Merge from mainline.

[bpt/emacs.git] / etc / NEWS.23

GNU Emacs NEWS -- history of user-visible changes.

Copyright (C) 2007-2011 Free Software Foundation, Inc.
See the end of the file for license conditions.

Please send Emacs bug reports to bug-gnu-emacs@gnu.org.
If possible, use M-x report-emacs-bug.

This file is about changes in Emacs version 23.

See files NEWS.22, NEWS.21, NEWS.20, NEWS.19, NEWS.18, and NEWS.1-17
for changes in older Emacs versions.

You can narrow news to a specific version by calling `view-emacs-news'
with a prefix argument or by typing C-u C-h C-n.

\f
* Installation Changes in Emacs 23.3

** New configure option --with-crt-dir specifies the location of your
crt*.o files, if they are in a non-standard location.  This is only
used on x86-64 and s390x GNU/Linux architectures.

* Changes in Emacs 23.3

** The last-resort backup file `%backup%~' is now written to
`user-emacs-directory', instead of the user's home directory.

** If Emacs creates `user-emacs-directory', that directory's
permissions are now set to rwx------, ignoring the umask.

\f
* Changes in Specialized Modes and Packages in Emacs 23.3

** Calendar and diary

*** The appt-add command takes an optional argument, the warning time.
This can be used in place of the default appt-message-warning-time.

** Python mode

*** You can allow inferior Python processes to load modules from the
current directory by setting `python-remove-cwd-from-path' to nil.

** Rmail

*** The default value of `rmail-enable-mime' is now t.  Rmail decodes
MIME contents automatically.  You can customize the variable
`rmail-enable-mime' back to `nil' to disable this automatic MIME
decoding.

*** The command `rmail-mime' change the displaying of a MIME message
between decoded presentation form and raw data if `rmail-enable-mime'
is non-nil.  And, with prefix argument, it change only the displaying
of the MIME entity at point.

*** The new command `rmail-mime-next-item' (bound to TAB) moves point
to the next item of MIME message.

*** The new command `rmail-mime-previous-item' (bound to backtab) moves
point to the previous item of MIME message.

*** The new command `rmail-mime-toggle-hidden' (RET) hide or show the
body of the MIME entity at point.

** VC and related modes

*** New VC command `vc-log-incoming', bound to `C-x v I'.
This shows a log of changes to be received with a pull operation.
For Git, this runs "git fetch" to make the necessary data available
locally; this requires version 1.7 or newer.

*** New VC command `vc-log-outgoing', bound to `C-x v O'.
This shows a log of changes to be sent in the next commit.

*** New VC command vc-find-conflicted-file.

*** The 'g' key in VC diff, log, log-incoming and log-outgoing buffers
reruns the corresponding VC command to compute an up to date version
of the buffer.

*** vc-dir for Bzr supports viewing shelve contents and shelving snapshots.

*** Special markup can be added to log-edit buffers.
You can add headers specifying additional information to be supplied
to the version control system.  For example:

  Author: J. R. Hacker <jrh@example.com>
  Fixes: 4204
  Actual text of log entry...

Bazaar recognizes the headers "Author", "Date" and "Fixes".
Git, Mercurial, and Monotone recognize "Author" and "Date".
Any unknown header is left as is in the message, so it is not lost.

** Obsolete packages

*** lmenu.el and cl-compat.el are now obsolete.

\f
* New Modes and Packages in Emacs 23.3

** smie.el is a generic navigation and indentation engine.
It takes a simple BNF description of the grammar, and provides both
sexp-style navigation (jumping over begin..end pairs) as well as
indentation, which can be adjusted via ad-hoc indentation rules.

\f
* Incompatible Lisp Changes in Emacs 23.3

** posn-col-row now excludes the header line from the row count
If the frame has a header line, posn-col-row will count row numbers
starting from the first line of text below the header line.

\f
* Lisp changes in Emacs 23.3

** `e' and `pi' are now called `float-e' and `float-pi'.
  The old names are obsolete.

** The use of unintern without an obarray arg is now obsolete.

** The function `princ-list' is now obsolete.

** The yank-handler argument to kill-region and friends is now obsolete.

** New function byte-to-string, like char-to-string but for bytes.

\f
* Changes in Emacs 23.3 on non-free operating systems

** The nextstep port can have different modifiers for the left and right
alt/option key by customizing the value for ns-right-alternate-modifier.

\f
* Installation Changes in Emacs 23.2

** New configure options for Emacs developers.
These are not new features; only the configure flags are new.

*** --enable-profiling builds Emacs with profiling enabled.
This might not work on all platforms.

*** --enable-checking[=OPTIONS] builds emacs with extra runtime checks.

** `make install' now consistently ignores umask, creating a
world-readable install.

** Emacs compiles with Gconf support, if it is detected.
Use the configure option --without-gconf to disable this.
This is used by the `font-use-system-font' feature (see below).

* Startup Changes in Emacs 23.2

** The command-line option -Q (--quick) also inhibits loading X resources.
However, if Emacs is compiled with the Lucid or Motif toolkit, X
resource settings for the graphical widgets are still applied.
On Windows, the -Q option causes Emacs to ignore Registry settings,
but environment variables set on the Registry are still honored.

*** The new variable `inhibit-x-resources' shows whether X resources
were loaded.

** New command-line option -mm (--maximized) maximizes the initial frame.

* Changes in Emacs 23.2

** The maximum size of buffers (and the largest fixnum) is doubled.
On typical 32bit systems, buffers can now be up to 512MB.

** The default value of `trash-directory' is now nil.
This means that `move-file-to-trash' trashes files according to
freedesktop.org specifications, the same method used by the Gnome,
KDE, and XFCE desktops.  (This change has no effect on Windows, which
uses `system-move-file-to-trash' for trashing.)

** The pointer now becomes invisible when typing.
Customize `make-pointer-invisible' to disable this feature.

** Font changes

*** Emacs can use the system default monospaced font in Gnome.
To enable this feature, set `font-use-system-font' to non-nil (it is
nil by default).  If the system default changes, Emacs changes also.
This feature requires Gconf support, which is automatically included
at compile-time if configure detects the gconf libraries (you can
disable this with the configure option --without-gconf).

*** On X11, Emacs reacts to Xft changes made by configuration tools,
via the XSETTINGS mechanism.  This includes antialias, hinting,
hintstyle, RGBA, DPI and lcdfilter changes.

** Killing a buffer with a running process now asks for confirmation.
To remove this query, remove `process-kill-buffer-query-function' from
`kill-buffer-query-functions', or set the appropriate process flag
with `set-process-query-on-exit-flag'.

** File-local variable changes

*** Specifying a minor mode as a local variables enables that mode,
unconditionally.  The previous behavior, toggling the mode, was
neither reliable nor generally desirable.

*** There are new commands for adding and removing file-local variables:
`add-file-local-variable', `delete-file-local-variable',
`add-file-local-variable-prop-line', and
`delete-file-local-variable-prop-line'.

*** There are new commands for adding and removing directory-local variables,
and copying them to and from file-local variable lists:
`add-dir-local-variable', `delete-dir-local-variable',
`copy-dir-locals-to-file-locals',
`copy-dir-locals-to-file-locals-prop-line' and
`copy-file-locals-to-dir-locals'.

** Internationalization changes

*** Unibyte sessions are now considered obsolete.
This refers to the EMACS_UNIBYTE environment variable as well as the
--unibyte, --multibyte, --no-multibyte, and --no-unibyte command line
arguments.  Customizing enable-multibyte-characters and setting
default-enable-multibyte-characters are also deprecated.

*** New coding system `utf-8-hfs'.
This is suitable for default-file-name-coding-system on Mac OS X; see
international/ucs-normalize.el.

** Function arguments in *Help* buffers are now shown in upper-case.
Customize `help-downcase-arguments' to t to show them in lower-case.

** New command `async-shell-command', bound globally to `M-&'.
This executes the command asynchronously, similar to calling `M-!' and
manually adding an ampersand to the end of the command.  With `M-&',
you don't need the ampersand.  The output appears in the buffer
`*Async Shell Command*'.

** When running in a new enough xterm (newer than version 242), Emacs
asks xterm what the background color is and it sets up faces
accordingly for a dark background if needed (the current default is to
consider the background light).

\f
* Editing Changes in Emacs 23.2

** Kill-ring and selection changes

*** If `select-active-regions' is t, any active region automatically
becomes the primary selection (for interaction with other window
applications).  If you enable this, you might want to bind
`mouse-yank-primary' to Mouse-2.

*** When `save-interprogram-paste-before-kill' is non-nil, the kill
commands save the interprogram-paste selection into the kill ring
before doing anything else.  This avoids losing the selection.

*** When `kill-do-not-save-duplicates' is non-nil, identical
subsequent kills are not duplicated in the `kill-ring'.

** Completion changes

*** The new command `completion-at-point' provides mode-sensitive completion.

*** tab-always-indent set to `complete' lets TAB do completion as well.

*** The new completion-style `initials' is available.
For instance, this can complete M-x lch to list-command-history.

*** The new variable `completions-format' determines how completions
are displayed in the *Completions* buffer.  If you set it to
`vertical', completions are sorted vertically in columns.

** The default value of `blink-matching-paren-distance' is increased.

** M-n provides more default values in the minibuffer for commands
that read file names.  These include the file name at point (when ffap
is loaded without ffap-bindings), the file name on the current line
(in Dired buffers), and the directory names of adjacent Dired windows
(for Dired commands that operate on several directories, such as copy,
rename, or diff).

** M-r is bound to the new `move-to-window-line-top-bottom'.
This moves point to the window center, top and bottom on successive
invocations, in the same spirit as the C-l (recenter-top-bottom)
command.

** The new variable `recenter-positions' determines the default
cycling order of C-l (`recenter-top-bottom').

** The abbrevs file is now a file named abbrev_defs in
user-emacs-directory; but the old location, ~/.abbrev_defs, is used if
that file exists.

\f
* Changes in Specialized Modes and Packages in Emacs 23.2

** The bookmark menu has a narrowing search via bookmark-bmenu-search.

** Calc

*** The Calc settings file is now a file named calc.el in
user-emacs-directory; but the old location, ~/.calc.el, is used if
that file exists.

*** Graphing commands (`g f' etc.) now work on MS-Windows, if you have
the native Windows port of Gnuplot version 3.8 or later installed.

** Calendar and diary

*** Fancy diary display is now the default.
If you prefer the simple display, customize `diary-display-function'.

*** The diary's fancy display now enables view-mode.

*** The command `calendar-current-date' accepts an optional argument
giving an offset from today.

** Desktop

*** The default value for `desktop-buffers-not-to-save' is nil.
This means Desktop will try restoring all buffers, when you restart
your Emacs session.  Also, `desktop-buffers-not-to-save' is only
effective for buffers that have no associated file.  If you want to
exempt buffers that do correspond to files, customize the value of
`desktop-files-not-to-save' instead.

** Dired

*** The new variable `dired-auto-revert-buffer', if non-nil, causes
Dired buffers to be reverted automatically on revisiting them.

