Mention the further asynchronousity

[gnu-emacs] / etc / NEWS

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

Copyright (C) 2014-2016 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 25.

See file HISTORY for a list of GNU Emacs versions and release dates.
See files NEWS.24, NEWS.23, NEWS.22, NEWS.21, NEWS.20, NEWS.19, NEWS.18,
and NEWS.1-17 for changes in older Emacs versions.

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

Temporary note:
+++ indicates that all necessary documentation updates are complete.
    (This means all relevant manuals in doc/ AND lisp doc-strings.)
--- means no change in the manuals is needed.
When you add a new item, use the appropriate mark if you are sure it applies,
otherwise leave it unmarked.

\f
* Installation Changes in Emacs 25.2

\f
* Startup Changes in Emacs 25.2

\f
* Changes in Emacs 25.2

+++
** The networking code has been reworked so that it's more
asynchronous than it was (when specifying :nowait t in
`make-network-process').  How asynchronous it is varies based on the
capabilities of the system, but on a typical GNU/Linux system the DNS
resolution, the connection, and (for TLS streams) the TLS negotiation
are all done without blocking the main Emacs thread.  To get
asynchronous TLS, the TLS boot parameters have to be passed in (see
the manual for details).

Certain process oriented functions (like `process-datagram-address')
will block until socket setup has been performed.  The recommended way
to deal with asynchronous sockets is to avoid interacting with them
until they have changed status to "run".  This is most easily done
from a process sentinel.

** It is possible to disable attempted recovery on fatal signals

Two new variables allow to disable attempts to recover from stack
overflow and to avoid automatic auto-save when Emacs is delivered a
fatal signal.  `attempt-stack-overflow-recovery', if set to `nil',
will disable attempts to recover from C stack overflows; Emacs will
then crash as with any other fatal signal.
`attempt-orderly-shutdown-on-fatal-signal', if set to `nil', will
disable attempts to auto-save the session and shut down in an orderly
fashion when Emacs receives a fatal signal; instead, Emacs will
terminate immediately.  Both variables are non-`nil' by default.
These variables are for users who would like to avoid the small
probability of data corruption due to techniques Emacs uses to recover
in these situations.

\f
* Editing Changes in Emacs 25.2

\f
* Changes in Specialized Modes and Packages in Emacs 25.2

** eww

+++
*** A new `s' command for switching to another eww buffer via the minibuffer.

+++
** The commands that add ChangeLog entries now prefer a VCS root directory
for the ChangeLog file, if none already exists.  Customize
`change-log-directory-files' to nil for the old behavior.

---
** Support for non-string values of `time-stamp-format' has been removed.

** Tramp

+++
*** New connection method "sg", which allows to edit files under
different group ID.

+++
*** New connection method "doas" for OpenBSD hosts.

\f
* New Modes and Packages in Emacs 25.2

\f
* Incompatible Lisp Changes in Emacs 25.2

\f
* Lisp Changes in Emacs 25.2

** New var syntax-ppss-table to control the syntax-table used in syntax-ppss

** Autoload files can be generated without timestamps,
by setting `autoload-timestamps' to nil.

\f
* Changes in Emacs 25.2 on Non-Free Operating Systems

\f
* Installation Changes in Emacs 25.1

+++
** Building Emacs now requires C99 or later.

+++
** Building Emacs now requires GNU make, version 3.81 or later.

+++
** New configure option --with-cairo.
This builds Emacs with Cairo drawing.  As a side effect, it provides
support for built-in printing, when Emacs was built with GTK+.
Cairo drawing is an experimental feature in Emacs, and subject to
change in future releases.

+++
** New configure option --with-modules.
This enables support for loading dynamic modules; see below.

---
** By default, Emacs no longer works on IRIX.  We expect that Emacs
users are not affected by this, as SGI stopped supporting IRIX in
December 2013.  If you are affected, please send a bug report.  You
should be able to work around the problem either by porting the Emacs
undumping code to GCC under IRIX, or by configuring --with-wide-int,
or by sticking with Emacs 24.4.

---
** The Emacs garbage collector assumes GC_MARK_STACK == GC_MAKE_GCPROS_NOOPS.
The GC_MAKE_GCPROS_NOOPS stack-marking variant has been the default
since Emacs 24.4, and the other variants were undocumented and were
obstacles to maintenance and development.  GC_MARK_STACK and its
related symbols have been removed from the C internals.

---
** 'configure' now prefers gnustep-config when configuring GNUstep.
If gnustep-config is not available, the old heuristics are used.

---
** 'configure' now prefers inotify to gfile for file notification,
unless gfile is explicitly requested via --with-file-notification='gfile'.

---
** 'configure' detects the kqueue file notification library on *BSD
and Mac OS X machines.

---
** The configure option '--with-pkg-config-prog' has been removed.
Use './configure PKG_CONFIG=/full/name/of/pkg-config' if you need to.

---
** The configure option '--with-mmdf' has been removed.
It was no longer useful, as it relied on libraries that are no longer
supported, and its presence led to confusion during configuration.
This affects only the 'movemail' utility; Emacs itself can still
process MMDF-format files as before.

+++
** The configure option '--enable-silent-rules' is now the default,
and silent rules are now quieter.  To get the old behavior where
'make' chatters a lot, configure with '--disable-silent-rules' or
build with 'make V=1'.

---
** The configure option '--with-gameuser' now allows you to specify a
group instead of a user if its argument is prefixed by ':' (a colon).
This will cause the game score files in ${localstatedir}/games/emacs
to be owned by that group, and the helper program for updating them to
be installed setgid.  The option now defaults to the 'games' group.

---
** The `grep-changelog' script (and its manual page) are no longer included.
It has no particular connection to Emacs and has not changed in years,
so if you want to use it, you can always take a copy from an older Emacs.

---
** Emacs 25 comes with a new set of icons.
Various resolutions are available as etc/images/icons/hicolor/*/apps/emacs.png.
The old Emacs logo icons are available as `emacs23.png' in the same location.

---
** New make target `check-expensive' to run additional tests.
This includes all tests which run via "make check", plus additional
tests which take more time to perform.

\f
* Startup Changes in Emacs 25.1

+++
** When Emacs is given a file as a command line argument and
`initial-buffer-choice' is non-nil, display both the file and
`initial-buffer-choice'.  When Emacs is given more than one file and
`initial-buffer-choice' is non-nil, show `initial-buffer-choice'
and *Buffer List*.  This makes Emacs convenient to use from the
command line when `initial-buffer-choice' is non-nil.

+++
** The value of ‘initial-scratch-message’ is now treated as a doc string
and can contain escape sequences for command keys, quotes, and the like.

\f
* Changes in Emacs 25.1

+++
** Xwidgets: a new feature for embedding native widgets inside Emacs buffers.
If you have gtk3 and webkitgtk3 installed, and Emacs was built with
xwidget support, you can access the embedded webkit browser with `M-x
xwidget-webkit-browse-url'.  This opens a new buffer with the embedded
browser.  The buffer will have a new mode, `xwidget-webkit-mode'
(similar to `image-mode'), which supports the webkit widget.

+++
*** New functions for xwidget-webkit mode `xwidget-webkit-insert-string',
`xwidget-webkit-adjust-size-dispatch', `xwidget-webkit-back',
`xwidget-webkit-browse-url', `xwidget-webkit-reload',
`xwidget-webkit-current-url', `xwidget-webkit-scroll-backward',
`xwidget-webkit-scroll-forward', `xwidget-webkit-scroll-down',
`xwidget-webkit-scroll-up'.

+++
** Emacs can now load shared/dynamic libraries (modules).
A dynamic Emacs module is a shared library that provides additional
functionality for use in Emacs Lisp programs, just like a package
written in Emacs Lisp would.  The functions `load', `require',
`load-file', etc. were extended to load such modules, as they do with
Emacs Lisp packages.  The new variable `module-file-suffix' holds the
system-dependent value of the file-name extension (`.so' on Posix
hosts) of the module files.

A module should export a C-callable function named
`emacs_module_init', which Emacs will call as part of the call to
`load' or `require' which loads the module.  It should also export a
symbol named `plugin_is_GPL_compatible' to indicate that its code is
released under the GPL or compatible license; Emacs will refuse to
load modules that don't export such a symbol.

If a module needs to call Emacs functions, it should do so through the
API defined and documented in the header file `emacs-module.h'.  Note
that any module that provides Lisp-callable functions will have to use
Emacs functions such as `fset' and `funcall', in order to register its
functions with the Emacs Lisp interpreter.

