1 GNU Emacs NEWS -- history of user-visible changes.
3 Copyright (C) 2014-2017 Free Software Foundation, Inc.
4 See the end of the file for license conditions.
6 Please send Emacs bug reports to bug-gnu-emacs@gnu.org.
7 If possible, use M-x report-emacs-bug.
9 This file is about changes in Emacs version 26.
11 See file HISTORY for a list of GNU Emacs versions and release dates.
12 See files NEWS.25, NEWS.24, NEWS.23, NEWS.22, NEWS.21, NEWS.20,
13 NEWS.19, NEWS.18, and NEWS.1-17 for changes in older Emacs versions.
15 You can narrow news to a specific version by calling 'view-emacs-news'
16 with a prefix argument or by typing C-u C-h C-n.
19 +++ indicates that all necessary documentation updates are complete.
20 (This means all relevant manuals in doc/ AND lisp doc-strings.)
21 --- means no change in the manuals is needed.
22 When you add a new item, use the appropriate mark if you are sure it applies,
25 * Installation Changes in Emacs 26.1
27 ** By default libgnutls is now required when building Emacs.
28 Use 'configure --with-gnutls=no' to build even when GnuTLS is missing.
30 ** GnuTLS version 2.12.2 or later is now required, instead of merely
31 version 2.6.6 or later.
33 ** The new option 'configure --with-mailutils' causes Emacs to rely on
34 GNU Mailutils to retrieve email. It is recommended, and is the
35 default if GNU Mailutils is installed. When --with-mailutils is not
36 in effect, the Emacs build procedure by default continues to build and
37 install a limited 'movemail' substitute that retrieves POP3 email only
38 via insecure channels; to avoid this problem, use either
39 --with-mailutils or --without-pop when configuring.
41 ** The new option 'configure --enable-gcc-warnings=warn-only' causes
42 GCC to issue warnings without stopping the build. This behavior is
43 now the default in developer builds. As before, use
44 '--disable-gcc-warnings' to suppress GCC's warnings, and
45 '--enable-gcc-warnings' to stop the build if GCC issues warnings.
47 ** When GCC warnings are enabled, '--enable-check-lisp-object-type' is
48 now enabled by default when configuring.
51 ** The Emacs server now has socket-launching support. This allows
52 socket based activation, where an external process like systemd can
53 invoke the Emacs server process upon a socket connection event and
54 hand the socket over to Emacs. Emacs uses this socket to service
55 emacsclient commands. This new functionality can be disabled with the
56 configure option '--disable-libsystemd'.
59 ** A systemd user unit file is provided. Use it in the standard way:
60 systemctl --user enable emacs
61 (If your Emacs is installed in a non-standard location, you may
62 need to copy the emacs.service file to eg ~/.config/systemd/user/)
64 ** New configure option '--disable-build-details' attempts to build an
65 Emacs that is more likely to be reproducible; that is, if you build
66 and install Emacs twice, the second Emacs is a copy of the first.
67 Deterministic builds omit the build date from the output of the
68 'emacs-version' and 'erc-cmd-SV' functions, and the leave the
69 following variables nil: 'emacs-build-system', 'emacs-build-time',
70 'erc-emacs-build-time'.
73 ** Emacs can now be built with support for Little CMS.
75 If the lcms2 library is installed, Emacs will enable features built on
76 top of that library. The new configure option '--without-lcms2' can
77 be used to build without lcms2 support even if it is installed. Emacs
78 linked to Little CMS exposes color management functions in Lisp: the
79 color metrics 'lcms-cie-de2000' and 'lcms-cam02-ucs'.
81 ** The configure option '--with-gameuser' now defaults to 'no',
82 as this appears to be the most common configuration in practice.
83 When it is 'no', the shared game directory and the auxiliary program
84 update-game-score are no longer needed and are not installed.
86 ** Emacs no longer works on IRIX. We expect that Emacs users are not
87 affected by this, as SGI stopped supporting IRIX in December 2013.
90 * Startup Changes in Emacs 26.1
93 ** New option '--fg-daemon'. This is the same as '--daemon', except
94 it runs in the foreground and does not fork. This is intended for
95 modern init systems such as systemd, which manage many of the traditional
96 aspects of daemon behavior themselves. '--bg-daemon' is now an alias
100 ** New option '--module-assertions'.
101 When given this option, Emacs will perform expensive correctness
102 checks when dealing with dynamic modules. This is intended for module
103 authors that wish to verify that their module conforms to the module
104 requirements. The option makes Emacs abort if a module-related
108 ** Emacs now supports 24-bit colors on capable text terminals
109 Terminal is automatically initialized to use 24-bit colors if the
110 required capabilities are found in terminfo. See the FAQ node
111 "Colors on a TTY" for more information.
114 ** Emacs now obeys the X resource "scrollBar" at startup.
115 The effect is similar to that of "toolBar" resource on the tool bar.
118 * Changes in Emacs 26.1
121 ** Functions in 'write-contents-functions' can fully short-circuit the
122 'save-buffer' process. Previously, saving a buffer that was not
123 visiting a file would always prompt for a file name. Now it only does
124 so if 'write-contents-functions' is nil (or all its functions return
125 nil). A non-nil buffer-local value for this variable is sufficient
126 for 'save-some-buffers' to consider the buffer for saving.
129 ** New variable 'executable-prefix-env' for inserting magic signatures.
130 This variable affects the format of the interpreter magic number
131 inserted by 'executable-set-magic'. If non-nil, the magic number now
132 takes the form "#!/usr/bin/env interpreter", otherwise the value
133 determined by 'executable-prefix', which is by default
134 "#!/path/to/interpreter". By default, 'executable-prefix-env' is nil,
135 so the default behavior is not changed.
138 ** The variable 'emacs-version' no longer includes the build number.
139 This is now stored separately in a new variable, 'emacs-build-number'.
142 ** Emacs now provides a limited form of concurrency with Lisp threads.
143 Concurrency in Emacs Lisp is "mostly cooperative", meaning that
144 Emacs will only switch execution between threads at well-defined
145 times: when Emacs waits for input, during blocking operations related
146 to threads (such as mutex locking), or when the current thread
147 explicitly yields. Global variables are shared among all threads, but
148 a 'let' binding is thread-local. Each thread also has its own current
149 buffer and its own match data.
151 See the chapter "Threads" in the ELisp manual for full documentation
155 ** The new user variable 'electric-quote-chars' provides a list
156 of curved quotes for 'electric-quote-mode', allowing user to choose
157 the types of quotes to be used.
160 ** The new user option 'electric-quote-context-sensitive' makes
161 'electric-quote-mode' context sensitive. If it is non-nil, you can
162 type an ASCII apostrophe to insert an opening or closing quote,
163 depending on context. Emacs will replace the apostrophe by an opening
164 quote character at the beginning of the buffer, the beginning of a
165 line, after a whitespace character, and after an opening parenthesis;
166 and it will replace the apostrophe by a closing quote character in all
170 ** The new variable 'electric-quote-inhibit-functions' controls when
171 to disable electric quoting based on context. Major modes can add
172 functions to this list; Emacs will temporarily disable
173 'electric-quote-mode' whenever any of the functions returns non-nil.
174 This can be used by major modes that derive from 'text-mode' but allow
175 inline code segments, such as 'markdown-mode'.
178 ** The new user variable 'dired-omit-case-fold' allows the user to
179 customize the case-sensitivity of dired-omit-mode. It defaults to
180 the same sensitivity as that of the filesystem for the corresponding
184 ** Emacs now uses double buffering to reduce flicker when editing and
185 resizing graphical Emacs frames on the X Window System. This support
186 requires the DOUBLE-BUFFER extension, which major X servers have
187 supported for many years. If your system has this extension, but an
188 Emacs built with double buffering misbehaves on some displays you use,
189 you can disable the feature by adding
191 '(inhibit-double-buffering . t)
193 to default-frame-alist. Or inject this parameter into the selected
194 frame by evaluating this form:
196 (modify-frame-parameters nil '((inhibit-double-buffering . t)))
199 The group 'wp', whose label was "text", is now deprecated.
200 Use the new group 'text', which inherits from 'wp', instead.
203 ** The new function 'call-shell-region' executes a command in an
204 inferior shell with the buffer region as input.