** DocView

*** When `doc-view-continuous' is non-nil, scrolling a line
on the page edge advances to the next/previous page.

** Elint

*** Elint now uses compilation-mode.

*** Elint can now scan individual files and whole directories,
and can be run in batch mode.

*** Elint does a more thorough initialization, and recognizes more built-in
functions and variables.  Customize `elint-scan-preloaded' if you want
to sacrifice some accuracy for a faster startup.

*** Elint attempts some basic understanding of featurep and (f)boundp tests.

*** Customize `elint-ignored-warnings' to suppress some warnings.

** GDB-UI

*** Toolbar functionality for reverse debugging.  Display of STL
collections as watch expressions.  These features require GDB 7.0 or later.

** Grep

*** A new command `zrgrep' searches recursively in gzipped files.

** Info

*** The new command `Info-virtual-index' bound to "I" displays a menu of
matched topics found in the index.

*** The new command `info-finder' replaces finder.el with a virtual Info
manual that generates an Info file which gives the same information
through a menu structure.

** LaTeX mode now provides completion (via completion-at-point).

** Message mode is now the default mode for composing mail.

The default for `mail-user-agent' is now message-user-agent, so the
C-x m (`compose-mail') command uses Message mode instead of Mail mode.

Message mode has been included in Emacs, as part of the Gnus package,
for several years.  It provides several features that are absent in
Mail mode, such as MIME handling.

*** If the user has not customized mail-user-agent, `compose-mail'
checks for Mail mode customizations, and issues a warning if these
customizations are found.  This alerts users who may otherwise be
unaware that their mail configuration has changed.

To disable this check, set compose-mail-user-agent-warnings to nil.

** The default value of mail-interactive is t, since Emacs 23.1.
(This was not announced at the time.)  It means that when sending mail,
Emacs will wait for the process sending mail to return.  If you
experience delays when sending mail, you may wish to set this to nil.

** nXML mode is now the default for editing XML files.

** pcomplete provides a new command `pcomplete-std-completion' which
is similar to `pcomplete' but using the standard completion UI code.

** Shell (and other comint modes)

*** M-s is no longer bound to `comint-next-matching-input'.

*** M-r is now bound to `comint-history-isearch-backward-regexp'.
This starts an incremental search of the comint/shell input history.

*** ansi-color is now enabled by default in Shell mode.
To disable it, set ansi-color-for-comint-mode to nil.

** Tramp

*** New connection methods "rsyncc", "imap" and "imaps".
On systems which support GVFS-Fuse, Tramp offers also the new
connection methods "dav", "davs", "obex" and "synce".

** VC and related modes

*** When using C-x v v or C-x v i on a unregistered file that is in a
directory not controlled by any VCS, ask the user what VC backend to
use to create a repository, create a new repository and register the
file.

*** New command `vc-root-print-log', bound to `C-x v L'.
This displays a `*vc-change-log*' buffer showing the history of the
version-controlled directory tree as a whole.

*** New command `vc-root-diff', bound to `C-x v D'.
This is similar to `vc-diff', but compares the entire directory tree
of the current VC directory with its working revision.

*** `C-x v l' and `C-x v L' do not show the full log by default.
The number of entries shown can be chosen interactively with a prefix
argument, or by customizing vc-log-show-limit.  The `*vc-change-log*'
buffer now contains buttons at the end of the buffer, which can be
used to increase the number of entries shown.  RCS, SCCS, and CVS do
not support this feature.

*** vc-annotate supports annotations through file copies and renames,
it displays the old names for the files and it can show logs/diffs for
the corresponding lines.  Currently only Git and Mercurial take
advantage of this feature.

*** The log command in vc-annotate can display a single log entry
instead of redisplaying the full log.  The RCS, CVS and SCCS VC
backends do not support this.

*** When a file is not found, VC will not try to check it out of RCS anymore.

*** Diff and log operations can be used from Dired buffers.

*** vc-git changes

**** The short log format for git makes use of the graph display,
so it's not supported on git versions earlier than 1.5.6.

**** vc-dir uses the --relative option of git, and so requires at least
git version 1.5.5.

**** Support for operating with stashes has been added to vc-dir:
the stash list is displayed in the *vc-dir* header, stashes can be
created, removed, applied and their content displayed.

*** vc-bzr supports operating with shelves: the shelve list is
displayed in the *vc-dir* header, shelves can be created, removed and applied.

*** log-edit-strip-single-file-name controls whether or not single filenames
are stripped when copying text from the ChangeLog to the *VC-Log* buffer.

** Miscellaneous

*** Interactively `multi-isearch-buffers' and `multi-isearch-buffers-regexp'
read buffer names to search, one by one, ended with RET.  With a prefix
argument, they ask for a regexp, and search in buffers whose names match
the specified regexp.  Interactively `multi-isearch-files' and
`multi-isearch-files-regexp' read file names to search, one by one,
ended with RET.  With a prefix argument, they ask for a wildcard, and
search in file buffers whose file names match the specified wildcard.

*** Autorevert Tail mode now works also for remote files.

*** The new eshell built-in commands `su' and `sudo' support Tramp.
Thus, they change `default-directory' to reflect the new user id, and
let commands run under that user's permissions.  This works even when
`default-directory' is already remote.  Calling the external commands
is possible via `*su' or `*sudo', respectively.

** Obsolete packages

*** sym-comp.el is now obsolete, superseded by completion-at-point.

*** lucid.el and levents.el are now obsolete.

\f
* New Modes and Packages in Emacs 23.2

** CEDET (the Collection of Emacs Development Tools) is now in Emacs.
This is a collection of packages to aid with using Emacs as an IDE
(integrated development environment):

*** The Semantic package allows the use of parsers to intelligently
edit and navigate source code.  Parsers for C/C++, Java, Javascript,
and several other languages are included by default, and Semantic can
also interface with external tools such as GNU Global and GNU Idutils.

To enable Semantic, use the global minor mode `semantic-mode'.
See the Semantic manual for details.

*** EDE (Emacs Development Environment) is a package for managing code
projects, including features such as automatic Makefile generation.

To enable EDE, use the minor mode `global-ede-mode'.
See the EDE manual for details.

*** SRecode is a library for recoding Semantic tags back into source
code.  It is currently used by some parts of Semantic and EDE; in the
future, it may be used for code generation features.

*** The EIEIO library implements a subset of the Common Lisp Object
System (CLOS).  It is used by the other CEDET packages.

** mpc.el is a front end for the Music Player Daemon.  Run it with M-x mpc.

** htmlfontify.el turns a fontified Emacs buffer into an HTML page.

** js.el is a new major mode for JavaScript files.

** imap-hash.el is a new library to address IMAP mailboxes as hashtables.

\f
* Incompatible Lisp Changes in Emacs 23.2

** The Lisp reader turns integers that are too large/small into floats.
For instance, on machines where `536870911' is the largest integer,
reading `536870912' gives the floating-point object `536870912.0'.

This change only concerns the Lisp reader; it does not affect how
actual integer objects overflow.

** Several obsolete functions removed.
The functions have been obsolete since Emacs 19, and are unlikely to
be in use:

  time-stamp-month-dd-yyyy, time-stamp-dd/mm/yyyy, time-stamp-mon-dd-yyyy
  time-stamp-dd-mon-yy, time-stamp-yy/mm/dd, time-stamp-yyyy/mm/dd,
  time-stamp-yyyy-mm-dd, time-stamp-yymmdd, time-stamp-hh:mm:ss,
  time-stamp-hhmm, baud-rate

** Support for generating Emacs 18 compatible bytecode (by setting
the variable `byte-compile-compatibility') has been removed.

** In image-mode.el `image-mode-maybe' is obsolete.
Instead, you can either use `image-mode' (which displays an image file
as the actual image initially), or `image-mode-as-text' (when you want
to display an image file as text initially).  `image-mode-as-text' is a
combination of a non-image mode from `auto-mode-alist' (or Fundamental
mode) and `image-minor-mode'.  `image-minor-mode' provides a `C-c C-c'
key binding to toggle image display.
`image-toggle-display-text' removes image properties.
`image-toggle-display-image' adds image properties.
`image-toggle-display' toggles between `image-mode-as-text' and `image-mode'.

\f
* Lisp changes in Emacs 23.2

** All the default-FOO variables that hold the default value of the FOO
variable, are now declared obsolete.

** read-key is a function halfway between read-event and read-key-sequence.
It reads a single key, but obeys input and escape sequence decoding.

** Frame parameter changes

*** You can give the `fullscreen' frame parameter the value `maximized'.
This maximizes the frame.

*** The new frame parameter `sticky' makes Emacs frames sticky in
virtual desktops.

** Completion changes

*** completion-base-size is obsoleted by completion-base-position.
This change causes a few backward incompatibilities, mostly with
choose-completion-string-functions where the `mini-p' argument has
been replaced by a `base-position' argument, and where the `base-size'
argument is now always nil.

*** New function `completion-in-region' to use the standard completion
facilities on a particular region of text.

*** The 4th arg to all-completions (aka hide-spaces) is declared obsolete.

*** completion-annotate-function specifies how to compute annotations
for completions displayed in *Completions*.

** Minibuffer changes

*** read-file-name-predicate is obsolete.  It was used to pass the predicate
to read-file-name-internal because read-file-name-internal abused its `pred'
argument to pass the current directory, but this hack is not needed
any more.

** Changes to file-manipulation functions

*** `delete-directory' has an optional parameter RECURSIVE.

*** New function `copy-directory', which copies a directory recursively.

** called-interactively-p now takes one argument and replaces interactive-p
which is now marked obsolete.

** New function set-advertised-calling-convention makes it possible
to obsolete arguments as well as make some arguments mandatory.

** You can control which binding is preferentially shown in menus and
docstrings by adding a `:advertised-binding' property to the corresponding
command's symbol.  That property can hold a single binding or a list
of bindings.

** Network and process changes

*** start-process-shell-command and start-file-process-shell-command
now only take a single `command' argument.

*** The new variable `process-file-side-effects' should be set to nil
if a `process-file' call does not change a remote file.  This allows
file name handlers such as Tramp to optimizations.

*** make-network-process can now also create `seqpacket' Unix sockets.

** Loading changes

*** eval-next-after-load is obsolete.

*** New hook `after-load-functions' run after loading an Elisp file.

** Byte compilation changes

*** Changing the file-names generated by byte-compilation by redefining
the function `byte-compile-dest-file' before loading bytecomp.el is obsolete.
Instead, customize byte-compile-dest-file-function.

*** `byte-compile-warnings' has new members, `constants' and `suspicious'.

** New macro with-silent-modifications to tweak text properties without
affecting the buffer's modification state.

** Hash tables have a new printed representation that is readable.
The feature `hashtable-print-readable' identifies this new
functionality.

** New functions for performing Unicode normalization:
ucs-normalize-NFD-region, ucs-normalize-NFD-string,
ucs-normalize-NFC-region, ucs-normalize-NFC-string,
ucs-normalize-NFKD-region, ucs-normalize-NFKD-string,
ucs-normalize-NFKC-region, ucs-normalize-NFKC-string,
ucs-normalize-HFS-NFD-region, ucs-normalize-HFS-NFD-string,
ucs-normalize-HFS-NFC-region, ucs-normalize-HFS-NFC-string.

** Face aliases can now be marked as obsolete, using the macro
`define-obsolete-face-alias'.

** New function `window-full-height-p', analogous to the full-width version.

\f
* Changes in Emacs 23.2 on non-free operating systems

** On MS-Windows, `display-time' now displays the system load average
as well as the time, as it does on GNU and Unix.

\f
* Installation Changes in Emacs 23.1

** The default X toolkit is now Gtk+, rather than Lucid.
The configure option `--with-gtk' has been removed.  Gtk is now the
default toolkit, but you can use --with-x-toolkit=gtk if necessary.

** New font code.
Fonts are handled by new code capable of dealing with multiple font
backends.  This uses the freetype and fontconfig libraries.

*** Emacs now accepts font names supplied in the fontconfig format
(e.g. "monospace-12:bold") and GTK format (e.g. "Monospace Bold 12").

*** Added support for local fonts (fonts installed on the machine
where Emacs is running).

*** Added support for the Xft library for antialiasing.

*** Added support for the otf library for complex text layout by
OpenType fonts.

*** Added support for the m17n library for text shaping.

** Changes to image support

*** configure now checks for libgif before libungif when searching for
a GIF library.

*** Emacs now supports the SVG image format through librsvg2.

*** Emacs now supports multi-page TIFF images.

** New NeXTSTEP-based port.
This provides support for GNUstep (via the GNUstep libraries) and Mac
OS X (via the Cocoa libraries).

Specify --with-ns to configure for this.  By default, a self-contained
app will be built (containing all lisp).  To install/share lisp with
other emacsen (e.g. X11 build) use --disable-ns-self-contained.  See
nextstep/README and nextstep/INSTALL in the Emacs source directory.

** Mac OS X is no longer supported via Carbon.
Use the NeXTSTEP port, described above.

** The new configuration option "--with-dbus" enables D-Bus language
bindings for Emacs.

** Support for many obsolete platforms has been removed.
See the list at the end of etc/MACHINES for details.

*** Support for systems without alloca has been removed.

*** Support for Sun windows has been removed.

*** The `emacstool' utility has been removed.

** The following platforms will be removed in a future Emacs version:
If you are still using Emacs on one of these platforms, please email
emacs-devel@gnu.org to inform the Emacs developers.

*** Old GNU/Linux systems based on libc version 5.

*** Old FreeBSD, NetBSD, and OpenBSD systems based on the COFF
executable format.

*** Solaris versions 2.6 and below.

*** Solaris on IBM RS6000 machines.

*** UNIX System V (the original SysV, not later platforms based on it).

*** Unixware on non-x86 machines.

*** Platforms not supporting shared libraries (i.e., requiring the
NO_SHARED_LIBS compilation flag).

** The configure options `--with-gcc', `--without-gcc' have been removed.
Configure will use gcc by default.  Set the CC environment variable if
you need control over which C compiler is used.

** The refcards are now shipped as PDF files.

** The manuals are now licensed under the GNU Free Documentation License v1.3,
or any later version.

** Emacs 23 comes with a new set of default icons.
Various resolutions are available as etc/images/icons/hicolor/*/apps/emacs.png.
The Emacs 22 icon is available as `emacs22.png' in the same location.
\f
* Changes in Emacs 23.1

** Improved X Window System support

*** Emacs now supports using both X displays and ttys in one session.
With an Emacs server active (M-x server-start), `emacsclient -t'
creates a tty frame connected to the running emacs server.  You can
use any number of different ttys.  `emacsclient -c' creates a new X11
frame on the current $DISPLAY (or a tty frame if $DISPLAY is not set).
There may be problems if a display exits unexpectedly and Emacs is compiled
with Gtk+, see etc/PROBLEMS.

You can test for the presence of this feature in your Lisp code by
testing for the `multi-tty' feature.

*** Emacs starts in the background, as a daemon, when given the
--daemon command line argument.  It disconnects from the terminal and
starts the server.  Clients can connect and create graphical or
terminal frames using emacsclient.

**** emacsclient starts emacs in daemon mode and connects to it when
--alternate-editor="" is used (or when the evironment variable
ALTERNATE_EDITOR is set to "") and emacsclient cannot connect to an
emacs server.

*** The new command close-display-connection closes a connection to a
remote display.  There are some bugs for Gtk+.  See etc/PROBLEMS.

*** Emacs now supports the XEmbed specification.
You can embed Emacs in another application on X11.  The new command line
option --parent-id is used to pass the parent window id to Emacs.  See
http://standards.freedesktop.org/xembed-spec/xembed-spec-latest.html
for details about XEmbed.

*** Emacs can now set the frame opacity.
The opacity of a frame can be controlled by setting the `alpha' frame
parameter.  This only takes effect on a compositing window manager for
the X Window System, such as Compiz, Beryl and Compiz Fusion, on Mac
OS X, or on Windows 2000 and later versions of Windows.

The alpha parameter should be an integer between 0 (transparent) and
100 (opaque), or a float number between 0.0 and 1.0.  It can also be a
cons cell (ACTIVE . INACTIVE), where ACTIVE is the opacity of an
active frame and INACTIVE is the opacity of non-active frames.

The variable `frame-alpha-lower-limit' defines a lower bound for the
opacity; the default is 20.

** Internationalization changes

*** The Emacs character set is now a superset of Unicode.
(It has about four times the code space, which should be plenty).

The internal encoding used for buffers and strings is now
Unicode-based and called `utf-8-emacs' (`emacs-internal' is an alias
for this).  This encoding is backward-compatible with Unicode's UTF-8
encoding.  The internal encoding previously used by Emacs,
`emacs-mule', is still available for reading and writing files.

During byte-compilation, Emacs 23 uses `utf-8-emacs' to write files.
As a result, byte-compiled files containing non-ASCII characters can't
be read by earlier versions of Emacs.  Files compiled by Emacs 20, 21,
or 22 are loaded correctly as `emacs-mule' (whether or not they
contain multibyte characters).  This takes somewhat more time, so it
may be worth recompiling existing .elc files which don't need to be
shared with older Emacsen.

*** There are new coding systems/aliases; see M-x list-coding-systems.

*** There is a new charset implementation with many new charsets.
See M-x list-character-sets.  New charsets can be defined conveniently
as tables of unicodes.

*** There are new language environments for Chinese-GBK,
Chinese-GB18030, Khmer, Bengali, Punjabi, Gujarati, Oriya, Telugu,
Sinhala, and TaiViet.

*** The minor modes unify-8859-on-encoding-mode and
unify-8859-on-decoding-mode are obsolete.

*** `ucs-insert' is bound to `C-x 8 RET' and in addition to hex numbers
accepts numbers in hash notation (e.g. #o21430 for octal, or #10r8984 for
decimal).  It also accepts Unicode character names with completion.

*** The `cyrillic-translit' input method supports many new characters.
Common typographical characters available from Unicode were added to
`cyrillic-translit': punctuation marks, accented characters, fractions,
and others.

** Emacs now supports serial port access on GNU/Linux, Unix, and
Windows.  The new command `serial-term' starts an interactive terminal
on a serial port.  The serial port can be configured at runtime with
the mode-line mouse menu.

** Menu Bar changes

*** In the Options menu, the "Set Default Font" item applies the
selected font to the `default' face on all frames, not just the
current frame.  Furthermore, if Emacs is compiled with both GTK and
Fontconfig support, the "Set Default Font" item uses the GTK font
selection dialog instead of an Emacs pop-up menu.

*** The font setting chosen by "Set Default Font" is saved if the
"Save Options" item is used.

*** The Tools menu contains a new Encryption/Decryption submenu.
This contains commands provided by EasyPG, the newly-included
interface to GnuPG (see New Modes and Packages).

*** In the Options menu, the "Truncate Long Lines in the Buffer" entry
has been replaced with a submenu offering three different ways to
handle long lines: truncation, continuation at the window edge, and
the new word wrapping behavior (see Editing Changes, below).

*** Improvements to menus for major and minor modes
More major and minor modes now have a mode specific menu, and existing
mode menus have been improved to include more functionality.

** Mode-line changes

*** The mode-line displays a `@', instead of `-', if the
default-directory for the current buffer is on a remote machine.

*** The mode-line displays a mode menu when mouse-1 is clicked on a
minor mode, in the same way as it already did for major modes.

*** The `mode-line-emphasis' face is used to highlight certain
mode-line information (e.g. waiting for a VC command to finish).

*** The mode-line tooltips have been improved to provide more details.

*** The VC, line/colum number and minor mode indicators on the mode
line are now interactive: mouse-1 can be used on them to pop up a menu.

** File deletion can make use of the Recycle Bin or system Trash folder.
Set `delete-by-moving-to-trash' non-nil to use this.  Deleted files
and directories will then be sent to the Recycle Bin on Windows, and
to `trash-directory' on other systems.

** Directory-local variables can now be defined.
By default, Emacs looks in .dir-locals.el for directory-local
variables.  For more information, see `dir-locals-set-directory-class'
and `dir-locals-set-class-variables'.

** Emacs can now use `auth-source' for authentication.
`smtpmail' and `url' (Tramp and Gnus also) use `auth-source' to obtain
login names and passwords.  The match, if found, is reported
in *Messages* with the password blanked out.

** `where-is-preferred-modifier' can specify your favorite modifier.

\f
* Startup Changes in Emacs 23.1

** The option `inhibit-startup-screen' (with aliases to old names
`inhibit-splash-screen' and `inhibit-startup-message') doesn't inhibit
display of the initial message in the *scratch* buffer.  If you don't
want to display the initial message in the *scratch* buffer at startup,
you can set the option `initial-scratch-message' to nil.

** New user option `initial-buffer-choice' specifies what to display
after starting Emacs: startup screen, *scratch* buffer, visiting a
file or directory.

** New alias `argv' for `command-line-args-left'
This is a convenience alias, so that one can write `(pop argv)'
inside of --eval command line arguments in order to access
following arguments.

** The abbrev file is no longer read at startup in batch mode.

** Emacs now supports invocation by an X session manager.
It can save a session and restore it later.  See the documentation of
the functions `emacs-session-save' and `emacs-session-restore'.
(Actually, this feature was introduced with Emacs 22, but it was not
documented.)
\f
* Incompatible Editing Changes in Emacs 23.1

** In Dired, `dired-flag-garbage-files' is rebound from `&' to `%&'
on the regexp command prefix map.

** In Dired-x, all command guesses for ! are now added to the default
list accessible by M-n instead of pushing all guesses temporarily into
the history list.

** In Isearch mode, a special case of typing `C-w' at the beginning of
the minibuffer that toggles word search (i.e. using key sequences
`C-s RET C-w' or `C-s M-e C-w') is obsolete.  You can use the global key
`M-s w' to start word search, or type `M-s w' in Isearch mode to
toggle word search.  To start nonincremental word search you can now use
`M-s w RET' and `M-s w C-r RET' instead of `C-s RET C-w' and `C-r RET C-w'.

** In Info, `Info-search' is unbound from `M-s' to allow using `M-s w'
for word search as well as other search commands from the global prefix
key `M-s'.  `Info-search' is still bound to `s', and also incremental
search commands `C-s', `C-M-s', `C-r', `C-M-r' are available for searching
through multiple Info nodes, together with their nonincremental versions
`C-s RET', `C-r RET', `C-M-s RET', `C-M-r RET', `M-s w RET'.

** In Text mode, `center-line' and `center-paragraph' are rebound from
`M-s' and `M-S' to global keys `M-o M-s' and `M-o M-S' on the global
prefix map `M-o', which is intended for such formatting commands.

** The following input methods were removed in Emacs 22.2, but this was
not advertised: danish-alt-postfix, esperanto-alt-postfix,
finnish-alt-postfix, german-alt-postfix, icelandic-alt-postfix,
norwegian-alt-postfix, scandinavian-alt-postfix, spanish-alt-postfix,
and swedish-alt-postfix.  Use the versions without "alt-", which are
identical.

\f
* Editing Changes in Emacs 23.1

** The C-n and C-p line-motion commands now move by screen lines,
taking continued lines and variable-width characters into account.
Setting `line-move-visual' to nil reverts this to the previous
behavior (i.e., motion by logical lines based on buffer contents
alone).

** C-x C-c now invokes `save-buffers-kill-terminal', and C-z now
invokes `suspend-frame'.  These changes are for compatibility with the
new multi-tty support (see `Improved X Window System support' above).

** Mark changes

*** Transient Mark mode is now on by default.

*** mark-even-if-inactive now defaults to t

*** When Transient Mark mode is on, C-SPC C-SPC pushes a mark without
activating it.

*** When Transient Mark mode is on, M-q now fills the region if the
region is active.  Otherwise, it fills the current paragraph.

*** When Transient Mark mode is on, M-$ now checks spelling of the
region if the region is active.  Otherwise, it checks spelling of the
word at point.

*** When Transient Mark mode is on, TAB now indents the region if the
region is active.

*** The variable `use-empty-active-region' controls whether an empty
active region in Transient Mark mode should make commands operate on
that empty region.

** Temporarily active regions

*** The new variable shift-select-mode, non-nil by default, controls
shift-selection.  When Shift Select mode is on, shift-translated
motion keys (e.g. S-left and S-down) activate and extend a temporary
region, similar to mouse-selection.

*** Temporarily active regions, created using shift-selection or
mouse-selection, are not necessarily deactivated in the next command.
They are only deactivated after point motion commands that are not
shift-translated, or after commands that would ordinarily deactivate
the mark in Transient Mark mode (e.g., any command that modifies the
buffer).

** Minibuffer and completion changes

*** Emacs may ask for confirmation before opening a non-existent file
or buffer.  By default, Emacs requests confirmation if you type RET
immediately after TAB, and the resulting input is not an existing file
or buffer; this usually happens when the minibuffer input did not
complete far enough and you entered RET by mistake.  In that case,
Emacs puts the message "[Confirm]" in the minibuffer; type RET again
to create the file or buffer.

The new variable confirm-nonexistent-file-or-buffer determines whether
Emacs asks for confirmation.  The default value is `after-completion'.
If you change it to t, Emacs always asks for confirmation; if you
change it to nil, Emacs never asks for confirmation.

*** The rules for performing completion have been changed.
When generating completion alternatives, Emacs now takes the
minibuffer text after point, if any, into account: this text is
treated as a substring of the remaining part of the completion
alternative (i.e., the part not matched by the minibuffer text before
point).  If no completion alternatives are found this way, Emacs
attempts to perform partial-completion.  If still no completion
alternatives are found, we fall back on the Emacs 22 rules for
performing completion.

The new variable `completion-styles' can be customized to choose your
favorite completion style.

*** When M-n in the minibuffer reaches the end of the list of defaults,
it adds the completion list to the end, so next M-n continues putting
completion items to the minibuffer.  The same principle applies to
incremental search commands as well: C-s or C-M-s starts searching
the default values and after the end of defaults they continue
searching minibuffer completion items.

*** Minibuffer input of shell commands now comes with completion.

*** In the `C-x d' (Dired) prompt, typing M-n gives the visited file
name of the current buffer.

*** In the M-! (shell-command) prompt, M-n provides some default commands.
These are guessed using the file extension of the current file, based
on the file-handlers specified in the operating system's `mailcap'
file.  The ! command in Dired (dired-do-shell-command) works
similarly, using the file displayed on the current line.

*** A list of regexp default values is available via M-n for `occur',
`keep-lines', `flush-lines' and `how-many'.  This list includes the active
region in transient-mark-mode, the word under the cursor, the last Isearch
regexp, the last Isearch string and the last replacement regexp.

*** When enable-recursive-minibuffers is non-nil, operations which use
switch-to-buffer (such as C-x b and C-x C-f) do not fail any more when
used in a minibuffer or a dedicated window.  Instead, they fallback on
using pop-to-buffer, which will use some other window.  This change
has no effect when enable-recursive-minibuffers is nil (the default).

*** Isearch started in the minibuffer searches in the minibuffer history.
Reverse Isearch commands (C-r, C-M-r) search in previous minibuffer
history elements, and forward Isearch commands (C-s, C-M-s) search in
next history elements.  When the reverse search reaches the first history
element, it wraps to the last history element, and the forward search
wraps to the first history element.  When the search is terminated, the
history element containing the search string becomes the current.

*** The variable read-file-name-completion-ignore-case overrides
completion-ignore-case for file name completion.

*** The variable read-buffer-completion-ignore-case overrides
completion-ignore-case for buffer name completion.

*** The new command `minibuffer-force-complete' chooses one of the
possible completions, rather than stopping at the common prefix.

*** If `completion-auto-help' is `lazy', Emacs shows the completions
buffer only on the second attempt to complete.  This was already
supported in `partial-completion-mode'.

** Face changes

*** S-down-mouse-1 now pops up a menu for changing the font and text
size of the default face in the current buffer.  The face is changed
via face remapping (see Lisp changes, below).

*** New commands to change the default face size in the current buffer.
To increase it, type `C-x C-+' or `C-x C-='.  To decrease it, type
`C-x C--'.  To restore the default (global) face size, type `C-x C-0'.
These work via Text Scale mode, a new minor mode.

The final key in the above commands may be repeated without the
leading `C-x', e.g. `C-x C-= C-= C-=' increases the face height by
three steps.  Each step scales the height of the default face by the
value of the variable `text-scale-mode-step'.

*** The commands buffer-face-mode and buffer-face-set can be used to
remap the default face in the current buffer.  See "Buffer Face mode",
under New Modes and Packages.

** Primary selection changes

*** You can disable kill ring commands from accessing the primary
selection by setting `x-select-enable-primary' to nil.

** Continuation lines can now be wrapped at word boundaries
(word-wrapping).  This is controlled by the new per-buffer variable
`word-wrap'.  Word wrapping does not take place if continuation lines
are not shown, e.g. if truncate-lines is non-nil.  The most convenient
way to enable word-wrapping is using the new minor mode Visual Line
mode; in addition to setting `word-wrap' to t, this rebinds some
editing commands to work on screen lines rather than text lines.  See
New Modes and Packages, below.

** Window management changes

*** truncate-partial-width-windows now accepts integer values, which
specify a minimum window width for partial-width windows, below which
lines are truncated.  The default has been changed to 50.

*** The new command balance-windows-area balances windows both
vertically and horizontally.

*** pop-to-buffer now always sets input focus when the popped-to window
is on a different frame.

** Miscellaneous changes:

*** C-l is bound to the new command recenter-top-bottom, rather than recenter.
This moves the current line to window center, top and bottom on
successive invocations.

*** scroll-preserve-screen-position also preserves the column position.

*** If `yank-pop-change-selection' is t, rotating the kill ring also
updates the selection or clipboard to the current yank, just as M-w
would do so with the text it copies to the kill ring.

*** C-M-% now shows replacement as it would look in the buffer, with
`\N' and `\&' substituted according to the match.  Old behavior can be
restored by customizing `query-replace-show-replacement'.

*** The command shell prompts for the default directory, when it is
called with a prefix and the default directory is a remote file name.
This is because some file name handlers (like ange-ftp) are not able to
run processes remotely.

*** The new command kill-matching-buffers kills buffers whose name
matches a regexp.

*** The value of comment-style now defaults to `indent'.
Thefore, comment-start markers are inserted at the current indentation
of the region to comment, rather than the leftmost column.

*** The new commands `pp-macroexpand-expression' and
`pp-macroexpand-last-sexp' pretty-print macro expansions.

*** The new command `set-file-modes' allows to set file's mode bits.
The mode bits can be specified in symbolic notation, like with GNU
Coreutils, in addition to an octal number.  `chmod' is a new
convenience alias for this function.

*** `next-error-recenter' specifies how next-error should recenter the
visited source file.  Its value can be a number (for example, 0 for
top line, -1 for bottom line), or nil for no recentering.

*** When typing in a password in the echo area, C-y yanks the current
kill into the password.

*** Tooltip frame parameters `font' and `color' in `tooltip-frame-parameters'
are ignored.  Customize the `tooltip' face instead.

*** `mkdir' is a new convenience alias for `make-directory'.
\f
* New Modes and Packages in Emacs 23.1

** Auto Composition Mode is a minor mode that composes characters
automatically when they are displayed.  It is globally on by default.
It uses `auto-composition-function' (default `auto-compose-chars').

** Bubbles, a new game, is similar to SameGame.

** Buffer Face mode is a minor mode for remapping the default face in
the current buffer.  The variable `buffer-face-mode-face' specifies
the face to remap to.  The command `buffer-face-set' prompts for a
face name, sets `buffer-face-mode-face' to it, and enables
buffer-face-mode.  See "Face changes", under Editing Changes, for a
description of face remapping.

** butterfly flips the desired bit on the drive platter.
See http://xkcd.com/378/

** bug-reference.el provides clickable links to bug reports.

** dbus.el provides D-Bus language bindings.
D-Bus is an inter-process communication mechanism for applications
residing on the same host.  See the manual for details.

** DocView mode allows viewing of PDF, PostScript and DVI documents.
One can also search for a regular expression in the document.  For
details, see the commentary in doc-view.el.

PDF and DVI files are now opened in Doc View mode by default.

In Postcript mode, C-c C-c launches Doc View minor mode for viewing
the postscript file.

** EasyPG provides an interface to the GNU Privacy Guard (GnuPG).
It includes a GnuPG keyring browser, cryptographic operations on
regions and files, and automatic encryption of *.gpg files.  For
details, see the EasyPG Assistant User's Manual.

** json.el is a library for parsing and generating JSON
(JavaScript Object Notation), a lightweight data-interchange format.

** linum.el is a new minor mode to display line numbers for the
current buffer.

** mairix.el is an interface to mairix, a free tool for indexing and
searching locally stored mail.  It allows you to query mairix and
display the search results with Rmail, Gnus and VM.  Note that there
is an existing Gnus back end, nnmairix.el, which should be used with
Maildir/MH setups.

** minibuffer-depth-indicate-mode shows the minibuffer depth in the prompt.

** nXML Mode
This is a new mode for editing XML documents.  It allows a schema to
be associated with the XML document being edited, using Relax NG as
the schema language.  The schema is used to provide two key features:

*** Continuous validation.  nXML validates as you type, highlighting
any invalid parts of your document.

*** Completion.  nXML can assist you in entering an element name,
attribute name or data value by using information about what is
allowed by the schema in that context.

** proced.el provides a Dired-like interface for operating on
processes.  Proced makes an Emacs buffer containing a listing of the
current processes.  You can use the normal Emacs commands to move
around in this buffer, and special Proced commands to operate on the
processes listed.  It is currently only functional on GNU/Linux,
MS-Windows and Solaris.

** Remember Mode is a mode for jotting down things to remember.
Notes can be saved to a Diary file.  For details, see the Remember
Manual.

** RST mode is a major mode for editing reStructuredText files.

** Ruby mode is a major mode for Ruby files.

** Visual Line mode provides support for editing by visual lines.
It turns on word-wrapping in the current buffer, and rebinds C-a, C-e,
and C-k to commands that operate by visual lines instead of logical
lines.  This is a more reliable replacement for longlines-mode.
This can also be turned on using the menu bar, via
Options -> Line Wrapping in this Buffer -> Word Wrap

** xesam.el is an implementation of Xesam, an interface to (desktop)
search engines like Beagle, Strigi, and Tracker.  The Xesam API
requires D-Bus for communication.

** zeroconf.el offers service discovery and service publishing
interfaces according to the zeroconf specification.  It communicates
with Avahi, a zeroconf implementation, via D-Bus messages on systems
which have installed this software.

** There is a new `whitespace' package.
(The pre-existing one has been renamed to `old-whitespace'.)
Now, besides reporting bogus blanks, the whitespace package has a
minor mode and a global minor mode to visualize blanks (TAB, (HARD)
SPACE and NEWLINE).  The visualization is made via faces and/or display
table.  It can also indicate lines that extend beyond a given column,
trailing blanks, and empty lines at the start or end of a buffer.
See `whitespace-style' for more details.  The `whitespace-action' option
specifies what to do when a buffer is visited, killed, or written.

\f
* Changes in Specialized Modes and Packages in Emacs 23.1

** Abbrev has been rewritten in Elisp and extended with more flexibility.

*** New functions: abbrev-get, abbrev-put, abbrev-table-get, abbrev-table-put,
abbrev-table-p, abbrev-insert, abbrev-table-menu.

*** Special hook `abbrev-expand-functions' obsoletes `pre-abbrev-expand-hook'.

*** `make-abbrev-table', `define-abbrev', `define-abbrev-table' all take
extra arguments for arbitrary properties.

*** New variable `abbrev-minor-mode-table-alist'.

*** `local-abbrev-table' can hold a list of abbrev-tables.

*** Abbrevs have now the following special properties:
`:count', `:system', `:enable-function', `:case-fixed'.

*** Abbrev-tables have now the following special properties:
`:parents', `:case-fixed', `:enable-function', `:regexp',
`abbrev-table-modiff'.

** Apropos

*** `apropos-library' describes the elements defined in a given library.

*** Set `apropos-compact-layout' is you want a more compact (but wider) layout.

** Archive Mode has basic support to browse Rar archives.
Note, however, that the free version of the unrar command only handles
versions 1 and 2 of the Rar format.

** BibTeX mode

*** New command `bibtex-initialize' (re)initializes BibTeX buffers.

*** New `bibtex-entry-format' options `whitespace', `braces', and
`string', disabled by default.

*** New variable `bibtex-cite-matcher-alist' contains rules to
identify cited keys in BibTeX entries, used by `bibtex-find-crossref'.

*** Command `bibtex-url' allows multiple URLs per entry.

** Bookmarks

*** bookmark.el saves bookmarks in a pre-Emacs-23-incompatible file format
bookmark.el can read a .emacs.bmk file saved by an older Emacs, but an
older Emacs cannot read one saved by Emacs 23.

** Calendar and diary

*** There is a new date style, `iso', essentially year/month/day.
The variable `european-calendar-style' is obsolete - use `calendar-date-style'.
Similarly, the commands `american-calendar' and `european-calendar'
should be replaced by `calendar-set-date-style'.

*** The calendar namespace has been rationalized.
All functions and variables now begin with a `calendar-', `diary-', or
`holiday-' prefix.  The various calendar systems have secondary
prefixes, eg `calendar-french-'.  The old names you are likely to use
directly still exist, for the time being, as aliases, but please start
using the new names.

*** The whitespace in the calendar layout can be customized.
See the variables:
calendar-left-margin, calendar-intermonth-spacing, calendar-column-width,
calendar-day-header-width, and calendar-day-digit-width.

*** Text (e.g. ISO weeks) can be displayed between the calendar months.
See the variables calendar-intermonth-header and calendar-intermonth-text.

*** The function `holiday-chinese' computes holidays on the Chinese calendar.
It has been used to add items to the list `holiday-oriental-holidays'.

*** `diary-remind' accepts a negative number -DAYS as a shorthand for
the list (1 2 ... DAYS).

** Change Log mode

*** The new command C-c C-f (change-log-find-file) finds the file
associated with the current log entry.

*** The new command C-c C-c (change-log-goto-source) goes to the
source code associated with a log entry.

** Compile and grep modes

*** The mode-line entry for the *compilation* and *grep* buffer is color coded.
It has different colors for to show that: (a) the command is still
running, (b) successful completion, (c) error.

*** compilation-auto-jump-to-first-error tells `compile' to jump to
the first error encountered during compilations.

*** compilation-scroll-output accepts a new value, `first-error', which
says to stop auto scrolling at the first error that occurs.

*** The `cc' alias for C++ files in `grep-file-aliases' has been
improved.  `hh' can be used to match C++ header files and `cchh' both
C++ sources and headers.

** Copyright

*** You can specify your copyright holders' names.
Only copyright lines with holders matching `copyright-names-regexp' are
considered for update.

*** Copyrights can be at the end of the buffer.
This is controlled by `copyright-at-end-flag' (used by, e.g., change-log-mode).

** Custom

*** defcustom accepts new keyword arguments, `:safe' and `:risky', which
set a variable's `safe-local-variable' and `risky-local-variable' property.

** Diff mode

*** diff-refine-hunk highlights word-level details of changes in a diff hunk.
It's used automatically as you move through hunks, see
diff-auto-refine-mode.  It is bound to `C-c C-b'.

*** diff-add-change-log-entries-other-window iterates through the diff
buffer and tries to create ChangeLog entries for each change.
It is bound to `C-x 4 A'.

*** Turning on `whitespace-mode' in a diff buffer will show trailing
whitespace problems in the modified lines.

** Dired

*** In Dired, C-x C-q now runs the command wdired-change-to-wdired-mode,
and C-x C-q in wdired-mode exits it with asking a question about
saving changes.

*** `&' runs the command `dired-do-async-shell-command' that executes
the command asynchronously without the need to manually add ampersand
to the end of the command.  Its output appears in the buffer `*Async Shell
Command*'.

*** `M-s f C-s' and `M-s f M-C-s' run Isearch that matches only at file names.
When a new user option `dired-isearch-filenames' is t, then even ordinary
Isearch started with `C-s' and `C-M-s' matches only at file names in the
Dired buffer.  When `dired-isearch-filenames' is `dwim' then activation of
file name Isearch depends on the position of point - if point is on a file
name initially, then Isearch matches only file names, otherwise it matches
everywhere in the Dired buffer.  You can toggle file names matching on or
off by typing `M-s f' in Isearch mode.

*** `M-s a C-s' and `M-s a M-C-s' run multi-file Isearch on the marked files.
They visit the first marked file in the sequence and display the usual Isearch
prompt for a string or a regexp where all Isearch commands are available.

*** `Q' in Dired provides two new keys for multi-file replacement.
The upper case key `Y' replaces all remaining matches in all remaining files
with no more questions.  The upper case key `N' stops doing replacements
in the current file and skips to the next file.  These multi-file keys
are available for all commands that use `tags-query-replace'
including `dired-do-query-replace-regexp', `vc-dir-query-replace-regexp',
`reftex-query-replace-document'.

** Fortran

*** The line length of fixed-form Fortran is not fixed at 72 any more.
Customize the variable `fortran-line-length' to change it.

*** In Fortran mode, M-; is now bound to the standard comment-dwim,
rather than fortran-indent-comment.

*** (The increasingly misnamed) F90 mode supports Fortran 2003 syntax.

** Gnus

*** The Gnus package has been updated
There are many new features, bug fixes and improvements; see the file
GNUS-NEWS or the node "No Gnus" in the Gnus manual for details.

*** In Emacs 23, Gnus uses Emacs' new internal coding system `utf-8-emacs' for
saving articles, drafts, and ~/.newsrc.eld.  These file may not be read
correctly in Emacs 22 and below.  If you want to Gnus across different Emacs
versions, you may set `mm-auto-save-coding-system' to `emacs-mule'.

*** Passwords are consistently loaded through `auth-source'
Gnus can use `auth-source' for POP and IMAP passwords.  Also see that
`smtpmail' and `url' support `auth-source' for SMTP and HTTP/HTTPS/RSS
authentication respectively.

** Help mode

*** New macro `with-help-window' should set up help windows better
than `with-output-to-temp-buffer' with `print-help-return-message'.

*** New option `help-window-select' permits to customize whether help
window shall be automatically selected when invoking help.

*** New variable `help-window-point-marker' permits one to specify a new
position for point in help window (for example in `view-lossage').

** Isearch

*** New command `isearch-forward-word' bound globally to `M-s w' starts
incremental word search.  New command `isearch-toggle-word' bound to the
same key `M-s w' in Isearch mode toggles word searching on or off
while Isearch is active.

*** New command `isearch-highlight-regexp' bound to `M-s h r' in Isearch
mode runs `highlight-regexp' (`hi-lock-face-buffer') with the current
search string as its regexp argument.  The same key `M-s h r' and
other keys on the `M-s h' prefix are bound globally to the command
`highlight-regexp' and other hi-lock commands.

*** New command `isearch-occur' bound to `M-s o' in Isearch mode
runs `occur' with the current search string.  The same key `M-s o'
is bound globally to the command `occur'.

*** Isearch can now search through multiple ChangeLog files.
When running Isearch in a ChangeLog file, if the search fails,
then another C-s tries searching the previous ChangeLog,
if there is one (e.g. going from ChangeLog to ChangeLog.12).
This is enabled if multi-isearch-search is non-nil.

*** Two new commands to start Isearch on a list of marked buffers
for buff-menu.el and ibuffer.el are bound to the keys `M-s a C-s' and
`M-s a M-C-s'.

*** The part of an Isearch that failed to match is highlighted in
`isearch-fail' face.

*** `C-h C-h' in Isearch mode displays isearch-specific Help screen,
`C-h b' displays all Isearch key bindings, `C-h k' displays the full
documentation of the given Isearch key sequence, `C-h m' displays
documentation for Isearch mode.  All the other Help commands exit
Isearch mode and execute their global definitions.

