What’s New in Emacs 24.3
Emacs version 24.3 is now released to the public. This release, unlike 24.2, is chock full of goodies. I’ve taken the liberty of annotating things that’re relevant to me — and hopefully you, too, dear reader — but I’ve limited my commentary to things I’m familiar with. Always keen to hear what you think about the changes in the comments.
You can retrieve Emacs 24.3 from one of these locations:
Note: As of 11 AM on 2013-03-11 I had issues with some mirrors not yet having the new version available.
What’s New in Emacs 24.3
Installation Changes in Emacs 24.3
The default X toolkit is now Gtk+ version 3.
If you don’t pass
--with-x-toolkitto configure, or if you use
--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
Although I always use Emacs in a window manager, and actively recommend that people who can do as well, this change is unlikely to affect me much at all. I don’t use scrollbars, toolbars or menubars.
New configure option
--enable-link-time-optimization, to utilize
an appropriate feature provided by GCC since version 4.5.0.
New configure option
--without-allto disable most of the optional
features (image support, etc.) that are normally enabled by default.
For the luddites.
New configure option
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-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-modehas been removed,
as it was confusingly-named and rarely useful.
The configure options
--program-transform-nameapply 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 installto prevent the installation
overwriting “emacs” in the installation bin/ directory with a link
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
vcdiffhave 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.elfiles 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.
--no-site-lispcommand line option now works for Nextstep builds.
Changes in Emacs 24.3
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
That’s a potentially useful change, though I cannot offhand recall any instances where I’ve been bitten by this. This is not going to guard against unloaded libraries if you are not looking up autoloaded commands. In other words, if you’re looking up an obscure function or variable and the library isn’t loaded, this won’t help at all.
C-h fnow reports previously-autoloaded functions as “autoloaded”,
even after their associated libraries have been loaded (and the
autoloads have been redefined as functions).
I would fill this under “Nice to know”.
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
explicitly to install ImageMagick image types; that function is called
automatically at startup, or when customizing an imagemagick- option.
Most excellent. This should help encourage the use of Imagemagick now that it’s loaded by default.
imagemagick-types-inhibitto t now disables the use of
ImageMagick to view images. (You must call
afterwards if you do not use customize to change this.)
… And this is how you disable it
The new variable
imagemagick-enabled-typesalso affects which
ImageMagick types are treated as images. The function
imagemagick-filter-typesreturns the list of types that will be
treated as images.
In minibuffer filename prompts,
C-M-bnow move to the
next and previous path separator, respectively.
With the caveat, I suppose, that this is not likely to work if you use iswitchb or IDO.
minibuffer-electric-default-modecan shorten “(default …)” to “[...]”
in minibuffer prompts. Just set
non-nil before enabling the mode.
mode-line-default-help-echospecifies the help text
(shown in a tooltip or in the echo area) for any part of the mode line
that does not have its own specialized help text.
You can now click mouse-3 in the coding system indicator to invoke
Server and client
emacsclient now obeys string values for
if it is told to open a new frame without specifying any file to visit
or expression to evaluate.
server-auth-keyspecifies a shared server key.
Emacs now generates backtraces on fatal errors.
On encountering a fatal error, Emacs now outputs a textual description
of the fatal signal, and a short backtrace on platforms like glibc
that support backtraces.
C-x C-qis now bound to the new minor mode
This minor mode replaces
toggle-read-only, which is now obsolete.
Interesting that they’ve moved it to a new minor mode. I imagine this change was effected to reduce the number of “magic states” a buffer could be in. As a mode, it also means you can customize it further like, say, adding hooks so you can gray out the text if it’s read only.
y-or-nprompts now allow you to scroll the selected window.
M-vat a y-or-n prompt scrolls forward or backward
respectively, without exiting from the prompt.
Very nice and welcome change.
In the Package Menu, newly-available packages are listed as “new”,
and sorted above the other “available” packages by default.
If your Emacs was built from a bzr checkout, the new variable
emacs-bzr-versioncontains information about the bzr revision used.
create-lockfilesspecifies usage of lockfiles.
It defaults to t. Changing it to nil inhibits the creation of lock
files (use this with caution).
enable-remote-dir-locals, if non-nil, allows directory-local
variables on remote hosts.
This is useful if you use dir-local variables remotely, but there’s an obvious security risk if you enable it.