Modules can create `user-ptr' Lisp objects that embed pointers to C
struct's defined by the module.  This is useful for keeping around
complex data structures created by a module, to be passed back to the
module's functions.  User-ptr objects can also have associated
"finalizers" -- functions to be run when the object is GC'ed; this is
useful for freeing any resources allocated for the underlying data
structure, such as memory, open file descriptors, etc.  A new
predicate `user-ptrp' returns non-nil if its argument is a `user-ptr'
object.

Loadable modules in Emacs are an experimental feature, and subject to
change in future releases.  For that reason, their support is disabled
by default, and must be enabled by using the `--with-modules' option
at configure time.

+++
** A second dir-local file (.dir-locals-2.el) is now accepted.
See the variable `dir-locals-file-2' for more information.

+++
** Network security (TLS/SSL certificate validity and the like) is
added via the new Network Security Manager (NSM) and controlled via
the `network-security-level' variable.

---
** International domain names (IDNA) are now encoded via the new
puny.el library, so that one can visit web sites like
"http://méxico.icom.museum".

+++
** C-h l now also lists the commands that were run.

** The new M-s M-w key binding uses eww to search the web for the
text in the region.

+++
** The new `timer-list' command lists all active timers in a buffer
where you can cancel them with the `c' command.

** M-x suggests shorthands and ignores obsolete commands for completion.
** x-select-enable-clipboard is renamed select-enable-clipboard.
x-select-enable-primary and renamed select-enable-primary.
Additionally they both now apply to all systems (OSX, GNUstep, Windows, you
name it), with the proviso that on some systems (e.g. Windows)
select-enable-primary is ineffective since the system doesn't
have the equivalent of a primary selection.

+++
** New option `switch-to-buffer-in-dedicated-window' allows you to
customize how `switch-to-buffer' proceeds interactively when the
selected window is strongly dedicated to its buffer.

+++
** The option `even-window-heights' has been renamed to
`even-window-sizes' and now handles window widths as well.

+++
** New function `read-multiple-choice' use to prompt for
multiple-choice questions, with a handy way to display help texts.

+++
** terpri gets an optional arg ENSURE to conditionally output a newline.

+++
** `insert-register' now leaves point after the inserted text
when called interactively.  A prefix argument toggles this behavior.

+++
** The new variable `term-file-aliases' replaces some files from lisp/term.
The function `tty-run-terminal-initialization' consults this variable
when deciding what terminal-specific initialization code to run.

---
** New variable `system-configuration-features', listing some of the
main features that Emacs was compiled with.  This is mainly intended
for use in Emacs bug reports.

+++
** A password is now hidden also when typed in batch mode.  Another
hiding character but the default `.' can be used by let-binding the
variable `read-hide-char'.

---
** New input methods: `tamil-dvorak' and `programmer-dvorak'.

\f
* Editing Changes in Emacs 25.1

+++
** M-x suggests shorthands and ignores obsolete commands for completion.

** Changes in undo

+++
*** Successive single-char deletions are collapsed in the undo-log just like
successive char insertions.  Which commands invoke this behavior is
controlled by the new `undo-auto-amalgamate' function.  See the node
"Undo" in the ELisp manual for more details.

+++
*** The heuristic used to insert `undo-boundary' after each command
has changed, so that if a command causes changes in more than just the
current buffer, Emacs now calls `undo-boundary' in every buffer
affected by the command.

+++
** New command `comment-line' bound to `C-x C-;'.

** New and improved facilities for inserting Unicode characters

---
*** Unicode names entered via C-x 8 RET now use substring completion by default.

+++
*** C-x 8 now has shorthands for these chars: ‐ ‑ ‒ – — ― ‘ ’ “ ” † ‡ • ′ ″
€ № ← → ↔ − ≈ ≠ ≤ ≥.  As before, you can type C-x 8 C-h to list shorthands.

+++
*** New minor mode electric-quote-mode for quoting ‘like this’ and “like this”
as you type.  See also the new variable ‘text-quoting-style’.

---
** New minor mode global-eldoc-mode is enabled by default.

---
** Emacs now uses "bracketed paste mode" on text terminals that support it.
Bracketed paste mode causes text terminals to wrap pasted text in special
escape sequences that allow Emacs to tell the difference between text
you type and text you paste from other applications.  Emacs then
avoids interpreting each character in the pasted text as it does with
keyboard input, which results in a paste experience similar to that
under a window system, and significant performance improvements when
pasting large amounts of text.

Bracketed paste mode is disabled by default, so Emacs automatically
enables it at startup if the terminal supports it.

+++
** Emacs now supports the latest version of the UBA.
The Emacs implementation of the Unicode Bidirectional Algorithm (UBA)
was updated to support all the latest additions and changes introduced
in Unicode Standard versions 6.3, 7.0, and the latest Unicode 8.0.
This includes full support for directional isolates and the
Bidirectional Parentheses Algorithm (BPA) specified by these Unicode
standards.

+++
** You can access `mouse-buffer-menu' (C-down-mouse-1) using C-f10.

+++
** New buffer-local `electric-pair-local-mode'.

+++
** New variable `fast-but-imprecise-scrolling' inhibits
fontification during full screen scrolling operations, giving less
hesitant operation during auto-repeat of C-v, M-v at the cost of
possible inaccuracies in the end position.

+++
** New documentation command `describe-symbol'.
Works for functions, variables, faces, etc.  It is bound to `C-h o' by
default.

+++
** New function `custom-prompt-customize-unsaved-options' checks for
unsaved customizations and prompts user to customize (if found).  It
is intended for adding to 'kill-emacs-query-functions'.

+++
** The old `C-x w' bindings in hi-lock-mode are officially deprecated
in favor of the global `M-s h' bindings introduced in Emacs-23.1.
They'll disappear soon.

\f
* Changes in Specialized Modes and Packages in Emacs 25.1

** Checkdoc

+++
*** New command `checkdoc-package-keywords' checks if the
current package keywords are recognized.  Set the new option
`checkdoc-package-keywords-flag' to non-nil to make
`checkdoc-current-buffer' call this function automatically.

+++
*** New function `checkdoc-file' checks for style errors.
It's meant for use together with `compile':
emacs -batch --eval "(checkdoc-file \"subr.el\")"

** Desktop

---
*** The desktop format version has been upgraded from 206 to 208.
Although Emacs 25.1 can read a version 206 desktop, earlier Emacsen
cannot read a version 208 desktop.  To upgrade your desktop file, you
must explicitly request the upgrade, by C-u M-x desktop-save.  You are
recommended to do this as soon as you have firmly upgraded to Emacs
25.1 (or later).  Should you ever need to downgrade your desktop file
to version 206, you can do this with C-u C-u M-x desktop-save.

+++
** New function `bookmark-set-no-overwrite' bound to C-x r M.
It raises an error if a bookmark of that name already exists,
unlike `bookmark-set' which silently updates an existing bookmark.

** Gnus

+++
*** New user options `mm-html-inhibit-images' and `mm-html-blocked-images'
now control how mm-* functions fetch and display images in an HTML
message.  Gnus still uses `gnus-inhibit-images' and `gnus-blocked-images'
for that purpose, i.e., binds mm-html- variables with those gnus-
variables, but other packages do not have to bind gnus- variables now.

---
*** `mm-inline-text-html-with-images' has been removed.
Use `mm-html-inhibit-images' instead.  Note that the value is opposite
in meaning.

** IMAP

---
*** `imap-ssl-program' has been removed, and imap.el uses the internal
GnuTLS encryption functions if possible.

** JSON

---
*** `json-pretty-print' and `json-pretty-print-buffer' now maintain
the ordering of object keys by default.

---
*** New commands `json-pretty-print-ordered' and
`json-pretty-print-buffer-ordered' pretty prints JSON objects with
object keys sorted alphabetically.

+++
** Prog mode has some support for multi-mode indentation.
This allows better indentation support in modes that support multiple
programming languages in the same buffer, like literate programming
environments or ANTLR programs with embedded Python code.

A major mode can provide indentation context for a sub-mode through
the `prog-indentation-context' variable.  To support this, modes that
provide indentation should use `prog-widen' instead of `widen' and
`prog-first-column' instead of a literal zero.  See the node
"Mode-Specific Indent" in the ELisp manual for more details.

** Prettify Symbols mode

+++
*** Prettify Symbols mode supports custom composition predicates.  By
overriding the default `prettify-symbols-compose-predicate', modes can
specify in which contexts a symbol may be displayed as some Unicode
character.  `prettify-symbols-default-compose-p' is the default which
is suitable for most programming languages such as C or Lisp (but not
(La)TeX).

+++
*** Symbols can be unprettified while point is inside them.
New variable `prettify-symbols-unprettify-at-point' configures this.

** Enhanced xterm support

---
*** The new variable `xterm-screen-extra-capabilities' for configuring xterm.
This variable tells Emacs which advanced capabilities are available in
the xterm terminal emulator used to display Emacs text-mode frames.
The default is to check each capability, and use it if available.
(This variable was introduced in Emacs 24.1, but was not announced in
its NEWS.)

---
*** Killing text now also sets the CLIPBOARD/PRIMARY selection
in the surrounding GUI (using the OSC-52 escape sequence).  This only works
if your xterm supports it and enables the `allowWindowOps' options (disabled
by default at least in Debian, for security reasons).

Similarly, you can yank the CLIPBOARD/PRIMARY selection (using the OSC-52
escape sequence) if your xterm has the feature enabled but for that you
additionally need to add `getSelection' to `xterm-extra-capabilities'.

+++
*** `xterm-mouse-mode' now supports mouse-tracking (if your xterm supports it).

---
** The `save-place' variable is replaced by `save-place-mode'.

** ERC

+++
*** ERC can now hide message types by network or channel.
`erc-hide-list' will hide all messages of the specified type, while
`erc-network-hide-list' and `erc-channel-hide-list' will only hide the
specified message types for the respective specified targets.

*** New variable `erc-default-port-tls' used to connect to TLS IRC
servers.

---
*** Reconnection is now asynchronous.

---
*** Nick completion is now case-insensitive again after inadvertently
being made case-sensitive in Emacs 24.2.

** MPC

---
*** New commands, key binds, and menu items.

**** `<' and `>' for navigating previous and next tracks in playlist

**** New play/pause command `mpc-toggle-play' bound to `s'

**** `g' bound to new command `mpc-seek-current' will navigate current
     track.

**** New commands `mpc-toggle-{consume,repeat,single,shuffle}' for
     toggling playback modes.

---
*** Now supports connecting to a UNIX domain socket.

---
*** Looks at more image file names to use as album art.
Case-insensitively tries for .folder.png (freedesktop) and folder.jpg
(XP) in addition to cover.jpg.

---
*** Searches in more locations for MPD configuration files.
MPD supports the XDG base directory specification since version 0.17.6.

** Midnight-mode

---
*** `midnight-mode' is now a proper minor mode.

---
*** clean-buffer-*-regexps can now specify buffers via predicate functions.

** package.el

+++
*** New "external" package status.
An external package is any installed package that's not built-in and
not from `package-user-dir', which usually means it's from an entry in
`package-directory-list'.  They are treated much like built-in
packages, in that they cannot be deleted through the package menu and
are not considered for upgrades.

The effect is that a user can manually place a specific version of a
package inside `package-directory-list' and the package menu will
always respect that.

+++
*** If a package is available on multiple archives and one has higher
priority (as per `package-archive-priorities') only that one is
listed.  This can be configured with `package-menu-hide-low-priority'.

+++
*** `package-menu-toggle-hiding' now toggles the hiding of packages.
This includes the above-mentioned low-priority packages, as well as
available packages whose version is lower than the currently installed
version (which were previously impossible to display).
This allows users to downgrade a package if a lower version is
available.

---
*** When filtering the package menu, keywords starting with "arc:" or
"status:" represent package archive or status, respectively, instead
of actual keywords.

---
*** Most functions which involve downloading information now take an
ASYNC argument.  If it is non-nil, package.el performs the download(s)
asynchronously.

---
*** New variable `package-menu-async' controls whether the
package-menu uses asynchronous downloads.

---
*** `package-install-from-buffer' and `package-install-file' work on directories.
This follows the same rules as installing from a .tar file, except the
-pkg file is optional.

---
*** Packages which are dependencies of other packages cannot be deleted.
The FORCE argument to `package-delete' overrides this.

---
*** New custom variable `package-selected-packages' tracks packages
which were installed by the user (as opposed to installed as
dependencies).  This variable can also be manually customized.

---
*** New command `package-install-selected-packages' installs all
packages from `package-selected-packages' which are currently missing.

---
*** New command `package-autoremove' removes all packages which were
installed strictly as dependencies but are no longer needed.

+++
** Shell

When you invoke `shell' interactively, the *shell* buffer will now
display in a new window.  However, you can customize this behavior via
the `display-buffer-alist' variable.  For example, to get
the old behavior -- *shell* buffer displays in current window -- use
(add-to-list 'display-buffer-alist
     '("^\\*shell\\*$" . (display-buffer-same-window))).

** EIEIO
+++
*** The `:protection' slot option is not obeyed any more.
+++
*** The `newname' argument to constructors is optional&deprecated.
If you need your objects to be named, do it by inheriting from `eieio-named'.
+++
*** The <class>-list-p and <class>-child-p functions are declared obsolete.
+++
*** The <class> variables are declared obsolete.
+++
*** The <initarg> variables are declared obsolete.
+++
*** defgeneric and defmethod are declared obsolete.
Use the equivalent facilities from cl-generic.el instead.
+++
*** `constructor' is now an obsolete alias for `make-instance'.
--- `pcase' accepts a new UPattern `eieio'.

** ido

+++
*** New command `ido-bury-buffer-at-head' bound to C-S-b
Bury the buffer at the head of `ido-matches', analogous to how C-k
kills the buffer at head.

---
*** A prefix argument to `ido-restrict-to-matches' will reverse its
meaning, and the list is restricted to those elements that do not
match the current input.

** Minibuffer

+++
*** You can use <UP> and <DOWN> arrow keys to move through history by lines.
The new commands `next-line-or-history-element' and
`previous-line-or-history-element', bound to <UP> and <DOWN> in the
minibuffer, allow by-line movement through minibuffer history,
similarly to an ordinary buffer.  Only when point moves over
the bottom/top of the minibuffer it goes to the next/previous history
element.  `M-p' and `M-n' still move directly to previous/next history
item as before.

** Search and Replace

+++
*** New user option `search-default-mode'
specifies the default mode for I-search.

+++
*** `isearch' and `query-replace' can now perform character folding in matches.
Isearch does that by default, while `query-replace' will do that if
the new variable `replace-character-fold' is customized to a non-nil
value.  This is analogous to case folding, but instead of disregarding
case variants, it disregards wider classes of distinctions between
similar characters.  (Case folding is a special case of character
folding.)  This means many characters in the search string will match
entire groups of characters instead of just themselves.

For instance, the " will match all variants of double quotes (like “
and ”), and the letter a will match all of its accented cousins, even
those composed of multiple characters, as well as many other symbols
like ℀, ℁, ⒜, and ⓐ.

+++
*** New function `character-fold-to-regexp' can be used
by searching commands to produce a regexp matching anything that
character-folds into STRING.

+++
*** The new M-s M-w key binding uses eww to search the web for the
text in the region.  The search engine to use for this is specified by
the customizable variable `eww-search-prefix'.

+++
*** Query-replace history is enhanced.
When query-replace reads the FROM string from the minibuffer, typing
`M-p' will now show previous replacements as "FROM SEP TO", where FROM
and TO are the original text and its replacement, and SEP is an arrow
string defined by the new variable `query-replace-from-to-separator'.
To select a prior replacement, type `M-p' until the desired
replacement appears in the minibuffer, and then exit the minibuffer by
typing RET.

** Calc
+++
*** If `quick-calc' is called with a prefix argument, insert the
result of the calculation into the current buffer.

+++
** In Edebug, you can now set the initial mode with C-x C-a C-m.  With
this you can tell Edebug not to stop at the start of the first
instrumented function.

** ElDoc

+++
*** New minor mode `global-eldoc-mode'
It is turned on by default, and affects `*scratch*' and other buffers
whose major mode supports Emacs Lisp.

---
*** `eldoc-documentation-function' now defaults to `ignore'

---
*** `describe-char-eldoc' displays information about character at point,
and can be used as a default value of `eldoc-documentation-function'.  It is
useful when, for example, one needs to distinguish various spaces (e.g. ] [,
] [, ] [, etc.) while using mono-spaced font.

** eww

---
*** HTML can now be rendered using variable-width fonts.

