Copyright (C) 2017-2018 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.
+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 27.
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.
+with a prefix argument or by typing 'C-u C-h C-n'.
Temporary note:
+++ indicates that all necessary documentation updates are complete.
** Emacs now uses GMP, the GNU Multiple Precision library.
By default, if 'configure' does not find a suitable libgmp, it
arranges for the included mini-gmp library to be built and used.
-The new 'configure' option --without-libgmp uses mini-gmp even if a
+The new 'configure' option '--without-libgmp' uses mini-gmp even if a
suitable libgmp is available.
** The new configure option '--with-json' adds support for JSON using
-the Jansson library. It is on by default; use 'configure
+the Jansson library. It is on by default; use './configure
--with-json=no' to build without Jansson support. The new JSON
functions 'json-serialize', 'json-insert', 'json-parse-string', and
'json-parse-buffer' are typically much faster than their Lisp
forces etags to use the C library's regex matcher even if the regex
substitute ordinarily would be used to work around compatibility problems.
-** Emacs has been ported to the -fcheck-pointer-bounds option of GCC.
+** Emacs has been ported to the '-fcheck-pointer-bounds' option of GCC.
This causes Emacs to check bounds of some arrays addressed by its
internal pointers, which can be helpful when debugging the Emacs
interpreter or modules that it uses. If your platform supports it you
** Emacs now normally uses a C pointer type instead of a C integer
type to implement Lisp_Object, which is the fundamental machine word
type internal to the Emacs Lisp interpreter. This change aims to
-catch typos and support -fcheck-pointer-bounds. The 'configure'
-option --enable-check-lisp-object-type is therefore no longer as
+catch typos and supports '-fcheck-pointer-bounds'. The 'configure'
+option '--enable-check-lisp-object-type' is therefore no longer as
useful and so is no longer enabled by default in developer builds,
to reduce differences between developer and production builds.
Units that are ordered after 'emacs.service' will only be started
after Emacs has finished initialization and is ready for use.
(If your Emacs is installed in a non-standard location and you copied the
-emacs.service file to eg ~/.config/systemd/user/, you will need to copy
+emacs.service file to eg "~/.config/systemd/user/", you will need to copy
the new version of the file again.)
\f
** emacsclient now supports the 'EMACS_SOCKET_NAME' environment variable.
The behavior is identical to 'EMACS_SERVER_FILE', in that the
command-line value specified via '--socket-name' will override the
-environment, and the natural default to TMPDIR, then '/tmp', continues
+environment, and the natural default to TMPDIR, then "/tmp", continues
to apply.
+++
text.
---
-** Show modeline tooltips only if the corresponding action applies.
+** Show mode line tooltips only if the corresponding action applies.
Customize the option 'mode-line-default-help-echo' to restore the old
behavior where the tooltip text is also shown when the corresponding
action does not apply.
** The German prefix and postfix input methods now support Capital sharp S.
---
-** New input methods hawaiian-postfix and hawaiian-prefix.
+** New input methods 'hawaiian-postfix' and 'hawaiian-prefix'.
+++
** New function 'exec-path'.
+++
** The new functions and commands 'text-property-search-forward' and
'text-property-search-backward' have been added. These provide an
-interface that's more like functions like @code{search-forward}.
+interface that's more like functions like 'search-forward'.
---
** More commands support noncontiguous rectangular regions, namely
navigation and editing of large files.
---
-** add-dir-local-variable now uses dotted pair notation syntax
-to write alists of variables to .dir-locals.el. This is the same
-syntax that you can see in the example of a .dir-locals.el file
-in (info "(emacs) Directory Variables")
+** 'add-dir-local-variable' now uses dotted pair notation syntax to
+write alists of variables to ".dir-locals.el". This is the same
+syntax that you can see in the example of a ".dir-locals.el" file in
+the node "(emacs) Directory Variables" of the user manual.
\f
* Changes in Specialized Modes and Packages in Emacs 27.1
+++
*** The Lisp Debugger is now based on 'backtrace-mode'.
Backtrace mode adds fontification and commands for changing the
-appearance of backtrace frames. See the node "Backtraces" in the Elisp
-manual for documentation of the new mode and its commands.
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
** Edebug
+++
*** Edebug's backtrace buffer now uses 'backtrace-mode'.
Backtrace mode adds fontification, links and commands for changing the
-appearance of backtrace frames. See the node "Backtraces" in the Elisp
-manual for documentation of the new mode and its commands.
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
The binding of 'd' in Edebug's keymap is now 'edebug-pop-to-backtrace'
which replaces 'edebug-backtrace'. Consequently Edebug's backtrace
+++
*** ERT's backtrace buffer now uses 'backtrace-mode'.
Backtrace mode adds fontification and commands for changing the
-appearance of backtrace frames. See the node "Backtraces" in the Elisp
-manual for documentation of the new mode and its commands.
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
** Gamegrid
---
*** The default value of 'nxml-sexp-element-flag' is now t.
-This means that pressing C-M-SPACE now selects the entire tree by
+This means that pressing 'C-M-SPACE' now selects the entire tree by
default, and not just the opening element.
** Eshell
*** The function 'eshell-uniquify-list' has been renamed from
'eshell-uniqify-list'.
-*** The function eshell/kill is now able to handle signal switches.
-Previously eshell/kill would fail if provided a kill signal to send to the
+*** The function 'eshell/kill' is now able to handle signal switches.
+Previously 'eshell/kill' would fail if provided a kill signal to send to the
process. It now accepts signals specified either by name or by its number.
** Shell
** Auth-source
---
-*** The Secret Service backend supports the :create key now.
+*** The Secret Service backend supports the ':create' key now.
** Tramp
+++
*** During user and host name completion in the minibuffer, results
from auth-source search are taken into account. This can be disabled
-by setting user option 'tramp-completion-use-auth-sources' to nil.
+by setting the user option 'tramp-completion-use-auth-sources' to nil.
+++
*** The user option 'tramp-ignored-file-name-regexp' allows to disable
---
** thingatpt.el supports a new "thing" called 'uuid'.
-A symbol 'uuid' can be passed to thing-at-point and it returns the
+A symbol 'uuid' can be passed to 'thing-at-point' and it returns the
UUID at point.
-
** Interactive automatic highlighting
+
+++
*** 'highlight-regexp' can now highlight subexpressions.
-The now command accepts a prefix numeric argument to choose the
+The new command accepts a prefix numeric argument to choose the
subexpression.
** Mouse display of minor mode menu
---
-*** 'minor-mode-menu-from-indicator' now display full minor mode name.
+*** 'minor-mode-menu-from-indicator' now displays full minor mode name.
When there is no menu for a mode, display the mode name after the
indicator instead of just the indicator (which is sometimes cryptic).
\f
* New Modes and Packages in Emacs 27.1
-** multifile.el lets one setup multifile operations like search&replace
+** multifile.el lets one setup multifile operations like search&replace.
+++
** Emacs can now visit files in archives as if they were directories.
This feature uses Tramp and works only on systems which support GVFS,
-i.e. GNU/Linux, roughly spoken. See the chapter "(tramp) Archive file
+i.e. GNU/Linux, roughly spoken. See the node "(tramp) Archive file
names" in the Tramp manual for full documentation of these facilities.
+++
-** New library for writing JSONRPC applications (https://jsonrpc.org)
+** New library for writing JSONRPC applications (https://jsonrpc.org).
The 'jsonrpc' library enables writing Emacs Lisp applications that
rely on this protocol. Since the protocol is designed to be
transport-agnostic, the library provides an API to implement new
** Backtrace mode improves viewing of Elisp backtraces.
Backtrace mode adds pretty printing, fontification and ellipsis
expansion to backtrace buffers produced by the Lisp debugger, Edebug
-and ERT. See the node "Backtraces" in the Elisp manual for
+and ERT. See the node "(elisp) Backtraces" in the Elisp manual for
documentation of the new mode and its commands.
\f
* Incompatible Lisp Changes in Emacs 27.1
-** define-fringe-bitmap is always defined, even when Emacs is built
+** 'define-fringe-bitmap' is always defined, even when Emacs is built
without any GUI support.
---
** Just loading a theme's file no longer activates the theme's settings.
Loading a theme with 'M-x load-theme' still activates the theme, as it
-did before. However, loading the theme's file with "M-x load-file",
+did before. However, loading the theme's file with 'M-x load-file',
or using 'require' or 'load' in a Lisp program, doesn't actually apply
the theme's settings until you either invoke 'M-x enable-theme' or
type 'M-x load-theme'. (In a Lisp program, calling 'enable-theme' or
The variable 'custom--inhibit-theme-enable' controls this behavior;
its default value changed in Emacs 27.1.
-** The 'repetitions' argument of 'benchmark-run' can now also be a variable.
+** The REPETITIONS argument of 'benchmark-run' can now also be a variable.
** The FILENAME argument to 'file-name-base' is now mandatory and no
longer defaults to 'buffer-file-name'.
dired-default-directory-alist, dired-enable-local-variables,
dired-hack-local-variables, dired-local-variables-file, dired-omit-here-always.
-** garbage collection no longer treats miscellaneous objects specially;
+** Garbage collection no longer treats miscellaneous objects specially;
they are now allocated like any other pseudovector. As a result, the
'garbage-collect' and 'memory-use-count' functions no longer return a
'misc' component, and the 'misc-objects-consed' variable has been
\f
* Lisp Changes in Emacs 27.1
-** lookup-key can take a list of keymaps as argument.
+** 'lookup-key' can take a list of keymaps as argument.
+++
** 'condition-case' now accepts 't' to match any error symbol.
Several primitive functions formerly returned floats or lists of
integers to represent integers that did not fit into fixnums. These
functions now simply return integers instead. Affected functions
-include functions like encode-char that compute code-points, functions
-like file-attributes that compute file sizes and other attributes,
-functions like process-id that compute process IDs, and functions like
-user-uid and group-gid that compute user and group IDs.
+include functions like 'encode-char' that compute code-points, functions
+like 'file-attributes' that compute file sizes and other attributes,
+functions like 'process-id' that compute process IDs, and functions like
+'user-uid' and 'group-gid' that compute user and group IDs.
+++
** Although the default timestamp format is still (HI LO US PS),
it is planned to change in a future Emacs version, to exploit bignums.
The documentation has been updated to mention that the timestamp
format may change and that programs should use functions like
-format-time-string, decode-time, and encode-time rather than probing
-the innards of a timestamp directly, or creating a timestamp by hand.
+'format-time-string', 'decode-time', and 'encode-time' rather than
+probing the innards of a timestamp directly, or creating a timestamp
+by hand.
+++
-** encode-time supports a new API (encode-time TIME &optional FORM).
+** 'encode-time' supports a new API '(encode-time TIME &optional FORM)'.
This can convert decoded times and Lisp time values to Lisp timestamps
-of various forms, including a new timestamp form (TICKS . HZ), where
+of various forms, including a new timestamp form '(TICKS . HZ)', where
TICKS is an integer and HZ is a positive integer denoting a clock
frequency. The old encode-time API is still supported.
+++
** New function 'time-equal-p' compares time values for equality.
-** define-minor-mode automatically documents the meaning of ARG.
+** 'define-minor-mode' automatically documents the meaning of ARG.
+++
** The function 'recenter' now accepts an additional optional argument.
** Window-specific face remapping.
Face specifications (of the kind used in 'face-remapping-alist')
now support filters, allowing faces to vary between different windows
-displaying the same buffer. See the Info node "Face Remapping" of the
-Emacs Lisp Reference manual for more detail.
+displaying the same buffer. See the node "(elisp) Face Remapping"
+of the Emacs Lisp Reference manual for more detail.
+++
** Special handling of buffer-local 'window-size-change-functions'.
window showing the buffer has changed its size.
+++
-** The function assoc-delete-all now takes an optional predicate argument.
+** The function 'assoc-delete-all' now takes an optional predicate argument.
+++
** New function 'string-distance' to calculate the Levenshtein distance
between two strings.
** 'print-quoted' now defaults to t, so if you want to see
-(quote x) instead of 'x you will have to bind it to nil where applicable.
+'(quote x)' instead of 'x you will have to bind it to nil where applicable.
+++
-** Numbers formatted via %o or %x may now be formatted as signed integers.
-This avoids problems in calls like (read (format "#x%x" -1)), and is
+** Numbers formatted via '%o' or '%x' may now be formatted as signed integers.
+This avoids problems in calls like '(read (format "#x%x" -1))', and is
more compatible with bignums, a planned feature. To get this
-behavior, set the experimental variable binary-as-unsigned to nil,
+behavior, set the experimental variable 'binary-as-unsigned' to nil,
and if the new behavior breaks your code please email
-32252@debbugs.gnu.org. Because %o and %x can now format signed
-integers, they now support the + and space flags.
+32252@debbugs.gnu.org. Because '%o' and '%x' can now format signed
+integers, they now support the '+' and space flags.
** To avoid confusion caused by "smart quotes", the reader signals an
error when reading Lisp symbols which begin with one of the following
+++
** Omitting variables after '&optional' and '&rest' is now allowed.
-For example (defun foo (&optional)) is no longer an error. This is
+For example '(defun foo (&optional))' is no longer an error. This is
sometimes convenient when writing macros. See the ChangeLog entry
titled "Allow '&rest' or '&optional' without following variable
(Bug#29165)" for a full listing of which arglists are accepted across
** Internal parsing commands now use 'syntax-ppss' and disregard
'open-paren-in-column-0-is-defun-start'. This affects mostly things like
'forward-comment', 'scan-sexps', and 'forward-sexp' when parsing backward.
-The new variable 'comment-use-syntax-ppss' can be set to nil to recover the old
-behavior if needed.
+The new variable 'comment-use-syntax-ppss' can be set to nil to recover
+the old behavior if needed.
** The 'server-name' and 'server-socket-dir' variables are set when a
socket has been passed to Emacs.
instead of just Microsoft platforms. This fixes a 'get-free-disk-space'
bug on OS X 10.8 and later.
+---
+** The function 'get-free-disk-space' returns now a non-nil value for
+remote systems, which support this check.
+
+++
** 'memory-limit' now returns a better estimate of memory consumption.
useful when a function makes a possibly large number of repetitive
changes and the change hooks are time consuming.
----
-** The function 'get-free-disk-space' returns now a non-nil value for
-remote systems, which support this check.
-
+++
** 'eql', 'make-hash-table', etc. now treat NaNs consistently.
Formerly, some of these functions ignored signs and significands of
NaNs. Now, all these functions treat NaN signs and significands as
-significant. For example, (eql 0.0e+NaN -0.0e+NaN) now returns nil
+significant. For example, '(eql 0.0e+NaN -0.0e+NaN)' now returns nil
because the two NaNs have different signs; formerly it returned t.
Also, Emacs now reads and prints NaN significands; e.g., if X is a
-NaN, (format "%s" X) now returns "0.0e+NaN", "1.0e+NaN", etc.,
+NaN, '(format "%s" X)' now returns "0.0e+NaN", "1.0e+NaN", etc.,
depending on X's significand.
+++
If the optional third argument is non-nil, 'make-string' will produce
a multibyte string even if its second argument is an ASCII character.
-** (format "%d" X) no longer mishandles a floating-point number X that
+** '(format "%d" X)' no longer mishandles a floating-point number X that
does not fit in a machine integer.
+++
-** In the DST slot, encode-time and parse-time-string now return -1
+** In the DST slot, 'encode-time' and 'parse-time-string' now return -1
if it is not known whether daylight saving time is in effect.
-Formerly they were inconsistent: encode-time returned t in this
-situation, whereas parse-time-string returned nil. Now they
+Formerly they were inconsistent: 'encode-time' returned t in this
+situation, whereas 'parse-time-string' returned nil. Now they
consistently use use nil to mean that DST is not in effect, and use -1
to mean that it is not known whether DST is in effect.
*** The default way the list of possible external viewers for MIME
types is sorted and chosen has changed. Earlier, the most specific
-viewer was chosen, even if there was a general override in ~/.mailcap.
-For instance, if /etc/mailcap has an entry for image/gif, that one
-will be chosen even if you have an entry for image/* in your
-~/.mailcap file. But with the new method, entries from ~/.mailcap
+viewer was chosen, even if there was a general override in "~/.mailcap".
+For instance, if "/etc/mailcap" has an entry for "image/gif", that one
+will be chosen even if you have an entry for "image/*" in your
+"~/.mailcap" file. But with the new method, entries from "~/.mailcap"
overrides all system and Emacs-provided defaults. To get the old
method back, set 'mailcap-prefer-mailcap-viewers' to nil.
** URL
-*** The file: handler no longer looks for index.html in directories if
-you ask it for a file:///dir URL. Since this is a low-level library,
-such decisions (if they are to be made at all) are left to
-higher-level functions.
+*** The 'file:' handler no longer looks for "index.html" in
+directories if you ask it for a "file:///dir" URL. Since this is a
+low-level library, such decisions (if they are to be made at all) are
+left to higher-level functions.
-** image-mode
+** Image mode
-*** image-mode started using ImageMagick by default for all images
+*** 'image-mode' started using ImageMagick by default for all images
some years back. It now respects 'imagemagick-types-inhibit' as a way
to disable that.
projects / emacs.git / commitdiff