The entry for PCL-CVS has been removed from the Tools menu.
The PCL-CVS commands are still available via the keyboard.
Using “unibyte: t” in Lisp source files is obsolete.
Use “coding: raw-text” instead.
In the buffer made by
M-x report-emacs-bug, the
has been changed to
The previous binding, introduced in Emacs 24.1, was a mistake, because
C-c LETTERbindings are reserved for user customizations.
New language environment: Persian.
New input method
Nextstep (GNUstep / Mac OS X) port
Support for fullscreen and the frame parameter fullscreen.
A much longed-for feature.
A file dialog is used for open/save operations initiated from the
Editing Changes in Emacs 24.3
Search and Replace
Non-regexp Isearch now performs “lax” space matching.
Each sequence of spaces in the supplied search string may match any
sequence of one or more whitespace characters, as specified by the
search-whitespace-regexp. (This variable is also used by a
similar existing feature for regexp Isearch.)
This is great as you can now find matches even though whitespacing may not be spot on.
New Isearch command
M-s SPCtoggles lax space matching.
This applies to both ordinary and regexp Isearch.
Handy if you don’t want fuzzy space matching.
query-replaceuses flexible whitespace matching too.
The default is nil.
M-s _starts a symbol (identifier) incremental search,
M-s _in Isearch toggles symbol search mode.
M-s cin Isearch toggles search case-sensitivity.
Very useful if you’re coding. It’s equivalent to wrapping an
isearch-forward-regexp regexp query in
\_>. Keep in mind that the definition of a symbol varies according to your major mode (and sometimes minor!). It’s usually set to rather sensible defaults in most programming major modes.
The word “char” here is rather misleading: it means the absolute position, as an integer, from the beginning of the buffer.
move-to-column) prompts for a column number if called
interactively with no prefix arg. Previously, it moved to column 1.
yank-handled-propertiesallows processing of text
properties on yanked text, in ways that are more general than just
removing them (as is done by
Useful if you want to strip out or alter properties on text when it’s yanked. This is unlikely to be of interest to anybody except module developers.
M-x delete-trailing-whitespace should delete trailing lines at the end
of the buffer. It defaults to t.
A nice and useful addition, but be wary as it defaults to true.
C-u M-=now counts lines/words/characters in the entire buffer.
C-x 8 RETis now bound to
insert-char, which is now a command.
ucs-insertis now an obsolete alias for
zkey no longer has a binding in most special modes.
It used to be bound to
zis too easy to
Rejoice all who have accidentally killed your buffers.
C-x r M-w(
It copies the region-rectangle as the last rectangle kill.
Very nice. This basically makes works exactly like
M-w does except it operates on a rect. No more killing then yanking if you want to copy a rect.
C-x r +is now overloaded to invoke
This small change has rather wide ramifications for those of you who use registers in macros. You can now collect text and append it to the end of a register instead of shunting it to a different buffer. Groundbreaking? Not quite, but very useful indeed.
register-separatorspecifies the register containing
the text to put between collected texts for use with
M-x append-to-register and M-x prepend-to-register.
Combined with the above, this enables you to collate appended texts with a separator symbol.
Changes in Specialized Modes and Packages in Emacs 24.3
Common Lisp emulation (CL)
CL’s main entry is now (require ‘cl-lib).
cl-libis like the old
clexcept that it uses the namespace cleanly;
i.e., all its definitions have the “cl-” prefix (and internal definitions
use the “cl–” prefix).
clprovided a feature under the name
provides it under the name
cl-fooinstead; with the exceptions of the
cldefinitions that had to use
foo*to avoid conflicts with
pre-existing Elisp entities. These have been renamed to
clis now deprecated and is mainly just a bunch of aliases that
provide the old, non-prefixed names. Some exceptions are listed below:
This is a good change but I doubt we will ever truly be rid of
cl, not for a long tie anyway.
cl-fletis not like
flet(which is deprecated).
Instead it obeys the behavior of Common-Lisp’s
In particular, in cl-flet function definitions are lexically scoped,
whereas in flet the scoping is dynamic.
cl-labelsis slightly different from
The difference is that it relies on the
(as opposed to the
lexical-letmachinery used previously) to capture
definitions in closures, so such closures will only work if
is in use.
cl-letfis not exactly like
The only difference is in details that relate to some deprecated usage
symbol-functionin place forms.
progvwas rewritten to use the
A side effect is that variables without corresponding values are bound
to nil rather than being made unbound.
