NEWS

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

Copyright (C) 2010-2013 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 24.

See files 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 updates to the manuals in doc/ are complete.
--- means no change in the manuals is needed.
When you add a new item, use the appropriate mark if you know it applies,
otherwise leave it unmarked.


* Installation Changes in Emacs 24.4

** Emacs can be compiled with ACL support.
This happens by default if a suitable support library is found at
build time, like libacl on GNU/Linux.  To prevent this, use the
configure option `--disable-acl'.

** Emacs can be compiled with file notification support.
This happens by default if a suitable system library is found at
build time.  To prevent this, use the configure option
`--with-file-notification-no'.  See below for file-notify features.
FIXME?  This feature is not available for the Nextstep port. (?)

** The configure option `without-compress-info' has been generalized,
and renamed to `without-compress-install'.  It now prevents compression
of _any_ files during installation.

** The configure option --with-crt-dir has been removed.
It is no longer needed, as the crt*.o files are no longer linked
specially.

** Directories passed to configure option `--enable-locallisppath' are
no longer created during installation.

** Emacs can be compiled with zlib support.  If this library is present
(which it normally is on most systems), the function
`zlib-decompress-region' becomes available, which can decompress gzip-
and zlib-format compressed data.

---
** Emacs for NS (OSX, GNUStep) can be built with ImageMagick support.
pkg-config is required to find ImageMagick libraries.

** For OSX >= 10.5, the Core text based font backend from the Mac port is used.
For GNUStep and OSX 10.4 the old backend is used.
To use the old backend by default, do on the command line:
% defaults write org.gnu.Emacs FontBackend ns


* Startup Changes in Emacs 24.4

+++
** When initializing `load-path', an empty element in the EMACSLOADPATH
environment variable (either leading, e.g., ":/foo"; trailing, e.g.,
"/foo:"; or embedded, e.g., "/foo::/bar") is replaced with the default
load-path (the one that would have been used if EMACSLOADPATH was unset).
This makes it easier to _extend_ the load-path via EMACSLOADPATH
(previously, EMACSLOADPATH had to specify the complete load-path,
including the defaults).  (In older versions of Emacs, an empty element
was replaced by ".", so use an explicit "." now if that is what you want.)

+++
** The -L option, which normally prepends its argument to load-path,
will instead append, if the argument begins with `:' (or `;' on MS Windows;
i.e., `path-separator').


* Changes in Emacs 24.4

+++
** Emacs now supports menus on text-mode terminals.
If the terminal supports a mouse, clicking on the menu bar, or on
sensitive portions of the mode line or header line, will drop down the
menu defined at that position.  Likewise, clicking C-mouse-2 or
C-mouse-2 or C-mouse-3 on the text area will pop up the menus defined
for those locations.

If the text terminal does not support a mouse, you can activate the
first menu-bar menu by typing F10, which invokes `menu-bar-open'.

If you want the previous behavior, whereby F10 invoked `tmm-menubar',
customize the option `tty-menu-open-use-tmm' to a non-nil value.
(Typing M-` will always invoke `tmm-menubar', even if
`tty-menu-open-use-tmm' is nil.)

** Key ? also describes prefix bindings like C-h.

+++
** `cache-long-line-scans' has been renamed to `cache-long-scans'
because it affects caching of paragraph scanning results as well.

+++
** `apropos-variable' is now `apropos-user-option'
`apropos-user-option' shows all user options while `apropos-variable'
shows all variables.  When called with a universal prefix argument,
the two commands swap their behaviors.  When `apropos-do-all' is
non-nil, they output the same results.

+++
** `eval-defun' on an already defined defcustom calls the :set function,
if there is one.

** If the new variable `enable-dir-local-variables' is nil,
directory local variables are ignored.  May be useful for some modes
that want to ignore directory-locals while still respecting file-locals.

** The option `set-mark-default-inactive' has been deleted.
This unfinished feature was introduced by accident in Emacs 23.1;
simply disabling Transient Mark mode does the same thing.

** `initial-buffer-choice' can now specify a function to set up the
initial buffer.

** The *Messages* buffer is created in a new major mode `messages-buffer-mode',
and read-only.  Code that might create the *Messages* buffer should
call the function `messages-buffer' to do so and set the mode.

** `remember-notes' creates a buffer whose content is saved on kill-emacs.
You may think of it as a *scratch* buffer whose content is preserved.
In fact, it was designed as a replacement for *scratch* buffer and can
be used that way by setting `initial-buffer-choice' to `remember-notes'
and `remember-notes-buffer-name' to "*scratch*".  Without the second
change, *scratch* buffer will still be there for notes that do not
need to be preserved.

** `write-region-inhibit-fsync' now defaults to t in batch mode.

** ACL support has been added.
+++
*** Emacs preserves the ACL entries of files when backing up.
+++
*** New functions `file-acl' and `set-file-acl' get and set the ACL
entries of a file.  On GNU/Linux, the POSIX ACL interface is used via
libacl.  On MS-Windows, the NT Security APIs are used to emulate the
POSIX ACL interfaces.

