Emacs NEWS.23

Table of Contents

GNU Emacs NEWS – history of user-visible changes.

Copyright (C) 2007-2023 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.

1. Installation Changes in Emacs 23.4

1.1. The MS-Windows build prefers libpng version 1.14 or later.

Versions of libpng before 1.14 had security issues, so we now recommend to use version 1.14 or later. Precompiled Windows binaries require version 1.14 or later. See README.W32 and nt/INSTALL for details and pointers to URLs where the latest libpng can be downloaded.

2. Changes in Specialized Modes and Packages in Emacs 23.4

2.1. EDE

2.1.1. New variable 「ede-project-directories」.

EDE now refuses to automatically load a project file (Project.ede) unless the file is in one of the directories specified by this variable. This reduces the risk of inadvertently loading malicious project files. The commands 'M-x ede-new' and 【M-x ede】 now offer to save directories to 「ede-project-directories」.

3. Changes in Emacs 23.4 on non-free operating systems

3.1. The MS-Windows port can now use more than 500MB of heap.

Depending on the available virtual memory, Emacs on Windows can now have up to 2GB of heap space. This allows, e.g., visiting several large (> 256MB) files in the same session.

4. Installation Changes in Emacs 23.3

4.1. 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.

5. Changes in Emacs 23.3

5.1. The last-resort backup file '%backup%~' is now written to

user-emacs-directory, instead of the user's home directory.

5.2. If Emacs creates user-emacs-directory, that directory's

permissions are now set to rwx-–—, ignoring the umask.

6. Changes in Specialized Modes and Packages in Emacs 23.3

6.1. Calendar and diary

6.1.1. The appt-add command takes an optional argument, the warning time.

This can be used in place of the default 「appt-message-warning-time」.

6.2. Python mode

6.2.1. You can allow inferior Python processes to load modules from the

current directory by setting 「python-remove-cwd-from-path」 to nil.

6.3. Rmail

6.3.1. 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.

6.3.2. 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.

6.3.3. The new command 「rmail-mime-next-item」 (bound to TAB) moves point

to the next item of MIME message.

6.3.4. The new command 「rmail-mime-previous-item」 (bound to backtab) moves

point to the previous item of MIME message.

6.3.5. The new command 「rmail-mime-toggle-hidden」 (RET) hide or show the

body of the MIME entity at point.

6.4. VC and related modes

6.4.1. 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.

6.4.2. 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.

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

6.4.4. 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.

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

6.4.6. 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.

6.5. Obsolete packages

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

7. New Modes and Packages in Emacs 23.3

7.1. 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.

8. Incompatible Lisp Changes in Emacs 23.3

8.1. 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.

9. Lisp changes in Emacs 23.3

9.1. 'e' and 'pi' are now called float-e and float-pi.

The old names are obsolete.

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

9.3. The function 「princ-list」 is now obsolete.

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

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

10. Changes in Emacs 23.3 on non-free operating systems

10.1. The NeXTstep port can have different modifiers for the left and right

alt/option key by customizing the value for ns-right-alternate-modifier.

11. Installation Changes in Emacs 23.2

11.1. New configure options for Emacs developers.

These are not new features; only the configure flags are new.

11.1.1. –enable-profiling builds Emacs with profiling enabled.

This might not work on all platforms.

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

11.2. 'make install' now consistently ignores umask, creating a

world-readable install.

11.3. 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).

12. Startup Changes in Emacs 23.2

12.1. 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.

12.1.1. The new variable inhibit-x-resources shows whether X resources

were loaded.

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

13. Changes in Emacs 23.2

13.1. The maximum size of buffers (and the largest fixnum) is doubled.

On typical 32bit systems, buffers can now be up to 512MB.

13.2. 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.)

13.3. The pointer now becomes invisible when typing.

Customize make-pointer-invisible to disable this feature.

13.4. Font changes

13.4.1. 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).

13.4.2. 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.

13.5. 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.

13.6. File-local variable changes

13.6.1. Specifying a minor mode as a local variables enables that mode,

unconditionally. The previous behavior, toggling the mode, was neither reliable nor generally desirable.

13.6.2. 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.

13.6.3. 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.

13.7. Internationalization changes

13.7.1. Unibyte sessions are now considered obsolete.

This refers to the EMACSUNIBYTE 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.

13.7.2. New coding system 「utf-8-hfs」.

This is suitable for default-file-name-coding-system on Mac OS X; see international/ucs-normalize.el.

13.8. Function arguments in Help buffers are now shown in upper-case.

Customize help-downcase-arguments to t to show them in lower-case.

13.9. 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'.

13.10. 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).

14. Editing Changes in Emacs 23.2

14.1. Kill-ring and selection changes

14.1.1. 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.

14.1.2. 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.

14.1.3. When kill-do-not-save-duplicates is non-nil, identical

subsequent kills are not duplicated in the kill-ring.

14.2. Completion changes

14.2.1. The new command completion-at-point provides mode-sensitive completion.

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

14.2.3. The new completion-style 'initials' is available.

For instance, this can complete M-x lch to list-command-history.