The following methods of extending
(use features from gv.el instead):
get-setf-methodno longer exists (see “Incompatible Lisp Changes”)
Changes are now highlighted using the same color scheme as in
modern VCSes. Deletions are displayed in red (new faces
smerge-refined-removed, and new definition
diff-removed), insertions in green (new faces
smerge-refined-added, and new definition of
More standardization. Good.
diff-use-changed-facedefines whether to use the
changes in context diffs.
The new command
whitespace introduced by a diff.
Ediff now uses the same color scheme as Diff mode.
A new version of python.el, which provides several new features, including:
per-buffer shells, better indentation, Python 3 support, and improved
shell-interaction compatible with iPython (and virtually any other
text based shell).
I blogged about a new python mode a long time ago and it seems it’s made it into trunk. That’s probably good news for most Python users, but as I haven’t yet explored the new python.el mode yet, I will cover this in much greater detail in another post.
Some user options have been replaced/renamed, including (old -> new):
python-indent -> python-indent-offset
python-guess-indent -> python-indent-guess-indent-offset
python-pdbtrack-do-tracking-p -> python-pdbtrack-activate
python-use-skeletons -> python-skeleton-autoinsert
Some user options have been removed, including:
python-indent-string-contents: Strings are never indented.
Comments are always considered as indentation markers.
python-continuation-offset: Indentation is automatically
calculated in a pep8 compliant way depending on the context.
Have no direct mapping as the shell interaction is completely different.
No longer relevant.
Some commands have been replaced (old -> new):
python-insert-class -> python-skeleton-class
python-insert-def -> python-skeleton-def
python-insert-for -> python-skeleton-for
python-insert-if -> python-skeleton-if
python-insert-try/except -> python-skeleton-try
python-insert-try/finally -> python-skeleton-try
python-insert-while -> python-skeleton-while
python-find-function -> python-nav-jump-to-defun
python-next-statement -> python-nav-forward-sentence
python-previous-statement -> python-nav-backward-sentence
python-beginning-of-defun-function -> python-nav-beginning-of-defun
python-end-of-defun-function -> python-nav-end-of-defun
python-send-buffer -> python-shell-send-buffer
python-send-defun -> python-shell-send-defun
python-send-region -> python-shell-send-region
python-send-region-and-go -> emulate with python-shell-send-region
python-send-string -> python-shell-send-string
python-switch-to-python -> python-shell-switch-to-shell
python-describe-symbol -> python-eldoc-at-point
Needless to say, the changes here are likely to break a lot of my custom Python code I’ve written over the years. If you’re relying on customizations to Python or modes that interact with it, I would probably ensure you can fix or live with broken modules until they’re fixed.
The D-Bus object manager interface is implemented.
Variables of type u)int32 and u)int64 accept floating points,
if their value does not fit into Emacs’s integer range.
dbus-call-methodis now non-blocking.
It can be interrupted by
Signals can also be sent as unicast messages.
The argument list of
dbus-register-signalhas been extended,
according to the new match rule types of D-Bus.
dbus-init-bussupports private connections.
There is a new function
desktop-pathno longer includes the “.” directory.
Desktop files are now located in ~/.emacs.d by default.
dired-do-async-shell-commandexecutes each file sequentially
if the command ends in
;(when operating on multiple files).
Otherwise, it executes the command on each file in parallel.
Very useful and good for people working with commands on many files.
M-nin the minibuffer of
dired-do-touchyanks the attributes of the
file at point.
Hah! This is superb. I really like this change. Now you’re probably thinking the command,
M-n, is arbitrary, but not so: in minibuffer prompts that command would go to the last used element in the minibuffer history; by re-using that command here, it achieves the same effect.
When the region is active,
mark/unmark/flag all files in the active region.
Can i hear a hallelujah? this is a most welcome change and one that should’ve been in dired since day one.
The minibuffer default for
dired-diff) has changed.
it is now the backup file for the file at point, if one exists.
in transient mark mode the default is the file at the active mark.
great idea but for most serious files you’re probably using
c-x v =, the vcs diff command.
M-=is no longer bound to
dired-backup-diffin Dired buffers.
The global binding for
count-words-regionis in effect.
New module “notifications”, which can send a notification when you
receive a private message or your nickname is mentioned.
ERC will look up server/channel names via auth-source and use any
channel keys found.
erc-lurker-hide-list, similar to
only applies to messages sent by lurkers.
C-c C-h), TAB indentation, filling and auto-filling,
fontification, comment handling, and customization have all been revised
That’s good. rST mode always did seem a bit… underdeveloped.
The reStructuredText syntax is more closely covered.
Sphinx support has been improved.
Sphinx support is very good news for Python docs writers and other fans of Sphinx.
rst-insert-listinserts new list or continues existing lists.
A negative prefix argument always works for
The window configuration is reset after displaying a TOC.
rst-versiondescribes the rst.el package version.
Support for percent literals and recognition of regular expressions
in method calls without parentheses with more methods, including Cucumber
Improved syntax highlighting and indentation.
ruby-toggle-block, bound to
Some non-standard keybindings/commands have been removed:
ruby-end-of-defunare replaced by
appropriate settings for the variables
These three changes are all part of a larger drive in Emacs to remove major mode-specific functions that’re better served with the built-in Emacs equivalents.
Non-standard keybindings for
newlinehave been removed.
Shell Script mode
Pairing of parens/quotes uses
electric-pair-modeinstead of skeleton-pair.
More duplicate cruft removed and standardized.
sh-electric-here-document-modenow controls auto-insertion of here-docs.
sh-use-smielets you choose a new indentation and navigation code.
The free software compiler GHDL is supported (and now the default).
Support for the VHDL-AMS packages has been added/updated.
Updated to the 2002 revision of the VHDL standard.
Accepts r and f as whitespace.
The faces used by Apropos are now directly customizable.
These faces are named
apropos-keybinding, and so on;
aproposCustom group for details.
The old options whose values specified faces to use have been removed
This package has been rewritten to use Tabulated List mode.
Buffer-menu-buffer+size-widthis now obsolete.
You can customize the header text that appears above each calendar month.
See the variable
New LaTeX calendar style, produced by
The calendars produced by cal-html include holidays.
cal-html-holidaysto change this.
The major modes from the parser generators “Bovine” and “Wisent”
are now properly integrated in Emacs. The file suffixes “.by” and “.wy”
auto-mode-alist, and the corresponding manuals are included.
Menu support for the “Configuration” feature. This allows users to
choose the active configuration (such as debug or install) from the menu.
ede-setto interactively set project-local variables.
Support for compiling, debugging, and running in “generic” projects.
Autoconf editing support for M4 macros with complex arguments.
Compilation support for the “linux” project type.
“simple” projects have been removed; use “generic” projects instead.
Support for parsing #include statements inside a namespace in C/C++.
Improved support for ‘extern “C”‘ declarations in C/C++.
The ability to ignore more common special C/C++ preprocessor symbols,
such as ‘__nonnull’ and ‘__asm’. Add ‘__cplusplus’ macro when parsing C++.
If available, include cdefs.h as an additional source of preprocessor symbols.
Improved C/C++ function pointer parsing.
In Python, support for converting imports to include file names.
Ability to dynamically determine the Python load path.
Support for the Python ‘WITH’ and ‘AT’ keywords.
Improved tooltip completion.
The SRecode manual is now included.
Tag generation supports constructor/destructor settings and system
Addition of ‘Framework’ support: Frameworks are specified when a
particular kind of library (such as Android) is needed in a common language
mode (like Java).
Support for nested templates and let variables override based on priority.
Support for merging tables from multiple related modes, such as
default -> c++ -> arduino.
Compile has a new option
custom-reset-button-menunow defaults to t.
Non-option variables are never matched in
customize-apropos-options(i.e., the prefix argument does nothing for
these commands now).
are now deprecated in favor of the customizable face
A pre-customization anachronism removed at last. Make sure you migrate your term color settings!
You can customize how to display ANSI terminal colors and styles
by customizing the corresponding
If, like me, you customized
ansi-color-names-vector to change the default term colours I suggest you switch to using the faces now. The good news here is you can, should desire to, change more than just the colours for each ANSI Color: there’s nothing stopping you from forcing a different font for certain colours.
The syntax has been extended in order to allow ad-hoc proxy definitions.
This is a great change and a most needed one if you want to
su to a different user once you’ve connected to a another host and you can’t be bothered figuring out how TRAMP proxies work.
Typically I can’t find any information about the new syntax anywhere… I’ll have to dig into the source code and write a post about it later. Despite my best attempts it seems I completely missed the new chapter, here
(info "(tramp)Ad-hoc multi-hops").
Remote processes are now also supported on remote MS-Windows hosts.
Structs made by
Previously, this slot stored semicolon-separated attribute-value pairs
appended to some imap URLs, but this is not compatible with RFC 3986.
So now the
filenameslot stores the entire path and query components,
attributesslot is always nil.
url-encode-urlfor encoding a URI string.
url-retrievefunction now uses this to encode its URL argument,
in case that is not properly encoded.
notifications.el supports now version 1.2 of the Notifications API.
notifications-get-capabilitiesreturns the supported
More misc changes
Flymake uses fringe bitmaps to indicate errors and warnings.
The FFAP option
ffap-url-unwrap-remotecan now be a list of strings,
specifying URL types that should be converted to remote file names at
the FFAP prompt. The default is now ‘(“ftp”).
derived-modefilter, bound to
The old binding for
/ M(filter by used-mode) is now bound to
mouse-avoidance-banish-positionspecifies where the
banishmouse avoidance setting moves the mouse.
In Perl mode, new option
closing brackets to be aligned with the line of the opening bracket.
In Proced mode, new command
proced-renicerenices marked processes.
async-shell-command-bufferspecifies the buffer to use
for a new asynchronous
shell-commandwhen the default output buffer
*Async Shell Command*is already in use.
Handy if you don’t want your shell output buffer overwritten when you run more than one asynchronous command.
SQL mode has a new option
If non-nil, newlines sent to the command interpreter will be escaped
by a backslash. The default does not escape the newlines and assumes
that the sql statement will be terminated by a semicolon.
tabulated-list-sort, bound to
Sin Tabulated List mode
(and modes that derive from it), sorts the column at point, or the Nth
column if a numeric prefix argument is given.
Its use should be pretty straight forward but I find that mode a bit buggy. Probably better if you stick to using the one in org mode.
which-func-modesnow defaults to t, so Which Function mode, when
enabled, applies to all applicable major modes.
A nice change as Which Function mode worked in more buffers than the
which-func-modes gave it credit for.
winner-mode-hooknow runs when the mode is disabled, as well as when
it is enabled.
Follow mode no longer works by using advice.
follow-intercept-processeshas been removed.
Hooks renamed to avoid obsolete “-hooks” suffix:
semantic-lex-reset-hooks -> semantic-lex-reset-functions
semantic-change-hooks -> semantic-change-functions
semantic-edits-new-change-hooks -> semantic-edits-new-change-functions
semantic-edits-delete-change-hooks -> semantic-edits-delete-change-functions
semantic-edits-reparse-change-hooks -> semantic-edits-reparse-change-functions
semanticdb-save-database-hooks -> semanticdb-save-database-functions
c-prepare-bug-report-hooks -> c-prepare-bug-report-hook
rcirc-sentinel-hooks -> rcirc-sentinel-functions
rcirc-receive-message-hooks -> rcirc-receive-message-functions
rcirc-activity-hooks -> rcirc-activity-functions
rcirc-print-hooks -> rcirc-print-functions
dbus-event-error-hooks -> dbus-event-error-functions
eieio-pre-method-execution-hooks -> eieio-pre-method-execution-functions
checkdoc-style-hooks -> checkdoc-style-functions
checkdoc-comment-style-hooks -> checkdoc-comment-style-functions
archive-extract-hooks -> archive-extract-hook
filesets-cache-fill-content-hooks -> filesets-cache-fill-content-hook
hfy-post-html-hooks -> hfy-post-html-hook
nndiary-request-create-group-hooks -> nndiary-request-create-group-functions
nndiary-request-update-info-hooks -> nndiary-request-update-info-functions
nndiary-request-accept-article-hooks -> nndiary-request-accept-article-functions
gnus-subscribe-newsgroup-hooks -> gnus-subscribe-newsgroup-functions
In most cases, assoc+member+push+delq work just as well.
And in any case it’s just a terrible package: ugly semantics, terrible
inefficiency, and not namespace-clean.
Incompatible Lisp Changes in Emacs 24.3
Docstrings starting with
*no longer indicate user options.
Only variables defined using
defcustomare considered user options.
user-variable-pis now an obsolete alias for
The return values of
and are now undefined. For backwards compatibility,
defmacrocurrently return the name of the newly defined
function/macro, but this should not be relied upon.
randomby default now returns a different random sequence in
every Emacs run. Use
(random S), where S is a string, to set the
random seed to a value based on S, in order to get a repeatable
sequence in later calls.
If the NEWTEXT arg to
replace-matchcontains a substring “?”,
that substring is inserted literally even if the LITERAL arg is
non-nil, instead of causing an error to be signaled.
select-windownow always makes the window’s buffer current.
It does so even if the window was selected before.
x-select-fontcan return a font spec, instead of a
font name as a string. Whether it returns a font spec or a font name
depends on the graphical library.
face-spec-setno longer sets frame-specific attributes when the
third argument is a frame (that usage was obsolete since Emacs 22.2).
set-buffer-multibytenow signals an error in narrowed buffers.
The CL package’s
get-setf-methodfunction no longer exists.
Generalized variables are now part of core Emacs Lisp, and implemented
differently to the way cl.el used to do it. It is not possible to
define a compatible replacement for
get-setf-method. See the file
gv.el for internal details of the new implementation.
The arguments of
dbus-register-signalare no longer just strings,
but keywords or keyword-string pairs. The old argument list will
still be supported for Emacs 24.x.
Miscellaneous name changes
Some Lisp symbols have been renamed to correct their spelling,
or to be more consistent with standard Emacs terminology.
hangul-input-method-inactivate -> hangul-input-method-deactivate
inactivate-input-method -> deactivate-input-method
quail-inactivate -> quail-deactivate
robin-inactivate -> robin-deactivate
viper-inactivate-input-method -> viper-deactivate-input-method
ucs-input-inactivate -> ucs-input-deactivate
The old hooks are still supported for backward compatibility, but they
are deprecated and will be removed eventually.
input-method-inactivate-hook -> input-method-deactivate-hook
robin-inactivate-hook -> robin-deactivate-hook
quail-inactivate-hook -> quail-deactivate-hook
follow-deactive-menu -> follow-inactive-menu
Some obsolete functions, variables, and faces have been removed:
Lisp Changes in Emacs 24.3
CL-style generalized variables are now in core Elisp.
popaccept generalized variables.
You can define your own generalized variables using
Emacs tries to macroexpand interpreted (non-compiled) files during load.
This can significantly speed up execution of non-byte-compiled code,
but can also bump into previously unnoticed cyclic dependencies.
These are generally harmless: they will simply cause the macro calls
to be left for later expansion (as before), but will result in a
warning (“Eager macro-expansion skipped due to cycle”) describing the cycle.
You may wish to restructure your code so this does not happen.
New sampling-based Elisp profiler.
Try M-x profiler-start, do some work, and then call M-x profiler-report.
When finished, use M-x profiler-stop. The sampling rate can be based on
CPU time or memory allocations.
defunalso accepts a (declare DECLS) form, like
The interpretation of the DECLS is determined by
Face underlining can now use a wave.
Now you can finally make misspelled words in
ispell-minor-mode look like Microsoft Word with squiggly underlines!
read-regexphas a new argument HISTORY; the first argument PROMPT
read-regexpaccepts a string ending with a colon and space, and its
second argument DEFAULTS can be a list of strings accessible via
in the minibuffer ahead of other hard-coded useful regexp-related values.
More commands use
read-regexpnow to read their regexp arguments.
Very useful change for those of us who use readers and often find ourselves reinventing the history wheel.
completion-table-with-quotingto handle completion
in the presence of quoting, such as file completion in shell buffers.
completion-table-subvertto use an existing completion
table, but with a different prefix.
New error type and new function
These do not trigger the debugger.
debugger-bury-or-kill, saying what to do with the
debugger buffer when exiting debug.
debug-on-messageto enter the debugger when a certain
message is displayed in the echo area. This can be useful when trying
to work out which code is doing something.
inhibit-debugger, automatically set to prevent accidental
fit-frame-to-bufferadjusts the frame height to
fit the contents.
fit-window-to-buffercan adjust the frame height
if the new option
with-temp-buffer-window, similar to
This is a useful command if you want to generate output with
prin1, etc. or print output from an external command in a separate window. I’m personally very happy to see this macro make an appearance.
temp-buffer-resize-modeno longer resizes windows that have been
switch-to-buffer-preserve-window-pointto restore a
window’s point when switching buffers.
New display action alist entries
specify the size of new windows created by
New display action alist entry
non-nil, specifies frame parameters to give any newly-created frame.
New display action alist entry
inhibit-switch-frame, if non-nil,
tells display action functions to avoid changing which frame is
New display action alist entry
previous-window, if non-nil,
specifies window to reuse in
New display action functions
now accept a third argument to avoid choosing the selected window.
Additional values recognized for option
The following variables are obsolete, as they can be replaced by
appropriate entries in the
in Emacs 24.1:
current-time-stringno longer requires that its argument’s year
must be in the range 1000..9999. It now works with any year supported
by the underlying C implementation.
current-timenow returns extended-format time stamps
(HIGH LOW USEC PSEC), where the new PSEC slot specifies picoseconds.
PSEC is typically a multiple of 1000 on current machines. Other
functions that use this format, such as
format-time-string, have been changed accordingly. Old-format time
stamps are still accepted.
The format of timers in
[TRIGGERED-P HI-SECS LO-SECS USECS REPEAT-DELAY FUNCTION ARGS IDLE-DELAY PSECS].
The PSECS slot is new, and uses picosecond resolution. It can be
accessed via the new
Last-modified time stamps in undo lists now are of the form
(t HI-SECS LO-SECS USECS PSECS) instead of (t HI-SECS . LO-SECS).
(Old MacDonald had a farm) EIEIO
Improved security when handling persistent objects:
eieio-persistent-readnow features optional arguments for specifying
the class to load, as well as a flag stating whether subclasses are allowed;
if provided, other classes will be rejected by the reader. For
compatibility with existing code, if the class is omitted only a
warning is issued.
New specialized reader for pulling in classes and signaling errors
without evaluation of suspicious code.
All slots that contain objects must have a :type. Slots with lists
of objects must use a new type predicate for a list of an object type.
find-functionand similar utilities, through the addition
of filename support to generated symbols.
Even more misc stuff
Floating point functions now always return special values like NaN,
instead of signaling errors, if given invalid args; e.g., (log -1.0).
Previously, they returned NaNs on some platforms but signaled errors
on others. The affected functions are acos, asin, tan, exp, expt,
log, log10, sqrt, and mod.
New fringe bitmap
Seems like flymake’s using it for errors. Neat.
Miscellaneous changes to special forms and macros
defmacroare now macros rather than special forms.
If you ever wanted to know how a function is created in Emacs, now you can look at the lisp code in
byte-run.el. Ditto for
kbdis now a function rather than a macro.
Miscellaneous new functions
set-temporary-overlay-mapsets up a temporary keymap that
takes precedence over most other maps for a short while (normally one key).
autoloadptests if its argument is an autoloaded object.
autoload-do-loadperforms the autoloading operation.
buffer-narrowed-ptests if the buffer is narrowed.
file-name-basereturns a file name sans directory and extension.
function-getfetches a function property, following aliases.
posnptests if an object is a
system-usersreturns the user names on the system.
system-groupsreturns the group names on the system.
tty-top-framereturns the topmost frame of a text terminal.
The following functions and variables are obsolete:
window-system-version(provides no useful information)
font-list-limit(has had no effect since Emacs < 23)
Changes in Emacs 24.3 on Non-Free Operating Systems
Cygwin builds can use the native MS Windows user interface.
--with-w32to configure. The default remains the X11 interface.
Two new functions are available in Cygwin builds:
cygwin-convert-file-name-to-windows. These functions allow Lisp
code to access the Cygwin file-name mapping machinery to convert
between Cygwin and Windows-native file and directory names.
When invoked with the -nw switch to run on the Windows text-mode terminal,
Emacs now supports
mouse-highlight, help-echo (in the echo area), and
On MS Windows Vista and later Emacs now supports symbolic links.
On MS Windows, you can pass
--without-libxml2to configure.bat to omit
support for libxml2, even if its presence is detected.
On Mac OS X, the Nextstep port requires OS X 10.4 or later.
On Mac OS X, configure no longer automatically adds the Fink “/sw”
directories to the search path. You must add them yourself if you want them.
Phew. That was a lot of changes and I’ve barely explained 10% of them. Let me know if I glossed over some cool new stuff.