*** When started in the minibuffer, Isearch searches in the minibuffer
history.  See `Minibuffer changes', above.

** MH-E

*** Upgraded to MH-E version 8.2.  See MH-E-NEWS for details.

** Python
*** The file etc/emacs.py now supports both Python 2 and 3, meaning
that either version can be used as inferior Python by python.el.

*** Python mode now has `pdbtrack' functionality.  When using pdb to
debug a Python program, pdbtrack notices the pdb prompt and displays
the source file and line that the program is stopped at, much the same
way as gud-mode does for debugging C programs with gdb.

** Recentf

*** The default value of `recentf-keep' prevents from checking of
remote files, if there is no established connection to the
corresponding remote host.

** Rmail

*** Rmail no longer converts the messages to Babyl format.
Instead, it uses UNIX mbox format, both on disk and in Rmail buffers,
and does conversion and decoding when a message is displayed.

The first time you visit an Rmail file in Babyl format, Rmail
automatically converts it to mbox format.  This is a one-time
conversion, but it can take a few minutes, depending on how fast is
your machine and on the size of the file.  You should find the rest of
Rmail usage unaltered.

However, M-x set-rmail-inbox-list now lasts only for one session
because there is no way to save the list of inbox files in an
mbox-format file.

Also, whereas with Babyl format M-x find-file would switch to Rmail
mode, with mbox format this is no longer the case (there being no way
to add an "-*- rmail-*-" cookie to an mbox file).  Use C-u M-x rmail
instead.

If you have written any extensions to Rmail, they are likely to need
updating.  Conceptually, the Rmail buffer that you see is no longer
just a narrowed portion of the whole.  So you cannot access the whole
of a message (or message collection) by a simple save-restriction and
widen.  Instead, there are two buffers: the rmail-buffer, and the
rmail-view-buffer.  The former is the buffer that you see, the latter
is invisible.  Most of the time, the invisible `view' buffer contains
the full contents of the Rmail file, and the Rmail buffer contains a
decoded copy of the current message (with only a subset of the
headers).  In this state, Rmail is said to be `swapped'.

You may find the following functions useful:

`rmail-get-header' and `rmail-set-header' get or set the value of a
message header, whether or not it is currently visible.

`rmail-apply-in-message' is a general purpose function that calls a
function (with arguments) which you specify on the full text of a given
message.  To further narrow to just the headers, search forward for "\n\n".

*** The new command `rmail-mime' displays MIME messages.
It is bound to `v' in Rmail buffers and summaries.  It displays plain
text and multipart messages in a temporary buffer, and offers buttons
to save attachments.

*** The command `rmail-redecode-body' no longer accepts the optional arg RAW.
Since Rmail now holds messages in their original undecoded form in a
separate buffer, `rmail-redecode-body' no longer encodes the original
message, and therefore there should be no need to avoid encoding it.

*** The o command is now `rmail-output'.  It is an all-purpose command
for copying messages from Rmail and appending them to files.  It
handles Babyl-format files as well as mbox-format files, and it
handles both kinds properly when they are visited in Emacs.  It always
copies the full headers of the message.

*** The C-o command is now `rmail-output-as-seen'.  It uses
the message as displayed, appending it to an mbox file.

*** The modified status of the Rmail buffer is reported in the mode-line.
Previously, this information was hidden.

** TeX modes

*** New option latex-indent-within-escaped-parens
permits to customize indentation of LaTeX environments delimited
by escaped parens.

** T-mouse Mode

*** If the gpm mouse server is running and t-mouse-mode is enabled,
Emacs uses a Unix socket in a GNU/Linux console to talk to server,
rather than faking events using the client program mev.  This C level
approach provides mouse highlighting and help echoing in the
minibuffer.

** Tramp

*** New connection methods.
The new methods "plinkx", "plink2", "psftp", "sftp" and "fish" have
been introduced.  There are also new so-called gateway methods
"tunnel" and "socks".

*** IPv6 addresses.
IPv6 addresses are supported now as host names.  They must be embedded
in square brackets, like in "/ssh:[::1]:".

*** Multihop syntax has been removed.
The pseudo-method "multi" has been removed.  Instead, multi hops
can be specified by the new variable `tramp-default-proxies-alist'.

*** More default settings.
Default values can be set via the variables `tramp-default-user',
`tramp-default-user-alist' and `tramp-default-host'.

*** Connection information is cached.
In order to reduce connection setup, information about used
connections is kept persistently in a file.  The name of this file is
defined in the variable `tramp-persistency-file-name'.

*** Control of remote processes.
Running processes on a remote host can be controlled by settings in
`tramp-remote-path' and `tramp-remote-process-environment'.

*** Success of remote copy is checked.
When the variable `file-precious-flag' is set, the success of a remote
file copy is checked via the file's checksum.

*** Passwords can be read from an authentification file.
Tramp uses the package `auth-source' to read passwords from a file, if
necessary.

** VC and related modes

*** VC now supports applying VC operations to a set of files at a time.
This enables VC to work much more effectively with changeset-oriented
version-control systems such as Subversion, GNU Arch, Mercurial, Git
and Bzr.  VC will now pass a multiple-file commit to these systems as
a single changeset.

*** vc-dir is a new command that displays file names and their VC
status.  It allows to apply various VC operations to a file, a
directory or a set of files/directories.

*** VC switches are no longer appended, rather the first non-nil value is used.
(This was for the most part true in Emacs 22, but was not advertised).
This is because there is an increasing variety of VC systems, and they
do not all accept the same "common" options.  For example, a CVS diff
command used to append the values of `vc-cvs-diff-switches',
`vc-diff-switches', and `diff-switches'.  Now the first non-nil value
from that sequence is used.  The special value `t' means "no switches".

*** Clicking on the VC mode-line entry now pops the VC menu.

*** The VC mode-line entry now has a tooltip that explains the VC file status.

*** In VC Annotate mode, the key bindings have changed to use lower
case keys instead of the upper case keys used in the past.

*** In VC Annotate mode, for VC systems that support changesets, you can
see the diff for the whole changeset (not only for the current file)
by typing the D key.  Using the "Show changeset diff of revision at
line" menu entry does the same thing.

*** In VC Annotate mode, you can type v to toggle the annotation visibility.

*** In VC Annotate mode, you can type f to show the file revision on
the current line.

*** Asynchronous VC commands display [Waiting...] in the mode-line
of the corresponding buffer as long as the asynchronous process is
active.

*** Log entries can be modified using the key "e" in log-view.
For now only CVS, RCS, SCCS and SVN support this functionality.
This is done by the `modify-change-comment' backend function.

*** In log-view-mode, for VC systems that support changesets, you can
see the diff for the whole changeset (not only for the current file)
by typing the D key or using the "Changeset Diff" menu entry.

*** In Log Edit mode,  C-c C-d now shows the diff for the files involved.

*** vc-git supports the "git grep" command.

*** VC Support for Meta-CVS has been removed for lack of a maintainer able
to update it to the new VC.

** Miscellaneous

*** comint-mode uses `start-file-process' now (see Lisp Changes).
If `default-directory' is a remote file name, subprocesses are started
on the corresponding remote system.

*** Eldoc highlights the function argument under point
with the face `eldoc-highlight-function-argument'.

*** In Etags, the --members option is now the default.
Use --no-members if you want the old default behavior of not tagging
struct members in C, members variables in C++ and variables in PHP.

*** The `gdb' command only works with the graphical interface now.
Use `gud-gdb' if you want the (old) text command mode.

*** goto-address.el provides two new minor modes, goto-address-mode and
goto-address-prog-mode, which buttonize URLS and email addresses.

*** The new command `eshell/info' runs info in an eshell buffer.

*** The new variable `ffap-rfc-directories' specifies a list of local
directories in which `ffap-rfc' will first search for RFCs.

*** hide-ifdef-mode allows shadowing ifdef-blocks instead of hiding them.
See option `hide-ifdef-shadow' and function `hide-ifdef-toggle-shadowing'.

*** `icomplete-prospects-height' now supersedes `icomplete-prospects-length'.

*** Info displays breadcrumbs in the header of the page.
See Info-breadcrumbs-depth to control it.

*** net-utils has an `iwconfig' command, similar to the existing `ifconfig'.
It is used to configure wireless interfaces.

*** The pcmpl-unix package supports hostname completion for ssh and scp.

*** sgml-electric-tag-pair-mode lets you simultaneously edit matched tag pairs.

*** smerge-refine highlights word-level details of changes in conflict.
It's used automatically as you move through conflicts, see
smerge-auto-refine-mode.

*** talk.el has been extended for multiple tty support.

*** A new command `display-time-world' has been added to the Time
package.  It creates a buffer with an updating time display using
several time zones.

*** The appearance of superscript and subscript in TeX is more customizable.
See the documentation of the variables: tex-fontify-script,
tex-font-script-display, tex-suscript-height-ratio, and
tex-suscript-height-minimum.

*** view-remove-frame-by-deleting is now by default t
since users found iconification of view-mode frames distracting.

*** WoMan tries to add locale-specific manual page directories to the
search path.  This can be disabled by setting `woman-locale' to nil.

\f
* Changes in Emacs 23.1 on non-free operating systems

** Case is now considered significant in completion on MS-Windows.
The default value of `completion-ignore-case' is now nil on
MS-Windows, the same as it is for other operating systems.  The
variable doesn't apply to reading a file name -- in that case Emacs
heeds `read-file-name-completion-ignore-case' instead.

** IPv6 is supported on MS-Windows.
Emacs now supports IPv6 on Windows XP and later, and earlier versions
of Windows with third party IPv6 stacks installed.  In Emacs 22, IPv6 was
supported on other platforms, but not on Windows due to using the winsock
1.1 header file, even though Emacs was linking to the winsock 2 library.

** Busy cursor (hourglass) now displays on MS-Windows.
When Emacs is busy, an hourglass mouse cursor is displayed on Windows.
In Emacs 22 only X supported the busy cursor.

** Battery status is available on MS-Windows
Emacs can now display the battery status in the mode-line when enabled with
display-battery-mode or from the Options menu.  More verbose battery
information is also available with the command `battery'.  In Emacs 22
battery status was supported only on GNU/Linux and Mac.

** More keys available on MS-Windows.
Keys normally associated with IMEs, and some exotic keys not normally found
on standard keyboards have been given names so they can be bound to functions
inside Emacs.  If there are keys on your keyboard that have not been exposed
to Emacs in the past, try C-h k to see if they are available now.

Emacs can now bind functions to the extra buttons for media player and
browser control present on some keyboards.  These buttons are disabled
by default, since enabling them prevents their system-wide use when
Emacs has focus.  To enable them, set the variable
w32-pass-multimedia-buttons to nil.  See the doc string of that variable
for the list of extra keys that are available.

** BDF fonts no longer supported on MS-Windows.
The font backend was completely rewritten for this release.  The focus
on Windows has been getting acceptable performance and full unicode
support, including complex script shaping for native Windows fonts.  A
rewrite of the BDF font support has not happened due to lack of time
and developers.  If demand still exists for such a backend even with
the improved language support for native Windows fonts, future
development in this direction will most likely be based on the
freetype library, giving access to a wider range of font formats.