14.2.4. 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.

14.3. The default value of blink-matching-paren-distance is increased.

14.4. 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).

14.5. 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.

14.6. The new variable recenter-positions determines the default

cycling order of C-l (recenter-top-bottom).

14.7. The abbrevs file is now a file named abbrevdefs in

user-emacs-directory; but the old location, ~/.abbrevdefs, is used if that file exists.

15. Changes in Specialized Modes and Packages in Emacs 23.2

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

15.2. Calc

15.2.1. 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.

15.2.2. New twos-complement display.

15.2.3. 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.

15.3. Calendar and diary

15.3.1. Fancy diary display is now the default.

If you prefer the simple display, customize 「diary-display-function」.

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

15.3.3. The command 「calendar-current-date」 accepts an optional argument

giving an offset from today.

15.4. Desktop

15.4.1. 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.

15.5. Dired

15.5.1. The new variable dired-auto-revert-buffer, if non-nil, causes

Dired buffers to be reverted automatically on revisiting them.

15.6. DocView

15.6.1. When 「doc-view-continuous」 is non-nil, scrolling a line

on the page edge advances to the next/previous page.

15.7. Elint

15.7.1. Elint now uses compilation-mode.

15.7.2. Elint can now scan individual files and whole directories,

and can be run in batch mode.

15.7.3. 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.

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

15.7.5. Customize 「elint-ignored-warnings」 to suppress some warnings.

15.8. GDB-UI

15.8.1. Toolbar functionality for reverse debugging. Display of STL

collections as watch expressions. These features require GDB 7.0 or later.

15.9. Grep

15.9.1. A new command 'zrgrep' searches recursively in gzipped files.

15.10. Info

15.10.1. The new command 'Info-virtual-index' bound to "I" displays a menu of

matched topics found in the index.

15.10.2. 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.

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

15.12. 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.

15.12.1. 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.

15.13. 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.

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

15.15. pcomplete provides a new command 「pcomplete-std-completion」 which

is similar to 'pcomplete' but using the standard completion UI code.

15.16. Shell (and other comint modes)

15.16.1. M-s is no longer bound to comint-next-matching-input.

15.16.2. M-r is now bound to comint-history-isearch-backward-regexp.

This starts an incremental search of the comint/shell input history.

15.16.3. ansi-color is now enabled by default in Shell mode.

To disable it, set ansi-color-for-comint-mode to nil.

15.17. Tramp

15.17.1. 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".

15.18. VC and related modes

15.18.1. 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.

15.18.2. 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.

15.18.3. 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.

15.18.4. 【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.

15.18.5. 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.

15.18.6. 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.

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

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

15.18.9. vc-git changes

  1. 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.

  2. vc-dir uses the –relative option of git, and so requires at least

    git version 1.5.5.

  3. 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.

15.18.10. vc-bzr supports operating with shelves: the shelve list is

displayed in the vc-dir header, shelves can be created, removed and applied.

15.18.11. 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.

15.19. Miscellaneous

15.19.1. 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.

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

15.19.3. 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.

15.20. Obsolete packages

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

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

16. New Modes and Packages in Emacs 23.2

16.1. 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):

16.1.1. 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.

16.1.2. 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.

16.1.3. 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.

16.1.4. The EIEIO library implements a subset of the Common Lisp Object

System (CLOS). It is used by the other CEDET packages.

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

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

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

16.5. imap-hash.el is a new library to address IMAP mailboxes as hash tables.

17. Incompatible Lisp Changes in Emacs 23.2

17.1. 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.

17.2. 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

17.3. Support for generating Emacs 18 compatible bytecode (by setting

the variable 「byte-compile-compatibility」) has been removed.

17.4. 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.

18. Lisp changes in Emacs 23.2

18.1. All the default-FOO variables that hold the default value of the FOO

variable, are now declared obsolete.

18.2. read-key is a mix between read-event and read-key-sequence.

It reads a single key, but obeys input and escape sequence decoding.

18.3. Frame parameter changes

18.3.1. You can give the 'fullscreen' frame parameter the value 'maximized'.

This maximizes the frame.

18.3.2. The new frame parameter 'sticky' makes Emacs frames sticky in

virtual desktops.

18.4. Completion changes

18.4.1. 「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.

18.4.2. New function completion-in-region to use the standard completion

facilities on a particular region of text.

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

18.4.4. 「completion-annotate-function」 specifies how to compute annotations

for completions displayed in Completions.

18.5. Minibuffer changes

18.5.1. 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.

18.6. Changes to file-manipulation functions

18.6.1. delete-directory has an optional parameter RECURSIVE.

18.6.2. New function copy-directory, which copies a directory recursively.

18.7. called-interactively-p now takes one argument and replaces interactive-p

which is now marked obsolete.

18.8. New function set-advertised-calling-convention makes it possible

to obsolete arguments as well as make some arguments mandatory.

18.9. 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.

18.10. Network and process changes

18.10.1. start-process-shell-command and start-file-process-shell-command

now only take a single 'command' argument.

