers-tab-visible-p nil))

You can change the location of the gutter using the menu item
`Options->Display->Default Gutter Location' or with (e.g.)

   (custom-set-variables '(default-gutter-position 'left))

However, currently only MS Windows supports tab widgets with
orientations other than vertical, and it doesn't currently support
gutters on the bottom of the frame.

** There is a new MS Windows installer, netinstall, ported from Cygwin.

Nearly complete automation of the XEmacs install process from
ftp.xemacs.org.  Includes selection of Lisp packages to install, etc.

** The subprocess quote-handling mechanism under Windows is much improved.

Specifically, the quote-handling mechanism has been completely rewritten,
and you should now be able to use single or double quotes to quote arguments
just like under Unix, and expect to get correct results regardless of the
shell you are using (e.g. CMD.EXE, bash from Cygwin, etc.).  For example,
the following command:

M-x grep '<<<<<<<' *.c

should work as intended.

** Printing support now available under MS Windows.

The File->Print... menu item pretty-prints using the standard MS
Windows printing facilities.  Unfortunately it's still rather
experimental.  There is a separate `msprinter' device tag for MS
Windows printers, and so you can control the way that faces appear on
the printer by using this tag to specify device-specific face
settings.

** Selection improvements.

*** Kill and yank now interact with the clipboard under Windows.

This was done by changing the default value of `interprogram-cut-function'
and `interprogram-paste-function'.  You can get the old behavior by
setting these to nil, and there is an option on the options menu to do
this.

*** MS Windows support for selection is now much more robust.

Generally selection should now do what you would expect under
MS Windows: the middle mouse button will paste your current selection
or the clipboard; conversions from different types of selection to the
clipboard can be made; the kill-ring and friends will be updated as
per X.

The only thing selection doesn't do is set the clipboard automatically
as this would break the MS Windows model.  If you want this behavior
then set `selection-sets-clipboard' to t.

*** Motif selection support is now more correct (but slower).

Changes have been made to allow correct operation of cut/copy/paste
operations between native widgets and XEmacs buffers.  However, this
can lead to a lot of X traffic which slows down the performance of
`C-k'. If you want the old behaviour then set
`x-selection-strict-motif-ownership' to nil.

** Mail spool locking now works correctly.

XEmacs has always come with a little auxiliary program, movemail,
which moves mail out of the system's spool area into user storage.  To
coordinate between XEmacs, the mail delivery agent, and other mail
user agents, movemail needs to properly lock the spool file before
moving it.  Movemail now correctly respects the --mail-locking option
to configure.  Moreover, movemail's locking behavior can be specified
at run-time, via a new command-line option -m to movemail, or through
the environment variable EMACSLOCKMETHOD.

When installing XEmacs, make sure you configure it according to your
environment's mail spool locking conventions.  When you're using a
binary kit, set the `mail-lock-method' variable at startup, or the
EMACSLOCKMETHOD environment variable.

** International support changes.

*** The default coding-priority-list is now safer.

This means that if you have no language environment set, Mule no
longer automatically recognizes ISO 2022 escapes in your files.  This
makes editing binary files safe.

*** International keysyms are now supported under X.

This means that XEmacs running under Mule will automatically recognize
the keysym `scaron' to be the lower-case `s' with caron in the Latin 2
character set.  (Specifically, it will bind the keysym to
`self-insert' and augment its `ascii-character' property.)  This is
very useful with XFree under European locales as shipped by recent
Linux distributions.  If XEmacs is compiled without Mule support, the
feature still works, but it is unaware of different character sets --
it unconditionally sets the `ascii-character' property to values in
the [160, 256) range.

*** MS Windows 1251 code page now supported.

It's available as coding system `windows-1251'.

*** Czech, Thai, Cyrillic-KOI8, Vietnamese, Ethiopic now supported.

*** Proper support for words in Latin 3 and Latin 4.

The appropriate characters in Latin 3 and Latin 4 character sets are
correctly defined as words.

** Help buffers contain hyperlinks, and other changes.

The help buffers created by C-h commands now contain hyperlinks to
other commands, functions and variables mentioned in the documentation.
Use button2 to follow a link.  Use button3 to bring up a context menu
that lets you follow the link, find the source for the item, do a tag
search, etc.  The buffers are also syntax-highlighted.

Help functions (e.g. `C-h f') now know how to print macro argument
lists.  If your macro definition included an argument list for the sake
of help output, you no longer need to do that.

** The modeline's text is now scrollable.

This is controlled by the variable `modeline-scrolling-method', which
you need to set to a non-nil value.  You can also choose scrolling
types; see the docstring of `modeline-scrolling-method' for more
information.

** The mouse wheel under MS Windows now functions correctly.

It scrolls the XEmacs window under the pointer, not the selected
window.

** Interactive searching and matching case improvements.

*** Incremental search will now highlight all visible matches.

This makes it easier to anticipate where consecutive C-s or C-r will
place the point.  If you want to disable the feature, set
`isearch-highlight-all-matches' to nil.

*** Interactive searches always respect uppercase characters.

Case sensitiveness in searching operations is normally controlled
by the variable `case-fold-search' (if non-nil, case is ignored while
searching).  This mechanism has now been slightly improved for
interactive searches: if the search string (or regexp) contains
uppercase characters, the searching is forced to be case-sensitive,
`case-fold-search'.

The new behavior affects all functions performing interactive
searches, like `zap-to-char', `list-matching-lines', `tags-search'
etc.  The incremental search facility has always behaved that way.

** Rectangle functions rewritten to avoid inserting extra spaces.

The rectangle functions have been almost completely rewritten in
order to avoid inserting undesirable spaces, notably at the end of
lines.  Two typical examples of the old behavior were
`string-rectangle', which filled all lines up to the right side of the
rectangle, and `clear-rectangle', which filled even empty lines up to
the left side.  All functions have been rewritten to avoid inserting
unwanted spaces, and an optional prefix now allows them to behave the
old way.

Also, the behavior of `string-rectangle' is now compliant with
`pending-delete-mode': if this mode is active, then the string
replaces the region rectangle.  Otherwise, the command does not delete
or overwrite any existing text.  For those who want that feature but do
not use pending-delete-mode, a new function, `replace-rectangle', is
available.

As a side effect, the FORCE argument to `move-to-column' now
understands the special value `coerce', which means that the line
should not be filled if it is too short to reach the desired column.

** New command `kill-entire-line' that always kills the entire line.

This kills the entire line at point, regardless of whether the point
is at the beginning of line, and regardless of the setting of
`kill-whole-line'.

** Default values correctly stored in minibuffer histories.

When you press RET at a minibuffer prompt that provides a default
value, the value is stored in history instead of an empty line.  Also,
you can now edit the default value by pressing the down arrow,
accessing the logical "future" value.  Not all minibuffer prompts have
yet been converted to support this feature.

** You can now create "indirect buffers", like in GNU Emacs.

An indirect buffer shares its text with another buffer ("base
buffer"), but has its own major mode, local variables, extents, and
narrowing.  An indirect buffer has a name of its own, distinct from
those of the base buffer and all other buffers.  An indirect buffer
cannot itself be visiting a file (though its base buffer can be).
The base buffer cannot itself be indirect.

Use (make-indirect-buffer BASE-BUFFER NAME) to make an indirect buffer
named NAME whose base is BASE-BUFFER.  If BASE-BUFFER is itself an
indirect buffer, its base buffer is used as the base for the new
buffer.

You can make an indirect buffer current, or switch to it in a window,
just as you would a non-indirect buffer.

The function `buffer-base-buffer' returns a buffer's base buffer or
nil, if given an ordinary (non-indirect) buffer.  The function
`buffer-indirect-children' returns a list of the indirect children of
a base buffer.

** Pixel-based scrolling has been implemented.
By default this will attempt to scroll in increments equal to the
height of the default face.  Set `window-pixel-scroll-increment' to
modify this behavior.

** Operation progress can be displayed using graphical widgets.
See `progress-feedback' for details.  This support has been switched
on by default for font-lock and some web browsing functions.  If you
do not like this behavior, set `progress-feedback-use-echo-area' to
nil.

** User names following a tilde can now be completed at file name prompts.
e.g. `C-x C-f ~hni<TAB>' will complete to `~hniksic/'.  To make this
operation faster, a cache of user names is maintained internally.

The new primitives available for this purpose are functions named
`user-name-completion' and `user-name-all-completions'.

** XEmacs can now play sound using Enlightenment Sound Daemon (ESD).
It will try NAS first, then ESD, then playing native sound directly.

** X-Face support is now available under MS Windows.
If an X-Face library built under MS Windows is available then XEmacs
will use this at build time.

** The PostgreSQL Relational Database Management System is now supported.
It is now possible to build XEmacs so that the programming interface
to the PostgreSQL RDBMS (libpq) is available in XEmacs Lisp.
Supported versions of PostgreSQL are 6.5.3 (earlier versions may work,
but have not been tested) and 7.0-beta1.

** Indentation no longer indents comments that begin at column zero.
This makes it easy to deal with commented out regions of code.

** Face and variable settings can have comments in Customize.
Customize now supports adding comments about your face and variable
settings using a new menu entry.  Comments for variables can also be
assigned by calling `customize-set-(value|variable)' with a prefix
argument.

** New locations for early package hierarchies.
XEmacs now locates the early package hierarchies at
~/.xemacs/mule-packages/ and ~/.xemacs/xemacs-packages/.  Previously,
the early packages were located in ~/.xemacs/.

** The `auto-save' library has been greatly improved.
(This lets you group all your auto-save files into one directory, and
is provided standardly with XEmacs.  See `etc/sample.init.el',
available on the Help menu, for more info on how to set it up.)
Specifically, it now works under MS Windows, and it uses a completely
reversible encoding (basically quoted-printable), so that all
filenames (as well as non-filename buffers) are successfully handled
regardless of any special characters in their names.

