Emacs NEWS.28

Table of Contents

GNU Emacs NEWS – history of user-visible changes.

Copyright (C) 2019-2023 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 28.

See file HISTORY for a list of GNU Emacs versions and release dates. See files NEWS.27, NEWS.26, …, 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 28.3

2. Startup Changes in Emacs 28.3

3. Changes in Emacs 28.3

4. Editing Changes in Emacs 28.3

5. Changes in Specialized Modes and Packages in Emacs 28.3

5.1. 「native-comp-driver-options」 on macOS.

The value of 「native-comp-driver-options」 has been changed to contain "-Wl,-w" to suppress warnings of the form

ld: warning: -undefined dynamiclookup may not work with chained fixups

emitted during native compilation on macOS 12.6 with Xcode 14.

6. New Modes and Packages in Emacs 28.3

7. Incompatible Lisp Changes in Emacs 28.3

8. Lisp Changes in Emacs 28.3

9. Changes in Emacs 28.3 on Non-Free Operating Systems

10. Installation Changes in Emacs 28.2

10.1. To install the Emacs binary in a non-standard directory, use '–bindir='.

If you install Emacs in a way that places the Emacs executable file in a directory other than "\({prefix}/bin", you will now need to specify that at configure time, if you build Emacs with native-compilation support. To this end, add the '--bindir=DIRECTORY' switch to the command line of the 'configure' script, where DIRECTORY is the directory in which you will install the executable file "emacs". This is required even if you place a symlink under "\){prefix}/bin" that points to the real executable file in some other DIRECTORY.

It is no longer enough to specify 'bindir=DIRECTORY' on the command line of the "make install" command.

The reason for this new requirement is that Emacs needs to locate at startup the directory with its "*.eln" natively-compiled files for the preloaded Lisp packages, and the relative name of that directory needs therefore to be recorded in the executable as part of the build.

11. Changes in Emacs 28.2

This is a bug-fix release with no new features.

12. Changes in Specialized Modes and Packages in Emacs 28.2

12.1. The command 「kdb-macro-redisplay」 was renamed to 「kmacro-redisplay」.

This is to fix an embarrassing typo in the original name.

12.2. desktop-save-mode now saves the desktop in save-buffers-kill-emacs.

Previously, the desktop was saved in kill-emacs via kill-emacs-hook. However, that violated the convention that functions in kill-emacs-hook cannot interact with the user, and in particular didn't play well with ending daemon sessions of Emacs. So we moved the saving of the desktop to save-buffers-kill-emacs, via kill-emacs-query-functions. To make sure the desktop is saved, terminate Emacs with save-buffers-kill-emacs, not with kill-emacs.

(This change was done in Emacs 28.1, but we didn't announce it in NEWS back then.)

13. Installation Changes in Emacs 28.1

13.1. Emacs now optionally supports native compilation of Lisp files.

To enable this, configure Emacs with the '–with-native-compilation' option. This requires the libgccjit library to be installed and functional, and also requires GCC and Binutils to be available when Lisp code is natively compiled. See the Info node "(elisp) Native Compilation" for more details.

If you build Emacs with native compilation, but without zlib, be sure to configure with the '–without-compress-install' option, so that the installed ".el" files are not compressed; otherwise, you will not be able to use JIT native compilation of the installed ".el" files.

Note that JIT native compilation is done in a fresh session of Emacs that is run in a subprocess, so it can legitimately report some warnings and errors that aren't uncovered by byte-compilation. We recommend examining any such warnings before you decide they are false.

13.2. The Cairo graphics library is now used by default if present.

'–with-cairo' is now the default, if the appropriate development files are found by 'configure'. Building with Cairo is known to cause some problems with bitmap fonts. This may require you to adjust your font settings, or to build with Xft support instead.

Note also that 'FontBackend' settings in ".Xdefaults" or ".Xresources", or 「font-backend」 frame parameter settings in your init files, may need to be adjusted, as 'xft' is no longer a valid backend when using Cairo. Use 'ftcrhb' if your Emacs was built with HarfBuzz text shaping support, and 'ftcr' otherwise. You can determine this by checking system-configuration-features. The 'ftcr' backend will still be available when HarfBuzz is supported, but will not be used by default. We strongly recommend building with HarfBuzz support. 'x' is still a valid backend.

13.3. 'configure' now warns about building with libXft support.

libXft is unmaintained, and causes a number of problems with modern fonts including but not limited to crashes; support for it may be removed in a future version of Emacs. Please consider using Cairo + HarfBuzz instead.

13.4. 'configure' now warns about not using HarfBuzz if using Cairo.

We want to encourage people to use the most modern font features available, and this is the Cairo graphics library + HarfBuzz for font shaping, so 'configure' now recommends that combination.

13.5. Building without double buffering support.

'configure –with-xdbe=no' can now be used to disable double buffering at build time.

13.6. The configure option '–without-makeinfo' has been removed.

This was only ever relevant when building from a repository checkout. This now requires makeinfo, which is part of the texinfo package.

13.7. New configure option '–disable-year2038'.

This causes Emacs to use only 32-bit timet on platforms that have both 32- and 64-bit timet. This may help when linking Emacs with a library with an ABI requiring traditional 32-bit timet. This option currently affects only 32-bit ARM and x86 running GNU/Linux with glibc 2.34 and later. Emacs now defaults to 64-bit timet on these platforms.

13.8. Support for building with '-fcheck-pointer-bounds' has been removed.

GCC has withdrawn the '-fcheck-pointer-bounds' option and support for its implementation has been removed from the Linux kernel.

13.9. The ftx font backend driver has been removed.

It was declared obsolete in Emacs 27.1.

13.10. Emacs no longer supports old OpenBSD systems.

OpenBSD 5.3 and older releases are no longer supported, as they lack proper pty support that Emacs needs.

14. Startup Changes in Emacs 28.1

14.1. In GTK builds, Emacs now supports startup notification.

This means that Emacs won't steal keyboard focus upon startup (when started via the Desktop) if the user is typing into another application.

14.2. Errors in kill-emacs-hook no longer prevent Emacs from shutting down.

If a function in that hook signals an error in an interactive Emacs, the user will be prompted on whether to continue. If the user doesn't answer within five seconds, Emacs will continue shutting down anyway.

14.3. Emacs now supports loading a Secure Computing filter.

This is supported only on capable GNU/Linux systems. To activate, invoke Emacs with the '–seccomp=FILE' command-line option. FILE must name a binary file containing an array of 'struct sockfilter' structures. Emacs will then install that list of Secure Computing filters into its own process early during the startup process. You can use this functionality to put an Emacs process in a sandbox to avoid security issues when executing untrusted code. See the manual page for 'seccomp' system call, for details about Secure Computing filters.

14.4. Emacs can support 24-bit color TTY without terminfo database.

If your text-mode terminal supports 24-bit true color, but your system lacks the terminfo database, you can instruct Emacs to support 24-bit true color by setting 'COLORTERM=truecolor' in the environment. This is useful on systems such as FreeBSD which ships only with "etc/termcap".

14.5. File names given on the command line are now pushed onto history.

The file names will be pushed onto file-name-history, like the names of files visited via 'C-x C-f' and other commands.

15. Changes in Emacs 28.1

15.1. Emacs now supports Unicode Standard version 14.0.

15.2. Improved support for Emoji.

On capable systems, Emacs now correctly displays Emoji and Emoji sequences by default, provided that a suitable font is available to Emacs. With a few exceptions, all of the Emoji sequences specified by Unicode 14.0 are automatically composed and displayed as a single colorful glyph. This is achieved by changes in the Emacs font configuration, and by additional character-composition rules for the Emoji codepoints that follow from the Unicode-defined sequences.

If your system lacks a suitable font, we recommend to install "Noto Color Emoji"; Emacs will use it automatically if it's installed. If you prefer to use another font for Emoji, customize your fontset like this:

(set-fontset-font t 'emoji '("My New Emoji Font" . "iso10646-1") nil 'prepend)

The Emoji characters are now assigned to a special script, 'emoji', so as to make it easier to customize fontsets for Emoji display, as in the above example. (Previously, the Emoji characters were assigned to the 'symbol' script, together with other symbol and punctuation characters.)

15.3. glyphless-char-display-control now applies to Variation Selectors.

VS-1 through VS-16 are now displayed as 「thin-space」 by default when not composed with previous characters (typically, as part of Emoji sequences).

15.4. New command execute-extended-command-for-buffer.

This new command, bound to 'M-S-x', works like execute-extended-command, but limits the set of commands to the commands that have been determined to be particularly useful with the current mode.

15.5. New user option read-extended-command-predicate.

This user option controls how 【M-x】 performs completion of commands when you type 'TAB'. By default, any command that matches what you have typed is considered a completion candidate, but you can customize this option to exclude commands that are not applicable to the current buffer's major and minor modes, and respect the command's completion predicate (if any).

15.6. Completion on 【M-x】 shows key bindings for commands.

When suggest-key-bindings is non-nil (as it is by default), the completion list popped up by 【M-x】 shows the key bindings for all the commands shown in the list of candidate completions that have a key binding.

15.7. New user option completions-detailed.

When non-nil, some commands like describe-symbol show more detailed completions with more information in completion prefix and suffix. The default is nil.

15.8. 【C-s】 in 【M-x】 now once again searches over completions.

In Emacs 23, typing 【M-x】 (read-extended-command) and then 【C-s】 (to do an interactive search) would search over possible completions. This was lost in Emacs 24, but is now back again.

15.9. User option completions-format supports a new value 「one-column」.

15.10. New system for displaying documentation for groups of functions.

This can either be used by saying 'M-x shortdoc-display-group' and choosing a group, or clicking a button in the "Help" buffers when looking at the doc string of a function that belongs to one of these groups.

15.11. New minor mode context-menu-mode for context menus popped by 「mouse-3」.

When this mode is enabled, clicking 「down-mouse-3」 (usually, the right mouse button) anywhere in the buffer pops up a menu whose contents depends on surrounding context near the mouse click. You can change the order of the default sub-menus in the context menu by customizing the user option context-menu-functions. You can also invoke the context menu by pressing 'S-<F10>' or, on macOS, by clicking 'C-down-mouse-1'.

15.12. A new keymap for buffer actions has been added.

The 【C-x x】 keymap now holds keystrokes for various buffer-oriented commands. The new keystrokes are 【C-x x g】 (revert-buffer-quick), 【C-x x r】 (rename-buffer), 【C-x x u】 (rename-uniquely), 【C-x x n】 (clone-buffer), 【C-x x i】 (insert-buffer), 【C-x x t】 (toggle-truncate-lines) and 【C-x x f】 (font-lock-update).

15.13. Modifiers now go outside angle brackets in pretty-printed key bindings.

For example, 'RET' with Control and Meta modifiers is now shown as 'C-M-<return>' instead of '<C-M-return>'. Either variant can be used as input; functions such as 'kbd' and read-kbd-macro accept both styles as equivalent (they have done so for a long time).

15.14. eval-expression no longer signals an error on incomplete expressions.

Previously, typing 'M-: ( RET' would result in Emacs saying "End of file during parsing" and dropping out of the minibuffer. The user would have to type 'M-: M-p' to edit and redo the expression. Now Emacs will echo the message and allow the user to continue editing.

15.15. eval-last-sexp now handles 'defvar''defcustom''defface' specially.

This command would previously not redefine values defined by these forms, but this command has now been changed to work more like eval-defun, and reset the values as specified.

15.16. New user option use-short-answers.

When non-nil, the function 'y-or-n-p' is used instead of yes-or-no-p. This eliminates the need to define an alias that maps one to another in the init file. The same user option also controls whether the function read-answer accepts short answers.

15.17. New user option kill-buffer-delete-auto-save-files.

If non-nil, killing a buffer that has an auto-save file will prompt the user for whether that auto-save file should be deleted. (Note that delete-auto-save-files, if non-nil, was previously documented to result in deletion of auto-save files when killing a buffer without unsaved changes, but this has apparently not worked for several decades, so the documented semantics of this variable has been changed to match the behavior.)

15.18. New user option next-error-message-highlight.

In addition to a fringe arrow, next-error error may now optionally highlight the current error message in the next-error buffer. This user option can be also customized to keep highlighting on all visited errors, so you can have an overview what errors were already visited.

15.19. New choice next-error-quit-window for next-error-found-function.

When next-error-found-function is customized to next-error-quit-window, then typing the numeric prefix argument 0 before the command next-error will quit the source window after visiting the next occurrence.

15.20. New user option file-preserve-symlinks-on-save.

This controls what Emacs does when saving buffers that visit files via symbolic links, and file-precious-flag is non-nil.

15.21. New user option copy-directory-create-symlink.

If non-nil, will make copy-directory (when used on a symbolic link) copy the link instead of following the link. The default is nil, so the default behavior is unchanged.

15.22. New user option ignored-local-variable-values.

This is the opposite of safe-local-variable-values – it's an alist of variable-value pairs that are to be ignored when reading a local-variables section of a file.

15.23. Specific warnings can now be disabled from the warning buffer.

When a warning is displayed to the user, the resulting buffer now has buttons which allow making permanent changes to the treatment of that warning. Automatic showing of the warning can be disabled (although it is still logged to the "Messages" buffer), or the warning can be disabled entirely.

15.24. ".dir-locals.el" now supports setting auto-mode-alist.

The new auto-mode-alist specification in ".dir-locals.el" files can now be used to override the global auto-mode-alist in the current directory tree.

15.25. User option uniquify-buffer-name-style can now be a function.

This user option can be one of the predefined styles or a function to personalize the uniquified buffer name.

15.26. remove-hook is now an interactive command.

15.27. expand-file-name now checks for null bytes in filenames.

The function will now check for null bytes in both NAME and DEFAULT-DIRECTORY arguments, as well as in the default-directory buffer-local variable, when its value is used. If null bytes are found, expand-file-name will signal an error. This means that practically all file-related operations will now check file names for null bytes, thus avoiding subtle bugs with silently using only the part of file name up to the first null byte.

15.28. Frames

15.28.1. The key prefix 【C-x 5 5】 displays next command buffer in a new frame.

It's bound to the command other-frame-prefix that requests the buffer of the next command to be displayed in a new frame.

15.28.2. New command clone-frame (bound to 【C-x 5 c】).

This is like 【C-x 5 2】, but uses the window configuration and frame parameters of the current frame instead of default-frame-alist. When called interactively with a prefix arg, the window configuration is not cloned.

15.28.3. Default values of frame-title-format and icon-title-format have changed.

These variables are used to display the title bar of visible frames and the title bar of an iconified frame. They now show the name of the current buffer and the text "GNU Emacs" instead of the value of invocation-name. To get the old behavior back, add the following to your init file:

(setq frame-title-format '(multiple-frames "%b" ("" invocation-name "@" system-name)))

15.28.4. New frame parameter 「drag-with-tab-line」.

This parameter, similar to 「drag-with-header-line」, allows moving frames by dragging the tab lines of their topmost windows with the mouse.

15.28.5. New optional behavior of delete-other-frames.

When invoked with a prefix argument, delete-other-frames now iconifies frames, rather than deleting them.

15.28.6. Commands set-frame-width and set-frame-height now prompt for values.

These commands now prompt for the value via the minibuffer, instead of requiring the user to specify the value via the prefix argument.

15.29. Windows

15.29.1. The key prefix 【C-x 4 1】 displays next command buffer in the same window.

It's bound to the command same-window-prefix that requests the buffer of the next command to be displayed in the same window.

15.29.2. The key prefix 【C-x 4 4】 displays next command buffer in a new window.

It's bound to the command other-window-prefix that requests the buffer of the next command to be displayed in a new window.

15.29.3. New command recenter-other-window, bound to 'S-M-C-l'.

Like recenter-top-bottom, but acting on the other window.

15.29.4. New user option delete-window-choose-selected.

This allows specifying how Emacs chooses which window will be the frame's selected window after the currently selected window is deleted.

15.29.5. New argument NO-OTHER for some window functions.

get-lru-window, get-mru-window and get-largest-window now accept a new optional argument NO-OTHER which, if non-nil, avoids returning a window whose 「no-other-window」 parameter is non-nil.

15.29.6. New display-buffer function display-buffer-use-least-recent-window.

This is like display-buffer-use-some-window, but won't reuse the current window, and when called repeatedly will try not to reuse a previously selected window.

15.29.7. New function window-bump-use-time.

This updates the use time of a window.

15.30. Minibuffer

15.30.1. Minibuffer scrolling is now conservative by default.

This is controlled by the new variable scroll-minibuffer-conservatively. It is t by default; setting it to nil will cause scrolling in the minibuffer obey the value of scroll-conservatively.

15.30.2. Improved handling of minibuffers on switching frames.

By default, when you switch to another frame, an active minibuffer now moves to the newly selected frame. Nevertheless, the effect of what you type in the minibuffer happens in the frame where the minibuffer was first activated. An alternative behavior is available by customizing minibuffer-follows-selected-frame to nil. Here, the minibuffer stays in the frame where you first opened it, and you must switch back to this frame to continue or abort its command. The old behavior, which mixed these two, can be approximated by customizing minibuffer-follows-selected-frame to a value which is neither nil nor t.

15.30.3. New user option read-minibuffer-restore-windows.

When customized to nil, it uses minibuffer-restore-windows in minibuffer-exit-hook to remove only the window showing the "Completions" buffer, but keeps all other windows created while the minibuffer was active.

15.30.4. New variable redisplay-adhoc-scroll-in-resize-mini-windows.

Customizing it to nil will disable the ad-hoc auto-scrolling of minibuffer text shown in mini-windows when resizing those windows. The default heuristics of that scrolling can be counter productive in some corner cases, though the cure might be worse than the disease. This said, the effect should be negligible in the vast majority of cases anyway.

15.31. Mode Line

15.31.1. New user option mode-line-compact.

If non-nil, repeating spaces are compressed into a single space. If 'long', this is only done when the mode line is longer than the current window width (in columns).

15.31.2. New user options to control format of line/column numbers in the mode line.

mode-line-position-line-format is the line number format (when line-number-mode is on), mode-line-position-column-format is the column number format (when column-number-mode is on), and mode-line-position-column-line-format is the combined format (when both modes are on).

15.32. Tab Bars and Tab Lines

15.32.1. The prefix key 【C-x t t】 can be used to display a buffer in a new tab.

Typing 【C-x t t】 before a command will cause the buffer shown by that command to be displayed in a new tab. 【C-x t t】 is bound to the command other-tab-prefix.

15.32.2. New command 'C-x t C-r' to open file read-only in the other tab.

15.32.3. The tab bar now supports more mouse commands.

Clicking 「mouse-2」 closes the tab, 「mouse-3」 displays the context menu with items that operate on the clicked tab. Dragging the tab with 「mouse-1」 moves it to another position on the tab bar. Mouse wheel scrolling switches to the previous/next tab, and holding the Shift key during scrolling moves the tab to the left/right.

15.32.4. Frame-specific appearance of the tab bar when tab-bar-show is a number.

When tab-bar-show is a number, the tab bar on different frames can be shown or hidden independently, as determined by the number of tabs on each frame compared to the numerical value of tab-bar-show.

15.32.5. New command toggle-frame-tab-bar.

It can be used to enable/disable the tab bar on the currently selected frame regardless of the values of tab-bar-mode and tab-bar-show. This allows enabling/disabling the tab bar independently on different frames.

15.32.6. New user option tab-bar-format defines a list of tab bar items.

When it contains tab-bar-format-global (possibly appended after tab-bar-format-align-right), then after enabling display-time-mode (or any other mode that uses global-mode-string) it displays time aligned to the right on the tab bar instead of on the mode line. When tab-bar-format-tabs is replaced with tab-bar-format-tabs-groups, the tab bar displays tab groups.

15.32.7. New optional key binding for tab-last.

If you customize the user option tab-bar-select-tab-modifiers to allow selecting tabs using their index numbers, the '<MODIFIER>-9' key is bound to tab-last, and switches to the last tab. Here <MODIFIER> is any of the modifiers in the list that is the value of tab-bar-select-tab-modifiers. You can also use positive indices, which count from the last tab: 1 is the last tab, 2 the one before that, etc.

15.32.8. New command tab-duplicate bound to 【C-x t n】.

15.32.9. 【C-x t N】 creates a new tab at the specified absolute position.

The position is provided as prefix arg, and specifies an index that starts at 1. Negative values count from the end of the tab bar.

15.32.10. 【C-x t M】 moves the current tab to the specified absolute position.

The position is provided as prefix arg, whose interpretation is as in 【C-x t N】.

15.32.11. 【C-x t G】 assigns a tab to a named group of tabs.

tab-close-group closes all tabs that belong to the selected group. The user option tab-bar-new-tab-group defines the default group of new tabs. After customizing tab-bar-tab-post-change-group-functions to tab-bar-move-tab-to-group, changing the group of a tab will also move it closer to other tabs in the same group.

15.32.12. New user option tab-bar-tab-name-format-function.

15.32.13. New user option 「tab-line-tab-name-format-function」.

15.32.14. The tabs in the tab line can now be scrolled using horizontal scroll.

If your mouse or trackpad supports it, you can now scroll tabs when the mouse pointer is in the tab line by scrolling left or right.

15.32.15. New tab-line faces and user options.

The face 「tab-line-tab-special」 is used for tabs whose buffers are special, i.e. buffers that don't visit a file. The face 「tab-line-tab-modified」 is used to display modified, file-backed buffers. The face 「tab-line-tab-inactive-alternate」 is used to display inactive tabs with an alternating background color, making them easier to distinguish, especially if the face 「tab-line-tab」 is configured to not display with a box; this alternate face is only applied when the user option 「tab-line-tab-face-functions」 is so configured. That option may also be used to customize tab-line faces in other ways.

15.33. Mouse wheel

15.33.1. Mouse wheel scrolling now defaults to one line at a time.

15.33.2. Mouse wheel scrolling now works on more parts of frame's display.

When using mouse-wheel-mode, the mouse wheel will now scroll also when the mouse cursor is on the scroll bars, fringes, margins, header line, and mode line. (mouse-wheel-mode is enabled by default on most graphical displays.)

15.33.3. Mouse wheel scrolling with Shift modifier now scrolls horizontally.

This works in text buffers and over images. Typing a numeric prefix arg (e.g. 【M-5】) before starting horizontal scrolling changes its step value. The value is saved in the user option mouse-wheel-scroll-amount-horizontal.

15.34. Customize

15.34.1. Customize buffers can now be reverted with 【C-x x g】.

15.34.2. Most customize commands now hide obsolete user options.

Obsolete user options are no longer shown in the listings produced by the commands 'customize', customize-group, customize-apropos and customize-changed.

To customize obsolete user options, use customize-option or customize-saved.

15.34.3. New SVG icons for checkboxes and arrows.

They will be used automatically instead of the old icons. If Emacs is built without SVG support, the old icons will be used instead.

15.35. Help

15.35.1. The order of things displayed in the "Help" buffer has been changed.

The indented "administrative" block (containing the "probably introduced" and "other relevant functions" (and similar things) has been moved to after the doc string.

15.35.2. New command describe-command shows help for a command.

This can be used instead of describe-function for interactive commands and is globally bound to 【C-h x】.

15.35.3. New command describe-keymap describes keybindings in a keymap.

15.35.4. New command apropos-function.

This works like 'C-u M-x apropos-command' but is more discoverable.

15.35.5. New keybinding 【C-h R】 prompts for an Info manual and displays it.

15.35.6. Keybindings in help-mode use the new 「help-key-binding」 face.

This face is added by substitute-command-keys to any "\[command]" substitution. The return value of that function should consequently be assumed to be a propertized string. To prevent the function from adding the 「help-key-binding」 face, call substitute-command-keys with the new optional argument NO-FACE non-nil.

Note that the new face will also be used in tooltips. When using the GTK toolkit, this is only true if 'x-gtk-use-system-tooltips' is t.

15.35.7. New user option help-enable-symbol-autoload.

If non-nil, displaying help for an autoloaded function whose 'autoload' form provides no documentation string will try to load the file it's from. This will give more extensive help for such functions.

15.35.8. The help-for-help ('C-h C-h') screen has been redesigned.

15.35.9. New convenience commands with short keys in the "Help" buffer.

New command help-view-source ('s') will view the source file (if any) of the current help topic. New command help-goto-info ('i') will look up the current symbol (if any) in Info. New command help-customize ('c') will customize the user option or the face (if any) whose doc string is being shown in the "Help" buffer.

15.35.10. New user option describe-bindings-outline.

It enables outlines in the output buffer of describe-bindings that can provide a better overview in a long list of available bindings.

15.35.11. New commands to describe buttons and widgets.

widget-describe (on a widget) will pop up the "Help" buffer and give a description of the properties. Likewise button-describe does the same for a button.

15.35.12. Improved "find definition" feature of "Help" buffers.

Now clicking on the link to find the definition of functions generated by cl-defstruct, or variables generated by define-derived-mode, for example, will go to the exact place where they are defined.

15.35.13. New commands 「apropos-next-symbol」 and 「apropos-previous-symbol」.

These new navigation commands are bound to 'n' and 'p' in 「apropos-mode」.

15.35.14. The command view-lossage can now be invoked from the menu bar.

The menu bar "Help" menu now has a "Show Recent Inputs" item under the "Describe" sub-menu.

15.35.15. New command lossage-size.

It allows users to change the maximum number of keystrokes and commands recorded for the purpose of view-lossage.

15.35.16. Closing the "Help" buffer from the toolbar now buries the buffer.

In previous Emacs versions, the "Help" buffer was killed instead when clicking the "X" icon in the tool bar.

15.35.17. 'g' (revert-buffer) in help-mode no longer requires confirmation.

15.36. File Locks

15.36.1. New user option lock-file-name-transforms.

This option allows controlling where lock files are written. It uses the same syntax as auto-save-file-name-transforms.

15.36.2. New user option remote-file-name-inhibit-locks.

When non-nil, this option suppresses lock files for remote files. Default is nil.

15.36.3. New minor mode lock-file-mode.

This command, called interactively, toggles the local value of create-lockfiles in the current buffer.

15.37. Emacs Server

15.37.1. New user option 「server-client-instructions」.

When emacsclient connects, Emacs will (by default) output a message about how to exit the client frame. If 「server-client-instructions」 is set to nil, this message is inhibited.

15.37.2. New command 「server-edit-abort」.

This command (not bound to any key by default) can be used to abort an edit instead of marking it as "Done" (which the 'C-x #' command does). The 'emacsclient' program exits with an abnormal status as result of this command.

15.37.3. New desktop integration for connecting to the server.

If your operating system's desktop environment is freedesktop.org-compatible (which is true of most GNU/Linux and other recent Unix-like desktops), you may use the new "Emacs (Client)" desktop menu entry to open files in an existing Emacs instance rather than starting a new one. The daemon starts if it is not already running.

15.38. Miscellaneous

15.38.1. New command font-lock-update, bound to 【C-x x f】.

This command updates the syntax highlighting in this buffer.

15.38.2. New command memory-report.

This command opens a new buffer called "Memory Report" and gives a summary of where Emacs is using memory currently.

15.38.3. New command submit-emacs-patch.

This works like report-emacs-bug, but is more geared towards sending patches to the Emacs issue tracker.

15.38.4. New face 「apropos-button」.

Applies to buttons that indicate a face.

15.38.5. New face font-lock-doc-markup-face.

Intended for documentation mark-up syntax and tags inside text that uses font-lock-doc-face, which it should appropriately stand out against and harmonize with. It would typically be used in structured documentation comments in program source code by language-specific modes, for mark-up conventions like Haddock, Javadoc or Doxygen. By default this face inherits from font-lock-constant-face.

15.38.6. New face box style 「flat-button」.

This is a plain 2D button, but uses the background color instead of the foreground color.

15.38.7. New faces 「shortdoc-heading」 and 「shortdoc-section」.

Applied to shortdoc headings and sections.

15.38.8. New face 「separator-line」.

This is used by make-separator-line (see below).

15.38.9. redisplay-skip-fontification-on-input helps Emacs keep up with fast input.

This is another attempt to solve the problem of handling high key repeat rate and other "slow scrolling" situations. It is hoped it behaves better than fast-but-imprecise-scrolling and jit-lock-defer-time. It is not enabled by default.

15.38.10. Obsolete aliases are no longer hidden from command completion.

Completion of command names now considers obsolete aliases as candidates, if they were marked obsolete in the current major version of Emacs. Invoking a command via an obsolete alias now mentions the obsolescence fact and shows the new name of the command.

15.38.11. Support for '(box . SIZE)' cursor-type.

By default, 'box' cursor always has a filled box shape. But if you specify cursor-type to be '(box . SIZE)', the cursor becomes a hollow box if the point is on an image larger than SIZE pixels in any dimension.

15.38.12. The user can now customize how "default" values are prompted for.

The new utility function format-prompt has been added which uses the new minibuffer-default-prompt-format user option to format "default" prompts. This means that prompts that look like "Enter a number (default 10)" can be customized to look like, for instance, "Enter a number [10]", or not have the default displayed at all, like "Enter a number". (This only affects callers that were altered to use format-prompt.)

15.38.13. New help window when Emacs prompts before opening a large file.

Commands like find-file or visit-tags-table ask to visit a file normally or literally when the file is larger than a certain size (by default, 9.5 MiB). Press '?' or 【C-h】 in that prompt to read more about the different options to visit a file, how you can disable the prompt, and how you can tweak the file size threshold.

15.38.14. Emacs now defaults to UTF-8 instead of ISO-8859-1.

This is only for the default, where the user has set no 'LANG' (or similar) variable or environment. This change should lead to no user-visible changes for normal usage.

15.38.15. global-display-fill-column-indicator-mode skips some buffers.

By default, turning on global-display-fill-column-indicator-mode doesn't turn on display-fill-column-indicator-mode in special-mode buffers. This can be controlled by customizing the user option global-display-fill-column-indicator-modes.

15.38.16. nobreak-char-display now also affects all non-ASCII space characters.

Previously, this was limited only to 'NO-BREAK SPACE' and hyphen characters. Now it also covers the rest of the non-ASCII Unicode space characters. Also, unlike in previous versions of Emacs, the non-ASCII characters are displayed as themselves when nobreak-char-display is t, i.e. they are not replaced on display with the ASCII space and hyphen characters.

15.38.17. New backward compatibility variable nobreak-char-ascii-display.

This variable is nil by default, and non-ASCII space and hyphen characters are displayed as themselves, even if nobreak-char-display is non-nil. If nobreak-char-ascii-display is set to a non-nil value, the non-ASCII space and hyphen characters are instead displayed as their ASCII counterparts: spaces and ASCII hyphen (a.k.a. "dash") characters. This provides backward compatibility feature for the change described above, where the non-ASCII characters are no longer replaced with their ASCII counterparts when nobreak-char-display is t. You may need this on text-mode terminals that produce messed up display when non-ASCII spaces and hyphens are written to the display. (This variable is only effective when nobreak-char-display is t.)

15.38.18. Improved support for terminal emulators that encode the Meta flag.

Some terminal emulators set the 8th bit of Meta characters, and then encode the resulting character code as if it were non-ASCII character above codepoint 127. Previously, the only way of using these in Emacs was to set up the terminal emulator to use the 'ESC' characters to send Meta characters to Emacs, e.g., send "ESC x" when the user types 【M-x】. You can now avoid the need for this setup of such terminal emulators by using the new input-meta-mode with the special value 'encoded' with these terminal emulators.

15.38.19. auto-composition-mode can now be selectively disabled on some TTYs.

Some text-mode terminals produce display glitches trying to compose characters. The auto-composition-mode can now have a string value that names a terminal type; if the value returned by the tty-type function compares equal with that string, automatic composition will be disabled in windows shown on that terminal. The Linux terminal sets this up by default.

15.38.20. Support for the 「strike-through」 face attribute on TTY frames.

If your terminal's termcap or terminfo database entry has the 'smxx' capability defined, Emacs will now emit the prescribed escape sequences necessary to render faces with the 「strike-through」 attribute on TTY frames.

15.38.21. TTY menu navigation is now supported in xterm-mouse-mode.

TTY menus support mouse navigation and selection when xterm-mouse-mode is active. When run on a terminal, clicking on the menu bar with the mouse now pops up a TTY menu by default instead of running the command tmm-menubar. To restore the old behavior, set the user option tty-menu-open-use-tmm to non-nil.

15.38.22. 'M-x report-emacs-bug' will no longer include "Recent messages" section.

These were taken from the "Messages" buffer, and may inadvertently leak information from the reporting user.

15.38.23. 'C-u M-x dig' will now prompt for a query type to use.

15.38.24. Rudimentary support for the 'st' terminal emulator.

Emacs now supports 256 color display on the 'st' terminal emulator.

15.38.25. Update IRC-related references to point to Libera.Chat.

The Free Software Foundation and the GNU Project have moved their official IRC channels from the Freenode network to Libera.Chat. For the original announcement and the follow-up update, including more details, see:

https://lists.gnu.org/archive/html/info-gnu/2021-06/msg00005.html https://lists.gnu.org/archive/html/info-gnu/2021-06/msg00007.html

Given the relocation of GNU and FSF's official IRC channels, as well as #emacs and various other Emacs-themed channels (see the link below) to Libera.Chat, IRC-related references in the Emacs repository have now been updated to point to Libera.Chat.


16. Incompatible Editing Changes in Emacs 28.1

16.1. toggle-truncate-lines now disables visual-line-mode.

This is for symmetry with visual-line-mode, which disables truncate-lines.

16.2. electric-indent-mode now also indents inside strings and comments.

(This only happens when indentation function also supports this.)

To recover the previous behavior you can use:

(add-hook 'electric-indent-functions (lambda (_) (if (nth 8 (syntax-ppss)) 'no-indent)))

16.3. The 【M-o】 (facemenu-keymap) global binding has been removed.

To restore the old binding, say something like:

(require 'facemenu) (define-key global-map "\M-o" 'facemenu-keymap) (define-key facemenu-keymap "\es" 'center-line) (define-key facemenu-keymap "\eS" 'center-paragraph)

The last two lines are not strictly necessary if you don't care about having those two commands on the 【M-o】 keymap; see the next section.

16.4. The 'M-o M-s' and 'M-o M-S' global bindings have been removed.

Use 'M-x center-line' and 'M-x center-paragraph' instead. See the previous section for how to get back the old bindings. Alternatively, if you only want these two commands to have the global bindings they had before, you can add the following to your init file:

(define-key global-map "\M-o\M-s" 'center-line) (define-key global-map "\M-o\M-S" 'center-paragraph)

16.5. The 'M-o M-o' global binding has been removed.

Use 'M-x font-lock-fontify-block' instead, or the new 【C-x x f】 command, which updates the syntax highlighting in the current buffer.

16.6. The escape sequence '\e[29~' in Xterm is now mapped to 'menu'.

Xterm sends this sequence for both 'F16' and 'Menu' keys It used to be mapped to 'print' but we couldn't find a terminal that uses this sequence for any kind of 'Print' key. This makes the Menu key (see https://en.wikipedia.org/wiki/Menu_key) work for context-menu-mode in Xterm.

16.7. New user option 「xterm-store-paste-on-kill-ring」.

If non-nil (the default), Emacs pushes pasted text onto the kill ring (if using an xterm-like terminal that supports bracketed paste). Setting this to nil inhibits that.

16.8. vc-print-branch-log shows the change log from its root directory.

It previously used to use the default directory.

16.9. project-shell and 'shell' now use pop-to-buffer-same-window.

This is to keep the same behavior as Eshell.

16.10. In nroff-mode, center-line is no longer bound to a key.

The original key binding was 【M-s】, which interfered with Isearch, since the latter uses 【M-s】 as a prefix key of the search prefix map.

16.11. In f90-mode, the backslash character ('\') no longer escapes.

For about a decade, the backslash character has no longer had a special escape syntax in Fortran F90. To get the old behavior back, say something like:

(modify-syntax-entry ?\\ "\\" f90-mode-syntax-table)

16.12. Setting fill-column to nil is obsolete.

This undocumented use of fill-column is now obsolete. To disable auto filling, turn off auto-fill-mode instead.

For instance, you could add something like the following to your init file:

(add-hook 'foo-mode-hook (lambda () (auto-fill-mode -1))

17. Editing Changes in Emacs 28.1

17.1. Input methods

17.1.1. Emacs now supports "transient" input methods.

A transient input method is enabled for inserting a single character, and is then automatically disabled. 'C-x \' temporarily enables the selected transient input method. Use 'C-u C-x \' to select a transient input method (which can be different from the input method enabled by 'C-\'). For example, 'C-u C-x \ compose RET' selects the 'compose' input method; then typing 'C-x \ 1 2' will insert the character '½', and disable the 'compose' input method afterwards. You can use 'C-x \' in incremental search to insert a single character to the search string.

17.1.2. New input method 'compose' based on X Multikey sequences.

17.1.3. New input method 「iso-transl」 with the same keys as 【C-x 8】.

After selecting it as a transient input method with 'C-u C-x \ iso-transl RET', it supports the same key sequences as 【C-x 8】, so e.g. like 'C-x 8 [' inserts a left single quotation mark, 'C-x \ [' does the same.

17.1.4. New user option read-char-by-name-sort.

It defines the sorting order of characters for completion of 【C-x 8 RET TAB】 and can be customized to sort them by codepoints instead of character names. Additionally, you can group characters by Unicode blocks after customizing completions-group and completions-group-sort.

17.1.5. Improved language transliteration in Malayalam input methods.

Added a new Mozhi scheme. The inapplicable ITRANS scheme is now deprecated. Errors in the Inscript method were corrected.

17.1.6. New input method 'cham'.

There's also a Cham greeting in "etc/HELLO".

17.1.7. New input methods for Lakota language orthographies.

Two orthographies are represented here, the Suggested Lakota Orthography and what is known as the White Hat Orthography. Input methods 「lakota-slo-prefix」, 「lakota-slo-postfix」, and 「lakota-white-hat-postfix」 have been added. There is also a Lakota greeting in "etc/HELLO".

17.2. Standalone 【M-y】 allows interactive selection from previous kills.

【M-y】 can now be typed after a command that is not a yank command. When invoked like that, it prompts in the minibuffer for one of the previous kills, offering completion and minibuffer-history navigation through previous kills recorded in the kill ring. A similar feature in Isearch can be invoked if you bind 'C-s M-y' to the command isearch-yank-pop. When the user option yank-from-kill-ring-rotate is nil the kill ring is not rotated after yank-from-kill-ring.

17.3. New user option word-wrap-by-category.

When word-wrap is enabled, and this option is non-nil, that allows Emacs to break lines after more characters than just whitespace characters. In particular, this significantly improves word-wrapping for CJK text mixed with Latin text.

17.4. New command undo-redo.

It undoes previous undo commands, but doesn't record itself as an undoable command. It is bound to 'C-?' and 'C-M-_', the first binding works well in graphical mode, and the second one is easy to hit on tty.

For full conventional undo/redo behavior, you can also customize the user option undo-no-redo to t.

17.5. New commands copy-matching-lines and kill-matching-lines.

These commands are similar to the command flush-lines, but add the matching lines to the kill ring as a single string, including the newlines that separate the lines.

17.6. New user option kill-transform-function.

This can be used to transform (and suppress) strings from entering the kill ring.

17.7. save-interprogram-paste-before-kill can now be a number.

In that case, it's interpreted as a limit on the size of the clipboard data that will be saved to the kill-ring prior to killing text: if the size of the clipboard data is greater than or equal to the limit, it will not be saved.

17.8. New user option tab-first-completion.

If tab-always-indent is 'complete', this new user option can be used to further tweak whether to complete or indent.

17.9. indent-tabs-mode is now a global minor mode instead of just a variable.

17.10. New choice 'permanent' for shift-select-mode.

When the mark was activated by shifted motion keys, non-shifted motion keys don't deactivate the mark after customizing shift-select-mode to 'permanent'. Similarly, the active mark will not be deactivated by typing shifted motion keys.

17.11. The "Edit => Clear" menu item now obeys a rectangular region.

17.12. New command revert-buffer-with-fine-grain.

Revert a buffer trying to be as non-destructive as possible, preserving markers, properties and overlays. The new variable revert-buffer-with-fine-grain-max-seconds specifies the maximum number of seconds that revert-buffer-with-fine-grain should spend trying to be non-destructive, with a default value of 2 seconds.

17.13. New command revert-buffer-quick.

This is bound to 【C-x x g】 and is like revert-buffer, but prompts less.

17.14. New user option revert-buffer-quick-short-answers.

This controls how the new revert-buffer-quick (【C-x x g】) command prompts. A non-nil value will make it use 'y-or-n-p' rather than yes-or-no-p. Defaults to nil.

17.15. New user option query-about-changed-file.

If non-nil (the default), Emacs prompts as before when re-visiting a file that has changed externally after it was visited the first time. If nil, Emacs does not prompt, but instead shows the buffer with its contents before the change, and provides instructions how to revert the buffer.

17.16. New value save-some-buffers-root of save-some-buffers-default-predicate.

When using this predicate, only buffers under the current project root will be considered when saving buffers with save-some-buffers.

17.17. New user option save-place-abbreviate-file-names.

This can simplify sharing the save-place-file file across different hosts.

17.18. New user options copy-region-blink-delay and delete-pair-blink-delay.

copy-region-blink-delay specifies a delay to indicate the region copied by kill-ring-save. delete-pair-blink-delay specifies a delay to show the paired character to delete.

17.19. zap-up-to-char now uses read-char-from-minibuffer.

This allows navigating through the history of characters that have been input. This is mostly useful for characters that have complex input methods where inputting the character again may involve many keystrokes.

17.20. Input history for goto-line can now be made local to every buffer.

In any event, line numbers used with goto-line are kept in their own history list. This should help make faster the process of finding line numbers that were previously jumped to. By default, all buffers share a single history list. To make every buffer have its own history list, customize the user option goto-line-history-local.

17.21. New command goto-line-relative for use in a narrowed buffer.

It moves point to the line relative to the accessible portion of the narrowed buffer. 'M-g M-g' in Info is rebound to this command. When widen-automatically is non-nil, goto-line widens the narrowed buffer to be able to move point to the inaccessible portion. goto-line-relative is bound to 【C-x n g】.

17.22. goto-char prompts for the character position.

When called interactively, goto-char now offers the position at point as the default.

17.23. Auto-saving via auto-save-visited-mode can now be inhibited.

Set the user option auto-save-visited-mode buffer-locally to nil to achieve that.

17.24. New command 「kdb-macro-redisplay」 to force redisplay in keyboard macros.

This command is bound to 'C-x C-k d'.

17.25. blink-cursor-mode is now enabled by default regardless of the UI.

It used to be enabled when Emacs is started in GUI mode but not when started in text mode. The cursor still only actually blinks in GUI frames.

17.26. show-paren-mode is now enabled by default.

To go back to the previous behavior, customize the user option of the same name to nil.

17.27. New minor mode show-paren-local-mode.

It serves as a local counterpart for show-paren-mode, allowing you to toggle it separately in different buffers. To use it only in programming modes, for example, add the following to your init file:

(add-hook 'prog-mode-hook #'show-paren-local-mode)

18. Changes in Specialized Modes and Packages in Emacs 28.1

18.1. Isearch and Replace

18.1.1. Interactive regular expression search now uses faces for sub-groups.

E.g., 'C-M-s foo-\([0-9]+\)' will now use the 「isearch-group-1」 face on the part of the regexp that matches the sub-expression "[0-9]+". By default, there are two faces for sub-group highlighting, but you can define more faces whose names are of the form 「isearch-group-N」, where N are successive numbers above 2.

This is controlled by the search-highlight-submatches user option. This feature is available only on terminals that have enough colors to distinguish between sub-expression highlighting.

18.1.2. Interactive regular expression replace now uses faces for sub-groups.

Like search-highlight-submatches, this is controlled by the new user option query-replace-highlight-submatches.

18.1.3. New key 'M-s M-.' starts isearch looking for the thing at point.

This key is bound to the new command isearch-forward-thing-at-point. The new user option isearch-forward-thing-at-point defines a list of symbols to try to get the "thing" at point. By default, the first element of the list is 'region' that tries to yank the currently active region to the search string.

18.1.4. New user option isearch-wrap-pause defines how to wrap the search.

There are choices to disable wrapping completely and to wrap immediately. When wrapping immediately, it consistently handles the numeric arguments of 【C-s】 (isearch-repeat-forward) and 【C-r】 (isearch-repeat-backward), continuing with the remaining count after wrapping.

18.1.5. New user option isearch-repeat-on-direction-change.

When this option is set, direction changes in Isearch move to another search match, if there is one, instead of moving point to the other end of the current match.

18.1.6. New user option isearch-allow-motion.

When isearch-allow-motion is set, the commands beginning-of-buffer, end-of-buffer, scroll-up-command and scroll-down-command, when invoked during Isearch, move respectively to the first occurrence of the current search string in the buffer, the last one, the first one after the current window, and the last one before the current window. Additionally, users can change the meaning of other motion commands during Isearch by using their 「isearch-motion」 property. The user option isearch-motion-changes-direction controls whether the direction of the search changes after a motion command.

18.1.7. New user option lazy-highlight-no-delay-length.

Lazy highlighting of matches in Isearch now starts immediately if the search string is at least this long. lazy-highlight-initial-delay still applies for shorter search strings, which avoids flicker in the search buffer due to too many matches being highlighted.

18.1.8. The default search-whitespace-regexp value has changed.

This used to be "\\s-+", which meant that it was mode-dependent whether newlines were included in the whitespace set. This has now been changed to only match spaces and tab characters.

18.2. Dired

18.2.1. New user option dired-kill-when-opening-new-dired-buffer.

If non-nil, Dired will kill the current buffer when selecting a new directory to display.

18.2.2. Behavior change on dired-do-chmod.

As a security precaution, Dired's 'M' command no longer follows symbolic links. Instead, it changes the symbolic link's own mode; this always fails on platforms where such modes are immutable.

18.2.3. Behavior change on dired-clean-confirm-killing-deleted-buffers.

Previously, if dired-clean-up-buffers-too was non-nil, and dired-clean-confirm-killing-deleted-buffers was nil, the buffers wouldn't be killed. This combination will now kill the buffers.

18.2.4. New user option dired-switches-in-mode-line.

This user option controls how 'ls' switches are displayed in the mode line, and allows truncating them (to preserve space on the mode line) or showing them literally, either instead of, or in addition to, displaying "by name" or "by date" sort order.

18.2.5. New user option dired-compress-directory-default-suffix.

This user option controls the default suffix for compressing a directory. If it's nil, ".tar.gz" will be used. Refer to dired-compress-files-alist for a list of supported suffixes.

18.2.6. New user option dired-compress-file-default-suffix.

This user option controls the default suffix for compressing files. If it's nil, ".gz" will be used. Refer to dired-compress-file-alist for a list of supported suffixes.

18.2.7. Broken and circular links are shown with the 「dired-broken-symlink」 face.

18.2.8. '=' (dired-diff) will now put all backup files into the 【M-n】 history.

When using '=' on a file with backup files, the default file to use for diffing is the newest backup file. You can now use 【M-n】 to quickly select a different backup file instead.

18.2.9. New user option dired-maybe-use-globstar.

If set, enables globstar (recursive globbing) in shells that support this feature, but have it turned off by default. This allows producing directory listings with files matching a wildcard in all the subdirectories of a given directory. The new variable dired-enable-globstar-in-shell lists which shells can have globstar enabled, and how to enable it.

18.2.10. New user option dired-copy-dereference.

If set to non-nil, Dired will dereference symbolic links when copying. This can be switched off on a per-usage basis by providing dired-do-copy with a 【C-u】 prefix.

18.2.11. New user option dired-do-revert-buffer.

Non-nil reverts the destination Dired buffer after performing one of these operations: dired-do-copy, dired-do-rename, dired-do-symlink, dired-do-hardlink.

18.2.12. New user option dired-mark-region.

This option affects all Dired commands that mark files. When non-nil and the region is active in Transient Mark mode, then Dired commands operate only on files in the active region. The values 'file' and 'line' of this user option define the details of marking the file at the end of the region.

18.2.13. State changing VC operations are supported in Dired.

These operations are supported on files and directories via the new command dired-vc-next-action.

18.2.14. dired-jump and dired-jump-other-window moved from 「dired-x」 to 'dired'.

The dired-jump and dired-jump-other-window commands have been moved from the 「dired-x」 package to 'dired'. The user option dired-bind-jump no longer has any effect and is now obsolete. The commands are now bound to 'C-x C-j' and 'C-x 4 C-j' by default.

To get the old behavior of dired-bind-jump back and unbind the above keys, add the following to your init file:

(global-set-key "\C-x\C-j" nil) (global-set-key "\C-x4\C-j" nil)

18.2.15. dired-query now uses read-char-from-minibuffer.

Using it instead of read-char-choice allows using 【C-x o】 to switch to the help window displayed after typing 【C-h】.

18.3. Emacs 28.1 comes with Org v9.5.

See the file ORG-NEWS for user-visible changes in Org.

18.4. Outline

18.4.1. New commands to cycle heading visibility.

Typing 'TAB' on a heading line cycles the current section between "hide all", "subheadings", and "show all" states. Typing 「S-TAB」 anywhere in the buffer cycles the whole buffer between "only top-level headings", "all headings and subheadings", and "show all" states.

18.4.2. New user option outline-minor-mode-cycle.

This user option customizes outline-minor-mode, with the difference that 'TAB' and 「S-TAB」 on heading lines cycle heading visibility. Typing 'TAB' on a heading line cycles the current section between "hide all", "subheadings", and "show all" states. Typing 「S-TAB」 on a heading line cycles the whole buffer between "only top-level headings", "all headings and subheadings", and "show all" states.

18.4.3. New user option outline-minor-mode-highlight.

This user option customizes outline-minor-mode. It puts highlighting on heading lines using standard outline faces. This works well only when there are no conflicts with faces used by the major mode.

18.5. Ispell

18.5.1. ispell-comments-and-strings now accepts START and END arguments.

These arguments default to the active region when used interactively.

18.5.2. New command ispell-comment-or-string-at-point.

18.5.3. New user option 「ispell-help-timeout」.

This controls how long the ispell help (on the '?' key) is displayed.

18.6. Flyspell mode

18.6.1. Corrections and actions menu can be optionally bound to 「mouse-3」.

When Flyspell mode highlights a word as misspelled, you can click on it to display a menu of possible corrections and actions. You can now easily bind this menu to 「down-mouse-3」 (usually the right mouse button) instead of 「mouse-2」 (the default) by enabling context-menu-mode.

18.6.2. The current dictionary is now displayed in the minor mode lighter.

Clicking the dictionary name changes the current dictionary.

18.7. Package

18.7.1. The new NonGNU ELPA archive is enabled by default alongside GNU ELPA.

Thus, packages on NonGNU ELPA will appear by default in the list shown by list-packages.

18.7.2. '/ s' (package-menu-filter-by-status) changed parameter handling.

The command was documented to take a comma-separated list of statuses to filter by, but instead it used the parameter as a regexp. The command has been changed so that it now works as documented, and checks statuses not as a regexp, but instead an exact match from the comma-separated list.

18.7.3. New command package-browse-url and keystroke 'w'.

18.7.4. New commands to filter the package list.

The filter commands are bound to the following keys:

key binding — --–— / a package-menu-filter-by-archive / d package-menu-filter-by-description / k package-menu-filter-by-keyword / N package-menu-filter-by-name-or-description / n package-menu-filter-by-name / s package-menu-filter-by-status / v package-menu-filter-by-version / m package-menu-filter-marked / u package-menu-filter-upgradable / / package-menu-clear-filter

18.7.5. Option to automatically native-compile packages upon installation.

Customize the user option package-native-compile to enable automatic native compilation of packages when they are installed. That option is nil by default; if set non-nil, and if your Emacs was built with native-compilation support, each package will be natively compiled when it is installed, by invoking an asynchronous Emacs subprocess to run the native-compilation of the package files. (Be sure to leave Emacs running until these asynchronous subprocesses exit, or else the native-compilation will be aborted when you exit Emacs.)

18.7.6. Column widths in list-packages display can now be customized.

See the new user options package-name-column-width, package-version-column-width, package-status-column-width, and package-archive-column-width.

18.8. Info

18.8.1. New user option 'Info-warn-on-index-alternatives-wrap'.

This option affects what happens when using the ',' command after looking up an entry with 'i' in info buffers. If non-nil (the default), the ',' command will now display a warning when proceeding beyond the final index match, and tapping ',' once more will then take you to the first match.

18.9. Abbrev mode

18.9.1. Emacs can now suggest to use an abbrev based on text you type.

A new user option, abbrev-suggest, enables the new abbrev suggestion feature. When enabled, if a user manually types a piece of text that could have saved enough typing by using an abbrev, a hint will be displayed in the echo area, mentioning the abbrev that could have been used instead.


18.10.1. Bookmarks can now be targets for new tabs.

When the bookmark.el library is loaded, a customize choice is added to tab-bar-new-tab-choice for new tabs to show the bookmark list.

18.10.2. New user option bookmark-set-fringe-mark.

If non-nil, setting a bookmark will set a fringe mark on the current line, and jumping to a bookmark will also set this mark.

18.10.3. New user option bookmark-menu-confirm-deletion.

In Bookmark Menu mode, Emacs by default does not prompt for confirmation when you type 'x' to execute the deletion of bookmarks that have been marked for deletion. However, if this new option is non-nil then Emacs will require confirmation with yes-or-no-p before deleting.

18.10.4. The list-bookmarks menu is now based on tabulated-list-mode.

The interactive bookmark list will now benefit from features in tabulated-list-mode like sorting columns or changing column width.

Support for the optional "inline" header line, allowing for a header without using header-line-format, has been dropped. The variables bookmark-bmenu-use-header-line and bookmark-bmenu-inline-header-height are now obsolete.

18.11. Recentf

18.11.1. The recentf files are no longer backed up.

18.11.2. recentf-auto-cleanup now repeats daily when set to a time string.

When recentf-auto-cleanup is set to a time string, it now repeats every day, rather than only running once after the mode is turned on.

18.12. Calc

18.12.1. The behavior when doing forward-delete has been changed.

Previously, using the 【C-d】 command would delete the final number in the input field, no matter where point was. This has been changed to work more traditionally, with 【C-d】 deleting the next character. Likewise, point isn't moved to the end of the string before inserting digits.

18.12.2. Setting the word size to zero disables word clipping.

The word size normally clips the results of certain bit-oriented operations such as shifts and bitwise XOR. A word size of zero, set by 'b w', makes the operation have effect on the whole argument values and the result is not truncated in any way.

18.12.3. The '/' operator now has higher precedence in (La)TeX input mode.

It no longer has lower precedence than '+' and '-'.

18.12.4. New user option 「calc-make-windows-dedicated」.

When this user option is non-nil, Calc will mark its windows as dedicated.

18.13. Calendar

18.13.1. New user option 「calendar-time-zone-style」.

If 'numeric', calendar functions (eg 「calendar-sunrise-sunset」) that display time zones will use a form like "+0100" instead of "CET".

18.14. Imenu

18.14.1. New user option imenu-max-index-time.

If creating the imenu index takes longer than specified by this option (default 5 seconds), imenu indexing is stopped.

18.15. Ido

18.15.1. Switching on ido-mode now also overrides ffap-file-finder.

18.15.2. Killing virtual ido buffers interactively will make them go away.

Previously, killing a virtual ido buffer with ido-kill-buffer didn't do anything. This has now been changed, and killing virtual buffers with that command will remove the buffer from recentf.

18.16. So Long

18.16.1. New 「so-long-predicate」 function 「so-long-statistics-excessive-p」.

It efficiently detects the presence of a long line anywhere in the buffer using buffer-line-statistics (see above). This is now the default predicate (replacing so-long-detected-long-line-p).

18.16.2. Default values 「so-long-threshold」 and 「so-long-max-lines」 increased.

The values of these user options have been raised to 10000 bytes and 500 lines respectively, to reduce the likelihood of false-positives when global-so-long-mode is enabled. The latter value is now only used by the old predicate, as the new predicate knows the longest line in the entire buffer.

18.16.3. 「so-long-target-modes」 now includes fundamental-mode by default.

This means that global-so-long-mode will also process files which were not recognized. (This only has an effect if set-auto-mode chooses fundamental-mode; buffers which are simply in fundamental-mode by default are unaffected.)

18.16.4. New user options to preserve modes and variables.

The new options 「so-long-mode-preserved-minor-modes」 and 「so-long-mode-preserved-variables」 allow specified mode and variable states to be maintained if so-long-mode replaces the original major mode. By default, these new options support view-mode.

18.17. Grep

18.17.1. New user option 「grep-match-regexp」 matches grep markers to highlight.

Grep emits SGR ANSI escape sequences to color its output. The new user option 「grep-match-regexp」 holds the regular expression to match the appropriate markers in order to provide highlighting in the source buffer. The user option can be customized to accommodate other grep-like tools.

18.17.2. The 'lgrep' command now ignores directories.

On systems where the grep command supports it, directories will be skipped.