18.10.2. 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.

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

18.11. Loading changes

18.11.1. 「eval-next-after-load」 is obsolete.

18.11.2. New hook after-load-functions run after loading an Elisp file.

18.12. Byte compilation changes

18.12.1. 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.

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

18.13. New macro with-silent-modifications to tweak text properties without

affecting the buffer's modification state.

18.14. Hash tables have a new printed representation that is readable.

The feature 「hashtable-print-readable」 identifies this new functionality.

18.15. 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」.

18.16. Face aliases can now be marked as obsolete, using the macro

define-obsolete-face-alias.

18.17. New function window-full-height-p, analogous to the full-width version.

19. Changes in Emacs 23.2 on non-free operating systems

19.1. On MS-Windows, display-time now displays the system load average

as well as the time, as it does on GNU and Unix.

20. Installation Changes in Emacs 23.1

20.1. 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.

20.2. New font code.

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

20.2.1. Emacs now accepts font names supplied in the fontconfig format

(example: "monospace-12:bold") and GTK format (example: "Monospace Bold 12").

20.2.2. Added support for local fonts (fonts installed on the machine

where Emacs is running).

20.2.3. Added support for the Xft library for antialiasing.

20.2.4. Added support for the otf library for complex text layout by

OpenType fonts.

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

20.3. Changes to image support

20.3.1. configure now checks for libgif before libungif when searching for

a GIF library.

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

20.3.3. Emacs now supports multi-page TIFF images.

20.4. 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 (example: X11 build) use –disable-ns-self-contained. See nextstep/README and nextstep/INSTALL in the Emacs source directory.

20.5. Mac OS X is no longer supported via Carbon.

Use the NeXTstep port, described above.

20.6. The new configuration option "–with-dbus" enables D-Bus language

bindings for Emacs.

20.7. Support for many obsolete platforms has been removed.

See the list at the end of etc/MACHINES for details.

20.7.1. Support for systems without alloca has been removed.

20.7.2. Support for Sun windows has been removed.

20.7.3. The 'emacstool' utility has been removed.

20.8. 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.

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

20.8.2. Old FreeBSD, NetBSD, and OpenBSD systems based on the COFF

executable format.

20.8.3. Solaris versions 2.6 and below.

20.8.4. Solaris on IBM RS6000 machines.

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

20.8.6. Unixware on non-x86 machines.

20.8.7. Platforms not supporting shared libraries (i.e., requiring the

NOSHAREDLIBS compilation flag).

20.9. 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.

20.10. The refcards are now shipped as PDF files.

20.11. The manuals are now licensed under the GNU Free Documentation License v1.3,

or any later version.

20.12. 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.

21. Changes in Emacs 23.1

21.1. Improved X Window System support

21.1.1. 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.

21.1.2. 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.

  1. emacsclient starts emacs in daemon mode and connects to it when

    –alternate-editor="" is used (or when the environment variable ALTERNATEEDITOR is set to "") and emacsclient cannot connect to an emacs server.

21.1.3. The new command close-display-connection closes a connection to a

remote display. There are some bugs for Gtk+. See etc/PROBLEMS.

21.1.4. 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 https://specifications.freedesktop.org/xembed-spec/xembed-spec-latest.html for details about XEmbed.

21.1.5. 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.

21.2. Internationalization changes

21.2.1. 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.

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

21.2.3. 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 Unicode code points.

21.2.4. There are new language environments for Chinese-GBK,

Chinese-GB18030, Khmer, Bengali, Punjabi, Gujarati, Oriya, Telugu, Sinhala, and TaiViet.

21.2.5. The minor modes unify-8859-on-encoding-mode and

unify-8859-on-decoding-mode are obsolete.

21.2.6. 「ucs-insert」 is bound to 【C-x 8 RET】 and in addition to hex numbers

accepts numbers in hash notation (example: #o21430 for octal, or #10r8984 for decimal). It also accepts Unicode character names with completion.

21.2.7. 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.

21.3. 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.

21.4. Menu Bar changes

21.4.1. 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.

21.4.2. The font setting chosen by "Set Default Font" is saved if the

"Save Options" item is used.

21.4.3. 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).

21.4.4. 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).

21.4.5. 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.

21.5. Mode-line changes

21.5.1. The mode-line displays a '@', instead of '-', if the

default-directory for the current buffer is on a remote machine.

21.5.2. 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.

21.5.3. The 「mode-line-emphasis」 face is used to highlight certain

mode-line information (example: waiting for a VC command to finish).

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

21.5.5. The VC, line/column number and minor mode indicators on the mode

line are now interactive: mouse-1 can be used on them to pop up a menu.

21.6. 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.

21.7. 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.

21.8. 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.

21.9. where-is-preferred-modifier can specify your favorite modifier.

22. Startup Changes in Emacs 23.1

22.1. 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.

22.2. New user option initial-buffer-choice specifies what to display

after starting Emacs: startup screen, scratch buffer, visiting a file or directory.

22.3. 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.

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

22.5. 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.)

23. Incompatible Editing Changes in Emacs 23.1

23.1. In Dired, dired-flag-garbage-files is rebound from '&' to '%&'

on the regexp command prefix map.

23.2. 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.

23.3. 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'.

23.4. 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】.

23.5. 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.

23.6. 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.

24. Editing Changes in Emacs 23.1

24.1. 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).

24.2. 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).

24.3. Mark changes

24.3.1. Transient Mark mode is now on by default.

24.3.2. mark-even-if-inactive now defaults to t

24.3.3. When Transient Mark mode is on, C-SPC C-SPC pushes a mark without

activating it.

24.3.4. When Transient Mark mode is on, M-q now fills the region if the

region is active. Otherwise, it fills the current paragraph.

24.3.5. 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.

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

region is active.

24.3.7. The variable use-empty-active-region controls whether an empty

active region in Transient Mark mode should make commands operate on that empty region.

24.4. Temporarily active regions

24.4.1. The new minor mode shift-select-mode, non-nil by default, controls

shift-selection. When Shift Select mode is on, shift-translated motion keys (example: S-left and S-down) activate and extend a temporary region, similar to mouse-selection.

24.4.2. Temporarily active regions, created using shift-selection or

mouse-selection, are not necessarily deactivated after the next command. They are deactivated only 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).

24.5. Minibuffer and completion changes

24.5.1. 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.

24.5.2. 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.

24.5.3. 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.

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

24.5.5. In the 【C-x d】 (Dired) prompt, typing M-n gives the visited file

name of the current buffer.

24.5.6. 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.

24.5.7. 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.

24.5.8. 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).

24.5.9. 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.

24.5.10. The variable read-file-name-completion-ignore-case overrides

completion-ignore-case for file name completion.

24.5.11. The variable read-buffer-completion-ignore-case overrides

completion-ignore-case for buffer name completion.

24.5.12. The new command minibuffer-force-complete chooses one of the

possible completions, rather than stopping at the common prefix.

24.5.13. 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」.

24.6. Face changes

24.6.1. 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).

24.6.2. 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】, example: '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」.

24.6.3. 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.

24.7. Primary selection changes

24.7.1. You can disable kill ring commands from accessing the primary

selection by setting 'x-select-enable-primary' to nil.

24.8. 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, example: 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.

24.9. Window management changes

24.9.1. 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.

24.9.2. The new command balance-windows-area balances windows both

vertically and horizontally.

24.9.3. pop-to-buffer now always sets input focus when the popped-to window

is on a different frame.

24.10. Miscellaneous changes:

24.10.1. 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.

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

24.10.3. 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.

24.10.4. 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.

24.10.5. 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.

24.10.6. The new command kill-matching-buffers kills buffers whose name

matches a regexp.

24.10.7. The value of comment-style now defaults to 'indent'.

Therefore, comment-start markers are inserted at the current indentation of the region to comment, rather than the leftmost column.

24.10.8. The new commands pp-macroexpand-expression and

pp-macroexpand-last-sexp pretty-print macro expansions.

24.10.9. 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.

24.10.10. 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.

24.10.11. When typing in a password in the echo area, C-y yanks the current

kill into the password.

24.10.12. Tooltip frame parameters 'font' and 'color' in tooltip-frame-parameters

are ignored. Customize the 'tooltip' face instead.

24.10.13. 'mkdir' is a new convenience alias for make-directory.

25. New Modes and Packages in Emacs 23.1

25.1. 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).

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

25.3. 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.

25.4. 'butterfly' flips the desired bit on the drive platter.

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

25.6. 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.

25.7. 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 PostScript mode, C-c C-c launches Doc View minor mode for viewing the PostScript file.

25.8. 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.

25.9. json.el is a library for parsing and generating JSON

(JavaScript Object Notation), a lightweight data-interchange format.

25.10. linum.el is a new minor mode to display line numbers for the

current buffer.

25.11. 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.

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

25.13. 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:

25.13.1. Continuous validation. nXML validates as you type, highlighting

any invalid parts of your document.

25.13.2. 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.

25.14. 'proced' 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.

25.15. 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.

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

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

25.18. 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

25.19. 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.

25.20. 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.

25.21. 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.

26. Changes in Specialized Modes and Packages in Emacs 23.1

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

26.1.1. New functions: abbrev-get, abbrev-put, abbrev-table-get,

abbrev-table-put, abbrev-table-p, abbrev-insert, abbrev-table-menu.

26.1.2. Special hook abbrev-expand-functions obsoletes 「pre-abbrev-expand-hook」.

26.1.3. make-abbrev-table, define-abbrev, define-abbrev-table all take

extra arguments for arbitrary properties.

26.1.4. New variable abbrev-minor-mode-table-alist.

26.1.5. local-abbrev-table can hold a list of abbrev-tables.

26.1.6. Abbrevs have now the following special properties:

':count', ':system', ':enable-function', ':case-fixed'.

26.1.7. Abbrev-tables have now the following special properties:

':parents', ':case-fixed', ':enable-function', ':regexp', 「abbrev-table-modiff」.

26.2. Apropos

26.2.1. apropos-library describes the elements defined in a given library.

26.2.2. Set apropos-compact-layout is you want a more compact (but wider) layout.

26.3. 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.

26.4. BibTeX mode

26.4.1. New command bibtex-initialize (re)initializes BibTeX buffers.

26.4.2. New 「bibtex-entry-format」 options 'whitespace', 'braces', and

'string', disabled by default.

26.4.3. New variable 「bibtex-cite-matcher-alist」 contains rules to

identify cited keys in BibTeX entries, used by 「bibtex-find-crossref」.

26.4.4. Command 「bibtex-url」 allows multiple URLs per entry.

26.5. Bookmarks

26.5.1. 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.

26.6. Calc

26.6.1. 'j *' (cal-sel-mult-both-sides) has an option to expand the denominator.

26.6.2. 「calc-embedded-word-regexp」 is used for finding words in

「calc-embedded-word」 in place of delimiters.

26.6.3. The separate Calc version number has been removed; use the Emacs

version for reference.

26.6.4. Support for using registers.

26.6.5. Support for Yacas, Maxima and Giac languages.

26.6.6. Addition of a menu.

26.6.7. Logistic non-linear curves have been added to curve-fitting.

26.6.8. New option to plot data points and curve when curve-fitting.

26.6.9. Unit conversions are now exact when possible.

26.6.10. The precedence of negation has been lowered.

26.7. Calendar and diary

26.7.1. 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」.

26.7.2. 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.

26.7.3. 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.

26.7.4. Text (example: ISO weeks) can be displayed between the calendar months.

See the variables calendar-intermonth-header and calendar-intermonth-text.

26.7.5. The function 「holiday-chinese」 computes holidays on the Chinese calendar.

It has been used to add items to the list holiday-oriental-holidays.

26.7.6. 「diary-remind」 accepts a negative number -DAYS as a shorthand for

the list (1 2 … DAYS).

26.8. Change Log mode

26.8.1. The new command C-c C-f (「change-log-find-file」) finds the file

associated with the current log entry.

26.8.2. The new command C-c C-c (「change-log-goto-source」) goes to the

source code associated with a log entry.

26.9. Compile and grep modes

26.9.1. 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.

26.9.2. compilation-auto-jump-to-first-error tells 'compile' to jump to

the first error encountered during compilations.

26.9.3. compilation-scroll-output accepts a new value, first-error, which

says to stop auto scrolling at the first error that occurs.

26.9.4. 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.

26.10. Copyright

26.10.1. You can specify your copyright holders' names.

Only copyright lines with holders matching 「copyright-names-regexp」 are considered for update.

26.10.2. Copyrights can be at the end of the buffer.

This is controlled by 「copyright-at-end-flag」 (used by, e.g., change-log-mode).

26.11. Custom

26.11.1. defcustom accepts new keyword arguments, ':safe' and ':risky', which

set a variable's 「safe-local-variable」 and 「risky-local-variable」 property.

26.12. Diff mode

26.12.1. 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'.

26.12.2. 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】.

26.12.3. Turning on whitespace-mode in a diff buffer will show trailing

whitespace problems in the modified lines.

26.13. Dired

26.13.1. 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.

26.13.2. '&' 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'.

26.13.3. '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.

26.13.4. '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.

26.13.5. '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」.

26.14. Fortran

26.14.1. The line length of fixed-form Fortran is not fixed at 72 any more.

Customize the variable 「fortran-line-length」 to change it.

26.14.2. In Fortran mode, M-; is now bound to the standard comment-dwim,

rather than fortran-indent-comment.

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

26.15. Gnus

26.15.1. 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.

26.15.2. 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」.

26.15.3. 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.

26.16. Help mode

26.16.1. New macro with-help-window should set up help windows better

than with-output-to-temp-buffer with 「print-help-return-message」.

26.16.2. New option help-window-select permits to customize whether help

window shall be automatically selected when invoking help.

26.16.3. New variable help-window-point-marker permits one to specify a new

position for point in help window (for example in view-lossage).

26.17. Isearch

26.17.1. 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.

26.17.2. 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.

26.17.3. 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'.

26.17.4. 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 (example: going from ChangeLog to ChangeLog.12). This is enabled if multi-isearch-search is non-nil.

26.17.5. 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'.

26.17.6. The part of an Isearch that failed to match is highlighted in

「isearch-fail」 face.

26.17.7. '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.

26.17.8. When started in the minibuffer, Isearch searches in the minibuffer

history. See 'Minibuffer changes', above.

26.18. MH-E

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

26.19. Python

26.19.1. 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.

26.19.2. 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.

26.20. Recentf

26.20.1. The default value of recentf-keep prevents from checking of

remote files, if there is no established connection to the corresponding remote host.

26.21. Rmail

26.21.1. 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".

26.21.2. 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.

26.21.3. 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.

26.21.4. 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.

26.21.5. The C-o command is now rmail-output-as-seen. It uses

the message as displayed, appending it to an mbox file.

26.21.6. The modified status of the Rmail buffer is reported in the mode-line.

Previously, this information was hidden.

26.22. TeX modes

26.22.1. New option 「latex-indent-within-escaped-parens」

permits to customize indentation of LaTeX environments delimited by escaped parens.

26.23. T-mouse Mode

26.23.1. 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.

26.24. Tramp

26.24.1. 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".

26.24.2. IPv6 addresses.

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

26.24.3. 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」.

26.24.4. More default settings.

Default values can be set via the variables 「tramp-default-user」, 「tramp-default-user-alist」 and 「tramp-default-host」.

26.24.5. 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」.

26.24.6. Control of remote processes.

Running processes on a remote host can be controlled by settings in 「tramp-remote-path」 and 「tramp-remote-process-environment」.

26.24.7. 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.

26.24.8. Passwords can be read from an authentication file.

Tramp uses the package 「auth-source」 to read passwords from a file, if necessary.

26.25. VC and related modes

26.25.1. 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.

26.25.2. 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.

26.25.3. 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".

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

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

26.25.6. In VC Annotate mode, the key bindings have changed to use lower

case keys instead of the upper case keys used in the past.

26.25.7. 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.

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

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

the current line.

26.25.10. Asynchronous VC commands display [Waiting…] in the mode-line

of the corresponding buffer as long as the asynchronous process is active.

26.25.11. 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.

26.25.12. 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.

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

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

26.25.15. VC Support for Meta-CVS has been removed for lack of a maintainer able

to update it to the new VC.

26.26. Miscellaneous

26.26.1. 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.

26.26.2. ElDoc highlights the function argument under point

with the face 「eldoc-highlight-function-argument」.

26.26.3. 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.

26.26.4. The 'gdb' command only works with the graphical interface now.

Use gud-gdb if you want the (old) text command mode.

26.26.5. goto-address provides two new minor modes, goto-address-mode and

goto-address-prog-mode, which buttonize URLS and email addresses.

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

26.26.7. The new variable 「ffap-rfc-directories」 specifies a list of local

directories in which 「ffap-rfc」 will first search for RFCs.

26.26.8. hide-ifdef-mode allows shadowing ifdef-blocks instead of hiding them.

See option 「hide-ifdef-shadow」 and function 「hide-ifdef-toggle-shadowing」.

26.26.9. icomplete-prospects-height now supersedes 「icomplete-prospects-length」.

26.26.10. Info displays breadcrumbs in the header of the page.

See Info-breadcrumbs-depth to control it.

26.26.11. net-utils has an 'iwconfig' command, similar to the existing 'ifconfig'.

It is used to configure wireless interfaces.

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

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

26.26.14. smerge-refine highlights word-level details of changes in conflict.

It's used automatically as you move through conflicts, see smerge-auto-refine-mode.

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

26.26.16. 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.

26.26.17. 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.

26.26.18. view-remove-frame-by-deleting is now by default t

since users found iconification of view-mode frames distracting.

26.26.19. WoMan tries to add locale-specific manual page directories to the

search path. This can be disabled by setting woman-locale to nil.

27. Changes in Emacs 23.1 on non-free operating systems

27.1. 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.

27.2. 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.

27.3. 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.

27.4. 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.

27.5. 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.

27.6. 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.

28. Incompatible Lisp Changes in Emacs 23.1

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

28.2. 'functionp' returns nil for special forms.

I.e., it only returns t for objects that can be passed to 'funcall'.

28.3. 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.

28.4. Process changes

28.4.1. The function 「dired-call-process」 has been removed.

28.4.2. 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.

28.5. 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.

28.6. mode-name is no longer guaranteed to be a string.

Use '(format-mode-line mode-name)' to ensure a string value.

28.7. The function 'x-font-family-list' has been removed.

Use the new function font-family-list (see Lisp Changes, below).

28.8. Internationalization changes

28.8.1. The value of the function 「charset-id」 is now always 0.

28.8.2. The functions 「register-char-codings」 and 「coding-system-spec」

have been removed.

28.8.3. 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.

28.8.4. 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:

  1. 'devanagari' and 「devan-util」, and all associated devanagari-* and

    dev-* functions and variables (formerly used for Devanagari script).

  2. 'kannada' and 「knd-util」, and all associated kannada-* and knd-*

    functions and variables (formerly used for Kannada script).

  3. 'malayalam' and 「mlm-util」, and all associated malayalam-* and

    mlm-* functions and variables (formerly used for Malayalam script).

  4. 'tamil' and 「tml-util」, and all associated tamil-* and tml-*

    functions and variables (formerly used for Tamil script).

28.8.5. 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.

28.8.6. 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.

28.9. 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.

28.10. 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.

28.11. The COUNT and SYSTEM-FLAG arguments to define-abbrev have been

removed. The function now takes extra arguments for specifying arbitrary abbrev properties.

28.12. 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.

29. Lisp Changes in Emacs 23.1

29.1. 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.

29.2. 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.

29.3. New variable user-emacs-directory.

Use this instead of "~/.emacs.d".

29.4. 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.

29.5. frame-inherited-parameters lets new frames inherit parameters from

the selected frame.

29.6. 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.

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

29.8. 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.

29.9. 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))

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

29.11. 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.)

29.12. 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.

29.13. The new macro declare-function suppresses compiler warnings about

undefined functions.

29.14. Changes to interactive function handling

29.14.1. 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).

29.14.2. 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.

29.14.3. 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.

29.15. Region changes

29.15.1. Commands should use use-region-p to test whether there is

an active region that they should operate on.

29.15.2. 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).

29.15.3. 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.

29.16. Emacs session information

29.16.1. The new variables before-init-time and after-init-time record the

value of current-time before and after Emacs loads the init files.

29.16.2. The new function emacs-uptime returns the uptime of an Emacs instance.

29.16.3. The new function emacs-init-time returns the duration of the

Emacs initialization.

29.17. Changes affecting display-buffer

29.17.1. 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.

29.17.2. If pop-up-frames has the value 「graphic-only」, display-buffer only

makes a separate frame on graphic displays.

29.17.3. 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.

29.18. Window parameters can now be defined.

These are analogous to frame parameters, but are associated with individual windows.

29.18.1. The new functions window-parameters, window-parameter, and

set-window-parameter are used to query and set window parameters.

29.19. Minibuffer and completion changes

29.19.1. 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.

29.19.2. 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.

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

minibuffer-local-filename-must-match-map.

29.19.4. The 「require-match」 argument to completing-read accepts the new

values 「confirm-only」 and 「confirm-after-completion」.

29.20. Search and replacement changes

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

29.20.2. New function match-substitute-replacement returns the result of

replace-match without actually using it in the buffer.

29.20.3. 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.

29.20.4. 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.

29.20.5. New keymap search-map bound to 【M-s】 provides global bindings

for search related commands.

29.20.6. New keymap multi-query-replace-map contains additional keys bound

to 「automatic-all」 and 「exit-current」 for multi-buffer interactive replacement.

29.20.7. The variable inhibit-changing-match-data, if non-nil, prevents

the search and match primitives from changing the match data.

29.20.8. 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.

29.21. File handling changes

29.21.1. set-file-modes is now interactive and can take the mode value in

symbolic notation thanks to auxiliary functions.

29.21.2. file-local-variables-alist stores an alist of file-local

variables defined in the current buffer.

29.22. Face-remapping

29.22.1. 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.

29.22.2. 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).

29.22.3. New functions:

  1. face-remap-add-relative adds a face remapping entry to the

    current buffer.

  2. 「face-remap-remove-relative」 removes a face remapping entry from

    the current buffer.

  3. face-remap-reset-base restores a face to its global definition.
  4. face-remap-set-base sets the base remapping of a face.

29.23. Process changes

29.23.1. 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.

29.23.2. The new function process-lines executes an external program and

returns its output as a list of lines.

29.24. Character code, representation, and charset changes.

29.24.1. 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.

29.24.2. Generic characters no longer exist.

29.24.3. The concept of a charset has changed. A single character may

belong to multiple charsets (example: a-grave, U+00E0, belongs to charsets unicode, iso-8859-1, iso-8859-3, etc).

  1. 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.

  2. A dynamic charset priority list is used to infer the charset of

    characters for display.

29.24.4. The functions split-char and make-char now accept up to 4

positional codes instead of just 2.

29.24.5. The functions encode-char and decode-char now accept any character sets.

29.24.6. The function define-charset now accepts a completely different

form of arguments (old-style arguments still work).

29.24.7. The value of the function char-charset depends on the current

priorities of charsets.

29.24.8. 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'.

29.24.9. 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.

29.24.10. 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.

29.24.11. New functions:

  1. 'characterp' returns t if and only if the argument is a character.

    This replaces 「char-valid-p」, which is now obsolete.

  2. max-char returns the maximum character code (currently #x3FFFFF).
  3. define-charset-alias defines an alias of a charset.
  4. set-charset-priority sets priorities of charsets.
  5. charset-priority-list returns a prioritized list of charsets.
  6. unibyte-string makes a unibyte string from bytes.
  7. define-char-code-property defines a character code property.
  8. char-code-property-description returns the description string of

    a character code property.

29.24.12. New variables:

  1. find-word-boundary-function-table is a char-table of functions to

    search for a word boundary.

  2. char-script-table is a char-table of script names.
  3. char-width-table is a char-table of character widths.
  4. print-charset-text-property controls how to handle 'charset' text

    property on printing a string.

  5. printable-chars is a char-table of printable characters.

29.25. Code conversion changes

29.25.1. The new function define-coding-system should be used to define a

coding system instead of 「make-coding-system」 (which is now obsolete).

29.25.2. The functions encode-coding-region and decode-coding-region

have an optional 4th argument to specify where the result of conversion should go.

29.25.3. The functions encode-coding-string and decode-coding-string

have an optional 4th argument specifying a buffer to store the result of conversion.

29.25.4. 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.

29.25.5. The functions 「set-coding-priority」 and 「make-coding-system」 are obsolete.

29.25.6. New functions:

  1. with-coding-priority executes Lisp code using the specified

    coding system priority order.

  2. check-coding-systems-region checks if the text in the region is

    encodable by the specified coding systems.

  3. coding-system-aliases returns a list of aliases of a coding system.
  4. coding-system-charset-list returns a list of charsets supported

    by a coding system.

  5. coding-system-priority-list returns a list of coding systems

    ordered by their priorities.

  6. set-coding-system-priority sets priorities of coding systems.
  7. coding-system-from-name returns a coding system matching with

    the argument name.

29.26. 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)

29.26.1. The new function robin-define-package defines a Robin package.

29.26.2. The new function robin-modify-package modifies an existing Robin package.

29.26.3. The new function robin-use-package starts using a Robin package

as an input method.

29.26.4. 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.

29.27. Changes related to the new font backend

29.27.1. 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.

29.27.2. 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'.

29.27.3. 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.

29.27.4. New functions:

  1. 'fontp' checks if the argument is a font-spec or font-entity.
  2. font-spec creates a new font-spec object.
  3. font-get returns a font property value.
  4. font-put sets a font property value.
  5. font-face-attributes returns a plist of face attributes set by a font.
  6. list-fonts returns a list of font-entities matching a font spec.
  7. find-font returns the font-entity best matching the given font spec.
  8. font-family-list returns a list of family names of available fonts.
  9. font-xlfd-name returns an XLFD name of a given font spec, font

    entity, or font object.

  10. clear-font-cache clears all font caches.

29.28. Changes related to multiple-terminal (multi-tty) support

29.28.1. $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.

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

29.28.3. 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.

29.28.4. The keyboard-translate-table variable and the terminal and

keyboard coding systems are now terminal-local.

29.28.5. You can specify a terminal device ('tty' parameter) and a terminal

type (tty-type parameter) to make-terminal-frame.

29.28.6. The function make-frame-on-display now works during a tty

session.

29.28.7. A new 'terminal' data type.

The functions get-device-terminal, terminal-parameters, terminal-parameter, set-terminal-parameter use this data type.

29.28.8. 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.

29.28.9. New hooks:

  1. before-hack-local-variables-hook is called after setting new

    variable file-local-variables-alist, and before actually applying the file-local variables.

  2. 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.

  3. The special hook delete-terminal-functions is called before

    deleting a terminal.

29.28.10. New functions:

  1. delete-terminal
  2. suspend-tty
  3. resume-tty.

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

29.29. Redisplay changes

29.29.1. For underlined characters, the distance between the underline and

the baseline is controlled by a new variable, underline-minimum-offset.

29.29.2. 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 (example: in before/after-strings).

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

29.29.4. 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.

29.29.5. redisplay-end-trigger-functions, set-window-redisplay-end-trigger,

and window-redisplay-end-trigger are obsolete. Use jit-lock-register instead.

29.29.6. 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.

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

29.31. Miscellaneous new functions

29.31.1. apply-partially performs a "curried" application of a function.

29.31.2. buffer-swap-text swaps text between two buffers. This can be

useful for modes such as tar-mode, archive-mode, RMAIL.

29.31.3. 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.

29.31.4. custom-note-var-changed tells Custom to treat the change in a

certain variable as having been made within Custom.

29.31.5. face-all-attributes returns an alist describing all the basic

attributes of a given face.

29.31.6. format-seconds converts a number of seconds into a readable

string of days, hours, etc.

29.31.7. image-refresh refreshes all images associated with a given image

specification.

29.31.8. 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.

29.31.9. read-color reads a color name using the minibuffer.

29.31.10. read-shell-command does what its name says, with completion. It

uses the minibuffer-local-shell-command-map for that.

29.31.11. 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.

29.31.12. 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.

29.31.13. 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).

29.32. Miscellaneous new variables

29.32.1. auto-save-include-big-deletions, if non-nil, means auto-save is

not turned off automatically after a big deletion.

29.32.2. read-circle, if nil, disables the reading of recursive Lisp

structures using the #N= and #N# syntax.

29.32.3. this-command-keys-shift-translated is non-nil if the key

sequence invoking the current command was found by shift-translation.

29.32.4. window-point-insertion-type determines the insertion-type of the

marker used for window-point.

29.32.5. bookmark provides bookmark-make-record-function so special major

modes like Info can teach bookmark.el how to save and restore the relevant data.

29.32.6. fill-forward-paragraph-function specifies which function the

filling code should use to find paragraph boundaries.

30. New Packages for Lisp Programming in Emacs 23.1

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

30.2. The new package 「check-declare」 verifies the accuracy of

declare-function macros (see Lisp Changes, above).

30.3. find-cmd can build 'find' commands using lisp syntax.

30.4. 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.

30.5. The new major mode special-mode is intended as a parent for

major modes such as those that set the "'mode-class 'special" property.

30.6. New package format-spec.el provides format-spec.


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 https://www.gnu.org/licenses/.

Created: 2023-08-03 Thu 12:13

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