** New variable `mswindows-alt-by-itself-activates-menu'.
If you set this variable to nil then pressing and releasing the Alt
key under MS Windows will no longer activate the menubar.  The default
is t.  This is not to be confused with `menu-accelerator-enabled',
which enables the use of Alt+<Letter> accelerators to invoke the
menus.

** Other init-file-related changes.

*** Init file in your home directory may be called `.emacs.el'.

Like in GNU Emacs 20.4 and on, you can now name the XEmacs init file
located in your home directory `.emacs.el'.  Formerly the name had to
be `.emacs'.  If you use the name `.emacs.el', you can byte-compile
the file in the usual way.

If both `.emacs' and `.emacs.el' exist, the latter file is the one
that is used.

*** New command-line switches -user-init-file and -user-init-directory.

These can be used to specify alternate locations for what is normally
~/.emacs and ~/.xemacs.

Moreover, the `-user <user>' command-line option (which used to only
work in unpredictable ways) is now equivalent to `-user-init-file
~<user>/.xemacs/init.el -user-init-directory ~<user>/.xemacs', or
`-user-init-file ~<user>/.emacs -user-init-directory ~<user>/.xemacs',
whichever init file comes first.

** Etags changes.

*** In DOS, etags looks for file.cgz if it cannot find file.c.

*** New option --ignore-case-regex is an alternative to --regex.
It is now possible to bind a regexp to a language, by prepending the
regexp with {lang}, where lang is one of the languages that `etags
--help' prints out.  This feature is useful especially for regex
files, where each line contains a regular expression.  The manual
contains details.

*** New option --declarations, for C-type languages.
In C and derived languages, etags creates tags for function
declarations when given the --declarations option.

*** In C++, tags are created for "operator".
The tags have the form "operator+", without spaces between the
keyword and the operator.

*** Ada now supported.
Tags are functions, procedures, packages, tasks, and types.

*** In Fortran, procedure is no longer tagged.

*** In Java, tags are created for "interface".

*** In Lisp, def-type constructs are now tagged.
This includes "(defstruct (foo", "(defun (operator" and similar constructs.

*** In Perl, the --globals option tags global variables.
my and local variables are tagged.

*** Python now supported.
def and class at the beginning of a line are tags.

*** New file extensions recognized: .ss, .pdb, .psw.
.ss files are Scheme files, .pdb is Postscript with C syntax, .psw is
for PSWrap.

\f
* Lisp and internal changes in XEmacs 21.4
==========================================

** A new portable dumper is available for beta testing.

Olivier Galibert has written a portable dumper for XEmacs, based on
initial work by Kyle Jones.  To perform even the most basic editor,
XEmacs requires some amount of Lisp code to be loaded.  To avoid
repeating the expensive loading process at every startup, XEmacs is
built in a special way.  Its C sources link into an executable called
`temacs', which loads the bootstrap Lisp code and uses a special
"unexec" call to dump the resulting memory image into a proper
`xemacs' executable on disk.  The unexec() process is hard to
implement correctly and makes XEmacs very hard to port to new
operating systems, or even to new releases of old systems.

The new portable dumper uses a different approach to dumping: instead
of dumping full-fledged executable, it only dumps out the initialized
data structures (both Lisp and C) into an external file.  A normally
running XEmacs only needs to mmap that file and relocate a bit to get
to the initialized data.  In that scheme, there is no difference
between `temacs' and `xemacs'.

Unfortunately, the portable dumper has not been completely finished
for this release, and will not be used by default.  However, if you
wish to experiment with it, or if you need to compile XEmacs on a new
and unsupported platform, you can test it by configuring XEmacs with
`--pdump' flag.

** Much effort has been invested to make XEmacs Lisp faster:

*** Many basic lisp operations are now faster.
This is especially the case when running a Mule-enabled XEmacs.

A general overhaul of the lisp engine should produce a speedup of 1.4
in a non-Mule XEmacs, and 2.1 in a Mule XEmacs.  These numbers were
obtained running `(byte-compile "simple.el")', which should be a
pretty typical test of "pure" Lisp.

*** Lisp hash tables have been re-implemented.  The Common Lisp style
hash table interface has been made standard, and moved from cl.el into
fast C code (See the section on hash tables in the XEmacs Lisp
Reference).  A speedup factor of 3 can be expected with code that
makes intensive use of hash tables.

*** The garbage collector has been tuned, leading to a speedup of
1.16.

*** The byte-compiler and the byte-optimizer have been tuned to
produce better code in many small ways.

*** The family of functions that iterate over lists, like `memq', and
`rassq', have been made a little faster (typically 1.3).

*** Lisp function calls are faster, by approximately a factor of two.
However, defining inline functions (via defsubst) still makes sense
for tight loops.

*** Finally, a few functions have had dramatic performance
improvements.  For example, `(last long-list)' is now 30 times faster.

Of course, your mileage will vary.

Many operations do not see any improvement.  Surprisingly, running
(font-lock-fontify-buffer) does not use the Lisp engine much at all.
Speeding up your favorite slow operation is an excellent project to
improve XEmacs.  Don't forget to profile!

** Native widgets can be displayed in buffers.

The glyph system has been extended to allow the display of glyphs that
are implemented as native window-system widgets.  Thus you can embed
buttons, scrollbars, combo boxes, edit fields and progress gauges in a
buffer.  As a side effect subwindow support now works once again.

All of this is still fairly experimental and there is no
documentation.  The current APIs might change in a future version of
XEmacs.  Some widgets are only available under MS Windows.  See the
file glyphs-test.el in the XEmacs src distribution for examples of
usage.

The buffers-tab functionality and progress gauge have been implemented
using this feature.

** Case translation now supports international characters.

*** Instead of being lists of 256-character strings, case tables are
now opaque objects.  The interface to access them is almost the same,
except it now works for international characters, and you can set the
case pairs using `put-case-table-pair'.  `set-case-table' and friends
still support the old list/string based interface for backward
compatibility.

*** As a consequence of this change, functions `downcase' and `upcase'
as well as all the case-transformation commands now work with
non-ASCII characters.  Built-in tables cover all the Latin character
sets that we support.  If your language has a distinction between
upper and lower case that is not handled by XEmacs/Mule, please let us
know.

*** The code that implements case-insensitive search has been modified
to respect the case table settings.  This also applies to regexp
search.

** Syntax tables may now be specified for a part of a buffer by
attaching the `syntax-table' property to an extent.  For compatibility
with GNU Emacs, you may use the text-property interface to achieve the
same result.

** Values of variables `user-init-file' and `user-init-directory' are
now absolute file/directory names.  Previously, both variables used to
be relative to `(concat "~" init-file-user)'.  This turned out to be
too complicated for most packages (and some core Lisp files) to use
correctly.  Also, the `init-file-user' variable has been obsoleted in
the process.

The user-visible options like `-u' have not changed their behavior.

** XEmacs finally has an automated test suite!
Although this is not yet very sophisticated, it is already responsible
for several important bug fixes in XEmacs.  To try it out, simply use
the makefile target `make check' after building XEmacs.

** Hash tables have been reimplemented.
As was pointed out above, the standard interface to hash tables is now
the Common Lisp interface, as described in Common Lisp, the Language
(CLtL2, by Steele).  The older interface (functions with names
containing the phrase `hashtable') will continue to work, but the
preferred interface now has names containing the phrase `hash-table'.

Here's the executive overview: create hash tables using
make-hash-table, and use gethash, puthash, remhash, maphash and
clrhash to manipulate entries in the hash table.  See the (updated)
Lisp Reference Manual for details.

** Lisp code handles circular lists much more robustly.
Many basic lisp functions used to loop forever when given a circular
list, expecting you to C-g (quit) out of the loop.  Now this is more
likely to trigger a `circular-list' error.  Printing a circular list
now results in something like this:

    (let ((x (cons 'foo 'foo)))
      (setcdr x x)
      x)
      => (foo ... <circular list>)

An extra bonus is that checking for circularities is not just
friendlier, but actually faster than checking for C-g.

** Functions for decoding base64 encoding are now available; see
`base64-encode-region', `base64-encode-string', `base64-decode-region'
and `base64-decode-string'.

** The functions `read-string', `read-expression', `eval-minibuffer',
`read-variable', `read-command', `read-function', `read-number',
`read-shell-command', `read-from-minibuffer', and `completing-read'
now take an additional argument which specifies the default value.  If
this argument is non-nil, it should be a string; that string is used
in two ways:

 * It is returned if the user enters empty input.
 * It is available as the logical "future" entry, by pressing the down
   arrow.

** LDAP changes.

*** The LDAP interface now consists of two layers, a low-level layer
that closely matches the LDAP C API, and a more convenient
higher-level set of functions.

*** The low-level functions that used to be named *-internal are now
named more simply: `ldap-open', `ldap-close', `ldap-search-basic',
`ldap-add', and `ldap-modify'.  They should be used directly for very
specific purposes (such as multiple operations on a connection) only.

*** The higher-level functions provide a more convenient way to access
LDAP directories hiding the subtleties of handling the connection,
translating arguments and ensuring compliance with LDAP
internationalization rules and formats (currently partly implemented
only.)  This layer provides atomic operations for searches,
modification, addition and deletion of multiple entries at once:
`ldap-search-entries', `ldap-add-entries', `ldap-delete-entries', and
`ldap-modify-entries'.

*** To maintain compatibility with previous code, the now obsolete
function `ldap-search' is now merely a wrapper that calls either
`ldap-search-basic' or `ldap-search-entries'.  Please don't use the
`ldap-search' function in your new programs -- a direct call to one of
the two replacements is more efficient and unambiguous.

** The arguments to `locate-file' are now more Lisp-like.  As before,
the usage is:

    (locate-file FILENAME PATH-LIST &optional SUFFIXES MODE)

Except that SUFFIXES are now a list of strings instead of a single,
colon-separated string.  MODE is now a symbol or a list of symbols
(symbols `exists', `executable', `writable', and `readable' are
supported) instead of an integer code.  See the documentation for
details.  Of course, the old form is still accepted for backward
compatibility.