\f
* Incompatible Lisp Changes in Emacs 23.1

** Variables cannot be both buffer-local and frame-local any more.

** `functionp' returns nil for special forms.
I.e., it only returns t for objects that can be passed to `funcall'.

** The behavior of map-char-table has changed.  It may call the
specified function with a cons (FROM . TO) as a key if characters in
that range have the same value.

** Process changes

*** The function `dired-call-process' has been removed.

*** The multibyteness of process filters is now determined by the
coding-system used for decoding.  The functions
`process-filter-multibyte-p' and `set-process-filter-multibyte' are
obsolete.

** The variable `byte-compile-warnings' can now be a list starting with `not',
meaning to disable the specified warnings.  The meaning of this list
may therefore be the reverse of what you expect (of course, this is
only an issue if you make use of the new `not' syntax).  Rather than
checking/manipulating elements directly, use the new functions
`byte-compile-warning-enabled-p', `byte-compile-disable-warning', and
`byte-compile-enable-warning.'

** `mode-name' is no longer guaranteed to be a string.
Use `(format-mode-line mode-name)' to ensure a string value.

** The function x-font-family-list has been removed.
Use the new function font-family-list (see Lisp Changes, below).

** Internationalization changes

*** The value of the function `charset-id' is now always 0.

*** The functions `register-char-codings' and `coding-system-spec'
have been removed.

*** The cpXXX coding systems are now supported automatically.
The functions cp-...-codepage, which you had to use in Emacs 22 to
enable support for these coding systems, have been deleted.

*** The following features have been removed.  They were used for
displaying various scripts with specific fonts, and are no longer
needed now that OpenType font support is available:

**** `devanagari' and `devan-util', and all associated devanagari-* and
dev-* functions and variables (formerly used for Devanagari script).

**** `kannada' and `knd-util', and all associated kannada-* and knd-*
functions and variables (formerly used for Kannada script).

**** `malayalam' and `mlm-util', and all associated malayalam-* and
mlm-* functions and variables (formerly used for Malayalam script).

**** `tamil' and `tml-util, and all associated tamil-* and tml-*
functions and variables (formerly used for Tamil script).

*** The meaning of NAME argument of `set-fontset-font' is changed.
Previously nil is accepted as the default fontset.  Now, nil is for
the fontset of the selected frame and t is for the default fontset.

*** The meaning of FONTSET argument of `print-fontset' is changed.
Now, nil is for the fontset of the selected frame and t is for the
default fontset.

** If a function in write-region-annotate-functions returns with a
different buffer current, Emacs no longer kills that buffer
automatically.  This behavior existed in previous versions of Emacs,
but was undocumented.  To kill a buffer after write-region, give the
variable `write-region-post-annotation-function' a buffer-local value
of `kill-buffer'.

** The variable temp-file-name-pattern has been removed.
This variable was only used by call-process-region, which now uses
temporary-file-directory instead.

** The COUNT and SYSTEM-FLAG arguments to define-abbrev have been
removed.  The function now takes extra arguments for specifying
arbitrary abbrev properties.

** end-of-defun-function is now guaranteed to work only when called
from the start of a defun.  It must now leave point exactly at the end
of defun, since `end-of-defun' now itself moves forward over
whitespace after calling it.

\f
* Lisp Changes in Emacs 23.1

** The new variable `generate-autoload-cookie' controls the magic comment
string used by `update-file-autoloads' to find autoloaded forms.  The
variable `generated-autoload-file' similarly controls the name of the
file where `update-file-autoloads' writes the calls to `autoload'.
The default values are ";;;###autoload" and `loaddefs.el',
respectively.

** New primitives `list-system-processes' and `process-attributes'
let Lisp programs access the processes that are running on the local
machine.  See the doc strings of these functions for more details.
Not all platforms support accessing this information; on those that
don't, these primitives will return nil.

** New variable `user-emacs-directory'.
Use this instead of "~/.emacs.d".

** If a local hook function has a non-nil `permanent-local-hook'
property, `kill-all-local-variables' does not remove it from the local
value of the hook variable; it remains even if you change major modes.

** `frame-inherited-parameters' lets new frames inherit parameters from
the selected frame.

** New keymap `input-decode-map' overrides like key-translation-map, but
applies before function-key-map.  Also it is terminal-local contrary to
key-translation-map.  Terminal-specific key-sequences are generally added to
this map rather than to function-key-map now.

** `ignore-errors' is now a standard macro (does not require the CL package).

** `interprogram-paste-function' can now return one string or a list
of strings.  In the latter case, Emacs puts the second and following
strings on the kill ring.

** In `condition-case', a handler can specify "let the debugger run first".
You do this by writing `debug' in the list of conditions to be handled,
like this:

    (condition-case nil
        (foo bar)
      ((debug error) nil))

** clone-indirect-buffer now runs the clone-indirect-buffer-hook.

** `beginning-of-defun-function' now takes one argument, the count given to
`beginning-of-defun'.  (N.B. `end-of-defun-function' doesn't take any
arguments.)

** `file-remote-p' has new optional parameters IDENTIFICATION and CONNECTED.
IDENTIFICATION specifies which part of the remote identifier has to be
returned.  With CONNECTED passed non-nil, it is checked whether a
remote connection has been established already.

** The new macro `declare-function' suppresses compiler warnings about
undefined functions.

** Changes to interactive function handling

*** The new interactive spec code ^ says to first call
handle-shift-selection if shift-select-mode is non-nil, before reading
the command arguments.  This is used for shift-selection (see above).

*** Built-in functions can now have an interactive specification that
is not a prompt string.  If the `intspec' parameter of a `DEFUN'
starts with a `(', the string is evaluated as a Lisp form.

*** The interactive-form of a function can be added post-facto via the
`interactive-form' symbol property.  Mostly useful to add complex
interactive forms to subroutines.

** Region changes

*** Commands should use `use-region-p' to test whether there is
an active region that they should operate on.

*** `region-active-p' returns non-nil when Transient Mark mode is
enabled and the mark is active.  Most commands that act specially on
the active region in Transient Mark mode should use `use-region-p'
instead of `region-active-p', because `use-region-p' obeys the new
user option `use-empty-active-region' (see Editing Changes, above).

*** If a command sets `transient-mark-mode' to (only . OLDVAL), that
means to activate transient-mark-mode temporarily, until the next
unshifted point motion command or mark deactivation.  Afterwards,
reset transient-mark-mode to the value OLDVAL.  The values `only' and
`identity', introduced in Emacs 22, are now deprecated.

** Emacs session information

*** The new variables `before-init-time' and `after-init-time' record the
value of `current-time' before and after Emacs loads the init files.

*** The new function `emacs-uptime' returns the uptime of an Emacs instance.

*** The new function `emacs-init-time' returns the duration of the
Emacs initialization.

** Changes affecting display-buffer

*** display-buffer tries to be smarter when splitting windows.
The new option split-window-preferred-function lets you specify your own
function to pop up new windows.  Its default value split-window-sensibly
can split a window either vertically or horizontally, whichever seems
more suitable in the current configuration.  You can tune the behavior
of split-window-sensibly by customizing split-height-threshold and the
new option split-width-threshold.  Both options now take the value nil
to inhibit splitting in one direction.  Setting split-width-threshold to
nil inhibits horizontal splitting and gets you the behavior of Emacs 22
in this respect.  In any case, display-buffer may now split the largest
window vertically even when it is not as wide as the containing frame.

*** If pop-up-frames has the value `graphic-only', display-buffer only
makes a separate frame on graphic displays.

*** select-frame and set-frame-selected-window have a new optional
argument NORECORD.  If non-nil, this will avoid messing with the order
of recently selected windows and the buffer list.

** Window parameters can now be defined.
These are analogous to frame parameters, but are associated with
individual windows.

*** The new functions window-parameters, window-parameter, and
set-window-parameter are used to query and set window parameters.

** Minibuffer and completion changes

*** A list of default values can be specified for the DEFAULT argument of
functions `read-from-minibuffer', `read-string', `read-command',
`read-variable', `read-buffer', `completing-read'.  Elements of this list
are available for inserting into the minibuffer by typing `M-n'.
For empty input these functions return the first element of this list.

*** New function `read-regexp' uses the regexp history and some useful
regexp defaults (string at point, last Isearch/replacement regexp/string)
via M-n when reading a regexp in the minibuffer.

*** minibuffer-local-must-match-filename-map is now named
minibuffer-local-filename-must-match-map.

*** The `require-match' argument to `completing-read' accepts the new
values `confirm-only' and `confirm-after-completion'.

** Search and replacement changes

*** The regexp form \(?<num>:<regexp>\) specifies the group number explicitly.

*** New function `match-substitute-replacement' returns the result of
`replace-match' without actually using it in the buffer.

*** The new variable `replace-search-function' determines the function
to use for searching in query-replace and replace-string.  The
function it specifies is called by `perform-replace' when its 4th
argument is nil.

*** The new variable `replace-re-search-function' determines the
function to use for searching in `query-replace-regexp',
`replace-regexp', `query-replace-regexp-eval', and
`map-query-replace-regexp'.  The function it specifies is called by
`perform-replace' when its 4th argument is non-nil.

*** New keymap `search-map' bound to `M-s' provides global bindings
for search related commands.

*** New keymap `multi-query-replace-map' contains additonal keys bound
to `automatic-all' and `exit-current' for multi-buffer interactive replacement.

*** The variable `inhibit-changing-match-data', if non-nil, prevents
the search and match primitives from changing the match data.

*** New functions `word-search-forward-lax' and `word-search-backward-lax'.
These are like `word-search-forward and `word-search-backward', except
that the end of the search string need not match a word boundary,
unless it ends in whitespace.

** File handling changes

*** set-file-modes is now interactive and can take the mode value in
symbolic notation thanks to auxiliary functions.

*** file-local-variables-alist stores an alist of file-local
variables defined in the current buffer.

** Face-remapping

*** Each face can be remapped to a different face definition using the
variable `face-remapping-alist'.  This is an alist that maps faces to
replacement definitions (which can be face names, lists of face names,
or attribute/value plists.  If this variable is buffer-local, the
remapping occurs only in that buffer.

*** text-scale-mode remaps the default face to a larger or smaller
size in the current buffer.  This feature is used by the Buffer Face
menu and the new `C-x C-+', `C-x C--', and `C-x C-0' commands (see
Editing Changes, above).

*** New functions:

**** `face-remap-add-relative' adds a face remapping entry to the
current buffer.

**** ``face-remap-remove-relative' removes a face remapping entry from
the current buffer.

**** `face-remap-reset-base' restores a face to its global definition.

**** `face-remap-set-base' sets the base remapping of a face.

** Process changes

*** The new function `start-file-process' is similar to `start-process',
but obeys file handlers.  The file handler is chosen based on
`default-directory'.  The functions `start-file-process-shell-command'
and `process-file-shell-command' are also new; they call internally
`start-file-process' and `process-file', respectively.