** New option `scroll-bar-adjust-thumb-portion'.
Available only on X, this option allows to control over-scrolling
using the scroll bar (i.e. dragging the thumb down even when the end
of the buffer is visible).

** New function `add-face-text-property' has been added, which can be
used to conveniently prepend/append new face attributes to text.

** In compiled Lisp files, the header no longer includes a timestamp.

** Multi-monitor support has been added.

*** New functions `display-monitor-attributes-list' and
`frame-monitor-attributes' can be used to obtain information about
each physical monitor on multi-monitor setups.

*** The functions `display-pixel-width' and `display-pixel-height' now
behave consistently among the platforms: they return the pixel width
or height for all physical monitors associated with the given display
as just they were on X11.  To get information for each physical
monitor, use the new functions above.  Similar notes also apply to
`x-display-pixel-width', `x-display-pixel-height', `display-mm-width',
`display-mm-height', `x-display-mm-width', and `x-display-mm-height'.

** New macro `alternatives-define' can be used to define generic commands.
Generic commands are interactive functions whose implementation can be
selected among several alternatives, as a matter of user preference.

** New hooks `focus-in-hook', `focus-out-hook'.
These are normal hooks run when an Emacs frame gains or loses input focus.

** The blink cursor stops blinking after 10 blinks (default) on X and NS.
You can change the default by customizing the variable blink-cursor-blinks.
Also timers for blinking are stopped when no blinking is done, so Emacs does
not consume CPU cycles.

** New command `frameset-to-register' is now bound to `C-x r f', replacing
`frame-configuration-to-register'.  It offers similar functionality, plus
some enhancements, like the ability to restore deleted frames.  Command
`frame-configuration-to-register' is still available, but unbound.

** The command `quail-help' is deleted.  Use `C-h C-\'
(`describe-input-method') instead.

** The default value of `comment-use-global-state' is changed to t,
and this variable has been marked obsolete.

** `fill-single-char-nobreak-p' prevents fill from breaking a line after
a 1-letter word, which is an error according to Polish and
Czech typography rules.  To globally enable this feature, evaluate:

  (add-hook 'fill-nobreak-predicate 'fill-single-char-nobreak-p)


* Editing Changes in Emacs 24.4

** Command `rectangle-mark-mode' bound to C-x SPC makes a rectangular region.
Most commands are still unaware of it, but kill/yank do work on the rectangle.

** C-x TAB enters a transient interactive mode.
You can then use the left/right cursor keys to move the block of text.

** `tab-stop-list' is now implicitly extended to infinity by repeating
the last step.  Its default value is changed to nil which means a tab
stop every `tab-width' columns.

** `split-window' is no longer a command, just a non-interactive function.
As a command it was a special case of `split-window-below', and as such
superfluous.  After being reimplemented in Lisp, its interactive form
was mistakenly retained.

** New commands `toggle-frame-fullscreen' and `toggle-frame-maximized',
bound to <f11> and M-<f10>, respectively.

** In keymaps where SPC scrolls, S-SPC now scrolls in the reverse direction.
Eg View mode, etc.

+++
** New option `visual-order-cursor-movement'.
If this is non-nil, cursor motion with arrow keys will follow the
visual order of characters on the screen: <left> always moves to the
left, <right> always moves to the right, disregarding the surrounding
bidirectional context.

** All register commands can now show help with preview.

** New command `kmacro-to-register' to store keyboard macros in registers.

** Shell Script mode

*** `sh-mode' now has the mode own `add-log-current-defun-function'.
You can pick the name of the function and the variables with `C-x 4 a'.


* Changes in Specialized Modes and Packages in Emacs 24.4

** prolog-use-smie has been removed, along with the non-SMIE indentation code.

** SMIE indentation can be customized via `smie-config'.
The customization can be guessed by Emacs by providing a sample indented
file and letting SMIE learn from it.

** sh-script now uses its SMIE indentation algorithm by default.

** The debugger's `e' command evaluates the code in the context at point.
This includes using the lexical environment at point, which means that
`e' now lets you access lexical variables as well.

** `eshell' now supports visual subcommands and options
Eshell has been able to handle "visual" commands (interactive,
non-line oriented commands such as top that require display
capabilities not provided by eshell) by running them in an Emacs
terminal emulator.  See `eshell-visual-commands'.

This feature has been extended to subcommands and options that make a
usually line-oriented command a visual command.  Typical examples are
"git log" and "git <command> --help" which display their output in a
pager by default.  See `eshell-visual-subcommands' and
`eshell-visual-options'.

** If your Emacs is compiled with libxml2 support, you can use the new
built-in web browser `eww'.

** `remember' can now store notes in separates files
You can use the new function `remember-store-in-files' within the
`remember-handler-functions' option.

See `remember-data-directory' and `remember-directory-file-name-format'
for new options related to this function.

** More packages look for ~/.emacs.d/<foo> additionally to ~/.<foo>.
Affected files:
~/.emacs.d/timelog	replaces  ~/.timelog
~/.emacs.d/vip		replaces  ~/.vip
~/.emacs.d/viper	replaces  ~/.viper
~/.emacs.d/ido.last	replaces  ~/.ido.last
~/.emacs.d/kkcrc	replaces  ~/.kkcrc
~/.emacs.d/quickurls	replaces  ~/.quickurls
~/.emacs.d/idlwave	replaces  ~/.idlwave
~/.emacs.d/bdfcache.el	replaces  ~/.bdfcache.el
~/.emacs.d/places	replaces  ~/.emacs-places
~/.emacs.d/shadows	replaces  ~/.shadows
~/.emacs.d/shadow_todo	replaces  ~/.shadow_todo
~/.emacs.d/strokes	replaces  ~/.strokes
~/.emacs.d/notes	replaces  ~/.notes
~/.emacs.d/type-break	replaces  ~/.type-break
Also the following files used by the now obsolete otodo-mode.el:
~/.emacs.d/todo-do	replaces  ~/.todo-do
~/.emacs.d/todo-done	replaces  ~/.todo-done
~/.emacs.d/todo-top	replaces  ~/.todo-top


** Delphi mode is now called OPascal mode.
*** All delphi-* variables and functions have been renamed to opascal-*.
*** `delphi-newline-always-indents' is not supported any more.
Use `electric-indent-mode' instead.
*** `delphi-tab' is gone, replaced by `indent-for-tab-command'.

** Eldoc Mode works properly in the minibuffer.

** jit-lock-debug-mode lets you use the debuggers on code run via jit-lock.

** completing-read-multiple's separator can now be a regexp.
The default separator is changed to allow surrounding spaces around the comma.

** Battery

*** Battery information via the BSD `apm' utility is now supported.

** Buffer Menu

*** `M-s a C-o' shows lines matching a regexp in marked buffers using Occur.

** Calendar and Diary

*** New faces: `calendar-weekday-header', `calendar-weekend-header',
`calendar-month-header'.

*** New option `calendar-day-header-array'.

*** The variable `calendar-font-lock-keywords' is obsolete.

+++
*** New variable `diary-from-outlook-function', used by the command
`diary-from-outlook'.

** VC and related modes

*** In VC directory mode, `D' displays diffs between VC-controlled
whole tree revisions.

*** In VC directory mode, `L' lists the change log for the current VC
controlled tree in a window.

*** In VC directory mode, `I' shows a log of changes that will be
received with a pull operation.

*** `C-x v G' (globally) and `G' (in VC directory mode) ignores a file
under current version control system.  When called with a prefix
argument, you can remove a file from the ignored file list.

*** `cvs-append-to-ignore' has been renamed to `vc-cvs-append-to-ignore'
because it is moved to vc-cvs.el.

** cl-lib

*** New macro cl-tagbody.

+++
*** letf is now just an alias for cl-letf.

** Calc

*** Calc by default now uses the Gregorian calendar for all dates, and
uses January 1, 1 AD as its day number 1.  Previously Calc used the
Julian calendar for dates before September 14, 1752, and it used
December 31, 1 BC as its day number 1; the new scheme is more
consistent with Calendar's calendrical system and day numbering.

*** The new variable `calc-gregorian-switch' lets you configure the
date when Calc switches from the Julian to the Gregorian calendar.
Nil, the default value, means to always use the Gregorian calendar.
The value (YEAR MONTH DAY) means to start using the Gregorian calendar
on the given date.

*** Support for ISO 8601 dates.

** Desktop

*** `desktop-auto-save-timeout' defines the number of seconds between
auto-saves of the desktop.

*** `desktop-restore-frames', enabled by default, allows saving and
restoring the frame/window configuration (frameset).  Additional options
`desktop-restore-in-current-display', `desktop-restore-reuses-frames'
and `desktop-restore-forces-onscreen' offer further customization.

** Dired

*** New minor mode `dired-hide-details-mode' hides details.

** ERC

*** New option `erc-accidental-paste-threshold-seconds'.
If set to a number, this can be used to avoid accidentally paste large
amounts of data into the ERC input.

** EPA

*** New option `epa-mail-aliases'.

You can set this to a list of alias expansions for keys to use
in `epa-mail-encrypt'.

If one element of the variable's value is ("foo@bar.com" "foo@hello.org"),
that means: when one of the recipients of the message being encrypted
is `foo@bar.com', encrypt the message for `foo@hello.org' instead.

If one element of the variable's value is ("foo@bar.com"),
that means: when one of the recipients of the message being encrypted
is `foo@bar.com', ignore that name as regards encryption.
This is useful to avoid a query when you have no key for that name.

---
** New F90 mode option `f90-smart-end-names'.

** Icomplete is a bit more like Ido.
*** key bindings to navigate through and select the completions.
*** The icomplete-separator is customizable, and its default has changed.
*** Removed icomplete-show-key-bindings.
*** Icomplete-mode by defaults applies to all forms of minibuffer completion.
(setq icomplete-with-completion-tables '(internal-complete-buffer))
will revert to the old behavior.


** New features for Octave mode:
*** Font locking for texinfo comments and new keywords
*** Completion in Octave file buffers
*** Eldoc support
*** Jump to definition
*** Documentation lookup/search
*** Code cleanup and various bug fixes

** Ido
*** Ido has a manual now.
*** `ido-use-virtual-buffers' takes a new value 'auto.
*** `ido-decorations' has been slightly extended to give a bit more control.

** Image mode

*** New commands `n' (`image-next-file') and `p' (`image-previous-file')
visit the next image file and the previous image file in the same
directory, respectively.

*** New commands to show specific frames of multi-frame images.
`f' (`image-next-frame') and `b' (`image-previous-frame') visit the
next or previous frame.  `F' (`image-goto-frame') shows a specific frame.

*** New commands to speed up, slow down, or reverse animation.

---
*** The command `image-mode-fit-frame' deletes other windows.
When toggling, it restores the frame's previous window configuration.
It also has an optional frame argument, which can be used by Lisp
callers to fit the image to a frame other than the selected frame.

** Info

*** New face `info-index-match' is used to highlight matches in index
entries displayed by `Info-index-next', `Info-virtual-index' and
`info-apropos'.

** Hi-Lock

*** New option `hi-lock-auto-select-face'.  When non-nil, hi-lock commands
will cycle through faces in `hi-lock-face-defaults' without prompting.

+++
*** New global command `M-s h .' (`highlight-symbol-at-point')
highlights the symbol found near point without prompting,
using the next face automatically.

** Search and Replace

*** New global command `M-s .' (`isearch-forward-symbol-at-point')
starts a symbol (identifier) incremental search forward with the
symbol found near point added to the search string initially.

*** `C-x 8 RET' in Isearch mode reads a character by its Unicode name
and adds it to the search string.

*** `M-s i' in Isearch mode toggles the variable `isearch-invisible'
between nil and the value of the option `search-invisible' (or `open'
when it's nil).

*** `query-replace' skips invisible text when `search-invisible' is nil,
and opens overlays with hidden text when `search-invisible' is `open'.

+++
*** By default, prefix arguments do not now terminate Isearch mode.
Set `isearch-allow-prefix' to nil to restore old behavior.

*** More Isearch commands accept prefix arguments, namely
`isearch-printing-char', `isearch-quote-char', `isearch-yank-word',
`isearch-yank-line'.

*** Word search now matches whitespace at the beginning/end
of the search string if it contains leading/trailing whitespace.
In an incremental word search or when using a non-nil LAX argument
of `word-search-regexp', the lax matching can also match part of
the first word (in addition to the lax matching of the last word).
The same rules are now applied to the symbol search with the difference
that it matches symbols, and non-symbol characters between symbols.

** MH-E has been updated to MH-E version 8.5.
See MH-E-NEWS for details.

---
** The unrmail command converts from BABYL to mboxrd rather than mboxo.
Customize `unrmail-mbox-format' to change this.

---
** Similarly, customize `rmail-mbox-format' to influence some minor aspects
of how Rmail displays non-MIME messages.

+++
** New function `ses-rename-cell' to give SES cells arbitrary names.

** trace-function was largely rewritten.
New features include:
- no prompting for the destination buffer, unless a prefix-arg was used.
- additionally to prompting for a destination buffer, when a prefix-arg is
  used, the user can enter a "context", i.e. Lisp expression whose value at the
  time the function is entered/exited will be printed along with the function
  name and arguments.  Useful to trace the value of (current-buffer) or
  (point) when the function is invoked.

** New command `delete-duplicate-lines' has new types of operation:
When its arg ADJACENT is non-nil (when called interactively with C-u C-u)
it works like the utility `uniq'.  Otherwise by default it deletes
duplicate lines everywhere in the region without regard to adjacency.
When its arg KEEP-BLANKS is non-nil (when called interactively with
C-u C-u C-u), duplicate blank lines are preserved.

** New `cycle-spacing' command allows cycling between having just one
space, no spaces, or reverting to the original spacing.  Like
`just-one-space' command it can handle or ignore newlines and
leave different number of spaces.

** Todo mode has been rewritten and enhanced.
New features include:
- support for multiple todo files and archive files of done items;
- renaming, reordering, moving, merging, and deleting categories;
- sortable tabular summaries of categories and the types of items they contain;
- cross-category lists of items filtered by specific criteria;
- more fine-grained interaction with the Emacs diary, by being able to decide
  for each todo item whether it appears in the Fancy Diary display;
- highly flexible new item insertion and item editing;
- moving items between categories, storing done items in their category or in
  archive files, undoing or unarchiving done items;
- reprioritizing items by inputting a numerical priority;
- extensive customizability of operation and display, including numerous faces.
The Todo mode user manual describes all commands and most user options.
To support some of these features, a new file format is used, which is
incompatible with the old format; however, you can convert old todo and done
item files to the new format on initializing the first new todo file, or at any
later time with the provided conversion command.  The old version of
todo-mode.el has been made obsolete and renamed otodo-mode.el.

** Tramp

*** The experimental url syntax for remote file names is withdrawn.

+++
*** New connection method "adb", which allows to access Android
devices by the Android Debug Bridge.  The variable `tramp-adb-program'
can be used to adapt the path of the "adb" program, if needed.

*** The connection methods "plink1", "ssh1", "ssh2", "scp1", "scp2",
"scpc" and "rsyncc" are discontinued.  The ssh option
"ControlMaster=auto" is set automatically in all ssh-based methods,
when possible.

+++
*** Handlers for `file-acl' and `set-file-acl' for remote machines
which support POSIX ACLs.

+++
*** Handlers for `file-notify-add-watch' and `file-notify-rm-watch'
for remote machines which support filesystem notifications.

** VHDL mode

*** New options: `vhdl-actual-generic-name', `vhdl-beautify-options'.

*** New commands: `vhdl-fix-statement-region', `vhdl-fix-statement-buffer'.

** Woman

*** The commands `woman-default-faces' and `woman-monochrome-faces'
are obsolete.  Customize the `woman-*' faces instead.

** Eshell

*** Added Eshell-Tramp module
External su and sudo commands are now the default; the internal,
Tramp-using variants can still be used by enabling the eshell-tramp
module.

** Package

*** The format of `archive-contents' files, generated by package
repositories, has changed to allow a new (fifth) element in the data
vectors, containing an associative list with extra properties.

*** `describe-package' buffer uses the `:url' extra property to
display a `Homepage' header, if it's present.

** New term.el option `term-suppress-hard-newline'.

** Obsolete packages:

*** Iswitchb is made obsolete by icomplete-mode.

*** longlines.el is obsolete; use visual-line-mode instead.

+++
*** sup-mouse.el.

*** terminal.el is obsolete; use term.el instead.

*** The previous version of todo-mode.el is obsolete and renamed otodo-mode.el.

*** xesam.el.

+++
*** yow.el is obsolete; use fortune.el or cookie1.el instead.

---
*** The Info-edit command is obsolete.  Editing Info nodes by hand
has not been relevant for some time.

** Shell

*** `explicit-bash-args' now always defaults to use --noediting.
During initialization, Emacs no longer expends a process to decide
whether it is safe to use Bash's --noediting option.  These days
--noediting is ubiquitous; it was introduced in 1996 in Bash version 2.

+++
** There is a new macro `skip-unless' for skipping ERT tests.  See the manual.

** Imenu

*** New option `imenu-generic-skip-comments-and-strings'.

** Ruby mode

*** New option `ruby-encoding-magic-comment-style'.

*** New option `ruby-custom-encoding-magic-comment-template'.

*** New mode menu.

*** Improved syntax highlighting and indentation.

*** Add more Ruby file types to `auto-mode-alist'.


* New Modes and Packages in Emacs 24.4

** New `superword-mode' in subword.el
`superword-mode' overrides the default word motion commands to treat
symbol_words as a single word, similar to what `subword-mode' does and
using the same internal functions.

** New nadvice.el package offering lighter-weight advice facilities.
It is layered as:
- add-function/remove-function which can be used to add/remove code on any
  function-carrying place, such as process-filters or `<foo>-function' hooks.
- advice-add/advice-remove to add/remove a piece of advice on a named function,
  much like `defadvice' does.

** New frameset.el package.
It provides a set of operations to save a frameset (the state of all
or a subset of the existing frames and windows, somewhat similar to a
frame configuration), both in-session and persistently, and restore it
at some point in the future.

+++
** The package filenotify.el provides an interface for file system
notifications.  It requires, that Emacs is compiled with one of the
low-level libraries gfilenotify.c, inotify.c or w32notify.c.


* Incompatible Lisp Changes in Emacs 24.4

** `kill-region' lost its `yank-handler' optional argument.

** `(input-pending-p)' no longer runs other timers which are ready to
run.  The new optional CHECK-TIMERS param allows for the prior behavior.

** `defvar' and `defcustom' in a let-binding affect the "external" default.

** The syntax of ?» and ?« is now punctuation instead of matched parens.
Some languages match those as »...« and others as «...» so better stay neutral.

** The default file coding for Emacs Lisp files is now utf-8.
(See file-coding-system-alist.)  In most cases, this change is transparent, but
files that contain unusual characters without specifying an explicit coding
system may fail to load with obscure errors.
You should either convert them to utf-8 or add an explicit `coding:' cookie.

** overriding-terminal-local-map does not replace the local keymaps any more.
It used to disable the minor mode, major mode, and text-property keymaps,
whereas now it simply has higher precedence.

** Default process filters and sentinels are not nil any more.
Instead they default to a function which does what the nil value used to do.

** `read-event' does not return decoded chars in ttys any more.
Just as was the case in Emacs-22 and before, decoding of tty input according to
keyboard-coding-system is not performed in read-event any more.  But contrary
to that past, it is still done before input-decode-map/function-key-map/...

** Removed inhibit-local-menu-bar-menus.

** frame-local variables that affect redisplay do not work any more.
More specifically, the redisplay does not bother to check for a frame-local
value when looking up variables.

** nil and "unbound" are indistinguishable in symbol-function.
`symbol-function' never signals `void-function' any more.
`fboundp' returns non-nil if the symbol was `fset' to nil.

** `defadvice' does not honor the `freeze' flag and cannot advise
special-forms any more.

** `dolist' in lexical-binding mode does not bind VAR in RESULT any more.
VAR was bound to nil which was not tremendously useful and just lead to
spurious warnings about an unused var.

** The return value of `backup-buffer' has changed.
The second argument is no longer an SELinux context, instead it is an
alist of extended attributes as returned by the new function
`file-extended-attributes'.  The attributes can be applied to another
file using `set-file-extended-attributes'.

** `visited-file-modtime' now returns -1 for nonexistent files.
Formerly it returned a list (-1 LOW USEC PSEC), but this was ambiguous
in the presence of files with negative time stamps.

** The cars of the elements in `interpreter-mode-alist' are now treated
as regexps rather than literal strings.  Technically this is an
incompatible change, but unless you are using interpreter-mode-alist
for something (not just adding elements to it), it ought not to affect you.


* Lisp Changes in Emacs 24.4

** New function get-pos-property.

** New hook `pre-redisplay-function'.

+++
** Functions that pop up menus and dialogs now work on all terminal types,
including TTYs.
This includes `x-popup-menu', `x-popup-dialog', `message-box',
`yes-or-no-p', etc.

The function `display-popup-menus-p' will now return non-nil for a
display or frame whenever a mouse is supported on that display or
frame.

** New bool-vector set operation functions:
*** `bool-vector-exclusive-or'
*** `bool-vector-union'
*** `bool-vector-intersection'
*** `bool-vector-set-difference'
*** `bool-vector-not'
*** `bool-vector-subsetp'
*** `bool-vector-count-consecutive'
*** `bool-vector-count-population'

** Comparison functions =, <, >, <=, >= now take many arguments.

** The second argument of `eval' can now be a lexical-environment.

** `with-demoted-errors' takes an additional argument `format'.
+++
** New function `define-error'.

** New hook `tty-setup-hook'.

+++
** New macro with-eval-after-load.  Like eval-after-load, but better behaved.

** New library helpers.el for misc helper functions
*** `hash-table-keys'
*** `hash-table-values'
*** `string-blank-p`
*** `string-empty-p`
*** `string-join`
*** `string-reverse`
*** `string-trim-left'
*** `string-trim-right'
*** `string-trim'

** Obsoleted functions:
*** `log10'
*** `dont-compile'
*** `lisp-complete-symbol'
*** `field-complete'
*** `minibuffer-completion-contents'
*** `isearch-nonincremental-exit-minibuffer'
*** `isearch-filter-visible'
*** `generic-make-keywords-list'

** `with-wrapper-hook' is obsoleted by `add-function'.
The few hooks that used with-wrapper-hook are replaced as follows:
*** `abbrev-expand-function' obsoletes `abbrev-expand-functions'.
*** `completion-in-region-function' obsoletes `completion-in-region-functions'.
*** `filter-buffer-substring-function' obsoletes `filter-buffer-substring-functions'.

** `byte-compile-interactive-only-functions' is now obsolete.
It has been replaced by the symbol property 'interactive-only.

** `split-string' now takes an optional argument TRIM.
The value, if non-nil, is a regexp that specifies what to trim from
the start and end of each substring.

** New function `string-suffix-p'.

** `get-upcase-table' is obsoleted by the new `case-table-get-table'.

** Support for filesystem notifications.
Emacs now supports notifications of filesystem changes, such as
creation, modification, and deletion of files.  This requires the
`glib' API, or the 'inotify' API (on GNU/Linux systems only).  On
MS-Windows systems, this is supported for Windows XP and newer
versions.

** Changes in autorevert.el

---
*** If Emacs is compiled with file notification support, notifications
are used instead of checking the time stamp of the files.  You can
disable this by setting the user option `auto-revert-use-notify' to
nil.  Alternatively, a regular expression of directories to be
excluded from file notifications can be specified by
`auto-revert-notify-exclude-dir-regexp'.

---
*** The new user option `auto-revert-remote-files' enables reversion
of remote files when set to non-nil.

** Face changes

*** The function `face-spec-set' is now analogous to `setq' for face specs.
Its third arg now accepts values specifying exactly which face spec to
set (defface, custom, or user spec), and it directly sets the relevant
property using the supplied face spec.

*** Face specs set via Custom themes now replace the `defface' spec
rather than inheriting from it (as do face specs set via Customize).

*** New face characteristic (supports :underline (:style wave))
specifies whether or not the terminal can display a wavy line.

*** New face spec attribute :distant-foreground
specifies foreground to use if background color is near the foreground
color that would otherwise have been used.

** Image API

+++
*** `image-animated-p' is now `image-multi-frame-p'.
It returns non-nil for any image that contains multiple frames,
whether or not it specifies a frame delay.

+++
*** When animating images that do not specify a frame delay,
Emacs uses `image-default-frame-delay'.

+++
*** New functions `image-current-frame' and `image-show-frame' for getting
and setting the current frame of a multi-frame image.

*** You can change the speed of animated images.

** Changes in encoding and decoding of text

---
*** New coding-system `prefer-utf-8'.
This is like `undecided' but prefers UTF-8 on decoding if the text to
be decoded does not contain any invalid UTF-8 sequences.  On encoding,
any non-ASCII characters are automatically encoded as UTF-8.

---
*** New attributes of coding-systems whose type is `undecided'.
Two new attributes, `:inhibit-null-byte-detection' and
`:inhibit-iso-escape-detection', determine how to detect encoding of
text that includes null bytes and ISO-2022 escape sequences,
respectively.  Each of these attributes can be either nil, zero, or
t.  If it is t, decoding text ignores null bytes and, respectively,
ISO-2022 sequences.  If it is nil, null bytes cause text to be decoded
with no-conversion and ISO-2022 sequences cause Emacs to assume the
text is encoded in one of the ISO-2022 encodings, such as
iso-2022-7bit.  If the value is zero, Emacs consults the variables
inhibit-null-byte-detection and inhibit-iso-escape-detection, which
see.
The new attribute `:prefer-utf-8', if non-nil, causes Emacs to prefer
UTF-8 encoding and decoding, whenever possible.

These attributes are only meaningful for coding-systems of type
`undecided'.  (The type of a coding-system is determined by its
`:coding-type' attribute and can be accessed by calling the
`coding-system-type' function.)

** The function `set-visited-file-modtime' now accepts a 0 or -1 argument
with the same interpretation as the returned value of `visited-file-modtime'.

** time-to-seconds is not obsolete any more.
** New functions special-form-p and macrop.
** Docstrings can be made dynamic by adding a `dynamic-docstring-function'
text-property on the first char.

** The `defalias-fset-function' property lets you catch calls to defalias
and redirect them to your own function instead of `fset'.

** The lock for 'DIR/FILE' is now 'DIR/.#FILE' and may be a regular file.
When you edit DIR/FILE, Emacs normally creates a symbolic link
DIR/.#FILE as a lock that warns other instances of Emacs that DIR/FILE
is being edited.  Formerly, if there was already a non-symlink file
named DIR/.#FILE, Emacs fell back on the lock names DIR/.#FILE.0
through DIR/.#FILE.9.  These fallbacks have been removed, so that
Emacs now no longer locks DIR/FILE in that case.

On file systems that do not support symbolic links, the lock is now a
regular file with contents being what would have been in the symlink.

** The 9th element returned by `file-attributes' is now unspecified.
Formerly, it was t if the file's gid would change if file were deleted
and recreated.  This value has been inaccurate for years on many
platforms, and nobody seems to have noticed or cared.

** The function `file-ownership-preserved-p' now has an optional
argument GROUP which causes it check for file group too.  This can be
used in place of the 9th element of `file-attributes'.

** New functions `group-gid' and `group-real-gid'.

** The 6th argument to `copy-file' has been renamed to
`preserve-extended-attributes' as it now handles both SELinux context
and ACL entries.

** The `common-substring' argument of display-completion-list is obsolete.
Either use `completion-all-completions' which already returns highlighted
strings (including for partial or substring completion) or call
`completion-hilit-commonality' to add the highlight.

** Changes to the Emacs Lisp Coding Conventions in Emacs 24.4

*** The package descriptor and name of global variables, constants,
and functions should be separated by two hyphens if the symbol is not
meant to be used by other packages.


* Changes in Emacs 24.4 on Non-Free Operating Systems

** The procedure for building Emacs on MS-Windows has changed.
It is now built by running the same configure script as on all other
platforms.  This requires the MSYS environment and MinGW development
tools.  See the updated instructions in nt/INSTALL for details.

Using the Posix configure script and Makefile's also means a change in
the directory structure of the Emacs installation on Windows.  It is
now the same as on GNU and Unix systems.  In particular, the auxiliary
programs, such as cmdproxy.exe and hexl.exe, are in
libexec/emacs/VERSION/i686-pc-mingw32 (where VERSION is the Emacs
version), version-independent site-lisp is in share/emacs/site-lisp,
version-specific Lisp files are in share/emacs/VERSION/lisp and in
share/emacs/VERSION/site-lisp, Info docs are in share/info, and data
files are in share/emacs/VERSION/etc.  (Emacs knows about all these
directories and will find the files in there automatically; there's no
need to set any variables due to this change.)

+++
** The "generate a backtrace on fatal error" feature now works on MS Windows.
The backtrace is written to the 'emacs_backtrace.txt' file in the
directory where Emacs was running.

+++
** The variable `buffer-file-type' is no longer supported.
Setting it has no effect, and %t in the mode-line format is ignored.
Likewise, `file-name-buffer-file-type-alist' is now obsolete, and
modifying it has no effect.

---
** Lock files now work on MS-Windows.
This allows to avoid losing your edits if the same file is being
edited in another Emacs session or by another user.  See the node
"Interlocking" in the Emacs User Manual for the details.  To disable
file locking, customize `create-lockfiles' to nil.

** Improved fullscreen support on Mac OS X.
Both native (>= OSX 10.7) and "old style" fullscreen are supported.
Customize `ns-use-native-fullscreen' to change style.  For >= 10.7
native is the default.


* Installation Changes in Emacs 24.3

** The default X toolkit is now Gtk+ version 3.
If you don't pass `--with-x-toolkit' to configure, or if you use
`--with-x-toolkit=gtk' or `--with-x-toolkit=yes', configure will try
to build with Gtk+ version 3, and if that fails, try Gtk+ version 2.
You can explicitly require a specific version by passing
`--with-x-toolkit=gtk2' or `--with-x-toolkit=gtk3' to configure.

** New configure option `--enable-link-time-optimization', to utilize
an appropriate feature provided by GCC since version 4.5.0.

** New configure option `--without-all' to disable most of the optional
features (image support, etc.) that are normally enabled by default.

** New configure option `--enable-gcc-warnings' (for developing/debugging
Emacs).  If building with GCC, this enables compile-time checks that
warn/give errors about possibly-questionable C code.  On a recent GNU
system there should be no warnings; on older and on non-GNU systems
the results may be useful to developers.

** The configure option `--enable-use-lisp-union-type' has been
renamed to `--enable-check-lisp-object-type', as the resulting
Lisp_Object type no longer uses a union to implement the compile time
check that this option enables.

** The configure option `--disable-maintainer-mode' has been removed,
as it was confusingly-named and rarely useful.

** The configure options `--program-prefix', `--program-suffix', and
`--program-transform-name' apply to more than just the installed
binaries.  Now they also affect the man pages, icons, and the
etc/emacs.desktop file; but not the info pages, since this would break
links between the various manuals.

** You can use `NO_BIN_LINK=t make install' to prevent the installation
overwriting "emacs" in the installation bin/ directory with a link
to "emacs-VERSION".

** Emacs uses libtinfo in preference to libncurses, if available.

** On FreeBSD and NetBSD, configure no longer adds /usr/local/lib and
/usr/pkg/lib to the linker search path.  You must add them yourself if
you want them.

** The standalone scripts `rcs-checkin' and `vcdiff' have been removed
(from the bin and libexec directories, respectively).  The former is
no longer relevant, the latter is replaced by lisp (in vc-sccs.el).


* Startup Changes in Emacs 24.3

** Emacs no longer searches for `leim-list.el' files beneath the standard
lisp/ directory.  There should not be any there anyway.  If you have
been adding them there, put them somewhere else; e.g., site-lisp.

** The `--no-site-lisp' command line option now works for Nextstep builds.


* Changes in Emacs 24.3

** Help

*** `C-h f' (`describe-function') can now perform autoloading.
When this command is called for an autoloaded function whose docstring
contains a key substitution construct, that function's library is
automatically loaded, so that the documentation can be shown
correctly.  To disable this, set `help-enable-auto-load' to nil.

*** `C-h f' now reports previously-autoloaded functions as "autoloaded",
even after their associated libraries have been loaded (and the
autoloads have been redefined as functions).

** ImageMagick

*** Images displayed via ImageMagick now support transparency and the
:background image specification property.

*** When available, ImageMagick support is automatically enabled.
It is no longer necessary to call `imagemagick-register-types'
explicitly to install ImageMagick image types; that function is called
automatically at startup, or when customizing an imagemagick- option.

*** Setting `imagemagick-types-inhibit' to t now disables the use of
ImageMagick to view images.  (You must call `imagemagick-register-types'
afterwards if you do not use customize to change this.)

*** The new variable `imagemagick-enabled-types' also affects which
ImageMagick types are treated as images.  The function
`imagemagick-filter-types' returns the list of types that will be
treated as images.

*** ImageMagick images now support the :max-width and :max-height
keywords.