207 ** The new user option 'shell-command-dont-erase-buffer' controls
208 if the output buffer is erased between shell commands; if non-nil,
209 the output buffer is not erased; this variable also controls where
210 to set the point in the output buffer: beginning of the output,
211 end of the buffer or save the point.
212 When 'shell-command-dont-erase-buffer' is nil, the default value,
213 the behavior of 'shell-command', 'shell-command-on-region' and
214 'async-shell-command' is as usual.
217 ** The new user option 'async-shell-command-display-buffer' controls
218 whether the output buffer of an asynchronous command is shown
219 immediately, or only when there is output.
222 ** The new user option 'mouse-select-region-move-to-beginning'
223 controls the position of point when double-clicking mouse-1 on the end
224 of a parenthetical grouping or string-delimiter: the default value nil
225 keeps point at the end of the region, setting it to non-nil moves
226 point to the beginning of the region.
229 ** The new user option 'mouse-drag-and-drop-region' allows to drag the
230 entire region of text to another place or another buffer.
233 ** The new user option 'confirm-kill-processes' allows the user to
234 skip a confirmation prompt for killing subprocesses when exiting
235 Emacs. When set to t (the default), Emacs will prompt for
236 confirmation before killing subprocesses on exit, which is the same
240 ** 'find-library-name' will now fall back on looking at 'load-history'
241 to try to locate libraries that have been loaded with an explicit path
245 ** Faces in 'minibuffer-prompt-properties' no longer overwrite properties
246 in the text in functions like 'read-from-minibuffer', but instead are
247 added to the end of the face list. This allows users to say things
248 like '(read-from-minibuffer (propertize "Enter something: " 'face 'bold))'.
251 ** The new variable 'extended-command-suggest-shorter' has been added
252 to control whether to suggest shorter 'M-x' commands or not.
255 ** icomplete now respects 'completion-ignored-extensions'.
258 ** Non-breaking hyphens are now displayed with the 'nobreak-hyphen'
259 face instead of the 'escape-glyph' face.
262 ** Approximations to quotes are now displayed with the new 'homoglyph'
263 face instead of the 'escape-glyph' face.
266 ** New face 'header-line-highlight'.
267 This face is the header-line analogue of 'mode-line-highlight'; it
268 should be the preferred mouse-face for mouse-sensitive elements in the
272 ** 'C-x h' ('mark-whole-buffer') will now avoid marking the prompt
276 ** 'find-library' now takes a prefix argument to pop to a different
280 ** 'fill-paragraph' no longer marks the buffer as changed unless it
281 actually changed something.
284 ** The locale language name 'ca' is now mapped to the language
285 environment 'Catalan', which has been added.
288 ** 'align-regexp' has a separate history for its interactive argument.
289 'align-regexp' no longer shares its history with all other
290 history-less functions that use 'read-string'.
293 ** The networking code has been reworked so that it's more
294 asynchronous than it was (when specifying :nowait t in
295 'make-network-process'). How asynchronous it is varies based on the
296 capabilities of the system, but on a typical GNU/Linux system the DNS
297 resolution, the connection, and (for TLS streams) the TLS negotiation
298 are all done without blocking the main Emacs thread. To get
299 asynchronous TLS, the TLS boot parameters have to be passed in (see
300 the manual for details).
302 Certain process oriented functions (like 'process-datagram-address')
303 will block until socket setup has been performed. The recommended way
304 to deal with asynchronous sockets is to avoid interacting with them
305 until they have changed status to "run". This is most easily done
306 from a process sentinel.
309 ** 'make-network-process' and 'open-network-stream' sometimes allowed
310 :service to be an integer string (e.g., :service "993") and sometimes
311 required an integer (e.g., :service 993). This difference has been
312 eliminated, and integer strings work everywhere.
315 ** It is possible to disable attempted recovery on fatal signals.
316 Two new variables support disabling attempts to recover from stack
317 overflow and to avoid automatic auto-save when Emacs is delivered a
318 fatal signal. 'attempt-stack-overflow-recovery', if set to 'nil',
319 will disable attempts to recover from C stack overflows; Emacs will
320 then crash as with any other fatal signal.
321 'attempt-orderly-shutdown-on-fatal-signal', if set to 'nil', will
322 disable attempts to auto-save the session and shut down in an orderly
323 fashion when Emacs receives a fatal signal; instead, Emacs will
324 terminate immediately. Both variables are non-'nil' by default.
325 These variables are for users who would like to avoid the small
326 probability of data corruption due to techniques Emacs uses to recover
330 ** File local and directory local variables are now initialized each
331 time the major mode is set, not just when the file is first visited.
332 These local variables will thus not vanish on setting a major mode.
335 ** A second dir-local file (.dir-locals-2.el) is now accepted.
336 See the variable 'dir-locals-file-2' for more information.
339 ** Connection-local variables can be used to specify local variables
340 with a value depending on the connected remote server. For details,
341 see the node "Connection Local Variables" in the ELisp manual.
344 ** International domain names (IDNA) are now encoded via the new
345 puny.el library, so that one can visit Web sites with non-ASCII URLs.
348 ** The new 'timer-list' command lists all active timers in a buffer,
349 where you can cancel them with the 'c' command.
352 ** 'switch-to-buffer-preserve-window-point' now defaults to t.
355 ** The new variable 'debugger-stack-frame-as-list' allows displaying
356 all call stack frames in a Lisp backtrace buffer as lists. Both
357 debug.el and edebug.el have been updated to heed to this variable.
360 ** Values in call stack frames are now displayed using 'cl-prin1'.
361 The old behaviour of using 'prin1' can be restored by customizing the
362 new option 'debugger-print-function'.
365 ** NUL bytes in text copied to the system clipboard are now replaced with "\0".
368 ** The new variable 'x-ctrl-keysym' has been added to the existing
369 roster of X keysyms. It can be used in combination with another
370 variable of this kind to swap modifiers in Emacs.
373 ** New input methods: 'cyrillic-tuvan', 'polish-prefix'.
376 ** The 'dutch' input method no longer attempts to support Turkish too.
377 Also, it no longer converts 'IJ' and 'ij' to the compatibility
378 characters U+0132 LATIN CAPITAL LIGATURE IJ and U+0133 LATIN SMALL
382 ** File name quoting by adding the prefix "/:" is now possible for the
383 local part of a remote file name. Thus, if you have a directory named
384 "/~" on the remote host "foo", you can prevent it from being
385 substituted by a home directory by writing it as "/foo:/:/~/file".
388 ** The new variable 'maximum-scroll-margin' allows having effective
389 settings of 'scroll-margin' up to half the window size, instead of
390 always restricting the margin to a quarter of the window.
393 ** Emacs can scroll horizontally using mouse, touchpad, and trackbar.
394 You can enable this by customizing 'mwheel-tilt-scroll-p'. If you
395 want to reverse the direction of the scroll, customize
396 'mwheel-flip-direction'.
399 ** Emacsclient has a new option -u/--suppress-output.
400 This option suppresses display of return values from the server
404 ** Emacsclient has a new option -T/--tramp.
405 This helps with using a local Emacs session as the server for a remote
406 emacsclient. With appropriate setup, one can now set the EDITOR
407 environment variable on a remote machine to emacsclient, and
408 use the local Emacs to edit remote files via Tramp. See the node
409 "emacsclient Options" in the user manual for the details.
412 ** New user option 'dig-program-options' and extended functionality
413 for DNS-querying functions 'nslookup-host', 'dns-lookup-host',
414 and 'run-dig'. Each function now accepts an optional name server
415 argument interactively (with a prefix argument) and non-interactively.
418 ** 'describe-key-briefly' now ignores mouse movement events.
421 ** The new variable 'eval-expression-print-maximum-character' prevents
422 large integers from being displayed as characters by 'M-:' and similar
426 ** Two new commands for finding the source code of Emacs Lisp
427 libraries: 'find-library-other-window' and 'find-library-other-frame'.
430 ** The new variable 'display-raw-bytes-as-hex' allows to change the
431 display of raw bytes from octal to hex.
434 ** You can now provide explicit field numbers in format specifiers.
435 For example, '(format "%2$s %1$s" "X" "Y")' produces "Y X".
438 ** Emacs now supports optional display of line numbers in the buffer.
439 This is similar to what linum-mode provides, but much faster and
440 doesn't usurp the display margin for the line numbers. Customize the
441 buffer-local variable 'display-line-numbers' to activate this optional
442 display. Alternatively, you can use the `display-line-numbers-mode'
443 minor mode or the global `global-display-line-numbers-mode'. When
444 using these modes, customize `display-line-numbers-type' with the same
445 value as you would use with `display-line-numbers'.
447 Line numbers are not displayed at all in minibuffer windows and in
448 tooltips, as they are not useful there.
450 Lisp programs can disable line-number display for a particular screen
451 line by putting the 'display-line-numbers-disable' text property or
452 overlay property on the first character of that screen line. This is
453 intended for add-on packages that need a finer control of the display.
455 Lisp programs that need to know how much screen estate is used up for
456 line-number display in a window can use the new function
457 'line-number-display-width'.
459 Linum mode and all similar packages are henceforth becoming obsolete.
460 Users and developers are encouraged to switch to this new feature
464 ** emacsclient now accepts command-line options in ALTERNATE_EDITOR
465 and --alternate-editor. For example, ALTERNATE_EDITOR="emacs -Q -nw".
466 Arguments may be quoted "like this", so that for example an absolute
467 path containing a space may be specified; quote escaping is not
471 * Editing Changes in Emacs 26.1
474 ** New variable 'column-number-indicator-zero-based'.
475 Traditionally, in Column Number mode, the displayed column number
476 counts from zero starting at the left margin of the window. This
477 behavior is now controlled by 'column-number-indicator-zero-based'.
478 If you would prefer for the displayed column number to count from one,
479 you may set this variable to nil. (Behind the scenes, there is now a
480 new mode line construct, '%C', which operates exactly as '%c' does
481 except that it counts from one.)
484 ** New single-line horizontal scrolling mode.
485 The 'auto-hscroll-mode' variable can now have a new special value,
486 'current-line', which causes only the line where the cursor is
487 displayed to be horizontally scrolled when lines are truncated on
488 display and point moves outside the left or right window margin.
491 ** New mode line constructs '%o' and '%q', and user option
492 'mode-line-percent-position'. '%o' displays the "degree of travel" of
493 the window through the buffer. Unlike the default '%p', this
494 percentage approaches 100% as the window approaches the end of the
495 buffer. '%q' displays the percentage offsets of both the start and
496 the end of the window, e.g. "5-17%". The new option
497 'mode-line-percent-position' makes it easier to switch between '%p',
498 '%P', and these new constructs.
501 ** Two new user options 'list-matching-lines-jump-to-current-line' and
502 'list-matching-lines-current-line-face' to show highlighted the current
503 line in *Occur* buffer.
506 ** The 'occur' command can now operate on the region.
509 ** New bindings for 'query-replace-map'.
510 'undo', undo the last replacement; bound to 'u'.
511 'undo-all', undo all replacements; bound to 'U'.
514 ** 'delete-trailing-whitespace' deletes whitespace after form feed.
515 In modes where form feed was treated as a whitespace character,
516 'delete-trailing-whitespace' would keep lines containing it unchanged.
517 It now deletes whitespace after the last form feed thus behaving the
518 same as in modes where the character is not whitespace.
521 ** Emacs no longer prompts about editing a changed file when the file's
522 content is unchanged. Instead of only checking the modification time,
523 Emacs now also checks the file's actual content before prompting the user.
526 ** Various casing improvements.
528 *** 'upcase', 'upcase-region' et al. convert title case characters
529 (such as Dz) into their upper case form (such as DZ).
531 *** 'capitalize', 'upcase-initials' et al. make use of title-case forms
532 of initial characters (correctly producing for example Džungla instead
533 of incorrect DŽungla).
535 *** Characters which turn into multiple ones when cased are correctly handled.
536 For example, fi ligature is converted to FI when upper cased.
538 *** Greek small sigma is correctly handled when at the end of the word.
539 Strings such as ΌΣΟΣ are now correctly converted to Όσος when
540 capitalized instead of incorrect Όσοσ (compare lowercase sigma at the
544 ** Emacs can now auto-save buffers to visited files in a more robust
545 manner via the new mode 'auto-save-visited-mode'. Unlike
546 'auto-save-visited-file-name', this mode uses the normal saving
547 procedure and therefore obeys saving hooks.
548 'auto-save-visited-file-name' is now obsolete.
551 ** New behavior of 'mark-defun'.
552 Prefix argument selects that many (or that many more) defuns.
553 Negative prefix arg flips the direction of selection. Also,
554 'mark-defun' between defuns correctly selects N following defuns (or
555 -N previous for negative arguments). Finally, comments preceding the
556 defun are selected unless they are separated from the defun by a blank
560 ** New command 'replace-buffer-contents'.
561 This command replaces the contents of the accessible portion of the
562 current buffer with the contents of the accessible portion of a
563 different buffer while keeping point, mark, markers, and text
564 properties as intact as possible.
567 ** New commands 'apropos-local-variable' and 'apropos-local-value.
568 These are buffer-local versions of 'apropos-variable' and
569 'apropos-value', respectively. They show buffer-local variables whose
570 names and values, respectively, match a given pattern.
573 ** More user control of reordering bidirectional text for display.
574 The two new variables, 'bidi-paragraph-start-re' and
575 'bidi-paragraph-separate-re', allow customization of what exactly are
576 paragraphs, for the purposes of bidirectional display.
579 * Changes in Specialized Modes and Packages in Emacs 26.1
582 ** New function `cl-generic-p'.
587 *** You can answer 'all' in 'dired-do-delete' to delete recursively all
588 remaining directories without more prompts.
591 *** Dired supports wildcards in the directory part of the file names.
594 *** You can now use '`?`' in 'dired-do-shell-command'.
595 It gets replaced by the current file name, like ' ? '.
598 *** A new option 'dired-always-read-filesystem' default to nil.
599 If non-nil, buffers visiting files are reverted before search them;
600 for instance, in 'dired-mark-files-containing-regexp' a non-nil value
601 of this option means the file is revisited in a temporary buffer;
602 this temporary buffer is the actual buffer searched: the original buffer
603 visiting the file is not modified.
606 *** Users can now customize mouse clicks in Dired in a more flexible way.
607 The new command 'dired-mouse-find-file' can be bound to a mouse click
608 and used to visit files/directories in Dired in the selected window.
609 The new command 'dired-mouse-find-file-other-frame' similarly visits
610 files/directories in another frame. You can write your own commands
611 that invoke 'dired-mouse-find-file' with non-default optional
612 arguments, to tailor the effects of mouse clicks on file names in
616 *** In wdired, when editing files to contain slash characters,
617 the resulting directories are automatically created. Whether to do
618 this is controlled by the 'wdired-create-parent-directories' variable.
621 *** 'W' is now bound to 'browse-url-of-dired-file', and is useful for
622 viewing HTML files and the like.
625 *** New variable 'dired-clean-confirm-killing-deleted-buffers'
626 controls whether Dired asks to kill buffers visiting deleted files and
627 directories. The default is t, so Dired asks for confirmation, to
628 keep previous behavior.
631 ** html2text is now marked obsolete.
634 ** smerge-refine-regions can refine regions in separate buffers
637 ** Info menu and index completion uses substring completion by default.
638 This can be customized via the info-menu category in
639 completion-category-override.
642 ** The ancestor buffer is shown by default in 3-way merges.
643 A new option ediff-show-ancestor and a new toggle
644 ediff-toggle-show-ancestor.
647 ** TeX: Add luatex and xetex as alternatives to pdftex
649 ** Electric-Buffer-menu
652 *** Key 'U' is bound to 'Buffer-menu-unmark-all' and key 'M-DEL' is
653 bound to 'Buffer-menu-unmark-all-buffers'.
658 *** Two new commands 'bs-unmark-all', bound to 'U', and
659 'bs-unmark-previous', bound to <backspace>.
664 *** Two new commands 'Buffer-menu-unmark-all', bound to 'U' and
665 'Buffer-menu-unmark-all-buffers', bound to 'M-DEL'.
670 *** 'checkdoc-arguments-in-order-flag' now defaults to nil.
675 *** The .newsrc file will now only be saved if the native select
676 method is an NNTP select method.
679 *** A new command for sorting articles by readedness marks has been
680 added: 'C-c C-s C-m C-m'.
685 *** New command 'ibuffer-jump'.
688 *** New filter commands 'ibuffer-filter-by-basename',
689 'ibuffer-filter-by-file-extension', 'ibuffer-filter-by-directory',
690 'ibuffer-filter-by-starred-name', 'ibuffer-filter-by-modified'
691 and 'ibuffer-filter-by-visiting-file'; bound respectively
692 to '/b', '/.', '//', '/*', '/i' and '/v'.
695 *** Two new commands 'ibuffer-filter-chosen-by-completion'
696 and 'ibuffer-and-filter', the second bound to '/&'.
699 *** The commands 'ibuffer-pop-filter', 'ibuffer-pop-filter-group',
700 'ibuffer-or-filter' and 'ibuffer-filter-disable' have the alternative
701 bindings '/<up>', '/S-<up>', '/|' and '/DEL', respectively.
704 *** The data format specifying filters has been extended to allow
705 explicit logical 'and', and a more flexible form for logical 'not'.
706 See 'ibuffer-filtering-qualifiers' doc string for full details.
709 *** A new command 'ibuffer-copy-buffername-as-kill'; bound
713 *** New command 'ibuffer-change-marks'; bound to '* c'.
716 *** A new command 'ibuffer-mark-by-locked' to mark
717 all locked buffers; bound to '% L'.
720 *** A new option 'ibuffer-locked-char' to indicate
721 locked buffers; Ibuffer shows a new column displaying
722 'ibuffer-locked-char' for locked buffers.
725 *** A new command 'ibuffer-unmark-all-marks' to unmark
726 all buffers without asking confirmation; bound to
727 'U'; 'ibuffer-do-replace-regexp' bound to 'r'.
730 *** A new command 'ibuffer-mark-by-content-regexp' to mark buffers
731 whose content matches a regexp; bound to '% g'.
734 *** Two new options 'ibuffer-never-search-content-name' and
735 'ibuffer-never-search-content-mode' used by
736 'ibuffer-mark-by-content-regexp'.
741 *** Support for opening links to man pages in Man or WoMan mode.
746 *** New user option 'comint-move-point-for-matching-input' to control
747 where to place point after C-c M-r and C-c M-s.
752 *** Messages from CMake are now recognized.
755 *** The number of errors, warnings, and informational messages is now
756 displayed in the mode line. These are updated as compilation
762 *** Grep commands will now use GNU grep's '--null' option if
763 available, which allows distinguishing the filename from contents if
764 they contain colons. This can be controlled by the new custom option
765 'grep-use-null-filename-separator'.
768 *** The grep/rgrep/lgrep functions will now ask about saving files
769 before running. This is controlled by the 'grep-save-buffers'
775 *** Edebug can be prevented from pausing 1 second after reaching a
776 breakpoint (e.g. with "f" and "o") by customizing the new option
777 'edebug-sit-on-break'.
780 *** New customizable option 'edebug-max-depth'
781 This allows to enlarge the maximum recursion depth when instrumenting
787 *** 'eshell-input-filter's value is now a named function
788 'eshell-input-filter-default', and has a new custom option
789 'eshell-input-filter-initial-space' to ignore adding commands prefixed
790 with blank space to eshell history.
795 *** New 'M-RET' command for opening a link at point in a new eww buffer.
798 *** A new 's' command for switching to another eww buffer via the minibuffer.
801 *** The 'o' command ('shr-save-contents') has moved to 'O' to avoid collision
802 with the 'o' command from 'image-map'.
805 *** A new command 'C' ('eww-toggle-colors') can be used to toggle
806 whether to use the HTML-specified colors or not. The user can also
807 customize the 'shr-use-colors' variable.
810 *** Images that are being loaded are now marked with gray
811 "placeholder" images of the size specified by the HTML. They are then
812 replaced by the real images asynchronously, which will also now
813 respect width/height HTML specs (unless they specify widths/heights
814 bigger than the current window).
817 *** The 'w' command on links is now 'shr-maybe-probe-and-copy-url'.
818 'shr-copy-url' now only copies the url at point; users who wish to
819 avoid accidentally accessing remote links may rebind 'w' and 'u' in
820 'eww-link-keymap' to it.
826 *** The commands 'find-alternate-file-other-window',
827 'dired-other-window', 'dired-other-frame', and
828 'display-buffer-other-window' are now remapped to Ido equivalents if
834 *** Images are automatically scaled before displaying based on the
835 'image-scaling-factor' variable (if Emacs supports scaling the images
839 *** It's now possible to specify aspect-ratio preserving combinations
840 of :width/:max-height and :height/:max-width keywords. In either
841 case, the "max" keywords win. (Previously some combinations would,
842 depending on the aspect ratio of the image, just be ignored and in
843 other instances this would lead to the aspect ratio not being
847 *** Images inserted with 'insert-image' and related functions get a
848 keymap put into the text properties (or overlays) that span the
849 image. This keymap binds keystrokes for manipulating size and
850 rotation, as well as saving the image to a file. These commands are
851 also available in 'image-mode'.
854 *** A new library for creating and manipulating SVG images has been
855 added. See the "SVG Images" section in the Lisp reference manual for
859 *** New setf-able function to access and set image parameters is
860 provided: 'image-property'.
863 *** New commands 'image-scroll-left' and 'image-scroll-right'
864 for 'image-mode' that complement 'image-scroll-up' and
865 'image-scroll-down': they have the same prefix arg behavior and stop
871 *** Now provides a minor mode 'image-dired-minor-mode' which replaces
872 the function 'image-dired-setup-dired-keybindings'.
875 *** Thumbnail generation is now asynchronous.
876 The number of concurrent processes is limited by the variable
877 'image-dired-thumb-job-limit'.
880 *** 'image-dired-thumbnail-storage' has a new option 'standard-large'
881 for generating 256x256 thumbnails according to the Thumbnail Managing
885 *** Inherits movement keys from 'image-mode' for viewing full images.
886 This includes the usual char, line, and page movement commands.
889 *** All the -options types have been changed to argument lists
890 instead of shell command strings. This change affects
891 'image-dired-cmd-create-thumbnail-options',
892 'image-dired-cmd-create-temp-image-options',
893 'image-dired-cmd-rotate-thumbnail-options',
894 'image-dired-cmd-rotate-original-options',
895 'image-dired-cmd-write-exif-data-options',
896 'image-dired-cmd-read-exif-data-options', and introduces
897 'image-dired-cmd-pngnq-options', 'image-dired-cmd-pngcrush-options',
898 'image-dired-cmd-create-standard-thumbnail-options'
901 *** Recognizes more tools by default, including pngnq-s9 and OptiPNG
904 *** 'find-file' and related commands now work on thumbnails and
905 displayed images, providing a default argument of the original file name
906 via an addition to 'file-name-at-point-functions'.
909 ** The default 'Info-default-directory-list' no longer checks some obsolete
910 directory suffixes (gnu, gnu/lib, gnu/lib/emacs, emacs, lib, lib/emacs)
911 when searching for info directories.
914 ** The commands that add ChangeLog entries now prefer a VCS root directory
915 for the ChangeLog file, if none already exists. Customize
916 'change-log-directory-files' to nil for the old behavior.
919 ** Support for non-string values of 'time-stamp-format' has been removed.
924 *** 'message-use-idna' now defaults to t (because Emacs comes with
925 built-in IDNA support now).
928 *** When sending HTML messages with embedded images, and you have
929 exiftool installed, and you rotate images with EXIF data (i.e.,
930 JPEGs), the rotational information will be inserted into the outgoing
931 image in the message. (The original image will not have its
932 orientation affected.)
935 *** The 'message-valid-fqdn-regexp' variable has been removed, since
936 there are now top-level domains added all the time. Message will no
937 longer warn about sending emails to top-level domains it hasn't heard
940 *** 'message-beginning-of-line' (bound to C-a) understands folded headers.
941 In 'visual-line-mode' it will look for the true beginning of a header
942 while in non-'visual-line-mode' it will move the point to the indented
948 *** The new variable 'package-gnupghome-dir' has been added to control
949 where the GnuPG home directory (used for signature verification) is
950 located and whether GnuPG's option "--homedir" is used or not.
953 *** Deleting a package no longer respects 'delete-by-moving-to-trash'.
958 *** The method part of remote file names is mandatory now.
959 A valid remote file name starts with "/method:host:" or
960 "/method:user@host:".
963 *** The new pseudo method "-" is a marker for the default method.
964 "/-::" is the shortest remote file name then.
967 *** The command 'tramp-change-syntax' allows to choose an alternative
968 remote file name syntax.
971 *** New connection method "sg", which supports editing files under a
975 *** New connection method "doas" for OpenBSD hosts.
978 *** New connection method "gdrive", which allows to access Google
979 Drive onsite repositories.
982 *** Gateway methods in Tramp have been removed.
983 Instead, the Tramp manual documents how to configure ssh and PuTTY
987 *** Setting the "ENV" environment variable in
988 'tramp-remote-process-environment' enables reading of shell
989 initialization files.
992 *** Tramp is able now to send SIGINT to remote asynchronous processes.
995 *** Variable 'tramp-completion-mode' is obsoleted.
998 ** 'auto-revert-use-notify' is set back to t in 'global-auto-revert-mode'.
1003 *** JS mode now sets 'comment-multi-line' to t.
1006 *** New variable 'js-indent-align-list-continuation', when set to nil,
1007 will not align continuations of bracketed lists, but will indent them
1008 by the fixed width 'js-indent-level'.
1013 *** Support for completing attribute values, at-rules, bang-rules,
1014 HTML tags, classes and IDs using the 'completion-at-point' command.
1015 Completion candidates for HTML classes and IDs are retrieved from open
1019 *** CSS mode now binds 'C-h S' to a function that will show
1020 information about a CSS construct (an at-rule, property, pseudo-class,
1021 pseudo-element, with the default being guessed from context). By
1022 default the information is looked up on the Mozilla Developer Network,
1023 but this can be customized using 'css-lookup-url-format'.
1026 *** CSS colors are fontified using the color they represent as the
1027 background. For instance, #ff0000 would be fontified with a red
1031 ** Emacs now supports character name escape sequences in character and
1032 string literals. The syntax variants \N{character name} and
1033 \N{U+code} are supported.
1036 ** Prog mode has some support for multi-mode indentation.
1037 This allows better indentation support in modes that support multiple
1038 programming languages in the same buffer, like literate programming
1039 environments or ANTLR programs with embedded Python code.
1041 A major mode can provide indentation context for a sub-mode through
1042 the 'prog-indentation-context' variable. To support this, modes that
1043 provide indentation should use 'prog-widen' instead of 'widen' and
1044 'prog-first-column' instead of a literal zero. See the node
1045 "Mode-Specific Indent" in the ELisp manual for more details.
1050 *** New variable 'erc-default-port-tls' used to connect to TLS IRC
1056 *** The new function 'url-cookie-delete-cookie' can be used to
1057 programmatically delete all cookies, or cookies from a specific
1061 *** 'url-retrieve-synchronously' now takes an optional timeout parameter.
1064 *** The URL package now support HTTPS over proxies supporting CONNECT.
1067 *** 'url-user-agent' now defaults to 'default', and the User-Agent
1068 string is computed dynamically based on 'url-privacy-level'.
1070 ** VC and related modes
1073 *** The VC state indicator in the mode line now defaults to more
1074 colorful faces to make it more obvious to the user what the state is.
1075 See the 'vc-faces' customization group.
1078 *** 'vc-dir-mode' now binds 'vc-log-outgoing' to 'O'; and has various
1079 branch-related commands on a keymap bound to 'B'.
1084 *** Opening a .h file will turn C or C++ mode depending on language used.
1085 This is done with the help of 'c-or-c++-mode' function which analyses
1086 contents of the buffer to determine whether it's a C or C++ source
1090 ** New DNS mode command 'dns-mode-ipv6-to-nibbles' to convert IPv6 addresses
1091 to a format suitable for reverse lookup zone files.
1096 *** Enchant is now supported as a spell-checker.
1098 Enchant is a meta-spell-checker that uses providers
1099 such as Hunspell to do the actual checking. With it, users can use
1100 spell-checkers not directly supported by Emacs, such as Voikko, Hspell
1101 and AppleSpell, more easily share personal word-lists with other
1102 programs, and configure different spelling-checkers for different
1103 languages. (Version 2.1.0 or later of Enchant is required.)
1108 *** Emacs no longer prompts the user before killing Flymake processes on exit.
1111 * New Modes and Packages in Emacs 26.1
1113 ** New Elisp data-structure library 'radix-tree'.
1115 ** New library 'xdg' with utilities for some XDG standards and specs.
1120 *** A new submode of 'html-mode', 'mhtml-mode', is now the default
1121 mode for *.html files. This mode handles indentation,
1122 fontification, and commenting for embedded JavaScript and CSS.
1124 ** New mode 'conf-toml-mode' is a sub-mode of conf-mode, specialized
1125 for editing TOML files.
1127 ** New mode 'conf-desktop-mode' is a sub-mode of conf-unix-mode,
1128 specialized for editing freedesktop.org desktop entries.
1130 ** New minor mode 'pixel-scroll-mode' provides smooth pixel-level scrolling.
1132 ** New major mode 'less-css-mode' (a minor variant of 'css-mode') for
1136 * Incompatible Lisp Changes in Emacs 26.1
1139 *** password-data is now a hash-table
1140 so that `password-read' can use any object for the `key' argument.
1143 *** Command 'dired-mark-extension' now automatically prepends a '.' to the
1144 extension when not present. The new command 'dired-mark-suffix' behaves
1145 similarly but it doesn't prepend a '.'.
1148 ** Certain cond/pcase/cl-case forms are now compiled using a faster jump
1149 table implementation. This uses a new bytecode op 'switch', which
1150 isn't compatible with previous Emacs versions. This functionality can
1151 be disabled by setting 'byte-compile-cond-use-jump-table' to nil.
1154 ** The alist 'ucs-names' is now a hash table.
1157 ** 'if-let' and 'when-let' are subsumed by 'if-let*' and 'when-let*'.
1158 The incumbent 'if-let' and 'when-let' are now marked obsolete.
1159 'if-let*' and 'when-let*' do not accept the single tuple special case.
1160 New macro 'and-let*' is an implementation of the Scheme SRFI-2 syntax
1161 of the same name. 'if-let*' and 'when-let*' now accept the same
1162 binding syntax as 'and-let*'.
1165 ** 'C-up', 'C-down', 'C-left' and 'C-right' are now defined in term
1166 mode to send the same escape sequences that xterm does. This makes
1167 things like forward-word in readline work.
1170 ** hideshow mode got four key bindings that are analogous to outline
1171 mode bindings: 'C-c @ C-a', 'C-c @ C-t', 'C-c @ C-d', and 'C-c @ C-e.'
1174 ** Customizable variable 'query-replace-from-to-separator'
1175 now doesn't propertize the string value of the separator.
1176 Instead, text properties are added by query-replace-read-from.
1177 Additionally, the new nil value restores pre-24.5 behavior
1178 of not providing replacement pairs via the history.
1181 ** Some obsolete functions, variables, and faces have been removed:
1182 *** make-variable-frame-local. Variables cannot be frame-local any more.
1183 *** From subr.el: window-dot, set-window-dot, read-input, show-buffer,
1184 eval-current-buffer, string-to-int
1185 *** icomplete-prospects-length.
1186 *** All the default-FOO variables that hold the default value of the
1187 FOO variable. Use 'default-value' and 'setq-default' to access and
1188 change FOO, respectively. The exhaustive list of removed variables is:
1189 'default-mode-line-format', 'default-header-line-format',
1190 'default-line-spacing', 'default-abbrev-mode', 'default-ctl-arrow',
1191 'default-truncate-lines', 'default-left-margin', 'default-tab-width',
1192 'default-case-fold-search', 'default-left-margin-width',
1193 'default-right-margin-width', 'default-left-fringe-width',
1194 'default-right-fringe-width', 'default-fringes-outside-margins',
1195 'default-scroll-bar-width', 'default-vertical-scroll-bar',
1196 'default-indicate-empty-lines', 'default-indicate-buffer-boundaries',
1197 'default-fringe-indicator-alist', 'default-fringe-cursor-alist',
1198 'default-scroll-up-aggressively', 'default-scroll-down-aggressively',
1199 'default-fill-column', 'default-cursor-type',
1200 'default-cursor-in-non-selected-windows',
1201 'default-buffer-file-coding-system', 'default-major-mode', and
1202 'default-enable-multibyte-characters'.
1203 *** Many variables obsoleted in 22.1 referring to face symbols
1206 ** The variable 'text-quoting-style' no longer affects the treatment
1207 of curved quotes in format arguments to functions like 'message' and
1208 'format-message'. In particular, when this variable's value is
1209 'grave', all quotes in formats are output as-is.
1212 ** Functions like 'check-declare-file' and 'check-declare-directory'
1213 now generate less chatter and more-compact diagnostics. The auxiliary
1214 function 'check-declare-errmsg' has been removed.
1217 ** The regular expression character class [:blank:] now matches
1218 Unicode horizontal whitespace as defined in the Unicode Technical
1219 Standard #18. If you only want to match space and tab, use [ \t]
1223 ** 'min' and 'max' no longer round their results.
1224 Formerly, they returned a floating-point value if any argument was
1225 floating-point, which was sometimes numerically incorrect. For
1226 example, on a 64-bit host (max 1e16 10000000000000001) now returns its
1227 second argument instead of its first.
1230 ** The variable 'old-style-backquotes' has been made internal and
1231 renamed to 'lread--old-style-backquotes'. No user code should use
1235 ** To avoid confusion caused by "smart quotes", the reader no longer
1236 accepts Lisp symbols which begin with the following quotation
1237 characters: ‘’‛“”‟〞"', unless they are escaped with backslash.
1240 ** 'default-file-name-coding-system' now defaults to a coding system
1241 that does not process CRLF. For example, it defaults to utf-8-unix
1242 instead of to utf-8. Before this change, Emacs would sometimes
1243 mishandle file names containing these control characters.
1246 ** 'file-attributes', 'file-symlink-p' and 'make-symbolic-link' no
1247 longer quietly mutate the target of a local symbolic link, so that
1248 Emacs can access and copy them reliably regardless of their contents.
1249 The following changes are involved.
1252 *** 'file-attributes' and 'file-symlink-p' no longer prepend "/:" to
1253 symbolic links whose targets begin with "/" and contain ":". For
1254 example, if a symbolic link "x" has a target "/y:z:", '(file-symlink-p
1255 "x")' now returns "/y:z:" rather than "/:/y:z:".
1258 *** 'make-symbolic-link' no longer looks for file name handlers of
1259 target when creating a symbolic link. For example,
1260 '(make-symbolic-link "/y:z:" "x")' now creates a symbolic link to
1261 "/y:z:" instead of failing.
1264 *** 'make-symbolic-link' removes the remote part of a link target if
1265 target and newname have the same remote part. For example,
1266 '(make-symbolic-link "/x:y:a" "/x:y:b")' creates a link with the
1267 literal string "a"; and '(make-symbolic-link "/x:y:a" "/x:z:b")'
1268 creates a link with the literal string "/x:y:a" instead of failing.
1271 *** 'make-symbolic-link' now expands a link target with leading "~"
1272 only when the optional third arg is an integer, as when invoked
1273 interactively. For example, '(make-symbolic-link "~y" "x")' now
1274 creates a link with target the literal string "~y"; to get the old
1275 behavior, use '(make-symbolic-link (expand-file-name "~y") "x")'. To
1276 avoid this expansion in interactive use, you can now prefix the link
1277 target with "/:". For example, '(make-symbolic-link "/:~y" "x" 1)'
1278 now creates a link to literal "~y".
1281 ** 'file-truename' returns a quoted file name if the target of a
1282 symbolic link has remote file name syntax.
1285 ** Module functions are now implemented slightly differently; in
1286 particular, the function 'internal--module-call' has been removed.
1287 Code that depends on undocumented internals of the module system might
1291 ** The argument LOCKNAME of 'write-region' is propagated to file name
1295 ** When built against recent versions of GTK+, Emacs always uses
1296 gtk_window_move for moving frames and ignores the value of the
1297 variable 'x-gtk-use-window-move'. The variable is now obsolete.
1300 ** Several functions that create or rename files now treat their
1301 destination argument specially only when it is a directory name, i.e.,
1302 when it ends in '/' on GNU and other POSIX-like systems. When the
1303 destination argument D of one of these functions is an existing
1304 directory and the intent is to act on an entry in that directory, D
1305 should now be a directory name. For example, (rename-file "e" "f/")
1306 renames to 'f/e'. Although this formerly happened sometimes even when
1307 D was not a directory name, as in (rename-file "e" "f") where 'f'
1308 happened to be a directory, the old behavior often contradicted the
1309 documentation and had inherent races that led to security holes. A
1310 call like (rename-file C D) that used the old, undocumented behavior
1311 can be written as (rename-file C (file-name-as-directory D)), a
1312 formulation portable to both older and newer versions of Emacs.
1313 Affected functions include add-name-to-file, copy-directory,
1314 copy-file, format-write-file, gnus-copy-file, make-symbolic-link,
1315 rename-file, thumbs-rename-images, and write-file.
1318 * Lisp Changes in Emacs 26.1
1321 ** The function 'assoc' now takes an optional third argument TESTFN.
1322 This argument, when non-nil, is used for comparison instead of
1326 ** New optional argument TESTFN in 'alist-get', 'map-elt' and 'map-put'.
1327 If non-nil, the argument specifies a function to use for comparison,
1328 instead of, respectively, 'assq' and 'eql'.
1331 ** New function 'seq-set-equal-p' to check if SEQUENCE1 and SEQUENCE2
1332 contain the same elements, regardless of the order.
1335 ** The new function 'mapbacktrace' applies a function to all frames of
1336 the current stack trace.
1339 ** The new function 'file-name-case-insensitive-p' tests whether a
1340 given file is on a case-insensitive filesystem.
1343 ** Several accessors for the value returned by 'file-attributes'
1344 have been added. They are: 'file-attribute-type',
1345 'file-attribute-link-number', 'file-attribute-user-id',
1346 'file-attribute-group-id', 'file-attribute-access-time',
1347 'file-attribute-modification-time',
1348 'file-attribute-status-change-time', 'file-attribute-size',
1349 'file-attribute-modes', 'file-attribute-inode-number',
1350 'file-attribute-device-number' and 'file-attribute-collect'.
1353 ** The new function 'buffer-hash' computes a fast, non-consing hash of
1354 a buffer's contents.
1357 ** 'interrupt-process' now consults the list 'interrupt-process-functions',
1358 to determine which function has to be called in order to deliver the
1359 SIGINT signal. This allows Tramp to send the SIGINT signal to remote
1360 asynchronous processes. The hitherto existing implementation has been
1361 moved to 'internal-default-interrupt-process'.
1364 ** The new function 'read-multiple-choice' prompts for multiple-choice
1365 questions, with a handy way to display help texts.
1368 ** 'comment-indent-function' values may now return a cons to specify a
1369 range of indentation.
1372 ** New optional argument TEXT in 'make-temp-file'.
1375 ** New function `define-symbol-prop'.
1380 ** New function 'secure-hash-algorithms' to list the algorithms that
1381 'secure-hash' supports.
1382 See the node "(elisp) Checksum/Hash" in the ELisp manual for details.
1385 ** Emacs now exposes the GnuTLS cryptographic API with the functions
1386 'gnutls-macs' and 'gnutls-hash-mac'; 'gnutls-digests' and
1387 'gnutls-hash-digest'; 'gnutls-ciphers' and 'gnutls-symmetric-encrypt'
1388 and 'gnutls-symmetric-decrypt'.
1389 See the node "(elisp) GnuTLS Cryptography" in the ELisp manual for details.
1392 ** Emacs now supports records for user-defined types, via the new
1393 functions 'make-record', 'record', and 'recordp'. Records are now
1394 used internally to represent cl-defstruct and defclass instances, for
1398 ** 'save-some-buffers' now uses 'save-some-buffers-default-predicate'
1399 to decide which buffers to ask about, if the PRED argument is nil.
1400 The default value of 'save-some-buffers-default-predicate' is nil,
1401 which means ask about all file-visiting buffers.
1404 ** string-(to|as|make)-(uni|multi)byte are now declared obsolete.
1407 ** New variable 'while-no-input-ignore-events' which allow
1408 setting which special events 'while-no-input' should ignore.
1409 It is a list of symbols.
1412 ** New function 'undo-amalgamate-change-group' to get rid of
1413 undo-boundaries between two states.
1416 ** New var 'definition-prefixes' is a hash table mapping prefixes to
1417 the files where corresponding definitions can be found. This can be
1418 used to fetch definitions that are not yet loaded, for example for
1422 ** New var 'syntax-ppss-table' to control the syntax-table used in
1426 ** 'define-derived-mode' can now specify an :after-hook form, which
1427 gets evaluated after the new mode's hook has run. This can be used to
1428 incorporate configuration changes made in the mode hook into the
1432 ** Autoload files can be generated without timestamps,
1433 by setting 'autoload-timestamps' to nil.
1434 FIXME As an experiment, nil is the current default.
1435 If no insurmountable problems before next release, it can stay that way.
1438 ** 'gnutls-boot' now takes a parameter ':complete-negotiation' that
1439 says that negotiation should complete even on non-blocking sockets.
1442 ** There is now a new variable 'flyspell-sort-corrections-function'
1443 that allows changing the way corrections are sorted.
1446 ** The new command 'fortune-message' has been added, which displays
1447 fortunes in the echo area.
1450 ** New function 'func-arity' returns information about the argument list
1451 of an arbitrary function. This generalizes 'subr-arity' for functions
1452 that are not built-in primitives. We recommend using this new
1453 function instead of 'subr-arity'.
1456 ** New function 'region-bounds' can be used in the interactive spec
1457 to provide region boundaries (for rectangular regions more than one)
1458 to an interactively callable function as a single argument instead of
1459 two separate arguments region-beginning and region-end.
1462 ** 'parse-partial-sexp' state has a new element. Element 10 is
1463 non-nil when the last character scanned might be the first character
1464 of a two character construct, i.e., a comment delimiter or escaped
1465 character. Its value is the syntax of that last character.
1468 ** 'parse-partial-sexp's state, element 9, has now been confirmed as
1469 permanent and documented, and may be used by Lisp programs. Its value
1470 is a list of currently open parenthesis positions, starting with the
1471 outermost parenthesis.
1474 ** 'read-color' will now display the color names using the color itself
1475 as the background color.
1478 ** The function 'redirect-debugging-output' now works on platforms
1479 other than GNU/Linux.
1482 ** The new function 'string-version-lessp' compares strings by
1483 interpreting consecutive runs of numerical characters as numbers, and
1484 compares their numerical values. According to this predicate,
1485 "foo2.png" is smaller than "foo12.png".
1488 ** Numeric comparisons and 'logb' no longer return incorrect answers
1489 due to internal rounding errors. For example, (< most-positive-fixnum
1490 (+ 1.0 most-positive-fixnum)) now correctly returns t on 64-bit hosts.
1493 ** The functions 'ffloor', 'fceiling', 'ftruncate' and 'fround' now
1494 accept only floating-point arguments, as per their documentation.
1495 Formerly, they quietly accepted integer arguments and sometimes
1496 returned nonsensical answers, e.g., (< N (ffloor N)) could return t.
1499 ** On hosts like GNU/Linux x86-64 where a 'long double' fraction
1500 contains at least EMACS_INT_WIDTH - 3 bits, 'format' no longer returns
1501 incorrect answers due to internal rounding errors when formatting
1502 Emacs integers with %e, %f, or %g conversions. For example, on these
1503 hosts (eql N (string-to-number (format "%.0f" N))) now returns t for
1504 all Emacs integers N.
1507 ** Calls that accept floating-point integers (for use on hosts with
1508 limited integer range) now signal an error if arguments are not
1509 integral. For example (decode-char 'ascii 0.5) now signals an error.
1512 ** The new function 'char-from-name' converts a Unicode name string
1513 to the corresponding character code.
1516 ** New functions 'sxhash-eq' and 'sxhash-eql' return hash codes of a
1517 Lisp object suitable for use with 'eq' and 'eql' correspondingly. If
1518 two objects are 'eq' ('eql'), then the result of 'sxhash-eq'
1519 ('sxhash-eql') on them will be the same.
1522 ** Function 'sxhash' has been renamed to 'sxhash-equal' for
1523 consistency with the new functions. For compatibility, 'sxhash'
1524 remains as an alias to 'sxhash-equal'.
1527 ** 'make-hash-table' now defaults to a rehash threshold of 0.8125
1528 instead of 0.8, to avoid rounding glitches.
1531 ** New function 'add-variable-watcher' can be used to call a function
1532 when a symbol's value is changed. This is used to implement the new
1533 debugger command 'debug-on-variable-change'.
1536 ** Time conversion functions that accept a time zone rule argument now
1537 allow it to be OFFSET or a list (OFFSET ABBR), where the integer
1538 OFFSET is a count of seconds east of Universal Time, and the string
1539 ABBR is a time zone abbreviation. The affected functions are
1540 'current-time-string', 'current-time-zone', 'decode-time',
1541 'format-time-string', and 'set-time-zone-rule'.
1544 ** 'format-time-string' now formats "%q" to the calendar quarter.
1547 ** New built-in function 'mapcan'.
1548 It avoids unnecessary consing (and garbage collection).
1551 ** 'car' and 'cdr' compositions 'cXXXr' and 'cXXXXr' are now part of Elisp.
1554 ** 'gensym' is now part of Elisp.
1557 ** Low-level list functions like 'length' and 'member' now do a better
1558 job of signaling list cycles instead of looping indefinitely.
1561 ** The new functions 'make-nearby-temp-file' and 'temporary-file-directory'
1562 can be used for creation of temporary files of remote or mounted directories.
1565 ** On GNU platforms when operating on a local file, 'file-attributes'
1566 no longer suffers from a race when called while another process is
1567 altering the filesystem. On non-GNU platforms 'file-attributes'
1568 attempts to detect the race, and returns nil if it does so.
1571 ** The new function 'file-local-name' can be used to specify arguments
1572 of remote processes.
1575 ** The new functions 'file-name-quote', 'file-name-unquote' and
1576 'file-name-quoted-p' can be used to quote / unquote file names with
1580 ** The new error 'file-missing', a subcategory of 'file-error', is now
1581 signaled instead of 'file-error' if a file operation acts on a file
1582 that does not exist.
1585 ** The function 'delete-directory' no longer signals an error when
1586 operating recursively and when some other process deletes the directory
1587 or its files before 'delete-directory' gets to them.
1590 *** New error type 'user-search-failed' like 'search-failed' but
1591 avoids debugger like 'user-error'.
1594 ** The function 'line-number-at-pos' now takes a second optional
1595 argument 'absolute'. If this parameter is nil, the default, this
1596 function keeps on returning the line number taking potential narrowing
1597 into account. If this parameter is non-nil, the function ignores
1598 narrowing and returns the absolute line number.
1601 ** The function 'color-distance' now takes a second optional argument
1602 'metric'. When non-nil, it should be a function of two arguments that
1603 accepts two colors and returns a number.
1605 ** Changes in Frame and Window Handling
1608 *** Resizing a frame no longer runs 'window-configuration-change-hook'.
1609 'window-size-change-functions' should be used instead.
1612 *** The new function 'frame-size-changed-p' can tell whether a frame has
1613 been resized since the last time 'window-size-change-functions' has been
1617 *** The function 'frame-geometry' now also returns the width of a
1618 frame's outer border.
1621 *** New frame parameters and changed semantics for older ones
1624 **** 'z-group' positions a frame above or below all others.
1627 **** 'min-width' and 'min-height' specify the absolute minimum size of a
1631 **** 'parent-frame' makes a frame the child frame of another Emacs
1632 frame. The section "Child Frames" in the Elisp manual describes the
1633 intrinsics of that relationship.
1636 **** 'delete-before' triggers deletion of one frame before that of
1640 **** 'mouse-wheel-frame' specifies another frame whose windows shall be
1644 **** 'no-other-frame' has 'next-frame' and 'previous-frame' skip this
1648 **** 'skip-taskbar' removes a frame's icon from the taskbar and has
1649 Alt-<TAB> skip this frame.
1652 **** 'no-focus-on-map' avoids that a frame gets input focus when mapped.
1655 **** 'no-accept-focus' means that a frame does not want to get input
1656 focus via the mouse.
1659 **** 'undecorated' removes the window manager decorations from a frame.
1662 **** 'override-redirect' tells the window manager to disregard this
1666 **** 'width' and 'height' allow to specify pixel values and ratios now.
1669 **** 'left' and 'top' allow to specify ratios now.
1672 **** 'keep-ratio' preserves size and position of child frames when their
1673 parent frame is resized.
1676 **** 'no-special-glyphs' suppresses display of truncation and
1677 continuation glyphs in a frame.
1680 **** 'auto-hide-function' and 'minibuffer-exit' handle auto hiding of
1681 frames and exiting from minibuffer individually.
1684 **** 'fit-frame-to-buffer-margins' and 'fit-frame-to-buffer-sizes'
1685 handle fitting a frame to its buffer individually.
1688 **** 'drag-internal-border', 'drag-with-header-line',
1689 'drag-with-mode-line', 'snap-width', 'top-visible' and 'bottom-visible'
1690 allow to drag and resize frames with the mouse.
1692 *** The new function 'frame-list-z-order' returns a list of all frames
1693 in Z (stacking) order.
1696 *** The function 'x-focus-frame' optionally tries to not activate its
1700 *** The variable 'focus-follows-mouse' has a third meaningful value
1701 'auto-raise' to indicate that the window manager automatically raises a
1702 frame when the mouse pointer enters it.
1705 *** The new function 'frame-restack' puts a frame above or below
1706 another on the display.
1709 *** The new face 'internal-border' specifies the background of a frame's
1713 *** The NORECORD argument of 'select-window' now has a meaningful value
1714 'mark-for-redisplay' which is like any other non-nil value but marks
1715 WINDOW for redisplay.
1718 *** Support for side windows is now official.
1719 The display action function 'display-buffer-in-side-window' will
1720 display its buffer in a side window. Functions for toggling all side
1721 windows on a frame, changing and reversing the layout of side windows
1722 and returning the main (major non-side) window of a frame are
1723 provided. For details consult the section "Side Windows" in the Elisp
1727 *** Support for atomic windows - rectangular compositions of windows
1728 treated by 'split-window', 'delete-window' and 'delete-other-windows'
1729 like a single live window - is now official. For details consult the
1730 section "Atomic Windows" in the Elisp manual.
1733 *** New 'display-buffer' alist entry 'window-parameters' allows to
1734 assign window parameters to the window used for displaying the buffer.
1737 *** New function 'display-buffer-reuse-mode-window' is an action function
1738 suitable for use in 'display-buffer-alist'. For example, to avoid
1739 creating a new window when opening man pages when there's already one,
1742 (add-to-list 'display-buffer-alist
1743 '("\\`\\*Man .*\\*\\'" .
1744 (display-buffer-reuse-mode-window
1745 (inhibit-same-window . nil)
1746 (mode . Man-mode))))
1749 *** New window parameter 'no-delete-other-windows' prevents that
1750 its window gets deleted by 'delete-other-windows'.
1753 *** New window parameters 'mode-line-format' and 'header-line-format'
1754 allow to override the buffer-local formats for this window.
1757 *** New command 'window-swap-states' swaps the states of two live
1761 *** New functions 'window-pixel-width-before-size-change' and
1762 'window-pixel-height-before-size-change' support detecting which
1763 window changed size when 'window-size-change-functions' are run.
1766 *** The new function 'window-lines-pixel-dimensions' returns the pixel
1767 dimensions of a window's text lines.
1770 *** The new function 'window-largest-empty-rectangle' returns the
1771 dimensions of the largest rectangular area not occupying any text in a
1775 *** The semantics of 'mouse-autoselect-window' has changed slightly.
1776 For details see the section "Mouse Window Auto-selection" in the Elisp
1780 ** 'tcl-auto-fill-mode' is now declared obsolete. Its functionality
1781 can be replicated simply by setting 'comment-auto-fill-only-comments'.
1783 ** New pcase pattern 'rx' to match against a rx-style regular expression.
1784 For details, see the doc string of 'rx--pcase-macroexpander'.
1787 * Changes in Emacs 26.1 on Non-Free Operating Systems
1790 ** Intercepting hotkeys on Windows 7 and later now works better.
1791 The new keyboard hooking code properly grabs system hotkeys such as
1792 Win-* and Alt-TAB, in a way that Emacs can get at them before the
1793 system. This makes the 'w32-register-hot-key' functionality work
1794 again on all versions of MS-Windows starting with Windows 7. On
1795 Windows NT and later you can now register any hotkey combination. (On
1796 Windows 9X, the previous limitations, spelled out in the Emacs manual,
1800 ** 'convert-standard-filename' no longer mirrors slashes on MS-Windows.
1801 Previously, on MS-Windows this function converted slash characters in
1802 file names into backslashes. It no longer does that. If your Lisp
1803 program used 'convert-standard-filename' to prepare file names to be
1804 passed to subprocesses (which is not the recommended usage of that
1805 function), you will now have to mirror slashes in your application
1806 code. One possible way is this:
1809 (while (string-match "/" file-name start)
1810 (aset file-name (match-beginning 0) ?\\)
1811 (setq start (match-end 0))))
1814 ** GUI sessions on MS-Windows now treat SIGINT like Posix platforms do.
1815 The effect of delivering a Ctrl-C (SIGINT) signal to a GUI Emacs on
1816 MS-Windows is now the same as on Posix platforms -- Emacs saves the
1817 session and exits. In particular, this will happen if you start
1818 emacs.exe from the Windows shell, then type Ctrl-C into that shell's
1822 ** 'signal-process' supports SIGTRAP on Windows XP and later.
1823 The 'kill' emulation on Windows now maps SIGTRAP to a call to the
1824 'DebugBreakProcess' API. This causes the receiving process to break
1825 execution and return control to the debugger. If no debugger is
1826 attached to the receiving process, the call is typically ignored.
1827 This is in contrast to the default action on POSIX Systems, where it
1828 causes the receiving process to terminate with a core dump if no
1829 debugger has been attached to it.
1832 ** 'set-mouse-position' and 'set-mouse-absolute-pixel-position' work
1836 ** Emacs can now be run as a GUI application from the command line on
1840 ** 'ns-appearance' and 'ns-transparent-titlebar' change the appearance
1841 of frame decorations on macOS 10.9+.
1844 ** 'ns-use-thin-smoothing' enables thin font smoothing on macOS 10.8+.
1847 ** 'process-attributes' on Darwin systems now returns more information.
1850 ----------------------------------------------------------------------
1851 This file is part of GNU Emacs.
1853 GNU Emacs is free software: you can redistribute it and/or modify
1854 it under the terms of the GNU General Public License as published by
1855 the Free Software Foundation, either version 3 of the License, or
1856 (at your option) any later version.
1858 GNU Emacs is distributed in the hope that it will be useful,
1859 but WITHOUT ANY WARRANTY; without even the implied warranty of
1860 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1861 GNU General Public License for more details.
1863 You should have received a copy of the GNU General Public License
1864 along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
1870 paragraph-separate: "[
\f]*$"