*** The new function `process-lines' executes an external program and
returns its output as a list of lines.

** Character code, representation, and charset changes.

*** In multibyte buffers and strings, characters are represented by
UTF-8 byte sequences.  The character code space is now 0x0..0x3FFFFF
with no gap; code points 0x0..0x10FFFF are Unicode characters of the
same code points, while code points 0x3FFF80..0x3FFFFF are raw 8-bit
bytes.

*** Generic characters no longer exist.

*** The concept of a charset has changed.  A single character may
belong to multiple charsets (e.g. a-grave, U+00E0, belongs to charsets
unicode, iso-8859-1, iso-8859-3, etc).

**** The dimension of a charset is now 1, 2, 3, or 4, and the size of
each dimension is no longer limited to 94 or 96.

**** A dynamic charset priority list is used to infer the charset of
characters for display.

*** The functions `split-char' and `make-char' now accept up to 4
positional codes instead of just 2.

*** The functions `encode-char' and `decode-char' now accept any character sets.

*** The function `define-charset' now accepts a completely different
form of arguments (old-style arguments still work).

*** The value of the function `char-charset' depends on the current
priorities of charsets.

*** The function get-char-code-property now accepts many Unicode base
character properties.  They are `name', `general-category',
`canonical-combining-class', `bidi-class', `decomposition',
`decimal-digit-value', `digit-value', `numeric-value', `mirrored',
`old-name', `iso-10646-comment', `uppercase', `lowercase', and
`titlecase'.

*** The functions `modify-syntax-entry' and `modify-category-entry' now
accept a cons of characters as the first argument, and modify all
entries in that range of characters.

*** Use of `translation-table-for-input' for character code unification
is now obsolete, since Emacs 23.1 and later uses Unicode as basis for
internal representation of characters.

*** New functions:

**** `characterp' returns t if and only if the argument is a character.
This replaces `char-valid-p', which is now obsolete.

**** `max-char' returns the maximum character code (currently #x3FFFFF).

**** `define-charset-alias' defines an alias of a charset.

**** `set-charset-priority' sets priorities of charsets.

**** `charset-priority-list' returns a prioritized list of charsets.

**** `unibyte-string' makes a unibyte string from bytes.

**** `define-char-code-property' defines a character code property.

**** `char-code-property-description' returns the description string of
a character code property.

*** New variables:

**** `find-word-boundary-function-table' is a char-table of functions to
search for a word boundary.

**** `char-script-table' is a char-table of script names.

**** `char-width-table' is a char-table of character widths.

**** `print-charset-text-property' controls how to handle `charset' text
property on printing a string.

**** `printable-chars' is a char-table of printable characters.

** Code conversion changes

*** The new function `define-coding-system' should be used to define a
coding system instead of `make-coding-system' (which is now obsolete).

*** The functions `encode-coding-region' and `decode-coding-region'
have an optional 4th argument to specify where the result of
conversion should go.

*** The functions `encode-coding-string' and `decode-coding-string'
have an optional 4th argument specifying a buffer to store the result
of conversion.

*** The new variable `inhibit-null-byte-detection' controls whether to
consider text with null bytes as binary data.  By default, it is
`nil', and Emacs uses `no-conversion' for any text containing null
bytes.

*** The functions `set-coding-priority' and `make-coding-system' are obsolete.

*** New functions:

**** `with-coding-priority' executes Lisp code using the specified
coding system priority order.

**** `check-coding-systems-region' checks if the text in the region is
encodable by the specified coding systems.

**** `coding-system-aliases' returns a list of aliases of a coding system.

**** `coding-system-charset-list' returns a list of charsets supported
by a coding system.

**** `coding-system-priority-list' returns a list of coding systems
ordered by their priorities.

**** `set-coding-system-priority' sets priorities of coding systems.

**** `coding-system-from-name' returns a coding system matching with
the argument name.

** There is a new input method, Robin, different from Quail.
It has three functionalities:
 i) a simple input method (converts an ASCII sequence into a string).
ii) converts an existing buffer substring into another string
iii) reverse conversion (each character produced by a
robin rule can hold the original ASCII sequence as a char-code-property)

*** The new function `robin-define-package' defines a Robin package.

*** The new function `robin-modify-package' modifies an existing Robin package.

*** The new function `robin-use-package' starts using a Robin package
as an input method.

*** The new function `string-to-unibyte' is like `string-as-unibyte'
but signals an error if STRING contains a non-ASCII, non-eight-bit
character.

** Changes related to the new font backend

*** Which font backends to use can be specified by the X resource
"FontBackend".  For instance, to use both X core fonts and Xft fonts:

Emacs.FontBackend: x,xft

If this resource is not set, Emacs tries to use all font backends
available on your graphic device.

*** New frame parameter `font-backend' specifies a list of
font-backends supported by the frame's graphic device.  On X, they are
currently `x' and `xft'.

*** The function `set-fontset-font' now accepts a script name as the
second argument, and has an optional 5th argument to control how to
set the font.

*** New functions:

**** `fontp' checks if the argument is a font-spec or font-entity.

**** `font-spec' creates a new font-spec object.

**** `font-get' returns a font property value.

**** `font-put' sets a font property value.

**** `font-face-attributes' returns a plist of face attributes set by a font.

**** `list-fonts' returns a list of font-entities matching a font spec.

**** `find-font' returns the font-entity best matching the given font spec.

**** `font-family-list' returns a list of family names of available fonts.

**** `font-xlfd-name' returns an XLFD name of a given font spec, font
entity, or font object.

**** `clear-font-cache' clears all font caches.

** Changes related to multiple-terminal (multi-tty) support

*** $TERM is now set to `dumb' for subprocesses.  If you want to know the
$TERM inherited by Emacs you will have to look inside initial-environment.

*** $DISPLAY is now dynamically inherited from the frame's `display'.

*** The `window-system' variable is now frame-local.  The new
`initial-window-system' variable contains the `window-system' value
for the first frame.  `window-system' is also now a function that
takes a frame argument.

*** The `keyboard-translate-table' variable and the terminal and
keyboard coding systems are now terminal-local.

*** You can specify a terminal device (`tty' parameter) and a terminal
type (`tty-type' parameter) to `make-terminal-frame'.

*** The function `make-frame-on-display' now works during a tty
session.

*** A new `terminal' data type.
The functions `get-device-terminal', `terminal-parameters',
`terminal-parameter', `set-terminal-parameter' use this data type.

*** Function key sequences are now mapped using `local-function-key-map',
a new variable.  This inherits from the global variable function-key-map,
which is not used directly any more.

*** New hooks:

**** before-hack-local-variables-hook is called after setting new
variable file-local-variables-alist, and before actually applying the
file-local variables.

**** `suspend-tty-functions' and `resume-tty-functions' are called
after a tty frame has been suspended or resumed, respectively.  The
functions are called with the terminal id of the frame being
suspended/resumed as a parameter.

**** The special hook `delete-terminal-functions' is called before
deleting a terminal.

*** New functions:

**** `delete-terminal'

**** `suspend-tty'

**** `resume-tty'.

*** `initial-environment' holds the environment inherited from Emacs's parent.

** Redisplay changes

*** For underlined characters, the distance between the underline and
the baseline is controlled by a new variable, `underline-minimum-offset'.

*** You can now pass the value of the `invisible' property to
invisible-p to check whether it would cause the text to be invisible.
This is convenient when checking invisibility of text with no buffer
position (e.g. in before/after-strings).

*** `clear-image-cache' can be told to flush only images of a specific file.

*** `vertical-motion' can now be given a goal column.
It now accepts a cons cell (COLS . LINES) in its first argument, which
says to stop, where possible, at a pixel x-position equal to COLS
times the default column width.

*** redisplay-end-trigger-functions, set-window-redisplay-end-trigger,
and window-redisplay-end-trigger are obsolete.  Use `jit-lock-register'
instead.

*** The new variables `wrap-prefix' and `line-prefix' specify display
specs which are appended at display-time to every continuation line
and non-continuation line, respectively.  In addition, Emacs
recognizes the `wrap-prefix' and `line-prefix' text or overlay
properties; these have the same effects as the variables of the same
name, but take precedence.

** The Lisp interpreter now treats non-breaking space as whitespace.

** Miscellaneous new functions

*** `apply-partially' performs a "curried" application of a function.

*** `buffer-swap-text' swaps text between two buffers.  This can be
useful for modes such as tar-mode, archive-mode, RMAIL.

*** `combine-and-quote-strings' produces a single string from a list of strings
sticking a separator string in between each pair, and quoting those
strings that include the separator as their substring.  Useful for
consing shell command lines from the individual arguments.

*** `custom-note-var-changed' tells Custom to treat the change in a
certain variable as having been made within Custom.

*** `face-all-attributes' returns an alist describing all the basic
attributes of a given face.

*** `format-seconds' converts a number of seconds into a readable
string of days, hours, etc.

*** `image-refresh' refreshes all images associated with a given image
specification.

*** `locate-user-emacs-file' helps packages to select the appropriate
place to save user-specific files.  It defaults to `user-emacs-directory'
unless the file already exists at $HOME.

*** `read-color' reads a color name using the minibuffer.

*** `read-shell-command' does what its name says, with completion.  It
uses the minibuffer-local-shell-command-map for that.

*** `split-string-and-unquote' splits a string into a list of substrings
on the boundaries of a given delimiter, and unquotes the substrings that
are quoted.  Useful for taking apart shell commands.

*** The two new functions `looking-at-p' and `string-match-p' can do
the same matching as `looking-at' and `string-match' without changing
the match data.

*** The two new functions `make-serial-process' and
`serial-process-configure' provide a Lisp interface to the new serial
port support (see Emacs changes, above).

** Miscellaneous new variables

*** `auto-save-include-big-deletions', if non-nil, means auto-save is
not turned off automatically after a big deletion.

*** `read-circle', if nil, disables the reading of recursive Lisp
structures using the #N= and #N# syntax.

*** `this-command-keys-shift-translated' is non-nil if the key
sequence invoking the current command was found by shift-translation.

*** `window-point-insertion-type' determines the insertion-type of the
marker used for window-point.

*** bookmark provides `bookmark-make-record-function' so special major
modes like Info can teach bookmark.el how to save and restore the
relevant data.

*** `fill-forward-paragraph-function' specifies which function the
filling code should use to find paragraph boundaries.

\f
* New Packages for Lisp Programming in Emacs 23.1

** The new package avl-tree.el deals with the AVL tree data structure.

** The new package check-declare.el verifies the accuracy of
declare-function macros (see Lisp Changes, above).

** find-cmd.el can build `find' commands using lisp syntax.

** The package misearch.el has been added.  It allows Isearch to search
through multiple buffers.  A variable `multi-isearch-next-buffer-function'
defines the function to call to get the next buffer to search in the series
of multiple buffers.  Top-level functions `multi-isearch-buffers',
`multi-isearch-buffers-regexp', `multi-isearch-files' and
`multi-isearch-files-regexp' accept a single argument that specifies
a list of buffers/files to search for a string/regexp.

** The new major mode `special-mode' is intended as a parent for
major modes such as those that set the "'mode-class 'special" property.

\f
----------------------------------------------------------------------
This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

\f
Local variables:
mode: outline
paragraph-separate: "[  \f]*$"
end: