Emacs 27 (Released 2020-08)
xtodo 2020-08-14 todo, work in progress
This page is a on-going list of tips and tricks about emacs 27. I'll be adding stuff here few times a week.
Emacs NEWS Files
2.1 Emacs can now use the XDG convention for init files.
XDG_CONFIG_HOME environment variable (which defaults to
~/.config) specifies the XDG configuration parent directory. Emacs
init.el and other configuration files inside the
However, Emacs will still initially look for init files in their
traditional locations if
~/.emacs exist, even if
$XDG_CONFIG_HOME_/emacs also exists. This means that you must delete
or rename any existing
~/.emacs to enable use of
the XDG directory.
~/.emacs.d does not exist, and Emacs has decided to use it
$XDG_CONFIG_HOME_/emacs does not exist), Emacs will create it.
Emacs will never create
Whichever directory Emacs decides to use, it will set user-emacs-directory to point to it.
2.2 Emacs can now be configured using an early init file.
The file is called
early-init.el, in user-emacs-directory. It is
loaded very early in the startup process: before graphical elements
such as the tool bar are initialized, and before the package manager
is initialized. The primary purpose is to allow customizing how the
package system is initialized given that initialization now happens
before loading the regular init file (see below).
We recommend against putting any customizations in this file that
don't need to be set up before initializing installed add-on packages,
because the early init file is read too early into the startup
process, and some important parts of the Emacs session, such as
window-system and other GUI features, are not yet set up, which could
make some customization fail to work.
2.3 Installed packages are now activated before loading the init file.
As a result of this change, it is no longer necessary to call
package-initialize in your init file.
Previously, a call to
package-initialize was automatically inserted
into the init file when Emacs was started. This call can now safely
be removed. Alternatively, if you want to ensure that your init file
is still compatible with earlier versions of Emacs, change it to:
(when (< emacs-major-version 27) (package-initialize))
However, if your init file changes the values of package-load-list or package-user-dir, or sets package-enable-at-startup to nil then it won't work right without some adjustment:
- You can move that code to the early init file (see above), so those settings apply before Emacs tries to activate the packages.
- You can use the new package-quickstart so activation of packages does not need to pay attention to package-load-list or package-user-dir any more.
3.1 Emacs now supports Unicode Standard version 13.0.
3.2 Emacs now supports resizing and rotating images without ImageMagick.
All modern systems support this feature. (On GNU and Unix systems, Cairo drawing or the XRender extension to X11 is required for this to be available; the configure script will test for it and, if found, enable scaling.)
The new function
image-transforms-p can be used to test whether any
given frame supports these capabilities.
4.20 Control+ mouse scroll to change the font size
also works with images. see Emacs: View Image File
3 Changes in Emacs 27.1
3.25 New function
This function returns non-nil if libxml support is both compiled in
and available at run time. Lisp programs should use this function to
detect built-in libxml support, instead of testing for that
indirectly, e.g., by checking that functions like
libxml-parse-html-region return nil.
a parameter that's called DISCARD-COMMENTS, but it really only
discards the top-level comment. Therefore this parameter is now
obsolete, and the new utility function
xml-remove-comments can be
used to remove comments before calling the libxml functions to parse
3.27 A new DOM (the XML/HTML document structure returned by functions
libxml-parse-html-region) traversal function has been added:
dom-search, which takes a DOM and a predicate and returns all nodes
3.30 The German prefix and postfix input methods now support Capital sharp S.
3.31 New input methods
3.32 New input methods
3.33 New input methods for several variants of the Sami language.
The Sami input methods include:
3.34 Japanese environments use UTF-8 by default.
In Japanese environments that do not specify encodings and are not based on MS-Windows, the default encoding is now utf-8 instead of japanese-iso-8bit.
3.41 The user option switch-to-visible-buffer is now obsolete.
Customize switch-to-prev-buffer-skip instead.
3.42 New user option switch-to-prev-buffer-skip.
This user option allows specifying the set of buffers that may be
stringently than the now obsolete switch-to-visible-buffer.
3.35 New function
This function by default returns the value of the corresponding
user option, but can optionally return the equivalent of
from a remote host.
3.36 The function
executable-find supports an optional argument REMOTE.
This triggers searching for the program on the remote host as indicated by default-directory.
flex completion style.
An implementation of popular
flex/fuzzy/scatter completion which
matches strings where the pattern appears as a subsequence. Put
simply, makes "foo" complete to both "barfoo" and "frodo". Add
to completion-styles or completion-category-overrides to use it.
2020-08-15 xahnote update Emacs: Name Completion and also possibly add config to my init and to my init tutorial
3.51 Emacs now optionally displays a fill column indicator.
This is similar to what
fill-column-indicator package provides, but
much faster and compatible with show-trailing-whitespace.
Customize the buffer-local user options display-fill-column-indicator and display-fill-column-indicator-character to activate the indicator.
The indicator is not displayed at all in minibuffer windows and in tooltips, as it is not useful there.
There are 2 new Buffer Local Variable and 1 face to customize this mode, they are described in the manual "(emacs) Display".
2020-08-15 xahnote update my tutorial and also possibly add config to my init and to my init tutorial
(customize -set-variable 'mouse-wheel-scroll -amount '(5 ((shift) . 1) ((control) . nil)))
4.7 New command
4.9 New user option electric-quote-replace-double.
This option controls whether '"' is replaced in
in addition to other quote characters. If non-nil, ASCII double-quote
characters that quote text "like this" are replaced by double
typographic quotes, “like this”, in text modes, and in comments in