Several bugs in locate-file have been fixed, most notably its failure
to call expand-file-name on elements of PATH-LIST.  Because of that
elements of load-path of the form "~/..." used to not work.
locate-file is now guaranteed to expand files during its course of
operation.

** `translate-region' has been improved in several ways.  Its TABLE
argument used to be a 256-character string.  In addition to this, it
can now also be a vector or a char-table, which makes the function
useful for Mule, which it wasn't.  If TABLE is a vector or a generic
char-table, you can map characters to strings instead of to other
characters.  For instance:

    (let ((table (make-char-table 'generic)))
      (put-char-table ?a "the letter a" table)
      (put-char-table ?b "" table)
      (put-char-table ?c ?\n table)
      (translate-region (point-min) (point-max) table))

** The new form `ignore-file-errors', similar to `ignore-errors' may
be used as a short-hand for condition-case when you wish to ignore
file-related error.  For example:

    (ignore-file-errors (delete-file "foo"))

** The first argument to `intern-soft' may now also be a symbol, like
with `unintern'.  If given a symbol, `intern-soft' will look for that
exact symbol rather than for any string.  This is useful when you want
to check whether a specific symbol is interned in an obarray, e.g.:

    (intern "foo")
    (intern-soft "foo")
      => foo
    (intern-soft (make-symbol "foo"))
      => nil

** The `keywordp' function now returns non-nil only on symbols
interned in the global obarray.  For example:

    (keywordp (intern ":foo" [0]))
      => nil
    (keywordp (intern ":foo"))       ; The same as (keywordp :foo)
      => t

This behavior is compatible with other code which treats symbols
beginning with colon as keywords only if they are interned in the
global obarray.  `keywordp' used to wrongly return t in both above
cases.

** The function `replace-in-string' has been rewritten to use
`replace-match'.  This not only makes it much faster, but adds all the
features of `replace-match'.

** New variables `this-command-properties' and
`last-command-properties' are now available for communication between
consecutive commands.  Commands should use these to communicate with
the pre/post-command hooks, subsequent commands, wrapping commands,
etc. in preference to looking at and/or setting `this-command'.

** New functions `add-one-shot-hook' and `add-local-one-shot-hook' make
it possible to add a "one-shot" hook, which is to say a hook that runs
only once, and automatically removes itself after the first time it
has run.

** The descriptor that specifies the text of a menu item can now be an
evaluated expression.  This makes it parallel with other descriptors,
which can also be expressions.

\f
* Changes in XEmacs 21.0
========================

** XEmacs has been unbundled into constituent installable packages.
See the Info documentation under "Packages" for more information.
See the file `etc/PACKAGES' in the distribution for a partial list of
packages available at the time of the 21.0 release.

** XEmacs is now supported under Microsoft Windows 95/98 and Windows
NT operating systems.  For starters, look at the XEmacs on Windows FAQ
at <URL:http://jagor.srce.hr/~hniksic/xemacs-on-windows-faq.txt>.  To
discuss Windows-specific issues, subscribe to the mailing list at
<xemacs-nt-request@xemacs.org>.

** XEmacs will now use `XEmacs' as its application class if it finds
any `XEmacs' resources in the resource database.  Otherwise, it will
continue to use the `Emacs' class.

** The options menu has been ported to Custom.
This means that each entry in the options menu acts as if you had customized
the corresponding variable by hand.  ### WARNING: there is currently no
upgrading function to help you port your old options settings to the new
format. Consequently, if you want to modify the options for XEmacs 21, you
will have to set them all again through the menu, and remove the code loading
.xemacs-options from your .emacs.

** When the Zmacs region is active, `M-x query-replace' and the other
replace commands now operate on the region contents only.

** XEmacs now is able to choose X visuals and use private colormaps.
The '-visual <visualStr>' command line option or the '.EmacsVisual'
Xresource controls which visual XEmacs will use, and
'-privateColormap' or '.privateColormap' will force XEmacs to create a
private colormap for use.  The syntax for the visual string is
"<visual><bitdepth>" where <visual> is one of 'StaticColor',
'TrueColor', 'GrayScale', 'PseudoColor' or 'DirectColor' and
<bitdepth> is the appropriate number of bits per pixel.  If an invalid
or non-supported combination is entered, XEmacs attempts to find a happy
medium.  The X creation mechanism will then determine if it needs to
create a colormap for use, or the presence of the private flags will
force it to create it.

** The `imenu' package has been ported to XEmacs and is available as a
package.

** `echo-keystrokes' can now be a floating-point number, so that you
can set it to intervals shorter than one second.

   (setq echo-keystrokes 0.1)

** The new command `center-to-window-line' works like `recenter'
(bound to `C-l'), only it does not redisplay the whole display area.

** The M-. command will now first search through exact tags matches,
and then through inexact matches, as one would expect.

** The new variable `user-full-name' can be used to customize one's
name when using the Emacs mail and news reading facilities.

Normally, `user-full-name' is a function that returns the full name of
a user or UID, as specified by the system -- for instance,
(user-full-name "root") returns something like "Super-User".  However,
when the function is called without arguments, it will return the
value of the `user-full-name' variable.  The `user-full-name' variable
is initialized using the environment variable NAME and (failing that)
the user's system name.

The behavior of the `user-full-name' function with an argument
specified is unchanged.

** The new command `M-x customize-changed-options' lets you customize
all the options whose default values have changed in recent Emacs
versions.  You specify a previous Emacs version number as argument,
and the command creates a customization buffer showing all the
customizable options whose default values were changed since that
version.

If you don't specify a particular version number argument, then the
customization buffer shows all the customizable options for which
Emacs versions of changes are recorded.

** The new command `add-log-convert' can be used to convert the
old-style (pre-20.3) ChangeLog buffers to new style, for
consistency.  A reminder: if you wish to revert to old-style
ChangeLogs instead, customize the value of `add-log-time-format'
variable.

** The new command `zap-up-to-char' is now available.  It is similar
to `zap-to-char', except that it does not delete the searched-for
character.  It is not bound to a key by default.

** You can now store a number into a register with `C-u NUMBER C-x r n'
REG, increment it by INC with `C-u INC C-x r + REG' (to increment by
one, omit C-u INC), and insert it in the buffer with `C-x r g REG'.
This is useful for writing keyboard macros.

** The M-: command, when given a prefix argument, will now insert its
result to the current buffer.

** The `C-h c' command, when given a prefix argument, will now insert
the message into the current buffer.

** Horizontally split windows may now be dragged using the mouse.
Because of this, the dividers between vertical windows are always
visible.  To turn it off, set `vertical-divider-always-visible-p' to
nil.

** XEmacs/Mule (internationalization) changes.

*** Mule support now works on TTY's.  Use `set-terminal-coding-system'
and `set-keyboard-coding-system' to specify the coding system of your
display and keyboard.

*** Egg/SJ3 input method is now officially supported.  Quail and
Egg/Skk have been available through the generalized Leim since 20.3.

*** Localized Japanese menubars are available if XEmacs is built with
XFONTSET and either the X11 libraries are built with X_LOCALE defined
or the native C libraries support Japanese localization.  This has
been available since 20.3, only it hasn't been announced before.

** Jamie Zawinski's `gdb-highlight' extension is now distributed with
the `debug' package.  gdb-highlight makes most objects printed in a
gdb buffer be mouse-sensitive: as text shows up in the buffer, it is
parsed, and objects which are recognized have context-sensitive
commands attached to them.  To use it, add the following to `.emacs':

  (add-hook 'gdb-mode-hook (lambda () (require 'gdb-highlight)))

** The package popper.el is now included in the edit-utils package.
It has been greatly enhanced with respect to the one once included
with the ilisp package and should work well under XEmacs 21.0.

** Gnuserv changes

*** Like the old 'gnudoit' program. Gnuclient -batch now can read from stdin.

*** Gnuclient -batch no longer breaks off the output at the first LF.

** C mode changes

*** Multiline macros are now handled, both as they affect indentation,
and as recognized syntax.  New syntactic symbol cpp-macro-cont is
assigned to second and subsequent lines of a multiline macro
definition.

*** A new style "user" which captures all non-hook-ified
(i.e. top-level) .emacs file variable setings and customizations.
Style "cc-mode" is an alias for "user" and is deprecated.  "gnu" style
is still the default however.

*** "java" style now conforms to Sun's JDK coding style.

*** There are new commands c-beginning-of-defun, c-end-of-defun which
are alternatives which you could bind to C-M-a and C-M-e if you prefer
them.  They do not have key bindings by default.

*** New and improved implementations of M-a (c-beginning-of-statement)
and M-e (c-end-of-statement).

*** C++ namespace blocks are supported, with new syntactic symbols
namespace-open, namespace-close, and innamespace.

*** File local variable settings of c-file-style and c-file-offsets
makes the style variables local to that buffer only.

*** New indentation functions c-lineup-close-paren,
c-indent-one-line-block, c-lineup-dont-change.

*** Improvements (hopefully!) to the way CC Mode is loaded.  You
should now be able to do a (require 'cc-mode) to get the entire
package loaded properly for customization in your .emacs file.  A new
variable c-initialize-on-load controls this and is t by default.

** In Text mode, now only blank lines separate paragraphs.
This makes it possible to get the full benefit of Adaptive Fill mode
in Text mode, and other modes derived from it (such as Mail mode).
TAB in Text mode now runs the command indent-relative; this makes a
practical difference only when you use indented paragraphs.

As a result, the old Indented Text mode is now identical to Text mode,
and is an alias for it.

If you want spaces at the beginning of a line to start a paragraph,
use the new mode, Paragraph Indent Text mode.

** Changes to Gnus, the XEmacs newsreader.

*** New functionality for using Gnus as an offline newsreader has been
added.  A plethora of new commands and modes have been added.  See the
Gnus manual for the full story.

*** The nndraft backend has returned, but works differently than
before.  All Message buffers are now also articles in the nndraft
group, which is created automatically.

*** `gnus-alter-header-function' can now be used to alter header
values.

*** `gnus-summary-goto-article' now accept Message-ID's.

*** A new Message command for deleting text in the body of a message
outside the region: `C-c C-v'.

*** You can now post to component group in nnvirtual groups with
`C-u C-c C-c'.

*** `nntp-rlogin-program' -- new variable to ease customization.

*** `C-u C-c C-c' in `gnus-article-edit-mode' will now inhibit
re-highlighting of the article buffer.

*** New element in `gnus-boring-article-headers' -- `long-to'.

*** `M-i' symbolic prefix command.  See the section "Symbolic
Prefixes" in the Gnus manual for details.

*** `L' and `I' in the summary buffer now take the symbolic prefix
`a' to add the score rule to the "all.SCORE" file.

*** `gnus-simplify-subject-functions' variable to allow greater
control over simplification.

*** `A T' -- new command for fetching the current thread.

*** `/ T' -- new command for including the current thread in the
limit.

*** `M-RET' is a new Message command for breaking cited text.

*** \\1-expressions are now valid in `nnmail-split-methods'.

*** The `custom-face-lookup' function has been removed.
If you used this function in your initialization files, you must
rewrite them to use `face-spec-set' instead.

*** Cancelling now uses the current select method.  Symbolic prefix
`a' forces normal posting method.

*** New command to translate M******** sm*rtq**t*s into proper text
-- `W d'.

*** For easier debugging of nntp, you can set `nntp-record-commands'
to a non-nil value.

*** nntp now uses ~/.authinfo, a .netrc-like file, for controlling
where and how to send AUTHINFO to NNTP servers.

*** A command for editing group parameters from the summary buffer
has been added.

*** A history of where mails have been split is available.

*** A new article date command has been added -- `article-date-iso8601'.

*** Subjects can be simplified when threading by setting
`gnus-score-thread-simplify'.

*** A new function for citing in Message has been added --
`message-cite-original-without-signature'.

*** `article-strip-all-blank-lines' -- new article command.

*** A new Message command to kill to the end of the article has
been added.

*** A minimum adaptive score can be specified by using the
`gnus-adaptive-word-minimum' variable.

*** The "lapsed date" article header can be kept continually
updated by the `gnus-start-date-timer' command.

*** Web listserv archives can be read with the nnlistserv backend.

*** Old dejanews archives can now be read by nnweb.

*** Byte-compilation of user-specs now works under XEmacs.

** The `dir' files are no longer essential for functioning of the Info
subsystem.  If the `dir' file does not exist in an Info directory, the
relevant information will be generated on-the-fly.

This behavior can be customized, look for `Info-auto-generate-directory'
and `Info-save-auto-generated-dir' in the `info' customization group.

\f
* Lisp and internal changes in XEmacs 21.0
==========================================

** It is now possible to build XEmacs with support for 31-bit Lisp
integers (normally, Lisp integers are only 28 bits wide on 32-bit
machines.)  Configure with --use-minimal-tagbits to test.  With this
change, the maximum buffer size on 32-bit machines is increased from
128M to 1G.  This setting will be made default in a future XEmacs
version.

** Specifier changes.

*** When instantiating a specifier, the window locale now has a higher
precedence than the buffer locale.  This is because the window locale
is more specific than the buffer locale.

*** The new macro `let-specifier' can be used to temporarily add
specifications to specifiers.  See the documentation for details.

*** The new specifiers `vertical-scrollbar-visible-p' and
`horizontal-scrollbar-visible-p' may be used to control scrollbar
visibility.  Previously, the only way to remove a scrollbar was to set
its size to 0.  This method is still supported for backward
compatibility.

*** The new specifiers `scrollbar-on-left-p' and `scrollbar-on-top-p'
may be used to control the position of the vertical and horizontal
toolbar.  Previously, their position could be changed only through the
use of X resources.

*** The new draggable vertical dividers between windows may be turned
off using the `vertical-divider-always-visible-p' specifier.  When
this is set to nil, the vertical dividers between windows are shown
only when needed, and they are not draggable.

Other properties of the vertical dividers may be controlled using
`vertical-divider-shadow-thickness', `vertical-divider-line-width' and
`vertical-divider-spacing' specifiers, which see.

** Frame focus management changes.

*** When the variable focus-follows-mouse is non-nil, `select-frame'
no longer permanently selects a different frame.  The frame selection
is temporary and is reverted when the current command terminates, much
like the buffer selected by `set-buffer'.  This is the same as in FSF
Emacs.

*** The new function `focus-frame' sets the window system focus to
FRAME (and selects it), regardless of the value of
`focus-follows-mouse'.  Doing this is not well behaved, so be
absolutely sure that you want this.

The code that uses `select-frame' only to get the window manager focus
should be changed to use `set-frame-focus' instead, so that they keep
working when `focus-follows-mouse' is non-nil.

*** The special forms `save-selected-frame' and `with-selected-frame'
can now be used to temporarily change selected frame.

*** The behavior of `other-frame' command (`C-x 5 o') is unaffected by
these changes.

** The function `select-window' now has an optional second argument
NORECORD which if non-nil inhibits the recording of a buffer change.

** The function `vertical-motion' now correctly handles the second,
optional WINDOW argument.  A new third argument PIXELS, if non-nil,
indicates that the returned motion should be in pixels.

** The new function `vertical-motion-pixels' is similar to
vertical-motion but takes as input a vertical motion in pixels.

** The new functions window-text-area-pixel-{width,height,edges} can
be used to obtain information about the text-displaying area of a
window.

** The new functions `shrink-window-pixels' and `enlarge-window-pixels'
can be used to adjust the size of a window by a pixel amount.

** The new function `window-displayed-text-pixel-height' can be used
to determine the height of the text actually displayed in a window.

** The arithmetic comparison functions <, >, =, /= now accept a
variable number of arguments.

This means that if you want to test whether A < B < C, you can write
it as (< A B C) instead of (and (< A B) (< B C)).  Likewise,
(apply #'> LIST) now tests if LIST is monotonously increasing -- and
so on.

** The XEmacs hashtables now have a consistent read/print syntax.
This means that a hashtable will be readably printed in a
structure-like form:

   #s(hashtable size 2 data (key1 value1 key2 value2))

When XEmacs reads this form, it will create a new hashtable according
to description.  This allows you to easily dump hashtables to files
using `prin1', and read them back in using `read'.

If `print-readably' is non-nil, a more relaxed syntax is used; for
instance:

   #<hashtable size 2/13 data (key1 value1 key2 value2) 0x874d>

** It is now possible to build XEmacs with LDAP support.
You will need to install a LDAP library first.  The following have
been tested:
  - LDAP 3.3 from the University of Michigan
    (get it from <URL:http://www.umich.edu/~dirsvcs/ldap/>)
  - OpenLDAP 1.0.3 from the OpenLDAP Foundation
    (get it from <URL:http://www.openldap.org/>)
  - LDAP SDK 1.0 from Netscape Corp.
    (get it from <URL:http://developer.netscape.com/>)

** When profiling is in effect, a call-count of all recorded functions
is now calculated.  This information is stored in
`call-count-profile-table', and is utilized by `profile-results' as
well as the new command `profile-call-count-results'.

** It is now an error to change the value of a symbol whose name
starts with a colon, if it is interned in the standard obarray.

However, setting such a symbol to its proper value, which is that
symbol itself, is not an error.  This is for the sake of programs that
support pre-19.12 XEmacs and pre-20 GNU Emacs by explicitly setting
these variables to themselves.

** The `concat' function no longer accepts integer arguments.

** The new function `string' concatenates all its argument characters
and returns the resulting string.  This is consistent with other
functions, like `list', `vector', etc.

** The function `temp-directory' is now available to return the
directory to store temporary files.  On Unix this will be obtained
from TMPDIR, defaulting to `/tmp'.

** The function load-average now accepts an optional argument
USE-FLOATS.  If it is non-nil, the load average values are returned as
floating point numbers, rather than as integers to be divided by 100.

** The `make-event' function now supports the TYPE and PLIST
arguments, which can be used to create various events from Lisp.  See
the documentation for details.

** `function-interactive' is a new function that returns the
interactive specification of a funcallable object.

** The new `lmessage' function allows printing of a formatted message
with a particular label.

   (lmessage 'progress "Processing... %d" counter)

This function is more convenient than `display-message' because it
automatically applies `format' to its arguments.

** The new `lwarn' function, analogous to `lmessage', allows printing
a formatted warning, with a non-default CLASS or LABEL.

** The new function `split-path' can now be used to explode the
components of a colon-separated search path into a list.

   (split-path "foo:bar")
     => ("foo" "bar")

** Specifiers and symbols whose value is a specifier are now allowed
as modeline specifications.

** defcustom now accepts the keyword `:version'.  Use this to specify
in which version of Emacs a certain variable's default value changed.
For example,

   (defcustom foo-max 34 "*Maximum number of foo's allowed."
     :type 'integer
     :group 'foo
     :version "21.0")

This information is used to control the customize-changed-options
command.

** The line number tracking in modeline is now efficient, even for
very large buffers.  This is achieved by caching the line numbers of
recent buffer positions, and reusing them.  This cache is used only in
the buffers where `line-number-mode' is in effect.

** When the new GNU Malloc aka Doug Lea Malloc is available, it will
be used.  This should result in better performance on Linux systems
with libc6.

** The code XEmacs uses to assemble its various paths into the
directory hierarchy has been rewritten to support the package system.
Look under "Startup Paths" in the Info documentation for more
information.

*** site-lisp is no longer part of the load-path by default.
Its use is deprecated, but you can specify --with-site-lisp=yes at the
configure command line to get it back.

*** `Info-default-directory-list' is now obsolete.  If you want to
change the path which XEmacs uses to search for info files, set
`Info-directory-list' instead.

\f
* For older news, see the file ONEWS.