18.17.3. Commands that use grep-find now follow symlinks for command-line args.

This is because the default value of 「grep-find-template」 now includes the 'find' option '-H'. Commands that use that variable, including indirectly via a call to xref-matches-in-directory, might be affected. In particular, there should be no need anymore to ensure any directory names on the 'find' command lines end in a slash. This change is for better compatibility with old versions of non-GNU 'find', such as the one used on macOS.

18.17.4. New utility function 「grep-file-at-point」.

This returns the name of the file at point (if any) in grep-mode buffers.

18.18. Shell

18.18.1. New command in shell-mode: shell-narrow-to-prompt.

This is bound to 【C-x n d】 in shell-mode buffers, and narrows to the command line under point (and any following output).

18.18.2. New user option shell-has-auto-cd.

If non-nil, shell-mode handles implicit "cd" commands, changing the directory if the command is a directory. Useful for shells like "zsh" that has this feature.

18.19. Term mode

18.19.1. New user option 「term-scroll-snap-to-bottom」.

By default, 'term' and ansi-term will now recenter the buffer so that the prompt is on the final line in the window. Setting this new user option to nil inhibits this behavior.

18.19.2. New user option 「term-set-terminal-size」.

If non-nil, the 'LINES' and 'COLUMNS' environment variables will be set based on the current window size. In previous versions of Emacs, this was always done (and that could lead to odd displays when resizing the window after starting). This variable defaults to nil.

18.19.3. 「term-mode」 now supports "bright" color codes.

"Bright" ANSI color codes are now displayed using the color values defined in 'term-color-bright-*'. In addition, bold text with regular ANSI colors can be displayed as "bright" if ansi-color-bold-is-bright is non-nil.

18.20. Eshell

18.20.1. 「eshell-hist-ignoredups」 can now also be used to mimic "erasedups" in bash.

18.20.2. Environment variable 'INSIDEEMACS' is now copied to subprocesses.

Its value contains the result of evaluating '(format "%s,eshell" emacs-version)'. Other package names, like "tramp", could also be included.

18.20.3. Eshell no longer re-initializes its keymap every call.

This allows users to use '(define-key eshell-mode-map …)' as usual. Some modules have their own minor mode now to account for these changes.

18.20.4. Support for bookmark.el.

The command bookmark-set (bound to 【C-x r m】) is now supported, and will create a bookmark that opens the current directory in Eshell.

18.21. Archive mode

18.21.1. Archive mode can now parse ".squashfs" files.

18.21.2. Can now modify members of 'ar' archives.

18.21.3. Display of summaries is unified between backends.

18.21.4. New user option and command to control displayed columns.

New user option 「archive-hidden-columns」 and new command 「archive-hideshow-column」 let you control which columns are displayed and which are kept hidden.

18.21.5. New command bound to 'C': 「archive-copy-file」.

This command extracts the file at point and writes its data to a file.

18.22. Browse URL

18.22.1. Added support for custom URL handlers.

There is a new variable browse-url-default-handlers and a user option browse-url-handlers being alists with '(REGEXP-OR-PREDICATE . FUNCTION)' entries allowing to define different browsing FUNCTIONs depending on the URL to be browsed. The variable is for default handlers provided by Emacs itself or external packages, the user option is for the user (and allows for overriding the default handlers).

Formerly, one could do the same by setting browse-url-browser-function to such an alist. This usage is still supported but deprecated.

18.22.2. Categorization of browsing commands into internal vs. external.

All standard browsing commands such as browse-url-firefox, browse-url-mail, or 'eww' have been categorized into internal (URL is browsed in Emacs) or external (an external application is spawned with the URL). This is done by adding a 「browse-url-browser-kind」 symbol property to the browsing commands. With a new command browse-url-with-browser-kind, an URL can explicitly be browsed with either an internal or external browser.

18.22.3. Support for browsing of remote files.

If a remote file is specified, a local temporary copy of that file is passed to the browser.

18.22.4. Support for the conkeror browser is now obsolete.

18.22.5. Support for the Mosaic browser has been removed.

This support has been obsolete since 25.1.

18.23. Completion list mode

18.23.1. Improved navigation in the "Completions" buffer.

New key bindings have been added to completion-list-mode: 'n' and 'p' now navigate completions, and 'M-g M-c' switches to the minibuffer and back to the completion list buffer.

18.24. Profiler

The results displayed by 「profiler-report」 now have the usage figures at the left hand side followed by the function name. This is intended to make better use of the horizontal space, in particular eliminating the truncation of function names. There is no way to get the former layout back.

18.25. Icomplete

18.25.1. New user option icomplete-matches-format.

This allows controlling the current/total number of matches for the prompt prefix.

18.25.2. New minor modes icomplete-vertical-mode and fido-vertical-mode.

These modes modify Icomplete (icomplete-mode) and Fido (fido-mode), to display completion candidates vertically instead of horizontally. In Icomplete, completions are rotated and selection kept at the top. In Fido, completions scroll like a typical dropdown widget. Both these new minor modes will turn on their non-vertical counterparts first, if they are not on already.

18.25.3. Default value of icomplete-compute-delay has been changed to 0.15 s.

18.25.4. Default value of icomplete-max-delay-chars has been changed to 2.

18.25.5. Reduced blinking while completing the next completions set.

Icomplete doesn't hide the hint with the previously computed completions anymore when compute delay is in effect, or the previous computation has been aborted by input. Instead it shows the previous completions until the new ones are ready.

18.25.6. Change in meaning of icomplete-show-matches-on-no-input.

Previously, choosing a different completion with commands like 'C-.' and then hitting 'RET' would choose the default completion. Doing this will now choose the completion under point instead. Also when this option is nil, completions are not shown when the minibuffer reads a file name with initial input as the default directory.

18.26. Windmove

18.26.1. New user options to customize windmove keybindings.

These options include windmove-default-keybindings, windmove-display-default-keybindings, windmove-delete-default-keybindings, windmove-swap-states-default-keybindings. Also new mode windmove-mode enables the customized keybindings.

18.27. Occur mode

18.27.1. New bindings in occur-mode.

The command next-error-no-select is now bound to 'n' and previous-error-no-select is bound to 'p'.

18.27.2. New command recenter-current-error.

It is bound to 'l' in Occur or compilation buffers, and recenters the current displayed occurrence/error.

18.27.3. Matches in target buffers are now highlighted as in compilation-mode.

The method of highlighting is specified by the user options next-error-highlight and next-error-highlight-no-select.

18.27.4. A fringe arrow in the "Occur" buffer indicates the selected match.

18.27.5. Occur mode may use a different type for 「occur-target」 property values.

The value was previously always a marker set to the start of the first match on the line but can now also be a list of '(BEGIN . END)' pairs of markers delimiting each match on the line. This is a fully compatible change to the internal occur-mode implementation, and code creating their own occur-mode buffers will work as before.

18.28. Emacs Lisp mode

18.28.1. The mode-line now indicates whether we're using lexical or dynamic scoping.

18.28.2. A space between an open paren and a symbol changes the indentation rule.

The presence of a space between an open paren and a symbol now is taken as a statement by the programmer that this should be indented as a data list rather than as a piece of code.

18.29. Lisp mode

18.29.1. New minor mode cl-font-lock-built-in-mode for lisp-mode.

The mode provides refined highlighting of built-in functions, types, and variables.

18.29.2. Lisp mode now uses common-lisp-indent-function.

To revert to the previous behavior, '(setq lisp-indent-function #'lisp-indent-function)' from lisp-mode-hook.

18.30. Change Logs and VC

18.30.1. vc-revert-show-diff now has a third possible value: 'kill'.

If this user option is 'kill', then the diff buffer will be killed after the vc-revert action instead of buried.

18.30.2. More VC commands can be used from non-file buffers.

The relevant commands are those that don't change the VC state. The non-file buffers which can use VC commands are those that have their default-directory under VC.

18.30.3. New face 「log-view-commit-body」.

This is used when expanding commit messages from vc-print-root-log and similar commands.

18.30.4. New faces for vc-dir buffers.

Those are: 「vc-dir-header」, 「vc-dir-header-value」, 「vc-dir-directory」, 「vc-dir-file」, 「vc-dir-mark-indicator」, 「vc-dir-status-warning」, 「vc-dir-status-edited」, 「vc-dir-status-up-to-date」, 「vc-dir-status-ignored」.

18.30.5. The responsible VC backend is now the most specific one.

vc-responsible-backend loops over the backends in vc-handled-backends to determine which backend is responsible for a specific (unregistered) file. Previously, the first matching backend was chosen, but now the one with the most specific path is chosen (in case there's a directory handled by one backend inside another).

18.30.6. New command vc-dir-root uses the root directory without asking.

18.30.7. New commands 「vc-dir-mark-registered-files」 (bound to '* r') and


18.30.8. Support for bookmark.el.

Bookmark locations can refer to VC directory buffers.

18.30.9. New user option 「vc-hg-create-bookmark」.

It controls whether a bookmark or branch will be created when you invoke 'C-u C-x v s' (vc-create-tag).

18.30.10. 「vc-hg」 now uses 'hg summary' to populate extra vc-dir headers.

18.30.11. New user option vc-git-revision-complete-only-branches.

If non-nil, only branches and remotes are considered when doing completion over Git branch names. The default is nil, which causes tags to be considered as well.

18.30.12. New user option vc-git-log-switches.

String or list of strings specifying switches for Git log under VC.

18.30.13. Command vc-switch-backend is now obsolete.

If you are still using it with any regularity, please file a bug report with some details.

18.30.14. New variable vc-git-use-literal-pathspecs.

The Git backend's function now treat all file names "literally", where some of them previously could interpret file names (pathspecs) as globs when they contain appropriate characters. Functions can bind the aforementioned variable to nil locally to avoid this.

18.31. Gnus

18.31.1. New user option 「gnus-topic-display-predicate」.

This can be used to inhibit the display of some topics completely.

18.31.2. nnimap now supports the oauth2.el library.

18.31.3. New Summary buffer sort options for extra headers.

The extra header sort option ('C-c C-s C-x') prompts for a header and fails if no sort function has been defined. Sorting by Newsgroups ('C-c C-s C-u') has been pre-defined.

18.31.4. The '#' command in the Group and Summary buffer now toggles,

instead of sets, the process mark.

18.31.5. New user option 「gnus-process-mark-toggle」.

If non-nil (the default), the '#' command in the Group and Summary buffers will toggle, instead of set, the process mark.

18.31.6. New user option 「gnus-registry-register-all」.

If non-nil (the default), create registry entries for all messages. If nil, don't automatically create entries, they must be created manually.

18.31.7. New user options to customize the summary line specs "%[" and "%]".

Four new options introduced in customization group 「gnus-summary-format」. These are 「gnus-sum-opening-bracket」, 「gnus-sum-closing-bracket」, 「gnus-sum-opening-bracket-adopted」, and 「gnus-sum-closing-bracket-adopted」. Their default values are "[", "]", "<", ">" respectively. These options control the appearance of "%[" and "%]" specs in the summary line format. "%[" will normally display the value of 「gnus-sum-opening-bracket」, but can also be 「gnus-sum-opening-bracket-adopted」 for the adopted articles. "%]" will normally display the value of 「gnus-sum-closing-bracket」, but can also be 「gnus-sum-closing-bracket-adopted」 for the adopted articles.

18.31.8. New user option 「gnus-paging-select-next」.

This controls what happens when using commands like 'SPC' and 'DEL' to page the current article. If non-nil (the default), go to the next/prev article, but if nil, do nothing at the end/start of the article.

18.31.9. New gnus-search library.

A new unified search syntax which can be used across multiple supported search engines. Set 「gnus-search-use-parsed-queries」 to non-nil to enable.

18.31.10. New value for user option 「smiley-style」.

Smileys can now be rendered with emojis instead of small images when using the new 'emoji' value in 「smiley-style」.

18.31.11. New user option 「gnus-agent-eagerly-store-articles」.

If non-nil (which is the default), the Gnus Agent will store all read articles in the Agent cache.

18.31.12. New user option 「gnus-global-groups」.

Gnus handles private groups differently from public (i.e., NNTP-like) groups. Most importantly, Gnus doesn't download external images from mail-like groups. This can be overridden by putting group names in 「gnus-global-groups」: Any group present in that list will be treated like a public group.

18.31.13. New scoring types for the Date header.

You can now score based on the relative age of an article with the new '<' and '>' date scoring types.

18.31.14. User-defined scoring is now possible.

The new type is 「score-fn」. More information in the Gnus manual node "(gnus) Score File Format".

18.31.15. New backend 'nnselect'.

The newly added 'nnselect' backend allows creating groups from an arbitrary list of articles that may come from multiple groups and servers. These groups generally behave like any other group: they may be ephemeral or persistent, and allow article marking, moving, deletion, etc. 'nnselect' groups may be created like any other group, but there are three convenience functions for the common case of obtaining the list of articles as a result of a search: 「gnus-group-make-search-group」 ('G g') that will prompt for an 'nnir' search query and create a persistent group for that search; 「gnus-group-read-ephemeral-search-group」 ('G G') that will prompt for an 'nnir' search query and create an ephemeral group for that search; and 「gnus-summary-make-group-from-search」 ('C-c C-p') that will create a persistent group with the search parameters of a current ephemeral search group.

As part of this addition, the user option 「nnir-summary-line-format」 has been removed; its functionality is now available directly in the 「gnus-summary-line-format」 specs '%G' and '%g'. The user option 「gnus-refer-thread-use-nnir」 has been renamed to 「gnus-refer-thread-use-search」.

18.31.16. New user option 「gnus-dbus-close-on-sleep」.

On systems with D-Bus support, it is now possible to register a signal to close all Gnus servers before the system sleeps.

18.31.17. The key binding of 「gnus-summary-search-article-forward」 has changed.

This command was previously on 【M-s】 and shadowed the global 【M-s】 search prefix. The command has now been moved to 'M-s M-s'. (For consistency, the 'M-s M-r' key binding has been added for the 「gnus-summary-search-article-backward」 command.)

18.31.18. The value for "all" in the 「large-newsgroup-initial」 group parameter has changed.

It was previously nil, which didn't work, because nil is indistinguishable from not being present. The new value for "all" is the symbol 'all'.

18.31.19. The name of dependent Gnus sessions has changed from "slave" to "child".

The names of the commands gnus-slave, gnus-slave-no-server and gnus-slave-unplugged have changed to gnus-child, gnus-child-no-server and gnus-child-unplugged respectively.

18.31.20. The 'W Q' summary mode command now takes a numerical prefix to

allow adjusting the fill width.

18.31.21. New variable 「mm-inline-font-lock」.

This variable is supposed to be bound by callers to determine whether inline MIME parts (that support it) are supposed to be font-locked or not.

18.32. Message

18.32.1. Respect 「message-forward-ignored-headers」 more.

Previously, this user option would not be consulted if 「message-forward-show-mml」 was nil and forwarding as MIME.

18.32.2. New user option 「message-forward-included-mime-headers」.

This is used when forwarding messages as MIME, but not using MML.

18.32.3. Message now supports the OpenPGP header.

To generate these headers, add the new function 「message-add-openpgp-header」 to 「message-send-hook」. The header will be generated according to the new 「message-openpgp-header」 user option.

18.32.4. A change to how "Mail-Copies-To: never" is handled.

If a user has specified "Mail-Copies-To: never", and Message was asked to do a "wide reply", some other arbitrary recipient would end up in the resulting "To" header, while the remaining recipients would be put in the "Cc" header. This is somewhat misleading, as it looks like you're responding to a specific person in particular. This has been changed so that all the recipients are put in the "To" header in these instances.

18.32.5. New command to start Emacs in Message mode to send an email.

Emacs can be defined as a handler for the "x-scheme-handler/mailto" MIME type with the following command: "emacs -f message-mailto %u". An "emacs-mail.desktop" file has been included, suitable for installing in desktop directories like "usr/share/applications" or "~.local/share/applications". Clicking on a 'mailto:' link in other applications will then open Emacs with headers filled out according to the link, example: "mailto:larsi@gnus.org?subject=This+is+a+test". If you prefer emacsclient, use "emacsclient -e '(message-mailto "%u")'" or "emacsclient-mail.desktop".

18.32.6. Change to default value of 「message-draft-headers」 user option.

The 'Date' symbol has been removed from the default value, meaning that draft or delayed messages will get a date reflecting when the message was sent. To restore the original behavior of dating a message from when it is first saved or delayed, add the symbol 'Date' back to this user option.

18.32.7. New command to take screenshots.

In Message mode buffers, the 'C-c C-p' (「message-insert-screenshot」) command has been added. It depends on using an external program to take the actual screenshot, and defaults to "ImageMagick import".

18.33. Smtpmail

18.33.1. smtpmail now supports using the oauth2.el library.

18.33.2. New user option 「smtpmail-store-queue-variables」.

If non-nil, SMTP variables will be stored together with the queued messages, and will then be used when sending with command smtpmail-send-queued-mail.

18.33.3. Allow direct selection of smtp authentication mechanism.

A server entry retrieved by auth-source can request a desired smtp authentication mechanism by setting a value for the key 「smtp-auth」.

18.34. ElDoc

18.34.1. New user option eldoc-echo-area-display-truncation-message.

If non-nil (the default), eldoc will display a message saying something like "(Documentation truncated. Use `M-x eldoc-doc-buffer' to see rest)" when a message has been truncated. If nil, truncated messages will be marked with just "…" at the end.

18.34.2. New hook eldoc-documentation-functions.

This hook is intended to be used for registering doc string functions. These functions don't need to produce the doc string right away, they may arrange for it to be produced asynchronously. The results of all doc string functions are accessible to the user through the user option eldoc-documentation-strategy.

18.34.3. New hook eldoc-display-functions.

This hook is intended to be used for displaying doc strings. The functions receive the doc string composed according to eldoc-documentation-strategy and are tasked with displaying it to the user. Examples of such functions would use the echo area, a separate buffer, or a tooltip.

18.34.4. New user option eldoc-documentation-strategy.

The built-in choices available for this user option let users compose the results of eldoc-documentation-functions in various ways, even if some of those functions are synchronous and some asynchronous. The user option replaces eldoc-documentation-function, which is now obsolete.

18.34.5. eldoc-echo-area-use-multiline-p is now handled by ElDoc.

The user option eldoc-echo-area-use-multiline-p is now handled by the ElDoc library itself. Functions in eldoc-documentation-functions don't need to worry about consulting it when producing a doc string.

18.35. Tramp

18.35.1. New connection method "mtp".

It allows accessing media devices like cell phones, tablets or cameras.

18.35.2. New connection method "sshfs".

It allows accessing remote files via a file system mounted with 'sshfs'.

18.35.3. Tramp supports SSH authentication via a hardware security key now.

This requires at least OpenSSH 8.2, and a FIDO U2F compatible security key, like yubikey, solokey, or nitrokey.

18.35.4. Trashed remote files are moved to the local trash directory.

All remote files that are trashed are moved to the local trash directory, except remote encrypted files, which are always deleted.

18.35.5. New command tramp-crypt-add-directory.

This command marks a remote directory to contain only encrypted files. See the "(tramp) Keeping files encrypted" node of the Tramp manual for details. This feature is experimental.

18.35.6. Support of direct asynchronous process invocation.

When Tramp connection property "direct-async-process" is set to non-nil for a given connection, make-process and start-file-process calls are performed directly as in "ssh … <command>". This avoids initialization performance penalties. See the "(tramp) Improving performance of asynchronous remote processes" node of the Tramp manual for details, and also for a discussion or restrictions. This feature is experimental.

18.35.7. New user option tramp-debug-to-file.

When non-nil, this user option instructs Tramp to mirror the debug buffer to a file under the "tmp" directory. This is useful, if (in rare cases) Tramp blocks Emacs, and we need further debug information.

18.35.8. Tramp supports lock files now.

In order to deactivate this, set user option remote-file-name-inhibit-locks to t.

18.35.9. Writing sensitive data locally requires confirmation.

Writing auto-save, backup or lock files to the local temporary directory must be confirmed. In order to suppress this confirmation, set user option tramp-allow-unsafe-temporary-files to t.

18.35.10. make-directory of a remote directory honors the default file modes.

18.36. GDB/MI

18.36.1. New user option 「gdb-registers-enable-filter」.

If non-nil, apply a register filter based on 「gdb-registers-filter-pattern-list」.

18.36.2. gdb-mi can now save and restore window configurations.

Use 「gdb-save-window-configuration」 to save window configuration to a file and 「gdb-load-window-configuration」 to load from a file. These commands can also be accessed through the menu bar under "Gud => GDB-Windows". 「gdb-default-window-configuration-file」, when non-nil, is loaded when GDB starts up.

18.36.3. gdb-mi can now restore window configuration after quitting.

Set 「gdb-restore-window-configuration-after-quit」 to non-nil and Emacs will remember the window configuration before GDB started and restore it after GDB quits. A toggle button is also provided under "Gud => GDB-Windows" menu item.

18.36.4. gdb-mi now has a better logic for displaying source buffers.

Now GDB only uses one source window to display source file by default. Customize 「gdb-max-source-window-count」 to use more than one window. Control source file display by 「gdb-display-source-buffer-action」.

18.36.5. The default value of 「gdb-mi-decode-strings」 is now t.

This means that the default coding-system is now used to decode strings and source file names from GDB.

18.37. Compilation mode

18.37.1. New function ansi-color-compilation-filter.

This function is meant to be used in compilation-filter-hook.

18.37.2. New user option ansi-color-for-compilation-mode.

This controls what ansi-color-compilation-filter does.

18.37.3. Regexp matching of messages is now case-sensitive by default.

The variable compilation-error-case-fold-search can be set for case-insensitive matching of messages when the old behavior is required, but the recommended solution is to use a correctly matching regexp instead.

18.37.4. New user option compilation-search-all-directories.

When doing parallel builds, directories and compilation errors may arrive in the "compilation" buffer out-of-order. If this option is non-nil (the default), Emacs will now search backwards in the buffer for any directory the file with errors may be in. If nil, this won't be done (and this restores how this previously worked).

18.37.5. Messages from ShellCheck are now recognized.

18.37.6. Messages from Visual Studio that mention column numbers are now recognized.

18.38. Hi Lock mode

18.38.1. Matching in hi-lock-mode can be case-sensitive.

The matching is case-sensitive when a regexp contains upper case characters and search-upper-case is non-nil. highlight-phrase also uses search-whitespace-regexp to substitute spaces in regexp search.

18.38.2. The default value of hi-lock-highlight-range was enlarged.

The new default value is 2000000 (2 megabytes).

18.39. Whitespace mode

18.39.1. New style 「missing-newline-at-eof」.

If present in whitespace-style (as it is by default), the final character in the buffer will be highlighted if the buffer doesn't end with a newline.

18.39.2. The default 「whitespace-enable-predicate」 predicate has changed.

It used to check elements in the list version of 「whitespace-global-modes」 with 'eq', but now uses derived-mode-p.

18.40. Texinfo

18.40.1. New user option 「texinfo-texi2dvi-options」.

This is used when invoking 'texi2dvi' from 「texinfo-tex-buffer」.

18.40.2. New commands for moving in and between environments.

An "environment" is something that ends with '@end'. The commands are 'C-c C-c C-f' (next end), 'C-c C-c C-b' (previous end), 'C-c C-c C-n' (next start) and 'C-c C-c C-p' (previous start), as well as 'C-c .', which will alternate between the start and the end of the current environment.

18.41. Rmail

18.41.1. New user option 「rmail-re-abbrevs」.

Its default value matches localized abbreviations of the "reply" prefix on the Subject line in various languages.

18.41.2. New user option 「rmail-show-message-set-modified」.

If set non-nil, showing an unseen message will set the Rmail buffer's modified flag. The default is nil, to preserve the old behavior.

18.42. CC mode

18.42.1. Added support for Doxygen documentation style.

'doxygen' is now a valid 'c-doc-comment-style' which recognizes all comment styles supported by Doxygen (namely '/', '/!', '/** … *' and '*! … *'. 'gtkdoc' remains the default for C and C++ modes; to use 'doxygen' by default one might evaluate:

(setq-default c-doc-comment-style '((java-mode . javadoc) (pike-mode . autodoc) (c-mode . doxygen) (c++-mode . doxygen)))

or use it in a custom 「c-style」.

18.42.2. Added support to line up '?' and ':' of a ternary operator.

The new 'c-lineup-ternary-bodies' function can be used as a lineup function to align question mark and colon which are part of a ternary operator ('?:'). For example:

return arg % 2 == 0 ? arg / 2

(3 * arg + 1);

To enable, add it to appropriate entries in 'c-offsets-alist', e.g.:

(c-set-offset 'arglist-cont '(c-lineup-ternary-bodies c-lineup-gcc-asm-reg)) (c-set-offset 'arglist-cont-nonempty '(c-lineup-ternary-bodies c-lineup-gcc-asm-reg c-lineup-arglist)) (c-set-offset 'statement-cont '(c-lineup-ternary-bodies +))

18.43. Images

18.43.1. You can explicitly specify baseuri for svg images.

':base-uri' image property can be used to explicitly specify baseuri for embedded images into svg. ':base-uri' is supported for both file and data svg images.

18.43.2. 「svg-embed-base-uri-image」 added to embed images.

「svg-embed-base-uri-image」 can be used to embed images located relatively to file-name-directory of the ':base-uri' svg image property. This works much faster than 「svg-embed」.

18.43.3. New function image-cache-size.

This function returns the size of the current image cache, in bytes.

18.43.4. Animated images stop automatically under high CPU pressure sooner.

Previously, an animated image would stop animating if any single image took more than two seconds to display. The new algorithm maintains a decaying average of delays, and if this number gets too high, the animation is stopped.

18.43.5. The 'n' and 'p' commands (next/previous image) now respect Dired order.

These commands would previously display the next/previous image in lexicographic order, but will now find the "parent" Dired buffer and select the next/previous image file according to how the files are sorted there. The commands have also been extended to work when the "parent" buffer is an archive mode (i.e., zip file or the like) or tar mode buffer.

18.43.6. image-converter is now restricted to formats in auto-mode-alist.

When using external image converters, the external program is queried for what formats it supports. This list may contain formats that are problematic in some contexts (like PDFs), so this list is now filtered based on auto-mode-alist. Only file names that map to image-mode are now supported.

18.43.7. The background and foreground of images now default to face colors.

When an image doesn't specify a foreground or background color, Emacs now uses colors from the face used to draw the surrounding text instead of the frame's default colors.

To load images with the default frame colors use the ':foreground' and ':background' image attributes, for example:

(create-image "filename" nil nil :foreground (face-attribute 'default :foreground) :background (face-attribute 'default :background))

This change only affects image types that support foreground and background colors or transparency, such as xbm, pbm, svg, png and gif.

18.43.8. Image smoothing can now be explicitly enabled or disabled.

Smoothing applies a bilinear filter while scaling or rotating an image to prevent aliasing and other unwanted effects. The new image property ':transform-smoothing' can be set to t to force smoothing and nil to disable smoothing.

The default behavior of smoothing on down-scaling and not smoothing on up-scaling remains unchanged.

18.43.9. New user option image-transform-smoothing.

This controls whether to use smoothing or not for an image. Values include nil (no smoothing), t (do smoothing) or a predicate function that's called with the image object and should return nil/t.

18.43.10. SVG images now support user stylesheets.

The ':css' image attribute can be used to override the default CSS stylesheet for an image. The default sets 「font-family」 and 「font-size」 to match the current face, so an image with 'height="1em"' will match the font size in use where it is embedded.

This feature relies on librsvg 2.48 or above being available.

18.43.11. Image properties support 'em' sizes.

Size image properties, for example ':height', ':max-height', etc., can be given a cons of the form '(SIZE . em)', where SIZE is an integer or float which is multiplied by the font size to calculate the image size, and 'em' is a symbol.

18.44. EWW

18.44.1. New user option 「eww-use-browse-url」.

This is a regexp that can be set to alter how links are followed in eww.

18.44.2. New user option 「eww-retrieve-command」.

This can be used to download data via an external command. If nil (the default), then url-retrieve is used. When 'sync', then url-retrieve-synchronously is used. A list of strings specifies an external program with parameters.

18.44.3. New Emacs command line convenience command.

The eww-browse command has been added, which allows you to register Emacs as a MIME handler for "text/x-uri", and will call 'eww' on the supplied URL. Usage example: "emacs -f eww-browse https://gnu.org".

18.44.4. 「eww-download-directory」 will now use the XDG location, if defined.

However, if "~/Downloads/" already exists, that will continue to be used.

18.44.5. The command 「eww-follow-link」 now supports custom 'mailto:' handlers.

The function that is invoked when clicking on or otherwise following a 'mailto:' link in an EWW buffer can now be customized. For more information, see the related entry about 「shr-browse-url」 below.

18.44.6. Support for bookmark.el.

The command bookmark-set (bound to 【C-x r m】) is now supported, and will create a bookmark that opens the current URL in EWW.

18.45. SHR

18.45.1. The command 「shr-browse-url」 now supports custom 'mailto:' handlers.

Clicking on or otherwise following a 'mailto:' link in an HTML buffer rendered by SHR previously invoked the command browse-url-mail. This is still the case by default, but if you customize browse-url-mailto-function or browse-url-handlers to call some other function, it will now be called instead of the default.

18.45.2. New user option 「shr-offer-extend-specpdl」.

If this is nil, rendering of HTML that requires enlarging max-specpdl-size, the number of Lisp variable bindings, will be aborted, and Emacs will not ask you whether to enlarge max-specpdl-size to complete the rendering. The default is t, which preserves the original behavior.

18.45.3. New user option 「shr-max-width」.

If this user option is non-nil, and 「shr-width」 is nil, then SHR will use the value of 「shr-max-width」 to limit the width of the rendered HTML. The default is 120 characters, so even if you have very wide frames, HTML text will be rendered more narrowly, which usually leads to a more readable text. Customize it to nil to get the previous behavior of rendering as wide as the window-width allows. If 「shr-width」 is non-nil, it overrides this option.

18.45.4. New faces for heading elements.

Those are 「shr-h1」, 「shr-h2」, 「shr-h3」, 「shr-h4」, 「shr-h5」, 「shr-h6」.

18.46. Project

18.46.1. New user option 「project-vc-merge-submodules」.

18.46.2. Project commands now have their own history.

Previously used project directories are now suggested by all commands that prompt for a project directory.

18.46.3. New prefix keymap project-prefix-map.

Key sequences that invoke project-related commands start with the prefix 【C-x p】. Type 'C-x p C-h' to show the full list.

18.46.4. New commands project-dired, project-vc-dir, project-shell,

project-eshell. These commands run Dired/VC-Dir and Shell/Eshell in a project's root directory, respectively.

18.46.5. New command project-compile.

This command runs compilation in the current project's root directory.

18.46.6. New command project-switch-project.

This command lets you "switch" to another project and run a project command chosen from a dispatch menu.

18.46.7. New commands project-shell-command and project-async-shell-command.

These commands run shell-command and async-shell-command in a project's root directory, respectively.

18.46.8. New user option 「project-list-file」.

This specifies the file in which to save the list of known projects.

18.46.9. New command 「project-remember-projects-under」.

This command can automatically locate and index projects in a directory and optionally also its subdirectories, storing them in 「project-list-file」.

18.46.10. New commands project-forget-project and 「project-forget-projects-under」.

These commands let you interactively remove entries from the list of projects in 「project-list-file」.

18.46.11. New command 「project-forget-zombie-projects」.

This command detects indexed projects that have since been deleted, and removes them from the list of known projects in 「project-list-file」.

18.46.12. project-find-file now accepts non-existent file names.

This is to allow easy creation of files inside some nested sub-directory.

18.46.13. project-find-file doesn't use the string at point as default input.

Now it's only suggested as part of the "future history", accessible via 【M-n】.

18.46.14. New command project-find-dir runs Dired in a directory inside project.

18.47. Xref

18.47.1. New user options to automatically show the first Xref match.

The new user option 「xref-auto-jump-to-first-definition」 controls the behavior of xref-find-definitions and its variants, like xref-find-definitions-other-window: if it's t or 'show', the first match is automatically displayed; if it's 'move', point in the "xref" buffer is automatically moved to the first match without displaying it. The new user option 「xref-auto-jump-to-first-xref」 changes the behavior of Xref commands such as xref-find-references, xref-find-apropos, and project-find-regexp, which are expected to display many matches that the user would like to visit. 「xref-auto-jump-to-first-xref」 changes their behavior much in the same way as 「xref-auto-jump-to-first-definition」 affects the 'xref-find-definitions*' commands.

18.47.2. New user options 「xref-search-program」 and 「xref-search-program-alist」.

So far 'grep' and 'ripgrep' are supported. 'ripgrep' seems to offer better performance in certain cases, in particular for case-insensitive searches.

18.47.3. New commands 「xref-prev-group」 and 「xref-next-group」.

These commands are bound respectively to 'P' and 'N', and navigate to the first item of the previous or next group in the "xref" buffer.

18.47.4. New alternative value for 「xref-show-definitions-function」:


18.47.5. The two existing alternatives for 「xref-show-definitions-function」

have been renamed to have "proper" public names and documented (「xref-show-definitions-buffer」 and 「xref-show-definitions-buffer-at-bottom」).

18.47.6. New command 「xref-quit-and-pop-marker-stack」.

This command is bound to 'M-,' in "xref" buffers. This combination is easy to press semi-accidentally if the user wants to go back in the middle of choosing the exact definition to go to, and this should do TRT.

18.47.7. New value 「project-relative」 for 「xref-file-name-display」.

If chosen, file names in "xref" buffers will be displayed relative to the 「project-root」 of the current project, when available.

18.47.8. Prefix arg of 「xref-goto-xref」 quits the "xref" buffer.

So typing 【C-u RET】 in the "xref" buffer quits its window before navigating to the selected location.

18.47.9. The 'TAB' key binding in "xref" buffers is obsolete.

Use 【C-u RET】 instead. The 'TAB' binding in "xref" buffers is still supported, but we plan on removing it in a future version; at that time, the command 「xref-quit-and-goto-xref」 will no longer have a key binding in 'xref–xref-buffer-mode-map'.

18.47.10. New user option 「etags-xref-prefer-current-file」.

When non-nil, matches for identifiers in the file visited by the current buffer will be shown first in the "xref" buffer.

18.47.11. The etags Xref backend now honors 「tags-apropos-additional-actions」.

You can customize it to augment the output of xref-find-apropos, like it affected the output of tags-apropos, which is obsolete since Emacs 25.1.

18.48. Battery

18.48.1. UPower is now the default battery status backend when available.

UPower support via the function 「battery-upower」 was added in Emacs 26.1, but was disabled by default. It is now the default value of 「battery-status-function」 when the system provides a UPower D-Bus service. The user options 「battery-upower-device」 and 「battery-upower-subscribe」 control which power sources to query and whether to respond to status change notifications in addition to polling, respectively.

18.48.2. A richer syntax can be used to format battery status information.

The user options 「battery-mode-line-format」 and 「battery-echo-area-format」 now support the full formatting syntax of the function format-spec documented under node "(elisp) Custom Format Strings". The new syntax includes specifiers for padding and truncation, amongst other things.

18.49. Bug Reference

18.49.1. Bug reference mode uses auto-setup.

If bug-reference-mode or bug-reference-prog-mode have been activated, their respective hook has been run, and both 「bug-reference-bug-regexp」 and 「bug-reference-url-format」 are still not set, it tries to guess appropriate values for those two variables. There are three guessing mechanisms so far: based on version control information of the current buffer's file, based on newsgroup/mail-folder name and several news and mail message headers in Gnus buffers, and based on IRC channel and network in rcirc and ERC buffers. All the mechanisms are extensible with custom rules, see the variables 「bug-reference-setup-from-vc-alist」, 「bug-reference-setup-from-mail-alist」, and 「bug-reference-setup-from-irc-alist」.

18.50. HTML mode

18.50.1. A new skeleton for adding relative URLs has been added.

It's bound to the 'C-c C-c f' keystroke, and prompts for a local file name.

18.51. Widget

18.51.1. widget-choose now supports menus in extended format.

18.51.2. The 「editable-list」 widget now supports moving items up and down.

You can now move items up and down by deleting and then reinserting them, using the 'DEL' and 'INS' buttons respectively. This is useful in Custom buffers, for example, to change the order of the elements in a list.

18.52. Diff

18.52.1. New face 「diff-changed-unspecified」.

This is used to highlight "changed" lines (those marked with '!') in context diffs, when diff-use-changed-face is non-nil.

18.52.2. New diff-mode font locking face 「diff-error」.

This face is used for error messages from 'diff'.

18.52.3. New command diff-refresh-hunk.

This new command (bound to 'C-c C-l') regenerates the current hunk.

18.53. Thing at point

18.53.1. New thing-at-point target: 「existing-filename」.

This is like 'filename', but is a full path, and is nil if the file doesn't exist.

18.53.2. New thing-at-point target: 'string'.

If point is inside a string, it returns that string.

18.53.3. New variable thing-at-point-provider-alist.

This allows mode-specific alterations to how thing-at-point works.

18.53.4. thing-at-point now respects fields.

thing-at-point (and all functions that use it, like symbol-at-point) will narrow to the current field (if any) before trying to identify the thing at point.

18.53.5. New function thing-at-mouse.

This is like thing-at-point, but uses the mouse event position instead.

18.54. Image Dired

18.54.1. New user option 「image-dired-thumb-visible-marks」.

If non-nil (the default), use the new face 「image-dired-thumb-mark」 for marked images.

18.54.2. New command 「image-dired-delete-marked」.

18.54.3. 「image-dired-mouse-toggle-mark」 is now sensitive to the active region.

If the region is active, this command now toggles Dired marks of all the thumbnails in the region.

18.55. Flymake mode

18.55.1. New command 「flymake-show-project-diagnostics」.

This lists all diagnostics for buffers in the currently active project. The listing is similar to the one obtained by 「flymake-show-buffer-diagnostics」, but adds a column for the project-relative file name. For backends which support it, 「flymake-show-project-diagnostics」 also lists diagnostics for files that have not yet been visited.

18.55.2. New user options to customize Flymake's mode-line.

The new user option 「flymake-mode-line-format」 is a mix of strings and symbols like 「flymake-mode-line-title」, 「flymake-mode-line-exception」 and 「flymake-mode-line-counters」. The new user option 「flymake-mode-line-counter-format」 is a mix of strings and symbols like 「flymake-mode-line-error-counter」, 「flymake-mode-line-warning-counter」 and 「flymake-mode-line-note-counter」.

18.56. Time

18.56.1. display-time-world has been renamed to world-clock.

world-clock creates a buffer with an updating time display using several time zones. It is hoped that the new names are more discoverable.

The following commands have been renamed:

display-time-world to world-clock 「display-time-world-mode」 to 「world-clock-mode」 「display-time-world-display」 to 「world-clock-display」 「display-time-world-timer」 to 「world-clock-update」

The following user options have been renamed:

「display-time-world-list」 to 「world-clock-list」 「display-time-world-time-format」 to 「world-clock-time-format」 「display-time-world-buffer-name」 to 「world-clock-buffer-name」 「display-time-world-timer-enable」 to 「world-clock-timer-enable」 「display-time-world-timer-second」 to 「world-clock-timer-second」

The old names are now obsolete.

18.56.2. 「world-clock-mode」 can no longer be turned on interactively.

Use world-clock to turn on that mode.

18.57. Python mode

18.57.1. New user option 「python-forward-sexp-function」.

This allows the user easier customization of whether to use block-based navigation or not.

18.57.2. 「python-shell-interpreter」 now defaults to python3 on systems with python3.

18.57.3. 'C-c C-r' can now be used on arbitrary regions.

The command previously extended the start of the region to the start of the line, but will now actually send the marked region, as documented.

18.58. Ruby mode

18.58.1. 「ruby-use-smie」 is declared obsolete.

SMIE is now always enabled and 「ruby-use-smie」 only controls whether indentation is done using SMIE or with the old ad-hoc code.

18.58.2. Indentation has changed when 「ruby-align-chained-calls」 is non-nil.

This previously used to align subsequent lines with the last sibling, but it now aligns with the first sibling (which is the preferred style in Ruby).

18.59. CPerl mode

18.59.1. New face 「perl-heredoc」, used for heredoc elements.

18.59.2. The command 「cperl-set-style」 offers the new value "PBP".

This value customizes Emacs to use the style recommended in Damian Conway's book "Perl Best Practices" for indentation and formatting of conditionals.

18.60. Perl mode

18.60.1. New face 「perl-non-scalar-variable」.

This is used to fontify non-scalar variables.

18.61. Octave mode

18.61.1. Line continuations in double-quoted strings now use a backslash.

Typing 'C-M-j' (bound to 「octave-indent-new-comment-line」) now follows the behavior introduced in Octave 3.8 of using a backslash as a line continuation marker within double-quoted strings, and an ellipsis everywhere else.

18.62. EasyPG

GPG key servers can now be queried for keys with the epa-search-keys command. Keys can then be added to your personal key ring.

18.63. Etags

18.63.1. Etags now supports the Mercury programming language.

18.63.2. Etags command line option '–declarations' now has Mercury-specific behavior.

All Mercury declarations are tagged by default. However, for compatibility with 'etags' support for Prolog, predicates and functions appearing first in clauses will also be tagged if 'etags' is invoked with the '–declarations' command-line option.

18.64. Comint

18.64.1. Support for OSC escape sequences.

Adding the new function comint-osc-process-output to comint-output-filter-functions enables the interpretation of OSC ("Operating System Command") escape sequences in comint buffers. By default, only OSC 8, for hyperlinks, and OSC 7, for directory tracking, are acted upon. Adding more entries to comint-osc-handlers allows a customized treatment of further escape sequences.

18.64.2. comint-delete-output can now save deleted text in the kill-ring.

Interactively, 'C-u C-c C-o' triggers this new optional behavior.

18.65. ANSI color

18.65.1. Colors are now defined by faces.

ANSI SGR codes now have corresponding faces to describe their appearance, e.g. 「ansi-color-bold」.

18.65.2. Support for "bright" color codes.

"Bright" ANSI color codes are now displayed when applying ANSI color filters using the color values defined by the faces 「ansi-color-bright-COLOR」. In addition, bold text with regular ANSI colors can be displayed as "bright" if ansi-color-bold-is-bright is non-nil.

18.66. ERC

Starting with Emacs 28.1 and ERC 5.4, see the ERC-NEWS file for user-visible changes in ERC.

18.67. Xwidget Webkit mode

18.67.1. New xwidget commands.

「xwidget-webkit-uri」 (return the current URL), 「xwidget-webkit-title」 (return the current title), and 「xwidget-webkit-goto-history」 (goto a point in history).

18.67.2. Downloading files from xwidget-webkit is now supported.

The new user option 「xwidget-webkit-download-dir」 says where to download to.

18.67.3. New command 「xwidget-webkit-clone-and-split-below」.

Open a new window below displaying the current URL.

18.67.4. New command 「xwidget-webkit-clone-and-split-right」.

Open a new window to the right displaying the current URL.

18.67.5. Pixel-based scrolling.

The 「xwidget-webkit-scroll-up」, 「xwidget-webkit-scroll-down」 commands now supports scrolling arbitrary pixel values. It now treats the optional 2nd argument as the pixel values to scroll.

18.67.6. New commands for scrolling.

The new commands 「xwidget-webkit-scroll-up-line」, 「xwidget-webkit-scroll-down-line」, 「xwidget-webkit-scroll-forward」, 「xwidget-webkit-scroll-backward」 can be used to scroll webkit by the height of lines or width of chars.

18.67.7. New user option 「xwidget-webkit-bookmark-jump-new-session」.

When non-nil, use a new xwidget webkit session after bookmark jump. Otherwise, it will use 「xwidget-webkit-last-session」.

18.68. Checkdoc

18.68.1. No longer warns about command substitutions by default.

Checkdoc used to warn about "too many command substitutions" (as in "\\[foo-command]"), even if you only used ten of them in a docstring. On modern machines, you can have hundreds or thousands of command substitutions before it becomes a performance issue, so this warning is now disabled by default. To re-enable this warning, customize the user option 「checkdoc-max-keyref-before-warn」.

18.68.2. New user option 「checkdoc-column-zero-backslash-before-paren」.

Checkdoc warns if there is a left parenthesis in column zero of a documentation string. That warning can now be disabled by customizing this new user option to nil. This is useful if you don't expect your code to be edited with an Emacs older than version 27.1.

18.68.3. Now checks the prompt format for yes-or-no-p.

In addition to verifying the format of the prompt for 'y-or-n-p', checkdoc will now check the format of yes-or-no-p.

18.68.4. New command checkdoc-dired.

This can be used to run checkdoc on files from a Dired buffer.

18.68.5. No longer checks for 'A-' modifiers.

Checkdoc recommends usage of command substitutions ("\\[foo-command]") in favor of writing keybindings like 【C-c f】. It now no longer warns about the 'A-' modifier as it is not used very much in practice, and this warning therefore mostly led to false positives.

18.69. Enriched mode

18.69.1. 【C-a】 is by default no longer bound to beginning-of-line-text.

This is so 【C-a】 works as in other modes, and in particular holding Shift while typing 【C-a】, i.e. 'C-S-a', will now highlight the text.

18.70. Gravatar

18.70.1. New user option 「gravatar-service」 for host to query for gravatars.

Defaults to 'gravatar', with 'unicornify' and 'libravatar' as options.

18.71. MH-E mail handler for Emacs

Functions and variables related to handling junk mail have been renamed to not associate color with sender quality.

18.71.1. New names for mh-junk interactive functions.

Function 「mh-junk-whitelist」 is renamed 「mh-junk-allowlist」. Function 「mh-junk-blacklist」 is renamed 「mh-junk-blocklist」.

18.71.2. New binding for 「mh-junk-allowlist」.

The key binding for 「mh-junk-allowlist」 is changed from 'J w' to 'J a'. The old binding is supported but warns that it is obsolete.

18.71.3. New names for some hooks.

「mh-whitelist-msg-hook」 is renamed 「mh-allowlist-msg-hook」. 「mh-blacklist-msg-hook」 is renamed 「mh-blocklist-msg-hook」.

18.71.4. New names for some user options.

User option 「mh-whitelist-preserves-sequences-flag」 is renamed 「mh-allowlist-preserves-sequences-flag」.

18.71.5. New names for some faces.

Face 「mh-folder-blacklisted」 is renamed 「mh-folder-blocklisted」. Face 「mh-folder-whitelisted」 is renamed 「mh-folder-allowlisted」.

18.72. Rcirc

18.72.1. rcirc now supports SASL authentication.

18.72.2. #emacs on Libera.chat has been added to 「rcirc-server-alist」.

18.72.3. rcirc connects asynchronously.

18.72.4. Integrate formatting into 「rcirc-send-string」.

The function now accepts a variable number of arguments.

18.72.5. Deprecate 「rcirc-command」 in favor of 「rcirc-define-command」.

The new macro handles multiple and optional arguments.

18.72.6. Add basic IRCv3 support.

This includes support for the capabilities: 「server-time」, 'batch', 「message-ids」, 「invite-notify」, 「multi-prefix」 and 「standard-replies」.

18.72.7. Add mouse property support to rcirc-track-minor-mode.

18.72.8. Improve support for IRC markup codes.

18.72.9. Check auth-sources for server passwords.

18.72.10. Implement repeated reconnection strategy.

See 「rcirc-reconnect-attempts」.

18.73. MPC

18.73.1. New command 「mpc-goto-playing-song」.

This command, bound to 'o' in any 「mpc-mode」 buffer, moves point to the currently playing song in the "MPC-Songs" buffer.

18.73.2. New user option 「mpc-cover-image-re」.

If non-nil, it is a regexp that should match a valid cover image.

18.74. Miscellaneous

18.74.1. shell-script-mode now supports outline-minor-mode.

The outline headings have lines that start with "###".

18.74.2. fileloop will now skip missing files instead of signaling an error.

18.74.3. tabulated-list-mode can now restore original display order.

Many commands (like 'C-x C-b') are derived from tabulated-list-mode, and that mode allows the user to sort on any column. There was previously no easy way to get back to the original displayed order after sorting, but giving a -1 numerical prefix to the sorting command will now restore the original order.

18.74.4. 【M-left】 and 【M-right】 now move between columns in tabulated-list-mode.

18.74.5. New variable hl-line-overlay-priority.

This can be used to change the priority of the hl-line overlays.

18.74.6. New command mailcap-view-file.

This command will open a viewer based on the file type, as determined by "~/.mailcap" and related files and variables.

18.74.7. New user option 「remember-diary-regexp」.

18.74.8. New user option 「remember-text-format-function」.

18.74.9. New user option authinfo-hide-elements.

This can be set to nil to inhibit hiding passwords in ".authinfo" files.

18.74.10. hexl-mode scrolling commands now heed next-screen-context-lines.

Previously, 「hexl-scroll-down」 and 「hexl-scroll-up」 would scroll up/down an entire window, but they now work more like the standard scrolling commands.

18.74.11. New user option 「bibtex-unify-case-function」.

This new option allows the user to customize how case is converted when unifying entries.

18.74.12. The user option 「bibtex-maintain-sorted-entries」 now permits

user-defined sorting schemes.

18.74.13. New user option 「reveal-auto-hide」.

If non-nil (the default), revealed text is automatically hidden when point leaves the text. If nil, the text is not hidden again. Instead the command 「reveal-hide-revealed」 can be used to hide all the revealed text.

18.74.14. New user option 「ffap-file-name-with-spaces」.

If non-nil, find-file-at-point and friends will try to guess more expansively to identify a file name with spaces. Default value is nil.

18.74.15. Two new commands for centering in doc-view-mode.

The new commands 「doc-view-center-page-horizontally」 (bound to 'c h') and 「doc-view-center-page-vertically」 (bound to 'c v') center the page horizontally and vertically, respectively.

18.74.16. 「tempo-define-template」 can now re-assign templates to tags.

Previously, assigning a new template to an already defined tag had no effect.

18.74.17. The width of the buffer-name column in list-buffers is now dynamic.

The width now depends on the width of the window, but will never be wider than the length of the longest buffer name, except that it will never be narrower than 19 characters.

18.74.18. New diary sexp 「diary-offset」.

It offsets another diary sexp by a number of days. This is useful when for example your organization has a committee meeting two days after every monthly meeting which takes place on the third Thursday, or if you would like to attend a virtual meeting scheduled in a different timezone causing a difference in the date.

18.74.19. The old non-SMIE indentation of sh-mode has been removed.

18.74.20. mspools-show is now autoloaded.

18.74.21. Loading 'dunnet' in batch mode doesn't start the game any more.

Instead you need to do "emacs –batch -f dunnet" to start the game in batch mode.

19. New Modes and Packages in Emacs 28.1

19.1. New mode repeat-mode to allow shorter key sequences.

Type 'M-x repeat-mode' to enable this mode. You can then type 【C-x u u】 instead of 'C-x u C-x u' to undo many changes, 【C-x o o】 instead of 'C-x o C-x o' to switch windows, 'C-x { { } } ^ ^ v v' to resize the selected window interactively, 【M-g n n p p】 to navigate next-error matches. Any other key exits this temporarily enabled transient mode that supports shorter keys, and then after exiting from this mode, the last typed key uses the default key binding.

The user option 「repeat-exit-key」 defines an additional key usable to exit the mode like isearch-exit ('RET').

The user option 「repeat-exit-timeout」 (default nil, which means forever) specifies the number of seconds of idle time after which to break the repetition chain automatically.

When user option 「repeat-keep-prefix」 is non-nil, the prefix arg of the previous command is kept. This can be used to e.g. reverse the window navigation direction with 'C-x o M– o o' or to set a new step with 'C-x { C-5 { { {', which will set the window resizing step to 5 columns.

Command 「describe-repeat-maps」 will display a buffer showing which commands are repeatable in repeat-mode.

19.2. New themes 「modus-vivendi」 and 「modus-operandi」.

These themes are designed to conform with the highest standard for color-contrast accessibility (WCAG AAA). You can load either of them using 'M-x customize-themes' or load-theme from your init file. Consult the Modus Themes Info manual for more information on the user options they provide.

19.3. Dictionary mode

This is a mode for searching a RFC 2229 dictionary server. 'dictionary' opens a buffer for starting operations. dictionary-search performs a lookup for a word. It also supports a dictionary-tooltip-mode which performs a lookup of the word under the mouse in 「dictionary-tooltip-dictionary」 (which must be customized first).

19.4. Lisp Data mode

The new command lisp-data-mode enables a major mode for buffers composed of Lisp symbolic expressions that do not form a computer program. The ".dir-locals.el" file is automatically set to use this mode, as are other data files produced by Emacs.

19.5. New global mode global-goto-address-mode.

This will enable goto-address-mode in all buffers.

19.6. transient.el

This library implements support for powerful keyboard-driven menus. Such menus can be used as simple visual command dispatchers. More complex menus take advantage of infix arguments, which are somewhat similar to prefix arguments, but are more flexible and discoverable.

19.7. hierarchy.el

This library can create, query, navigate and display hierarchical structures.

19.8. New major mode for displaying the "etc/AUTHORS" file.

This new etc-authors-mode provides font-locking for displaying the "etc/AUTHORS" file from the Emacs distribution, and not much else.

20. Incompatible Lisp Changes in Emacs 28.1

20.1. Emacs now prints a backtrace when signaling an error in batch mode.

This makes debugging Emacs Lisp scripts run in batch mode easier. To get back the old behavior, set the new variable backtrace-on-error-noninteractive to a nil value.

20.2. Some floating-point numbers are now handled differently by the Lisp reader.

In previous versions of Emacs, numbers with a trailing dot and an exponent were read as integers and the exponent ignored: 2.e6 was interpreted as the integer 2. Such numerals are now read as floats with the exponent included: 2.e6 is now read as the floating-point value 2000000.0. That is, '(read-from-string "1.e3")' => '(1000.0 . 4)' now.

20.3. 'equal' no longer examines some contents of window configurations.

Instead, it considers window configurations to be equal only if they are 'eq'. To compare contents, use compare-window-configurations instead. This change helps fix a bug in sxhash-equal, which returned incorrect hashes for window configurations and some other objects.

20.4. The lexical-binding local variable is always enabled.

Previously, if enable-local-variables was nil, a lexical-binding local variable would not be heeded. This has now changed, and a file with a lexical-binding cookie is always heeded. To revert to the old behavior, set permanently-enabled-local-variables to nil.

20.5. '&rest' in argument lists must always be followed by a variable name.

Omitting the variable name after '&rest' was previously tolerated in some cases but not consistently so; it could lead to crashes or outright wrong results. Since the utility was marginal at best, it is now an error to omit the variable.

20.6. kill-all-local-variables has changed how it handles non-symbol hooks.

The function is documented to eliminate all buffer-local bindings except variables with a 「permanent-local」 property, or hooks that have elements with a 「permanent-local-hook」 property. In addition, it would also keep lambda expressions in hooks sometimes. The latter has now been changed: The function will now also remove these.

20.7. Temporary buffers no longer run certain buffer hooks.

The macros with-temp-buffer and with-temp-file no longer run the hooks kill-buffer-hook, kill-buffer-query-functions, and buffer-list-update-hook for the temporary buffers they create. This avoids slowing them down when a lot of these hooks are defined.

20.8. New face 「child-frame-border」 and frame parameter 「child-frame-border-width」.

The face and width of child frames borders can now be determined separately from those of normal frames. To minimize backward incompatibility, child frames without a 「child-frame-border-width」 parameter will fall back to using 「internal-border-width」. However, the new 「child-frame-border」 face does constitute a breaking change since child frames' borders no longer use the 「internal-border」 face.

20.9. run-at-time now tries harder to implement the t TIME parameter.

If TIME is t, the timer runs at an integral multiple of REPEAT. (I.e., if given a REPEAT of 60, it'll run at 08:11:00, 08:12:00, 08:13:00.) However, when a machine goes to sleep (or otherwise didn't get a time slot to run when the timer was scheduled), the timer would then fire every 60 seconds after the time the timer was fired. This has now changed, and the timer code now recomputes the integral multiple every time it runs, which means that if the laptop wakes at 08:16:43, it'll fire at that time, but then at 08:17:00, 08:18:00…

20.10. parse-partial-sexp now signals an error if TO is smaller than FROM.

Previously, this would lead to the function interpreting FROM as TO and vice versa, which would be confusing when passing in OLDSTATE, which refers to the old state at FROM.

20.11. global-mode-string constructs should end with a space.

This was previously not formalized, which led to combinations of modes displaying data "smushed together" on the mode line.

20.12. overlays-in now handles zero-length overlays slightly differently.

Previously, zero-length overlays at the end of the buffer were included in the result (if the region queried for stopped at that position). The same was not the case if the buffer had been narrowed to exclude the real end of the buffer. This has now been changed, and zero-length overlays at point-max are always included in the results.

20.13. replace-match now runs modification hooks slightly later.

The function is documented to leave point after the replacement text, but this was not always the case if a modification hook inserted text in front of the replaced text – replace-match would instead leave point where the end of the inserted text would have been before the hook ran. replace-match now always leaves point after the replacement text.

20.14. completing-read-default sets completion variables buffer-locally.

minibuffer-completion-table and related variables are now set buffer-locally in the minibuffer instead of being set via a global let-binding.

20.15. XML serialization functions now reject invalid characters.

Previously, 「xml-print」 would produce invalid XML when given a string with characters that are not valid in XML (see https://www.w3.org/TR/xml/#charsets). Now it rejects such strings.

20.16. JSON

20.16.1. JSON number parsing is now stricter.

Numbers with a leading plus sign, leading zeros, or a missing integer component are now rejected by json-read and friends. This makes them more compliant with the JSON specification and consistent with the native JSON parsing functions.

20.16.2. JSON functions support the semantics of RFC 8259.

The JSON functions json-serialize, json-insert, json-parse-string, and json-parse-buffer now implement some of the semantics of RFC 8259 instead of the earlier RFC 4627. In particular, these functions now accept top-level JSON values that are neither arrays nor objects.

20.16.3. Some JSON encoding functions are now obsolete.

The functions json-encode-number, json-encode-hash-table, json-encode-key, and json-encode-list are now obsolete.

The first two are kept as aliases of json-encode, which should be used instead. Uses of json-encode-list should be changed to call one of json-encode, json-encode-alist, json-encode-plist, or json-encode-array instead.

20.16.4. Native JSON functions now signal an error if libjansson is unavailable.

This affects json-serialize, json-insert, json-parse-string, and json-parse-buffer. This can happen if Emacs was compiled with libjansson, but the DLL cannot be found and/or loaded by Emacs at run time. Previously, Emacs would display a message and return nil in these cases.

20.17. The use of positional arguments in define-minor-mode is obsolete.

These were actually rendered obsolete in Emacs 21 but were never marked as such.

20.18. pcomplete-ignore-case is now an obsolete alias of completion-ignore-case.

20.19. 「completions-annotations」 face is not used when the caller puts own face.

This affects the suffix specified by completion 「annotation-function」.

20.20. An active minibuffer now has major mode minibuffer-mode.

This is instead of the erroneous minibuffer-inactive-mode it formerly had.

20.21. make-text-button no longer modifies text properties of its first argument.

When its first argument is a string, make-text-button no longer modifies the string's text properties; instead, it uses and returns a copy of the string. This helps avoid trouble when strings are shared or constants.

20.22. Some properties from completion tables are now preserved.

If minibuffer-allow-text-properties is non-nil, doing completion over a table of strings with properties will no longer remove all the properties before returning. This affects things like completing-read.

20.23. dns-query now consistently uses Lisp integers to represent integers.

Formerly it made an exception for integer components of SOA records, because SOA serial numbers can exceed fixnum ranges on 32-bit platforms. Emacs now supports bignums so this old glitch is no longer needed.

20.24. The '&define' keyword in an Edebug specification now disables backtracking.

The implementation was buggy, and multiple '&define' forms in an '&or' form should be exceedingly rare. See the Info node "(elisp) Backtracking" in the Emacs Lisp reference manual for background.

20.25. The error 「ftp-error」 belongs also to category 「remote-file-error」.

20.26. The WHEN argument of make-obsolete and related functions is mandatory.

The use of those functions without a WHEN argument was marked obsolete back in Emacs 23.1. The affected functions are: make-obsolete, define-obsolete-function-alias, make-obsolete-variable, define-obsolete-variable-alias.

20.27. inhibit-nul-byte-detection is renamed to inhibit-null-byte-detection.

20.28. Some functions are no longer considered safe by 'unsafep':

replace-regexp-in-string, 'catch', 'throw', 'error', 'signal' and play-sound-file.

20.29. 'sql-*-statement-starters' are no longer user options.

These variables describe facts about the SQL standard and product-specific additions. There should be no need for users to customize them.

20.30. Some locale-related variables have been removed.

The Lisp variables 「previous-system-messages-locale」 and 「previous-system-time-locale」 have been removed, as they were created by mistake and were not useful to Lisp code.

20.31. Function 「lm-maintainer」 is replaced with 「lm-maintainers」.

The former is now declared obsolete.

20.32. facemenu.el is no longer preloaded.

To use functions/variables from the package, you now have to say '(require 'facemenu)' or similar.

20.33. facemenu-color-alist is now obsolete, and is not used.

20.34. The variable keyboard-type is obsolete and not dynamically scoped any more.

20.35. The 'values' variable is now obsolete.

Using it just contributes to the growth of the Emacs memory footprint.

20.36. The load-dangerous-libraries variable is now obsolete.

It was used to allow loading Lisp libraries compiled by XEmacs, a modified version of Emacs which is no longer actively maintained. This is no longer supported, and setting this variable has no effect.

20.37. The macro with-displayed-buffer-window is now obsolete.

Use macro with-current-buffer-window with action alist entry 「body-function」.

20.38. The rfc2368.el library is now obsolete.

Use rfc6068.el instead. The main difference is that 「rfc2368-parse-mailto-url」 and 「rfc2368-unhexify-string」 assumed that the strings were all-ASCII, while rfc6068-parse-mailto-url and 「rfc6068-unhexify-string」 parse UTF-8 strings.

20.39. The inversion.el library is now obsolete.

20.40. The metamail.el library is now obsolete.

20.41. Edebug changes

20.41.1. 「get-edebug-spec」 is obsolete, replaced by 「edebug-get-spec」.

20.41.2. The spec operator ':name NAME' is obsolete, use '&name' instead.

20.41.3. The spec element 「function-form」 is obsolete, use 'form' instead.

20.41.4. New function def-edebug-elem-spec to define Edebug spec elements.

These used to be defined with def-edebug-spec thus conflating the two name spaces, which lead to name collisions. The use of def-edebug-spec to define Edebug spec elements is declared obsolete.

20.42. The sb-image.el library is now obsolete.

This was a compatibility kludge which is no longer needed.

20.43. Some libraries obsolete since Emacs 23 have been removed:

ledit.el, lmenu.el, lucid.el and old-whitespace.el.

20.44. Some functions and variables obsolete since Emacs 23 have been removed:

「GOLD-map」, 「advertised-xscheme-send-previous-expression」, 「allout-init」, 「bookmark-jump-noselect」, 「bookmark-read-annotation-text-func」, 「buffer-menu-mode-hook」, 'c-forward-into-nomenclature', 「char-coding-system-table」, 「char-valid-p」, 「charset-bytes」, 「charset-id」, charset-list, 「choose-completion-delete-max-match」, 「complete-in-turn」, 「completion-base-size」, 「completion-common-substring」, 「crm-minibuffer-complete」, 「crm-minibuffer-complete-and-exit」, 「crm-minibuffer-completion-help」, 「custom-mode」, 「custom-mode-hook」, 「define-key-rebound-commands」, 「define-mode-overload-implementation」, 「detect-coding-with-priority」, 「dirtrack-debug」, 「dirtrack-debug-toggle」, 「dynamic-completion-table」, 「easy-menu-precalculate-equivalent-keybindings」, 「epa-display-verify-result」, 「epg-passphrase-callback-function」, 「erc-announced-server-name」, 「erc-default-coding-system」, 「erc-process」, 「erc-send-command」, 「eshell-report-bug」, 「eval-next-after-load」, 「exchange-dot-and-mark」, 「ffap-bug」, 「ffap-submit-bug」, 「ffap-version」, 「file-cache-mouse-choose-completion」, 「forward-point」, 「generic-char-p」, 「global-highlight-changes」, 「hi-lock-face-history」, 「hi-lock-regexp-history」, 「highlight-changes-active-string」, 「highlight-changes-initial-state」, 「highlight-changes-passive-string」, 'icalendar–datetime-to-noneuropean-date', 「image-mode-maybe」, 'imenu-example–name-and-position', 「ispell-aspell-supports-utf8」, 「lisp-mode-auto-fill」, 「locate-file-completion」, 「make-coding-system」, 「menu-bar-files-menu」, 「minibuffer-local-must-match-filename-map」, 「mouse-choose-completion」, 「mouse-major-mode-menu」, 「mouse-popup-menubar」, 「mouse-popup-menubar-stuff」, 「newsticker-groups-filename」, 「nnir-swish-e-index-file」, 「nnmail-fix-eudora-headers」, 「non-iso-charset-alist」, 「nonascii-insert-offset」, 「nonascii-translation-table」, 「password-read-and-add」, 「pre-abbrev-expand-hook」, 「princ-list」, 「print-help-return-message」, 「read-file-name-predicate」, 「remember-buffer」, 「rmail-highlight-face」, 「rmail-message-filter」, 「semantic-after-idle-scheduler-reparse-hooks」, 「semantic-after-toplevel-bovinate-hook」, 「semantic-before-idle-scheduler-reparse-hooks」, 「semantic-before-toplevel-bovination-hook」, 「semantic-bovinate-from-nonterminal-full」, 「semantic-bovinate-region-until-error」, 「semantic-bovinate-toplevel」, 「semantic-bovination-working-type」, 「semantic-decorate-pending-decoration-hooks」, 「semantic-edits-incremental-reparse-failed-hooks」, 「semantic-eldoc-current-symbol-info」, 「semantic-expand-nonterminal」, 「semantic-file-token-stream」, 「semantic-find-dependency」, 「semantic-find-nonterminal」, 「semantic-flex」, 「semantic-flex-buffer」, 「semantic-flex-keyword-get」, 「semantic-flex-keyword-p」, 「semantic-flex-keyword-put」, 「semantic-flex-keywords」, 「semantic-flex-list」, 「semantic-flex-make-keyword-table」, 「semantic-flex-map-keywords」, 「semantic-flex-token-end」, 「semantic-flex-token-start」, 「semantic-flex-token-text」, 「semantic-imenu-bucketize-type-parts」, 「semantic-imenu-expand-type-parts」, 「semantic-imenu-expandable-token」, 「semantic-init-db-hooks」, 「semantic-init-hooks」, 「semantic-init-mode-hooks」, 「semantic-java-prototype-nonterminal」, 「semantic-nonterminal-abstract」, 「semantic-nonterminal-full-name」, 「semantic-nonterminal-leaf」, 「semantic-nonterminal-protection」, 「semantic-something-to-stream」, 「semantic-tag-make-assoc-list」, 「semantic-token-type-parent」, 「semantic-toplevel-bovine-cache」, 「semantic-toplevel-bovine-table」, 「semanticdb-mode-hooks」, 「set-coding-priority」, 「shadows-compare-text-p」, 「shell-dirtrack-toggle」, 「speedbar-navigating-speed」, 「speedbar-update-speed」, 't-mouse-mode', 「term-dynamic-simple-complete」, 「tooltip-hook」, 「tpu-have-ispell」, 「url-generate-unique-filename」, 「url-temporary-directory」, 「vc-arch-command」, 「vc-default-working-revision」 (variable), 「vc-mtn-command」, 「vc-revert-buffer」, 「vc-workfile-version」, 「vcursor-toggle-vcursor-map」, 「w32-focus-frame」, 「w32-select-font」, 「wisent-lex-make-token-table」.

20.45. Some functions and variables obsolete since Emacs 22 have been removed:

「erc-current-network」, 「gnus-article-hide-pgp-hook」, 「gnus-inews-mark-gcc-as-read」, 「gnus-treat-display-xface」, 「gnus-treat-strip-pgp」, 「nnmail-spool-file」.

20.46. The obsolete function 「thread-alive-p」 has been removed.

20.47. The variable 「force-new-style-backquotes」 has been removed.

This removes the final remaining trace of old-style backquotes.

20.48. Some obsolete variable and function aliases in dbus.el have been removed.

In Emacs 24.3, the variable 「dbus-event-error-hooks」 was renamed to 「dbus-event-error-functions」 and the function 「dbus-call-method-non-blocking」 was renamed to 「dbus-call-method」. The old names, which were kept as obsolete aliases of the new names, have now been removed.

20.49. find-function-source-path renamed and re-documented.

The find-function command (and various related commands) were documented to respect find-function-source-path, and to search for objects in files specified by that variable. It's unclear when this actually changed, but at some point (perhaps decades ago) these commands started using load-history to determine where symbols had been defined (which is much faster). The doc strings of all the affected function have been updated. find-function-source-path was still being used by find-library and related commands, so the user option has been renamed to find-library-source-path, and find-function-source-path is now an obsolete variable alias.

20.50. The macro vc-call no longer evaluates its second argument twice.

20.51. Xref migrated from EIEIO to cl-defstruct for its core objects.

This means that 'oref' and with-slots no longer works on them, and make-instance can no longer be used to create those instances (which wasn't recommended anyway). Packages should restrict themselves to using functions like 「xref-make」, 「xref-make-match」, 'xref-make-*-location', as well as accessor functions 「xref-item-summary」 and 「xref-item-location」.

Among the benefits are better performance (noticeable when there are a lot of matches) and improved flexibility: 「xref-match-item」 instances do not require that 'location' inherits from 「xref-location」 anymore (that class was removed), so packages can create new location types to use with "match items" without adding EIEIO as a dependency.

21. Lisp Changes in Emacs 28.1

21.1. The 'interactive' syntax has been extended to allow listing applicable modes.

Forms like '(interactive "p" dired-mode)' can be used to annotate the commands as being applicable for modes derived from dired-mode, or if the mode is a minor mode, when the current buffer has that minor mode activated. Note that using this form will create byte code that is not compatible with byte code in previous Emacs versions. Also note that by default these annotations have no effect, unless the new user option read-extended-command-predicate option is customized to call command-completion-default-include-p or a similar function.

21.2. New 'declare' forms to control completion of commands in 【M-x】.

'(declare (completion PREDICATE))' can be used as a general predicate to say whether the command should be considered a completion candidate when completing with 【M-x TAB】.

'(declare (modes MODE…))' can be used as a short-hand way of saying that the command should be considered a completion candidate when completing on commands from buffers in major modes derived from MODE…, or, if it's a minor mode, when that minor mode is enabled in the current buffer.

Note that these forms will only have their effect for 【M-x】 if the read-extended-command-predicate user option is customized to call command-completion-default-include-p or a similar function. The default value of read-extended-command-predicate is nil, which means no commands that match what you have typed are excluded from being completion candidates. The forms will, however, be used by 'M-S-x' by default.

21.3. define-minor-mode now takes an ':interactive' argument.

This can be used for specifying which modes this minor mode is meant for, or to make the new minor mode non-interactive. The default value is t.

21.4. define-derived-mode now takes an ':interactive' argument.

This can be used to control whether the defined mode is a command or not, and is useful when defining commands that aren't meant to be used by users directly.

21.5. define-globalized-minor-mode now takes a ':predicate' parameter.

This can be used to control which major modes the minor mode should be used in.

21.6. condition-case now allows for a success handler.

It is written as '(:success BODY…)' where BODY is executed whenever the protected form terminates without error, with the specified variable bound to the value of the protected form.

21.7. New function benchmark-call to measure the execution time of a function.

Additionally, the number of repetitions can be expressed as a minimal duration in seconds.

21.8. The value thrown to the 'exit' label can now be a function.

This is in addition to values t or nil. If the value is a function, the command loop will call it with zero arguments before returning.

21.9. The behavior of format-spec is now closer to that of 'format'.

In order for the two functions to behave more consistently, format-spec now pads and truncates based on string width rather than length, and also supports format specifications that include a truncating precision field, such as "%.2a".

21.10. 'defvar' detects the error of defining a variable currently lexically bound.

Such mixes are always signs that the outer lexical binding was an error and should have used dynamic binding instead.

21.11. New variable inhibit-mouse-event-check.

If bound to non-nil, a command with '(interactive "e")' doesn't signal an error when invoked by input event that is not a mouse click (e.g., a key sequence).

21.12. New variable redisplay-skip-initial-frame to enable batch redisplay tests.

Setting it to nil forces the redisplay to do its job even in the initial frame used in batch mode.

21.13. Doc strings can now link to customization groups.

Text like "customization group `whitespace'" will be made into a button. When clicked, it will open a Custom buffer displaying that customization group.

21.14. Doc strings can now link to man pages.

Text like "man page `chmod(1)'" will be made into a button. When clicked, it will open a Man mode buffer displaying that man page.

21.15. Buffers can now be created with certain hooks disabled.

The functions get-buffer-create and generate-new-buffer accept a new optional argument INHIBIT-BUFFER-HOOKS. If non-nil, the new buffer does not run the hooks kill-buffer-hook, kill-buffer-query-functions, and buffer-list-update-hook. This avoids slowing down internal or temporary buffers that are never presented to users or passed on to other applications.

21.16. New command make-directory-autoloads.

This does the same as the old command update-directory-autoloads, but has different semantics: Instead of passing in the output file via the dynamically bound 「generated-autoload-file」 variable, the output file is now an explicit parameter.

21.17. Dragging a file into Emacs pushes the file name onto file-name-history.

21.18. The 'easymenu' library is now preloaded.

21.19. The 「iso-transl」 library is now preloaded.

This means that keystrokes like 'Alt-[' are defined by default, instead of only becoming available after doing (for instance) 'C-x 8 <letter>'.

21.20. ':safe' settings in 'defcustom' are now propagated to the loaddefs files.

21.21. New ':type' for 'defcustom' for nonnegative integers.

The new 'natnum' type can be used for options that should be nonnegative integers.

21.22. ERT can now output more verbose test failure reports.

If the 'EMACSTESTVERBOSE' environment variable is set, failure summaries will include the failing condition.

21.23. Byte compiler changes

21.23.1. New byte-compiler check for missing dynamic variable declarations.

It is meant as an (experimental) aid for converting Emacs Lisp code to lexical binding, where dynamic (special) variables bound in one file can affect code in another. For details, see the Info node "(elisp) Converting to Lexical Binding".

21.23.2. byte-recompile-directory can now compile symlinked "*.el" files.

This is achieved by giving a non-nil FOLLOW-SYMLINKS parameter.

21.23.3. The byte-compiler now warns about too wide documentation strings.

By default, it will warn if a documentation string is wider than the largest of byte-compile-docstring-max-column or fill-column characters.

21.23.4. byte-compile-file optional argument LOAD is now obsolete.

To load the file after byte-compiling, add a call to 'load' from Lisp or use 'M-x emacs-lisp-byte-compile-and-load' interactively.

21.24. Macroexp

21.24.1. New function macroexp-file-name to know the name of the current file.

21.24.2. New function macroexp-compiling-p to know if we're compiling.

21.24.3. New function macroexp-warn-and-return to help emit warnings.

This used to be named 'macroexp–warn-and-return' and has proved useful and well-behaved enough to lose the "internal" marker.

21.25. map.el

21.25.1. Alist keys are now consistently compared with 'equal' by default.

Until now, map-elt and map-delete compared alist keys with 'eq' by default. They now use 'equal' instead, for consistency with 'map-put!' and map-contains-key.

21.25.2. Pcase 'map' pattern added keyword symbols abbreviation.

A pattern like '(map :sym)' binds the map's value for ':sym' to 'sym', equivalent to '(map (:sym sym))'.

21.25.3. The function map-copy now uses copy-alist on alists.

This is a slightly deeper copy than the previous copy-sequence.

21.25.4. The function map-contains-key now supports plists.

21.25.5. More consistent duplicate key handling in map-merge-with.

Until now, map-merge-with promised to call its function argument whenever multiple maps contained 'eql' keys. However, this did not always coincide with the keys that were actually merged, which could be 'equal' instead. The function argument is now called whenever keys are merged, for greater consistency with map-merge and map-elt.

21.26. Pcase

21.26.1. The 'or' pattern now binds the union of the vars of its sub-patterns.

If a variable is not bound by the subpattern that matched, it gets bound to nil. This was already sometimes the case, but it is now guaranteed.

21.26.2. The 'pred' pattern can now take the form '(pred (not FUN))'.

This is like '(pred (lambda (x) (not (FUN x))))' but results in better code.

21.26.3. New function pcase-compile-patterns to write other macros.

21.26.4. Added 「cl-type」 pattern.

The new 「cl-type」 pattern compares types using cl-typep, which allows comparing simple types like '(cl-type integer)', as well as forms like '(cl-type (integer 0 10))'.

21.26.5. New macro pcase-setq.

This macro is the 'setq' equivalent of pcase-let, which allows for destructuring patterns in a 'setq' form.

21.27. Edebug

21.27.1. Edebug specification lists can use some new keywords:

  1. '&interpose SPEC FUN ARGS…' lets FUN control parsing after SPEC.

    More specifically, FUN is called with 'HEAD PF ARGS…' where PF is a parsing function that expects a single argument (the specs to use) and HEAD is the code that matched SPEC.

  2. '&error MSG' unconditionally aborts the current edebug instrumentation.
  3. '&name SPEC FUN' extracts the current name from the code matching SPEC.

21.28. Dynamic modules changes

21.28.1. Type aliases for module functions and finalizers.

The module header "emacs-module.h" now contains type aliases 'emacsfunction' and 'emacsfinalizer' for module functions and finalizers, respectively.

21.28.2. Module functions can now be made interactive.

Use 'makeinteractive' to give a module function an interactive specification.

21.28.3. Module functions can now install an optional finalizer.

The finalizer is called when the function object is garbage-collected. Use 'setfunctionfinalizer' to set the finalizer and 'getfunctionfinalizer' to retrieve it.

21.28.4. Modules can now open a channel to an existing pipe process.

Modules can use the new module function 'openchannel' to do that. On capable systems, modules can use this functionality to asynchronously send data back to Emacs.

21.28.5. A new module API 'makeunibytestring'.

It can be used to create Lisp strings with arbitrary byte sequences (a.k.a. "raw bytes").

21.29. Shorthands for Lisp symbols.

Shorthands are a general purpose namespacing system to make Emacs Lisp's symbol-naming etiquette easier to use. A shorthand is any symbolic form found in Lisp source that "abbreviates" a symbol's print name. Among other applications, this feature can be used to avoid name clashes and namespace pollution by renaming an entire file's worth of symbols with proper and longer prefixes, without actually touching the Lisp source. For details, see the Info node "(elisp) Shorthands".

21.30. New function string-search.

This function takes two string parameters and returns the position of the first instance of the former string in the latter.

21.31. New function string-replace.

This function works along the line of replace-regexp-in-string, but it matches on fixed strings instead of regexps, and does not change the global match state.

21.32. New function ensure-list.

This function makes a list of its object if it's not a list already. If it's already a list, the list is returned as is.

21.33. New function split-string-shell-command.

This splits a shell command string into separate components, respecting quoting with single ('like this') and double ("like this") quotes, as well as backslash quoting (like\ this).

21.34. New function string-clean-whitespace.

This removes whitespace from a string.

21.35. New function string-fill.

Word-wrap a string so that no lines are longer that a specific length.

21.36. New function string-limit.

Return (up to) a specific substring length.

21.37. New function string-lines.

Return a list of strings representing the individual lines in a string.

21.38. New function string-pad.

Pad a string to a specific length.

21.39. New function string-chop-newline.

Remove a trailing newline from a string.

21.40. New function replace-regexp-in-region.

21.41. New function replace-string-in-region.

21.42. New function file-name-with-extension.

This function allows a canonical way to set/replace the extension of a file name.

21.43. New function file-modes-number-to-symbolic to convert a numeric

file mode specification into symbolic form.

21.44. New function file-name-concat.

This appends file name components to a directory name and returns the result.

21.45. New function file-backup-file-names.

This function returns the list of file names of all the backup files for the specified file.

21.46. New function directory-empty-p.

This predicate tests whether a given file name is an accessible directory and whether it contains no other directories or files.

21.47. New function buffer-local-boundp.

This predicate says whether a symbol is bound in a specific buffer.

21.48. New function 'always'.

This is identical to 'ignore', but returns t instead.

21.49. New function sxhash-equal-including-properties.

This is identical to sxhash-equal but also accounts for string properties.

21.50. New function buffer-line-statistics.

This function returns some statistics about the line lengths in a buffer.

21.51. New function color-values-from-color-spec.

This can be used to parse RGB color specs in several formats and convert them to a list '(R G B)' of primary color values.

21.52. New function custom-add-choice.

This function can be used by modes to add elements to the 'choice' customization type of a variable.

21.53. New function decoded-time-period.

It interprets a decoded time structure as a period and returns the equivalent period in seconds.

21.54. New function dom-print.

21.55. New function dom-remove-attribute.

21.56. New function 「dns-query-asynchronous」.

It takes the same parameters as dns-query, but adds a callback parameter.

21.57. New function garbage-collect-maybe to trigger GC early.

21.58. New function get-locale-names.

This utility function returns a list of names of locales available on the current system.

21.59. New function insert-into-buffer.

This inserts the contents of the current buffer into another buffer.

21.60. New function json-available-p.

This predicate returns non-nil if Emacs is built with libjansson support, and it is available on the current system.

21.61. New function 「mail-header-parse-addresses-lax」.

This takes a comma-separated string and returns a list of mail/name pairs.

21.62. New function 「mail-header-parse-address-lax」.

Parse a string as a mail address-like string.

21.63. New function make-closure.

This function is used internally by the byte-compiler: calls to it are inserted into the generated bytecode to handle closures more efficiently than the old code which relied on make-byte-code instead. It also makes the disassembly more readable.

21.64. New function make-separator-line.

Make a string appropriate for usage as a visual separator line.

21.65. New function num-processors.

Return the number of processors on the system.

21.66. New function object-intervals.

This function returns a copy of the list of intervals (i.e., text properties) in the object in question (which must either be a string or a buffer).

21.67. New function process-lines-ignore-status.

This is like process-lines, but does not signal an error if the return status is non-zero. process-lines-handling-status has also been added, and takes a callback to handle the return status.

21.68. New function require-theme.

This function is like 'require', but searches custom-theme-load-path instead of load-path. It can be used by Custom themes to load supporting Lisp files when 'require' is unsuitable.

21.69. New function seq-union.

This function takes two sequences and returns a list of all elements that appear in either of them, with no two elements that compare equal appearing in the result.

21.70. New function syntax-class-to-char.

This does almost the opposite of string-to-syntax – it returns the syntax descriptor (a character) given a raw syntax descriptor (an integer).

21.71. New functions null-device and path-separator.

These functions return the connection local value of the respective variables. This can be used for remote hosts.

21.72. New predicate functions 'length<', 'length>' and 'length='.

Using these functions may be more efficient than using 'length' (if the length of a (long) list is being computed just to compare this length to a number).

21.73. New macro 'dlet' to dynamically bind variables.

21.74. New macro with-existing-directory.

This macro binds default-directory to some other existing directory if default-directory doesn't exist, and then executes the body forms.

21.75. New variable current-minibuffer-command.

This is like this-command, but it is bound recursively when entering the minibuffer.

21.76. New variable inhibit-interaction to make user prompts signal an error.

If this is bound to something non-nil, functions like read-from-minibuffer, read-char (and related) will signal an 「inhibited-interaction」 error.

21.77. New variable indent-line-ignored-functions.

This allows modes to cycle through a set of indentation functions appropriate for those modes.

21.78. New variable print-integers-as-characters modifies integer printing.

If this variable is non-nil, character syntax is used for printing numbers when this makes sense, such as '?A' for 65.

21.79. New variable tty-menu-calls-mouse-position-function.

This controls whether mouse-position-function is called by functions that retrieve the mouse position when that happens during TTY menu handling. Lisp programs that set mouse-position-function should also set this variable non-nil if they are compatible with the tty menu handling.

21.80. New variables that hold default buffer names for shell output.

The new constants shell-command-buffer-name and shell-command-buffer-name-async store the default buffer names for the output of, respectively, synchronous and async shell commands.

21.81. New variables read-char-choice-use-read-key and 'y-or-n-p-use-read-key'.

When non-nil, then functions read-char-choice and 'y-or-n-p' (respectively) use the function read-key to read a character instead of using the minibuffer.

21.82. New variable global-minor-modes.

This variable holds a list of currently enabled global minor modes (as a list of symbols).

21.83. New buffer-local variable local-minor-modes.

This permanently buffer-local variable holds a list of currently enabled non-global minor modes in the current buffer (as a list of symbols).

21.84. New completion function 「affixation-function」 to add prefix/suffix.

It accepts a list of completions and should return a list where each element is a list with three elements: a completion, a prefix string, and a suffix string.

21.85. New completion function 「group-function」 for grouping candidates.

It takes two arguments: a completion candidate and a 'transform' flag.

21.86. New error symbol 「minibuffer-quit」.

Signaling it has almost the same effect as 'quit' except that it doesn't cause keyboard macro termination.

21.87. New error symbol 「remote-file-error」, a subcategory of 「file-error」.

It is signaled if a remote file operation fails due to internal reasons, and could block Emacs. It does not replace 「file-error」 signals for the usual cases. Timers, process filters and process functions, which run remote file operations, shall protect themselves against this error.

If such an error occurs, please report this as bug via 'M-x report-emacs-bug'. Until it is solved you could ignore such errors by performing

(setq debug-ignored-errors (cons 'remote-file-error debug-ignored-errors))

21.88. New macro named-let.

It provides Scheme's "named let" looping construct.

21.89. Emacs now attempts to test for high-rate subprocess output more fairly.

When several subprocesses produce output simultaneously at high rate, Emacs will now by default attempt to service them all in a round-robin fashion. Set the new variable process-prioritize-lower-fds to a non-nil value to get back the old behavior, whereby after reading from a subprocess, Emacs would check for output of other subprocesses in a way that is likely to read from the same process again.

21.90. set-process-buffer now updates the process mark.

The mark will be set to point to the end of the new buffer.

21.91. unlock-buffer displays warnings instead of signaling.

Instead of signaling 「file-error」 conditions for file system level errors, the function now calls display-warning and continues as if the error did not occur.

21.92. read-char-from-minibuffer and 'y-or-n-p' support help-form.

If you bind help-form to a non-nil value while calling these functions, then pressing 【C-h】 (help-char) causes the function to evaluate help-form and display the result.

21.93. read-number now has its own history variable.

Additionally, the function now accepts an optional HIST argument which can be used to specify a custom history variable.

21.94. set-window-configuration now takes two optional parameters,

DONT-SET-FRAME and DONT-SET-MINIWINDOW. The first of these, when non-nil, instructs the function not to select the frame recorded in the configuration. The second prevents the current minibuffer being replaced by the one stored in the configuration.

21.95. count-windows now takes an optional parameter ALL-FRAMES.

The semantics are as with walk-windows.

21.96. truncate-string-ellipsis now uses '…' by default.

Modes that use truncate-string-to-width with non-nil, non-string argument ELLIPSIS, will now indicate truncation using '…' when the selected frame can display it, and using "…" otherwise.

21.97. string-width now accepts two optional arguments FROM and TO.

This allows calculating the width of a substring without consing a new string.

21.98. directory-files now takes an additional COUNT parameter.

The parameter makes directory-files return COUNT first file names from a directory. If MATCH is also given, the function will return first COUNT file names that match the expression. The same COUNT parameter has been added to directory-files-and-attributes.

21.99. count-lines can now ignore invisible lines.

This is controlled by the optional parameter IGNORE-INVISIBLE-LINES.

21.100. count-words now crosses field boundaries.

Originally, count-words would stop counting at the first field boundary it encountered; now it keeps counting all the way to the region's (or buffer's) end.

21.101. File-related APIs can optionally follow symlinks.

The functions file-modes, set-file-modes, and set-file-times now have an optional argument specifying whether to follow symbolic links.

21.102. format-seconds can now be used for sub-second times.

The new optional "," parameter has been added, and '(format-seconds "%mm %,1ss" 66.4)' will now result in "1m 6.4s".

21.103. parse-time-string can now parse ISO 8601 format strings.

These have a format like "2020-01-15T16:12:21-08:00".

21.104. lookup-key is more allowing when searching for extended menu items.

When looking for a menu item '[menu-bar Foo-Bar]', first try to find an exact match, then look for the lowercased '[menu-bar foo-bar]'. It will only try to downcase ASCII characters in the range "A-Z". This improves backwards-compatibility when converting menus to use easy-menu-define.

21.105. make-network-process, make-serial-process ':coding' behavior change.

Previously, passing ':coding nil' to either of these functions would override any non-nil binding for coding-system-for-read and coding-system-for-write. For consistency with make-process and make-pipe-process, passing ':coding nil' is now ignored. No code in Emacs depended on the previous behavior; if you really want the process' coding-system to be nil, use set-process-coding-system after the process has been created, or pass in ':coding '(nil nil)'.

21.106. open-network-stream now accepts a ':coding' argument.

This allows specifying the coding systems used by a network process for encoding and decoding without having to bind 'coding-system-for-{read,write}' or call set-process-coding-system.

21.107. open-network-stream can now take a ':capability-command' that's a function.

The function is called with the greeting from the server as its only parameter, and allows sending different TLS capability commands to the server based on that greeting.

21.108. 「open-gnutls-stream」 now also accepts a ':coding' argument.

21.109. process-attributes now works under OpenBSD, too.

21.110. format-spec now takes an optional SPLIT parameter.

If non-nil, format-spec will split the resulting string into a list of strings, based on where the format specs (and expansions) were.

21.111. unload-feature now also tries to undo additions to buffer-local hooks.

21.112. while-no-input-ignore-events accepts more special events.

The special events 「dbus-event」 and 「file-notify」 are now ignored in while-no-input when added to this variable.

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

do not support the old calling conventions any longer.

21.114. yes-or-no-p and 'y-or-n-p' PROMPT parameter no longer needs trailing space.

In other words, the prompt can now end with "?" instead of "? ". This has been the case since Emacs 24.4 but was not announced or documented until now. (Checkdoc has also been updated to accept this convention.)

21.115. The UNIQUIFY argument in auto-save-file-name-transforms can be a symbol.

If this symbol is one of the members of secure-hash-algorithms, Emacs constructs the nondirectory part of the auto-save file name by applying that secure-hash to the buffer file name. This avoids any risk of excessively long file names.

21.116. New user option process-file-return-signal-string.

It controls, whether process-file returns a string when a remote process is interrupted by a signal.

21.117. EIEIO Changes

21.117.1. The macro oref-default can now be used with 'setf'.

It is now defined as a generalized variable that can be used with 'setf' to modify the value stored in a given class slot.

21.117.2. 'form' in '(eql form)' specializers in cl-defmethod is now evaluated.

This corresponds to the behavior of defmethod in Common Lisp Object System. For compatibility, '(eql SYMBOL)' does not evaluate SYMBOL, for now.

21.118. D-Bus

21.118.1. Property values can be typed explicitly.

「dbus-register-property」 and 「dbus-set-property」 accept now optional type symbols. Both functions propagate D-Bus errors.

21.118.2. Registered properties can have the new access type ':write'.

21.118.3. In case of problems, handlers can emit proper D-Bus error messages now.

21.118.4. D-Bus errors, which have been converted from incoming D-Bus error

messages, contain the error name of that message now.

21.118.5. D-Bus messages can be monitored with the new command dbus-monitor.

21.118.6. D-Bus events have changed their internal structure.

They carry now the destination and the error-name of an event. They also keep the type information of their arguments. Use the 'dbus-event-*' accessor functions.

21.119. Buttons

21.119.1. New minor mode button-mode.

This minor mode does nothing except install button-buffer-map as a minor mode map (which binds the 'TAB' / 「S-TAB」 key bindings to navigate to buttons), and can be used in any view-mode-like buffer that has buttons in it.

21.119.2. New utility function button-buttonize.

This function takes a string and returns a string propertized in a way that makes it a valid button.

21.120. text-scale-mode can now adjust font size of the header line.

When the new buffer local variable text-scale-remap-header-line is non-nil, text-scale-adjust will also scale the text in the header line when displaying that buffer.

This is useful for major modes that arrange their display in a tabular form below the header line. It is enabled by default in tabulated-list-mode and its derived modes, and disabled by default elsewhere.

21.121. 'ascii' is now a coding system alias for 「us-ascii」.

21.122. New coding-systems for EBCDIC variants.

New coding-systems 'ibm256', 'ibm273', 'ibm274', 'ibm277', 'ibm278', 'ibm280', 'ibm281', 'ibm284', 'ibm285', 'ibm290', 'ibm297'. These are variants of the EBCDIC encoding tailored to some European and Japanese locales. They are also available as aliases 'ebcdic-cp-*' (e.g., 「ebcdic-cp-fi」 for the Finnish variant 'ibm278'), and 'cp2xx' (e.g., 'cp278' for 'ibm278'). There are also new charsets 'ibm2xx' to support these coding-systems.

21.123. New "Bindat type expression" description language.

This new system is provided by the new macro 「bindat-type」 and obsoletes the old data layout specifications. It supports arbitrary-size integers, recursive types, and more. See the Info node "(elisp) Byte Packing" in the ELisp manual for more details.

21.124. New macro with-environment-variables.

This macro allows setting environment variables temporarily when executing a form.

22. Changes in Emacs 28.1 on Non-Free Operating Systems

22.1. On MS-Windows, Emacs can now use the native image API to display images.

Emacs can now use the MS-Windows GDI+ library to load and display images in JPEG, PNG, GIF and TIFF formats. This support is available unless Emacs was configured '–without-native-image-api'.

This feature is experimental, and needs to be turned on to be used. To turn this on, set the variable w32-use-native-image-API to a non-nil value. Please report any bugs you find while using the native image API via 'M-x report-emacs-bug'.

22.2. On MS-Windows, Emacs can now toggle the IME.

A new function w32-set-ime-open-status can now be used to disable and enable the MS-Windows native Input Method Editor (IME) at run time. A companion function w32-get-ime-open-status returns the current IME activation status.

22.3. On macOS, 's-<left>' and 's-<right>' are now bound to

move-beginning-of-line and move-end-of-line respectively. The commands to select previous/next frame are still bound to 's-~' and 's-`'.

22.4. On macOS, Emacs can now load dynamic modules with a ".dylib" suffix.

module-file-suffix now has the value ".dylib" on macOS, but the ".so" suffix is supported as well.

22.5. On macOS, the user option make-pointer-invisible is now honored.

22.6. On macOS, Xwidget is now supported.

If Emacs was built with xwidget support, you can access the embedded webkit browser with command xwidget-webkit-browse-url. Viewing two instances of xwidget webkit is not supported.

22.6.1. New user option 「xwidget-webkit-enable-plugins」.

If non-nil, enable plugins in xwidget. (This is only available on macOS.)

22.7. New macOS Contacts back-end for EUDC.

This backend works on newer versions of macOS and is generally preferred over the eudcb-mab.el backend.

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 12:09