+++
*** A new command `F' (`eww-toggle-fonts') can be used to toggle
whether to use variable-pitch fonts or not.  The user can also
customize the `shr-use-fonts' variable.

+++
*** A new command `C' (`eww-toggle-colors') can be used to toggle
whether to use the HTML-specified colors or not.  The user can also
customize the `shr-use-colors' variable.

+++
*** A new command `R' (`eww-readable') will try do identify the main
textual parts of a web page and display only that, leaving menus and
the like off the page.

---
*** Images that are being loaded are now marked with grey
"placeholder" images of the size specified by the HTML.  They are then
replaced by the real images asynchronously, which will also now
respect width/height HTML specs (unless they specify widths/heights
bigger than the current window).

---
*** You can now use several eww buffers in parallel by renaming eww
buffers you want to keep separate.

+++
*** Partial state of the eww buffers (the URIs and the titles of the
pages visited) is now preserved in the desktop file.

+++
*** `eww-after-render-hook' is now called after eww has rendered
the data in the buffer.

---
*** The `eww-reload' command now takes a prefix to not reload via
the net, but just use the local copy of the HTML.

+++
*** The DOM shr and eww uses has been changed to the general Emacs
xml.el/libxml2 DOM, and a new package dom.el has been added to
interact with this DOM.  See the Emacs Lisp manual for interface
details.

+++
*** `mailcap-mime-data' is now consulted when displaying PDF files.

+++
*** The new `S' command will list all eww buffers, and allow managing
them.

---
*** https pages with valid certificates have headers marked in green, while
invalid certificates are marked in red.

** Message mode

---
*** text/html messages that contain inline image parts will be
transformed into multipart/related messages before sending.

---
*** The `message-valid-fqdn-regexp' variable has been removed, since
there are now top-level domains added all the time.  Message will no
longer warn about sending emails to top-level domains it hasn't heard
about.

*** `message-beginning-of-line' (bound to C-a) understands folded headers.
In `visual-line-mode' it will look for the true beginning of a header
while in non-`visual-line-mode' it will move the point to the indented
header’s value.

+++
** In Show Paren Mode, a parenthesis can be highlighted when point
stands inside it, and certain parens can be highlighted when point is
at BOL or EOL, or in whitespace there.  To enable these, customize,
respectively, `show-paren-when-point-inside-paren' or
`show-paren-when-point-in-periphery'.

---
** If gpg2 exists on the system, it is now used as the default value
of `epg-gpg-program' (instead of gpg).

** Images

+++
*** Images are automatically scaled before displaying based on the
`image-scaling-factor' variable (if Emacs supports scaling the images
in question).

+++
*** Images inserted with `insert-image' and related functions get a
keymap put into the text properties (or overlays) that span the
image.  This keymap binds keystrokes for manipulating size and
rotation, as well as saving the image to a file.

+++
*** A new library for creating and manipulating SVG images has been
added.  See the "SVG Images" section in the lispref manual for
details.

+++
*** New setf-able function to access and set image parameters is
provided: `image-property'.


** Lisp mode

---
*** Strings after `:documentation' are highlighted as docstrings.
This enhances Lisp mode fontification to handle documentation of the
form `(:documentation "the doc string")' used in Common Lisp code for
CLOS class and slot documentation.

** Rectangle editing

+++
*** Rectangle Mark mode can have corners past EOL or in the middle of a TAB.

+++
*** C-x C-x in rectangle-mark-mode now cycles through the four corners.
*** `string-rectangle' provides on-the-fly preview of the result.

+++
** New font-lock functions `font-lock-ensure' and `font-lock-flush'.
These should be used in preference to `font-lock-fontify-buffer' when
called from Lisp.

---
** Macro `minibuffer-with-setup-hook' can optionally append a function
to `minibuffer-setup-hook'.

If the first argument of the macro is of the form `(:append FUN)',
then FUN will be appended to `minibuffer-setup-hook', instead of
prepending it.

** cl-lib
+++
*** New functions `cl-fresh-line', `cl-digit-char-p', and `cl-parse-integer'.

---
*** `pcase' accepts the new UPattern `cl-struct'.

** Calendar and diary

+++
*** The default `diary-file' is now located in .emacs.d.

+++
*** New commands to insert diary entries with Chinese dates:
`diary-chinese-insert-anniversary-entry' `diary-chinese-insert-entry'
`diary-chinese-insert-monthly-entry', `diary-chinese-insert-yearly-entry'.

+++
*** The calendar can now list and mark diary entries with Chinese dates.
See `diary-chinese-list-entries' and `diary-chinese-mark-entries'.

---
*** The option `calendar-mode-line-format' can now be nil,
which means to do nothing special with the mode line in calendars.

+++
*** New option `calendar-weekend-days'.
The option customizes which day headers receive the
`calendar-weekend-header' face.

---
*** New optional args N and STRING for ‘holiday-greek-orthodox-easter’.

---
*** Many items obsolete since at least version 23.1 have been removed.
The majority were function/variable/face aliases, too numerous to list here.
The remainder were:

**** Functions `calendar-one-frame-setup', `calendar-only-one-frame-setup',
`calendar-two-frame-setup', `european-calendar', `american-calendar'.

**** Hooks `cal-menu-load-hook', `cal-x-load-hook'.

**** Macro `calendar-for-loop'.

**** Variables `european-calendar-style', `diary-face', `hebrew-holidays-{1,4}'.

**** The nil and list forms of `diary-display-function'.

+++
** New ERT function `ert-summarize-tests-batch-and-exit'.
If the output of ERT tests in batch mode execution can be saved to a
log file, then it can be passed as an argument to the above function
to produce a neat summary.

---
** New js.el option `js-indent-first-init'.
It was renamed from `js-indent-first-initialiser', to avoid issues
with American vs British spelling.

** Info

---
** Info mode now displays symbol names in fixed-pitch font.
If you want to get the old behavior back, customize the `Info-quoted'
face to use the same definitions as the default face.

---
*** `Info-fontify-maximum-menu-size' can be t for no limit.

+++
*** `info-display-manual' can now be given a prefix argument which (any
non-nil value) directs the command to limit the completion
alternatives to currently visited manuals.

---
** ntlm.el has support for NTLM2.

** Rmail

+++
*** The Rmail commands `d', `C-d' and `u' take optional repeat counts
to delete or undelete multiple messages.

+++
*** Rmail can now render HTML mail messages if your Emacs was built with
libxml2 or if you have the Lynx browser installed.  By default, Rmail
will display the HTML version of a mail message that has both HTML and
plain text parts, if display of HTML email is possible; customize the
`rmail-mime-prefer-html' option to `nil' if you don't want that.

+++
*** In the commands that make summaries by subject, recipients, or senders,
you can no longer use commas to separate regular expressions.

+++
** SES now supports local printer functions; see `ses-define-local-printer'.

** Shell-script Mode
---
*** In sh-mode you can now use `sh-shell' as a file-local variable to
specify the type of shell in use (bash, csh, etc).

---
*** New value `always' for `sh-indent-after-continuation'.
This provides old-style ("dumb") indentation of continued lines.
See the doc string of `sh-indent-after-continuation' for details.

** TLS
---
*** Fatal TLS errors are now silent by default.

---
*** If Emacs isn't built with TLS support, an external TLS-capable
program is used instead.  This program used to be run in --insecure
mode by default, but has now changed to be secure instead, and will
fail if you try to connect to non-verifiable hosts.  This is
controlled by the `tls-program' variable.

** URL

+++
*** The URL package accepts now the protocols "ssh", "scp" and "rsync".
When `url-handler-mode' is enabled, file operations for these
protocols as well as for "telnet" and "ftp" are passed to Tramp.

+++
*** The URL package allows customizing the `url-user-agent' string.
The new `url-user-agent' variable can be customized to be a string or
a function.

---
*** The new interface variable `url-request-noninteractive' can be used
to specify that we're running in a noninteractive context, and that
we should not be queried about things like TLS certificate validity.

---
*** If URL is used with a https connection, the first callback argument
plist will contain a :peer element that has the output of
`gnutls-peer-status' (if Emacs is built with GnuTLS support).

+++
*** The new function `url-cookie-delete-cookie' can be used to
programmatically delete all cookies, or cookies from a specific
domain.

** Tramp

+++
*** New connection method "afp", which allows you to access Mac OS X
volumes via the Apple Filing Protocol.

+++
*** New connection method "nc", which allows you to access dumb
busyboxes.

+++
*** Method-specific parameters can be overwritten now with variable
`tramp-connection-properties'.

---
*** Handler for `file-notify-valid-p' for remote machines that support
filesystem notifications.

** SQL mode

---
*** New user variable `sql-default-directory' enables remote
connections using Tramp.

---
*** New command `sql-send-line-and-next'.
This command, bound to `C-c C-n' by default, sends the current line to
the SQL process and advances to the next line, skipping whitespace and
comments.

---
*** Added support for Vertica SQL.

** VC and related modes

+++
*** Basic push support, via `vc-push', bound to `C-x v P'.
Implemented for Bzr, Git, Hg.  As part of this change, the pre-existing
(undocumented) command vc-hg-push now behaves slightly differently.

+++
*** The new command vc-region-history shows the log+diff of the active region.

+++
*** You can refresh the VC state of a file buffer with `M-x vc-refresh-state'.
This command is useful when you perform version control commands
outside Emacs (e.g., from the shell prompt), or if you switch the VC
back-end for the buffer's file, or remove it from version control.

+++
*** New option `vc-annotate-background-mode' controls whether
the color range from `vc-annotate-color-map' is applied to the
background or to the foreground.

+++
*** `compare-windows' now compares text with the most recently selected window
instead of the next window.  If you want the previous behavior of
comparing with the next window, customize the new option
`compare-windows-get-window-function' to the value
`compare-windows-get-next-window'.

---
*** Two new faces `compare-windows-removed' and `compare-windows-added'
replace the face `compare-windows', which is now an obsolete alias for
`compare-windows-added'.

---
*** The VC state indicator in the mode line now has different faces
corresponding to each of the possible states.  See the `vc-faces'
customization group.

---
*** `log-edit-insert-changelog' converts "(tiny change)" to
"Copyright-paperwork-exempt: yes".  Set `log-edit-rewrite-tiny-change'
nil to disable this.

---
** VHDL mode now supports VHDL'08.

** Calculator

---
*** Decimal display mode uses "," groups, so it's more
fitting for use in money calculations

---
*** Factorial works with non-integer inputs.

** Hide-IfDef mode

---
*** Hide-IfDef mode now support full C/C++ expressions in macros,
macro argument expansion, interactive macro evaluation and automatic
scanning of #define'd symbols.

---
*** New command `hif-evaluate-macro', bound to `C-c @ e', displays the
result of evaluating a macro.

---
*** New command `hif-clear-all-ifdef-define', bound to `C-c @ C', clears
all defined symbols in `hide-ifdef-env'.

---
*** New custom variable `hide-ifdef-header-regexp' to define C/C++ header
file name patterns.  Defaults to files whose extension is one of `.h',
`.hh', `.hpp', `.hxx', or `.h++', matched case-insensitively.

---
*** New custom variable `hide-ifdef-expand-reinclusion-protection' to prevent
reinclusion protected (a.k.a. "idempotent") header files from being hidden.
(This could happen when an idempotent header file is visited again,
when its guard symbol is already defined.)  Defaults to `t'.

---
*** New custom variable `hide-ifdef-exclude-define-regexp' to define symbol
name patterns (e.g. all "FOR_DOXYGEN_ONLY_*") to be ignored when
looking for macro definitions.  By default, no symbols are ignored.

** TeX mode

+++
*** New custom variable `tex-print-file-extension' to help users who
use PDF instead of DVI.

+++
*** TeX mode now supports Prettify Symbols mode.  When enabling
`prettify-symbols-mode' in a tex-mode buffer, \alpha ... \omega, and
many other math macros are displayed using unicode characters.

+++
** New `big-indent' style in `whitespace-mode' highlights deep indentation.
By default, 32 consecutive spaces or four consecutive TABs are
considered to be too deep, but the new variable
`whitespace-big-indent-regexp' can be customized to change that.

---
** New options in `tildify-mode'.
New options `tildify-space-string', `tildify-pattern', and
`tildify-foreach-region-function' variables make
`tildify-string-alist', `tildify-pattern-alist', and
`tildify-ignored-environments-alist' variables (as well as a few
helper functions) obsolete.

+++
** New package Xref replaces Etags's front-end and UI

The new package Xref provides a generic framework and new commands to
find and move to definitions of functions, macros, data structures
etc., as well as go back to the location where you were before moving
to a definition.  It supersedes and obsoletes many Etags commands,
while still using the etags.el code that reads the TAGS tables as one
of its back-ends.

The command `xref-find-definitions' replaces `find-tag' and provides
an interface to pick one definition among several.
`tags-loop-continue' is now unbound.  `xref-pop-marker-stack' replaces
`pop-tag-mark', but has a keybinding (`M-,') different from the one
`pop-tag-mark' used.

`xref-find-definitions-other-window' replaces `find-tag-other-window'.
`xref-find-definitions-other-frame' replaces `find-tag-other-frame'.
`xref-find-apropos' replaces `find-tag-regexp'.

As a result of this, the following commands are now obsolete:
`find-tag-other-window', `find-tag-other-frame', `find-tag-regexp',
`tags-apropos'.

`tags-loop-continue' is not obsolete because it's still useful in
`tags-search' and `tags-query-replace', for which there are no direct
replacements yet.

+++
*** Variants of `tags-search' and `tags-query-replace' in Dired were also
replaced by xref-style commands, see the "Dired" section below.

+++
*** New variables

`find-tag-marker-ring-length' is now an obsolete alias for
`xref-marker-ring-length'.  `find-tag-marker-ring' is now an obsolete
alias for a private variable.  `xref-push-marker-stack' and
`xref-pop-marker-stack' should be used instead to manipulate the stack
of searches for definitions.

---
*** `xref-find-definitions' and `describe-function' now display
information about mode local overrides (defined by cedet/mode-local.el
`define-overloadable-function' `define-mode-local-overrides').

The framework's Lisp API is still experimental and can change in major,
backward-incompatible ways.

---
** New package Project

The new package Project provides generic infrastructure for dealing
with projects.  The main commands included in it are
`project-find-file' and `project-find-regexp'.

The Lisp API of this package is still experimental.

** EUDC
EUDC's LDAP backend has been improved.

+++
*** EUDC supports LDAP-over-SSL URLs (ldaps://).

---
*** EUDC passes LDAP passwords through a pipe to the ldapsearch
subprocess instead of on the command line.

---
*** EUDC handles LDAP wildcards automatically so the user shouldn't
need to configure this manually anymore.

+++
*** The LDAP configuration section of EUDC's manual has been
rewritten.

There have also been customization changes.

+++
*** New custom variable `eudc-server-hotlist' to allow specifying
multiple EUDC servers in init file.

+++
*** Custom variable `eudc-inline-query-format' defaults to completing
on email and firstname instead of surname.

---
*** Custom variable `eudc-expansion-overwrites-query' defaults to nil
to avoid interfering with the kill ring.

+++
*** Custom variable `eudc-inline-expansion-format' defaults to
"Firstname Surname <mail-address>".

+++
*** Custom variable `eudc-options-file' defaults to
"~/.emacs.d/eudc-options".

---
*** New custom variable `ldap-ldapsearch-password-prompt-regexp' to
allow overriding the regular expression that recognizes the ldapsearch
command line's password prompt.

---
EUDC's BBDB backend now supports BBDB 3.

---
EUDC's PH backend (eudcb-ph.el) is obsolete.

** Eshell

+++
*** The new built-in command `clear' can scroll window contents out of sight.
If provided with an optional non-nil argument, the scrollback contents will be cleared.

+++
*** New buffer syntax '#<buffer-name>', which is equivalent to
'#<buffer buffer-name>'.  This shorthand makes interacting with
buffers from eshell more convenient.  Custom variable
`eshell-buffer-shorthand', which has been broken for a while, has been
removed.

+++
*** By default, eshell "visual" program buffers (created by
`eshell-visual-commands' and similar custom vars) are no longer killed
when their processes die.  This fixes issues with short-lived commands
and makes visual programs more useful in general.  For example, if
"git log" is a visual command, it will always show the visual command
buffer, even if the "git log" process dies.  For the old behavior,
make the new option `eshell-destroy-buffer-when-process-dies' non-nil.

** Browse-url

---
*** Support for the Google Chrome web browser.

---
*** Support for the Conkeror web browser.

---
*** Support for several ancient browsers is now officially obsolete.

+++
** tar-mode: new `tar-new-entry' command, allowing for new members to
be added to the archive.

---
** Autorevert: dired buffers are also auto-reverted via file
notifications, if Emacs is compiled with file notification support.

** File Notifications

+++
*** The kqueue library is integrated for *BSD and Mac OS X machines.

+++
*** The new event `stopped' signals, that a file notification watch is
not active any longer.

+++
*** The new function `file-notify-valid-p' checks, whether a file
notification descriptor still corresponds to an activate watch.

** Dired

+++
*** The command `dired-do-compress' bound to `Z' now can compress
directories and decompress zip files.

+++
*** New command `dired-do-compress-to' bound to `c' can be used to
compress many marked files into a single named archive.  The
compression command is determined from the new
`dired-compress-files-alist' variable.

+++
*** `W' is now bound to `browse-url-of-dired-file', and is useful for
viewing HTML files and the like.

*** New user interface for the `A' and `Q' commands.
These keys, now bound to `dired-do-find-regexp' and
`dired-do-find-regexp-and-replace', work similarly to `xref-find-apropos'
and `xref-query-replace-in-results': they present the matches
in the `*xref*' buffer and let you move through the matches.  No need
to use `tags-loop-continue' to resume the search or replace loop.  The
previous commands, `dired-do-search' and
`dired-do-query-replace-regexp', are still available, but not bound to
keys; rebind `A' and `Q' to invoke them if you want the old behavior
back.  We intend to obsolete the old commands in a future release.

** Tabulated List Mode

+++
*** It is now safe for a mode that derives `tabulated-list-mode' to not
call `tabulated-list-init-header', in which case it will have no
header.

+++
*** `tabulated-list-print' takes a second optional argument, update,
which specifies an alternative printing method which is faster when
few or no entries have changed.

** Obsolete packages

---
*** gulp.el

---
*** landmark.el (moved to elpa.gnu.org)

\f
* New Modes and Packages in Emacs 25.1

---
** pinentry.el allows GnuPG passphrase to be prompted through the
minibuffer instead of a graphical dialog, depending on whether the gpg
command is called from Emacs (i.e., INSIDE_EMACS environment variable
is set).  This feature requires newer versions of GnuPG (2.1.5 or
later) and Pinentry (0.9.5 or later).

+++
** cl-generic.el provides CLOS-style multiple-dispatch generic functions.
The main entry points are `cl-defgeneric' and `cl-defmethod'.  See the
node "Generic Functions" in the Emacs Lisp manual for more details.

---
** scss-mode (a minor variant of css-mode) is a major mode for editing
SCSS (Sassy CSS) files.

---
** let-alist is a new macro (and a package) that allows one to easily
let-bind the values stored in an alist.

---
** `tildify-mode' allows automatic insertion of hard spaces as one
types the text.  Breaking line after a single-character words is
forbidden by Czech and Polish typography (and may be discouraged in
other languages), so `auto-tildify-mode' makes it easier to create
a typographically-correct documents.

---
** The `seq' library adds sequence manipulation functions and macros
that complement basic functions provided by subr.el.  All functions
are prefixed with `seq-' and work on lists, strings and vectors.
`pcase' accepts a new Upattern `seq'.

---
** The `map' library provides map-manipulation functions that work on
alists, hash-table and arrays.  All functions are prefixed with
`map-'.  `pcase' accepts a new UPattern `map'.

---
** The `thunk' library provides functions and macros to control the
evaluation of forms.

---
** js-jsx-mode (a minor variant of js-mode) provides indentation
support for JSX, an XML-like syntax extension to ECMAScript.

\f
* Incompatible Lisp Changes in Emacs 25.1

---
** `setq' and `setf' must now be called with an even number of
arguments.  The earlier behavior of silently supplying a nil to the
last variable when there was an odd number of arguments has been
eliminated.

+++
** `syntax-begin-function' is declared obsolete.
Removed font-lock-beginning-of-syntax-function and the SYNTAX-BEGIN
slot in font-lock-defaults.

+++
** `package-initialize' now sets `package-enable-at-startup' to nil if
called during startup.  Users who call this function in their init
file and still expect it to be run after startup should set
`package-enable-at-startup' to t after the call to
`package-initialize'.

---
** `:global' minor mode use `setq-default' rather than `setq'.
This means that you can't use `make-local-variable' and expect them to
"magically" become buffer-local.

+++
** `track-mouse' no longer freezes the shape of the mouse pointer.
The `track-mouse' form no longer refrains from changing the shape of
the mouse pointer for the entire time the body of that form is
executed.  Lisp programs that use `track-mouse' for dragging across
large portions of the Emacs display, and want to avoid changes in the
pointer shape during dragging, should bind the variable `track-mouse'
to the special value `dragging' in the body of the form.

---
** The optional `predicate' argument of `lisp-complete-symbol' no longer
has any effect.  (This change was made in Emacs 24.4 but was not
advertised at the time.)

+++
** `indirect-function' does not signal `void-function' any more.
This is mostly a bug-fix, since this change was missed back in 24.4 when
symbol-function was changed not to signal `void-function' any more.

+++
*** As a consequence, the second arg of `indirect-function' is now obsolete.

+++
** Comint, term, and compile do not set the EMACS env var any more.
Use the INSIDE_EMACS environment variable instead.

+++
** `save-excursion' does not save&restore the mark any more.
Use `save-mark-and-excursion' if you want the old behavior.

+++
** `read-buffer' and `read-buffer-function' can now be called with a 4th
argument (`predicate').

+++
** `completion-table-dynamic' by default stays in the minibuffer.
The minibuffer will be the current buffer when the function is called.
If you want the old behavior of calling the function in the buffer
from which the minibuffer was entered, use the new argument
`switch-buffer' to `completion-table-dynamic'.

---
** window-configurations no longer record the buffers' marks.

---
** inhibit-modification-hooks now also inhibits lock-file checks, as well as
active region handling.

+++
** deactivate-mark is now buffer-local.

+++
** `cl-the' now asserts that its argument is of the given type.

+++
** `process-running-child-p' may now return a numeric process
group ID instead of `t'.

+++
** Mouse click events on mode line or header line no longer include
any reference to a buffer position.  The 6th member of the mouse
position list returned for such events is now nil.

---
** Menu items in keymaps do not support the "key shortcut cache" any more.
These slots used to hold key-shortcut data, but have been obsolete since
Emacs-21.

---
** Emacs no longer downcases the first letter of a system diagnostic
when signaling a file error.  For example, it now reports "Permission
denied" instead of "permission denied".  The old behavior was problematic
in languages like German where downcasing rules depend on grammar.

+++
** New variable ‘text-quoting-style’ to control how Emacs translates quotes.
Set it to ‘curve’ for curved single quotes ‘like this’, to ‘straight’
for straight apostrophes 'like this', and to ‘grave’ for grave accent
and apostrophe `like this'.  The default value nil acts like ‘curve’
if curved single quotes are displayable, and like ‘grave’ otherwise.
The new variable affects display of diagnostics and help, but not of info.

+++
** substitute-command-keys now replaces quotes.
That is, it converts documentation strings’ quoting style as per the
value of ‘text-quoting-style’.  Doc strings in source code can use
either curved single quotes or grave accents and apostrophes.  As
before, characters preceded by \= are output as-is.

+++
** Message-issuing functions ‘error’, ‘message’, etc. now convert quotes.
They use the new ‘format-message’ function instead of plain ‘format’,
so that they now follow user preference as per ‘text-quoting-style’
when processing curved single quotes, grave accents, and apostrophes
in their format argument.

+++
** The character classes [:alpha:] and [:alnum:] in regular expressions
now match multibyte characters using Unicode character properties.
If you want the old behavior where they matched any character with
word syntax, use `\sw' instead.

+++
** The character classes [:graph:] and [:print:] in regular expressions
no longer match every multibyte character.  Instead, Emacs now
consults the Unicode character properties to determine which
characters are graphic or printable.  In particular, surrogates and
unassigned codepoints are now rejected.  If you want the old behavior,
use [:multibyte:] instead.

+++
** The `diff' command uses the unified format now.  To restore the old
behavior, set `diff-switches' to `-c'.

---
** `grep-template' and `grep-find-template' values don't include the
--color argument anymore.  It's added at the <C> place holder position
dynamically.  Any third-party code that changes these templates should
be updated accordingly.

+++
** ‘(/ N)’ is now equivalent to ‘(/ 1 N)’ rather than to ‘(/ N 1)’.
The new behavior is compatible with Common Lisp and with XEmacs.
This change does not affect Lisp code intended to be portable to
Emacs 24.2 and earlier, which did not support unary ‘/’.

+++
** The `default-directory' value doesn't have to end slash.  To make
that happen, `unhandled-file-name-directory' now defaults to calling
`file-name-as-directory'.

\f
* Lisp Changes in Emacs 25.1

** pcase
+++
*** New UPatterns `quote', `app'.
+++
*** New UPatterns can be defined with `pcase-defmacro'.
+++
*** New vector QPattern.

---
** syntax-propertize is now automatically called on-demand during forward
parsing functions like `forward-sexp'.

+++
** New hooks `prefix-command-echo-keystrokes-functions' and
`prefix-command-preserve-state-hook' allow the definition of prefix
commands other than the predefined `C-u'.

+++
** New functions `filepos-to-bufferpos' and `bufferpos-to-filepos'.
These allow conversion between buffer positions and the corresponding
file byte offsets, given the file's encoding.

+++
** The default value of `load-read-function' is now `read'.
Previously, the default value of `nil' implied using `read'.

+++
** New hook `pre-redisplay-functions'.
It is a bit easier to use than `pre-redisplay-function'.

+++
** The second arg of `looking-back' should always be provided explicitly.
Previously, it was an optional argument, now it's mandatory.

+++
** Text properties `intangible', `point-entered', and `point-left' are obsolete.
Replaced by properties `cursor-intangible' and `cursor-sensor-functions',
implemented by the new `cursor-intangible-mode' and
`cursor-sensor-mode' minor modes.

+++
** `inhibit-point-motion-hooks' now defaults to `t' and is obsolete.
Use the new minor modes `cursor-intangible-mode' and
`cursor-sensor-mode' instead.

+++
** New process type `pipe', which can be used in combination with the
`:stderr' keyword of make-process to handle standard error output
of subprocess.

+++
** New function `make-process' provides an alternative interface to
`start-process'.  It allows programs to set process parameters such as
process filter, sentinel, etc., through keyword arguments (similar to
`make-network-process').

+++
** A new function `directory-files-recursively' returns all matching
files (recursively) under a directory.

+++
** New variable `inhibit-message', when bound to non-nil, inhibits
`message' and related functions from displaying messages in the echo
area.  The output is still logged to the *Messages* buffer.

+++
** A new text property `inhibit-read-only' can be used in read-only
buffers to allow certain parts of the text to be writable.

+++
** A new variable `comment-end-can-be-escaped' is useful in languages
   such as C and C++ where line comments with escaped newlines are
   continued to the next line.

+++
** New macro `define-advice'.

+++
** Emacs Lisp now supports generators.
See the "Generators" section of the ELisp manual for the details.

+++
** New finalizer facility for running code when objects become unreachable.
See the "Finalizer Type" subsection in the ELisp manual for the
details.

---
** lexical closures can use (:documentation FORM) to build their docstring.
It should be placed right where the docstring would be, and FORM is then
evaluated (and should return a string) when the closure is built.

+++
** define-inline provides a new way to define inlinable functions.

+++
** New function `macroexpand-1' to perform a single step of macro expansion.

+++
** Some "x-*" functions were obsoleted and/or renamed:
*** x-select-text is renamed gui-select-text.
*** x-selection-value is renamed gui-selection-value.
*** x-get-selection is renamed gui-get-selection.
*** x-get-clipboard and x-clipboard-yank are marked obsolete.
*** x-get-selection-value is renamed to gui-get-primary-selection.
*** x-set-selection is renamed to gui-set-selection

+++
** New function `string-greaterp', which return the opposite result of
`string-lessp'.

+++
** The new functions `string-collate-lessp' and `string-collate-equalp'
preserve the collation order as defined by the system's locale(1)
environment.  For the time being this is implemented for modern POSIX
systems and for MS-Windows, for other systems they fall back to their
counterparts `string-lessp' and `string-equal'.

+++
** The new function `string-version-lessp' compares strings by
interpreting consecutive runs of numerical characters as numbers, and
compares their numerical values.  According to this predicate,
"foo2.png" is smaller than "foo12.png".

---
*** The ls-lisp package uses `string-collate-lessp' to sort file names.
The effect is that, on systems that use ls-lisp for Dired, the default
sort order of the files in Dired is now different from what it was in
previous versions of Emacs.  In particular, the file names are sorted
disregarding punctuation, accents, and diacritics, and letter case is
ignored.  For example, files whose name begin with a period will no
longer appear near the beginning of the directory listing.  If you
want the old, locale-independent sorting, customize the new option
`ls-lisp-use-string-collate' to the nil value.

+++
*** The MS-Windows specific variable `w32-collate-ignore-punctuation',
if set to a non-nil value, causes the above 2 functions to ignore
symbol and punctuation characters when collating strings.  This
emulates the behavior of modern Posix platforms when the locale's
codeset is "UTF-8" (as in "en_US.UTF-8").  This is needed because
MS-Windows doesn't support UTF-8 as codeset in its locales.

+++
** New function `alist-get', which is also a valid place (aka lvalue).

+++
** New function `funcall-interactively', which works like `funcall'
but makes `called-interactively-p' treat the function as (you guessed it)
called interactively.

+++
** New function `function-put' to use instead of `put' for function properties.

+++
** The new function `bidi-find-overridden-directionality' allows you to
find characters whose directionality was, perhaps maliciously,
overridden by directional override control characters.  Lisp programs
can use this to detect potential phishing of URLs and other links that
exploits bidirectional display reordering.

+++
** The new function `buffer-substring-with-bidi-context' allows you to
copy a portion of a buffer into a different location while preserving
the visual appearance both of the copied text and the text at
destination, even when the copied text includes mixed bidirectional
text and directional control characters.

+++
** New properties that can be specified with `declare':
*** (interactive-only INSTEAD), says to use INSTEAD for non-interactive use.
*** (pure VAL), if VAL is non-nil, indicates the function is pure.
*** (side-effect-free VAL), if VAL is non-nil, indicates the function does not
have side effects.

+++
** New macro `with-file-modes', for evaluating expressions with default file
permissions set to temporary values (e.g., for creating private files).

+++
** You can access the slots of structures using `cl-struct-slot-value'.

+++
** Function `sort' can deal with vectors.

---
** Function `system-name' now returns an updated value if the current
system's name has changed or if the Emacs process has changed systems,
and to avoid long waits it no longer consults DNS to canonicalize the
name.  The variable `system-name' is now obsolete.

+++
** Function `write-region' no longer outputs "Wrote FILE" in batch mode.

---
** If `pwd' is called with a prefix argument, insert the current default
directory at point.

+++
** New functions return extended information about fonts and faces.

+++
*** The function `font-info' now returns more details about a font.
In particular, it now returns the average width of the font's
characters, which can be used for geometry-related calculations.

+++
*** A new function `default-font-width' returns the average width of a
character in the current buffer's default font.  If the default face
is remapped (see `face-remapping-alist'), the value for the remapped
face is returned.  This function complements the existing function
`default-font-height'.

+++
*** New functions `window-font-height' and `window-font-width' return
the height and average width of characters in a specified face and
window.  If FACE is remapped (see `face-remapping-alist'), the
function returns the information for the remapped face.

+++
*** A new function `window-max-chars-per-line' returns the maximal
number of characters that can be displayed on one line.  If a face
and/or window are provided, these values are used for the
calculation.  This function is different from `window-body-width' in
that it accounts for (i) continuation glyphs, (ii) the size of the
font, and (iii) the specified window.

---
** New utilities in subr-x.el:
*** New macros `if-let' and `when-let' allow defining bindings and to
    execute code depending whether all values are true.
*** New macros `thread-first' and `thread-last' allow threading a form
    as the first or last argument of subsequent forms.

+++
** Documentation strings now support quoting with curved single quotes
‘like-this’ in addition to the old style with grave accent and
apostrophe `like-this'.  The new style looks better on today's displays.
In the new Electric Quote mode, you can enter curved single quotes
into documentation by typing ` and '.  Outside Electric Quote mode,
you can enter them by typing ‘C-x 8 [’ and ‘C-x 8 ]’, or (if your Alt
key works) by typing ‘A-[’ and ‘A-]’.  As described above under
‘text-quoting-style’, the user can specify how to display doc string
quotes.

+++
** New function ‘format-message’ is like ‘format’ and also converts
curved single quotes, grave accents and apostrophes as per
‘text-quoting-style’.

+++
** show-help-function's arg is converted via substitute-command-keys
before being passed to the function.  Help strings, help-echo
properties, etc. can therefore contain command key escapes and
quotation marks.

+++
** Time-related changes:

*** Time conversion functions now accept an optional ZONE argument
that specifies the time zone rules for conversion.  ZONE is omitted or
nil for Emacs local time, t for Universal Time, ‘wall’ for system wall
clock time, or a string as in ‘set-time-zone-rule’ for a time zone
rule.  The affected functions are ‘current-time-string’,
‘current-time-zone’, ‘decode-time’, and ‘format-time-string’.  The
function ‘encode-time’, which already accepted a simple time zone rule
argument, has been extended to accept all the new forms.

*** Time-related functions now consistently accept numbers
(representing seconds since the epoch) and nil (representing the
current time) as well as the usual list-of-integer representation.
Affected functions include `current-time-string', `current-time-zone',
`decode-time', `float-time', `format-time-string', `seconds-to-time',
`time-add', `time-less-p', `time-subtract', `time-to-day-in-year',
`time-to-days', and `time-to-seconds'.

*** The `encode-time-value' and `with-decoded-time-value' macros have
been obsoleted.

*** `calendar-next-time-zone-transition', `time-add', and
`time-subtract' no longer return time values in the obsolete and
undocumented integer-pair format.  Instead, they return a list of two
integers.

+++
** New function `set-binary-mode' allows switching a standard stream
of the Emacs process to binary I/O mode.

+++
** The new function `directory-name-p' can be used to check whether a file
name (as returned from, for instance, `file-name-all-completions') is
a directory file name.  It returns non-nil if the last character in
the name is a directory separator character (forward slash on GNU and
Unix systems, forward- or backslash on MS-Windows and MS-DOS).

---
** ASCII approximations to curved quotes are put in standard-display-table
if the terminal cannot display curved quotes.

+++
** Standard output and error streams now transliterate characters via
standard-display-table, and encode output using locale-coding-system.
To force a specific encoding, bind `coding-system-for-write' to the
coding-system of your choice when invoking functions like `prin1' and
`message'.

+++
** New var `truncate-string-ellipsis' to choose how to indicate truncation.

+++
** New possible value for `system-type': `nacl'.
This is used by Google's Native Client (NaCl).

** Miscellaneous name change

---
For consistency with the usual Emacs spelling, the Lisp variable
`hfy-optimisations' has been renamed to `hfy-optimizations'.
The old name should still work, as an obsolescent alias.

** Changes in Frame- and Window- Handling

+++
*** Emacs can now draw horizontal scroll bars on some platforms that
provide toolkit scroll bars, namely Gtk+, Lucid, Motif and Windows.
Horizontal scroll bars are turned off by default.

**** New function `horizontal-scroll-bars-available-p' telling whether
    horizontal scroll bars are available on the underlying system.

**** New mode `horizontal-scroll-bar-mode' to toggle horizontal scroll
    bars on all existing and future frames.

**** New function `toggle-horizontal-scroll-bar' to toggle horizontal
    scroll bars on the selected frame.

**** New frame parameters `horizontal-scroll-bars' and
    `scroll-bar-height' to set horizontal scroll bars and their height
    for individual frames and in `default-frame-alist'.

**** New functions `frame-scroll-bar-height' and
    `window-scroll-bar-height' return the height of horizontal scroll
    bars on a specific frame or window.

**** `set-window-scroll-bars' now accepts five parameters where the last
    two specify height and type of the window's horizontal scroll bar.

**** `window-scroll-bars' now returns type and sizes of horizontal scroll
    bars too.

**** New buffer-local variables `horizontal-scroll-bar' and
    `scroll-bar-height'.

+++
*** New functions `frame-geometry' and `frame-edges' give access to a
frame's geometry.

+++
*** New functions `mouse-absolute-pixel-position' and
`set-mouse-absolute-pixel-position' get/set screen coordinates of the
mouse cursor.

+++
*** The function `window-edges' now accepts three additional arguments to
retrieve body, absolute and pixel edges of the window.

+++
*** The functions `window-inside-edges', `window-inside-pixel-edges' and
`window-inside-absolute-pixel-edges' have been renamed to respectively
`window-body-edges', `window-body-pixel-edges' and
`window-absolute-body-pixel-edges'.  The old names are kept as aliases.

+++
*** New function `window-absolute-pixel-position' to get the screen
coordinates of a visible buffer position.

+++
*** The height of a frame's menu and tool bar are no longer counted in the
frame's text height.  This means that the text height stands only for
the height of the frame's root window plus that of the echo area (if
present).  This was already the behavior for frames with external tool
and menu bars (like in the Gtk builds) but has now been extended to all
builds.

+++
*** Frames now do not necessarily preserve the number of columns or lines
they display when setting default font, menu bar, fringe width, or
scroll bars.  In particular, maximized and fullscreen frames are
conceptually never resized if such settings change.  For fullheight and
fullwidth frames, the behavior may depend on the toolkit used.
**** New option `frame-inhibit-implied-resize' if non-nil, means that
   setting default font, menu bar, fringe width, or scroll bars of a
   specific frame does not resize that frame in order to preserve the
   number of columns or lines it displays.

+++
*** New function `window-preserve-size' allows you to preserve the size of
a window without "fixing" it.  It's supported by `fit-window-to-buffer',
`temp-buffer-resize-mode' and `display-buffer'.

+++
*** New `display-buffer' action function `display-buffer-use-some-frame'.
This displays the buffer in an existing frame other than the current
frame, and allows the caller to specify a frame predicate to exclude
frames.

+++
*** New minor mode `window-divider-mode' and options
`window-divider-default-places', `window-divider-default-bottom-width'
and `window-divider-default-right-width'.

---
** Tearoff menus and detachable toolbars for Gtk+ have been removed.
Those features have been deprecated in Gtk+ for a long time.

** Etags

+++
*** etags no longer qualifies class members by default.

By default, `etags' will not qualify class members for C-like
object-oriented languages with their class names and namespaces, and
will remove qualifications used explicitly in the code from the tag
names it puts in TAGS files.  This is so the etags.el back-end for
`xref-find-definitions' is more accurate and produces less false
positives.

Use --class-qualify (-Q) if you want the old default behavior of
qualifying class members in C++, Java, and Objective C.  Note that
using -Q might make some class members become "unknown" to `M-.'
(`xref-find-definitions'); if so, you can use `C-u M-.' to specify the
qualified names by hand.

+++
*** New language Ruby

Names of modules, classes, methods, functions, and constants are
tagged.  Overloaded operators are also tagged.

+++
*** New language Go
Names of packages, functions, and types are tagged.

+++
*** Improved support for Lua

Etags now tags functions even if the "function" keyword follows some
whitespace at line beginning.

\f
* Changes in Emacs 25.1 on Non-Free Operating Systems

---
** MS-Windows specific Emacs build scripts are no longer in the distribution
This includes the makefile.w32-in files in various subdirectories, and
the support files.  The file nt/configure.bat now just tells the user
to use the procedure described in nt/INSTALL, by running the Posix
`configure' script in the top-level directory.

---
** Building Emacs for MS-Windows requires at least Windows XP
or Windows Server 2003.  The built binaries still run on all versions
of Windows starting with Windows 9X.

+++
** Emacs running on MS-Windows now supports the daemon mode.

---
** The byte counts in etags-generated TAGS files are now the same on
MS-Windows as they are on other platforms.

---
** On OS X, configure creates a Cocoa ("Nextstep") build by default.
Pass '--without-ns' to configure to create an X11 build, the old default.

---
** OS X 10.5 or older is no longer supported.

---
** OS X on PowerPC is no longer supported.

---
** New variable `ns-use-fullscreen-animation' controls animation for
non-native NS fullscreen.  The default is nil.  Set to t to enable
animation when entering and leaving fullscreen.  For native OSX fullscreen
this has no effect.

---
** The new function 'w32-application-type' returns the type of an
MS-Windows application given the name of its executable program file.

** New variable `w32-pipe-buffer-size'.
It can be used to tune the size of the buffer of pipes created for
communicating with subprocesses, when the program run by a subprocess
exhibits unusual buffering behavior.  Default is zero, which lets the
OS use its default size.

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

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

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

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

\f
Local variables:
coding: utf-8
mode: outline
paragraph-separate: "[  \f]*$"
end: