GNU Emacs NEWS -- history of user-visible changes. Copyright (C) 2017-2018 Free Software Foundation, Inc. See the end of the file for license conditions. Please send Emacs bug reports to bug-gnu-emacs@gnu.org. If possible, use M-x report-emacs-bug. This file is about changes in Emacs version 27. See file HISTORY for a list of GNU Emacs versions and release dates. See files NEWS.26, NEWS.25, ..., 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, * Installation Changes in Emacs 27.1 ** The new configure option '--with-json' adds support for JSON using the Jansson library. It is on by default; use 'configure --with-json=no' to build without Jansson support. The new JSON functions 'json-serialize', 'json-insert', 'json-parse-string', and 'json-parse-buffer' are typically much faster than their Lisp counterparts from json.el. ** Emacs has been ported to the -fcheck-pointer-bounds option of GCC. This causes Emacs to check bounds of some arrays addressed by its internal pointers, which can be helpful when debugging the Emacs interpreter or modules that it uses. If your platform supports it you can enable it when configuring, e.g., './configure CFLAGS="-g3 -O2 -mmpx -fcheck-pointer-bounds"' on Intel MPX platforms. ** Emacs now normally uses a C pointer type instead of a C integer type to implement Lisp_Object, which is the fundamental machine word type internal to the Emacs Lisp interpreter. This change aims to catch typos and support -fcheck-pointer-bounds. The 'configure' option --enable-check-lisp-object-type is therefore no longer as useful and so is no longer enabled by default in developer builds, to reduce differences between developer and production builds. * Startup Changes in Emacs 27.1 * Changes in Emacs 27.1 --- ** The new option 'tooltip-resize-echo-area' avoids truncating tooltip text on GUI frames when tooltips are displayed in the echo area. Instead, it resizes the echo area as needed to accommodate the full tool-tip text. --- ** Show modeline tooltips only if the corresponding action applies. Customize the option 'mode-line-default-help-echo' to restore the old behavior where the tooltip text is also shown when the corresponding action does not apply. +++ ** New function 'logcount' calculates an integer's Hamming weight. +++ ** New function 'libxml-available-p'. 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. +++ ** New function 'fill-polish-nobreak-p', to be used in 'fill-nobreak-predicate'. It blocks line breaking after a one-letter word, also in the case when this word is preceded by a non-space, but non-alphanumeric character. +++ ** The limit on repetitions in regexps has been raised to 2^16-1. It was previously limited to 2^15-1. For example, the following regular expression was previously invalid, but is now accepted: x\{32768\} ** 'print' and related functions now escape more chars in symbols. They now escape any symbol character that is outside the documented set of characters that do not need escaping. For example, (print (intern "n\u0456l")) now outputs "n\іl" instead of "nіl", as a hint to the reader that the "і" is not the usual U+0069 LATIN SMALL LETTER I, but is instead U+0456 CYRILLIC SMALL LETTER BYELORUSSIAN-UKRAINIAN I. * Editing Changes in Emacs 27.1 --- ** New variable 'x-wait-for-event-timeout'. This controls how long Emacs will wait for updates to the graphical state to take effect (making a frame visible, for example). +++ ** New user option 'electric-quote-replace-double'. This option controls whether '"' is replaced in 'electric-quote-mode', 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 non-text modes. * Changes in Specialized Modes and Packages in Emacs 27.1 ** Ecomplete *** The ecomplete sorting has changed to a decay-based algorithm. This can be controlled by the new `ecomplete-sort-predicate' variable. *** The 'ecompleterc' file is now placed in ~/.emacs.d/ecompleterc by default Of course it will still find it if you have it in ~/.ecompleterc ** Smtpmail Authentication mechanisms can be added via external packages, by defining new cl-defmethod of smtpmail-try-auth-method. ** Footnote-mode *** Support Hebrew-style footnotes *** Footnote text lines are now aligned. Can be controlled via the new variable 'footnote-align-to-fn-text'. ** CSS mode --- *** A new command 'css-cycle-color-format' for cycling between color formats (e.g. "black" => "#000000" => "rgb(0, 0, 0)") has been added, bound to 'C-c C-f'. ** Dired +++ *** The new user option 'dired-create-destination-dirs' controls whether 'dired-do-copy' and 'dired-rename-file' should create non-existent directories in the destination. ** Ibuffer --- *** New filter ibuffer-filter-by-process; bound to '/E'. ** Edebug +++ *** The runtime behavior of Edebug's instrumentation can be changed using the new variables 'edebug-behavior-alist', 'edebug-after-instrumentation-function' and 'edebug-new-definition-function'. Edebug's behavior can be changed globally or for individual definitions. ** Enhanced xterm support *** New variable 'xterm-set-window-title' controls whether Emacs sets the XTerm window title. This feature is experimental and is disabled by default. ** Gamegrid ** ERT +++ *** New variable 'ert-quiet' allows to make ERT output in batch mode less verbose by removing non-essential information. --- *** Gamegrid now determines its default glyph size based on display dimensions, instead of always using 16 pixels. As a result, Tetris, Snake and Pong are more playable on HiDPI displays. ** Filecache --- *** Completing filenames in the minibuffer via 'C-TAB' now uses the styles as configured by the variable 'completion-styles'. ** New macros 'thunk-let' and 'thunk-let*'. These macros are analogue to 'let' and 'let*', but create bindings that are evaluated lazily. ** Eshell --- *** Expansion of history event designators is disabled by default. To restore the old behavior, use (add-hook 'eshell-expand-input-functions #'eshell-expand-history-references) ** Tramp +++ *** New connection method "owncloud", which allows to access OwnCloud or NextCloud hosted files and directories. * New Modes and Packages in Emacs 27.1 +++ ** Emacs can now visit files in archives as if they were directories. This feature uses Tramp and works only on systems which support GVFS, i.e. GNU/Linux, roughly spoken. See the chapter "(tramp) Archive file names" in the Tramp manual for full documentation of these facilities. * Incompatible Lisp Changes in Emacs 27.1 ** The FILENAME argument to 'file-name-base' is now mandatory and no longer defaults to 'buffer-file-name'. --- ** The function 'eldoc-message' now accepts a single argument. Programs that called it with multiple arguments before should pass them through 'format' first. Even that is discouraged: for ElDoc support, you should set 'eldoc-documentation-function' instead of calling 'eldoc-message' directly. ** Old-style backquotes now generate an error. They have been generating warnings for a decade. To interpret old-style backquotes as new-style, bind the new variable 'force-new-style-backquotes' to t. ** Defining a Common Lisp structure using 'cl-defstruct' or 'cl-struct-define' whose name clashes with a builtin type (e.g., 'integer' or 'hash-table') now signals an error. * Lisp Changes in Emacs 27.1 +++ ** New function assoc-delete-all. ** 'print-quoted' now defaults to t, so if you want to see (quote x) instead of 'x you will have to bind it to nil where applicable. ** To avoid confusion caused by "smart quotes", the reader signals an error when reading Lisp symbols which begin with one of the following quotation characters: ‘’‛“”‟〞＂＇. A symbol beginning with such a character can be written by escaping the quotation character with a backslash. For example: (read "‘smart") => (invalid-read-syntax "strange quote" "‘") (read "\\‘smart") == (intern "‘smart") ** Internal parsing commands now use syntax-ppss and disregard open-paren-in-column-0-is-defun-start. This affects mostly things like forward-comment, scan-sexps, and forward-sexp when parsing backward. The new variable 'comment-use-syntax-ppss' can be set to nil to recover the old behavior if needed. --- ** The 'file-system-info' function is now available on all platforms. instead of just Microsoft platforms. This fixes a 'get-free-disk-space' bug on OS X 10.8 and later (Bug#28639). --- ** The function 'get-free-disk-space' returns now a non-nil value for remote systems, which support this check. +++ ** The function 'make-string' accepts an additional optional argument. If the optional third argument is non-nil, 'make-string' will produce a multibyte string even if its second argument is an ASCII character. ** New JSON parsing and serialization functions 'json-serialize', 'json-insert', 'json-parse-string', and 'json-parse-buffer'. These are implemented in C using the Jansson library. --- ** The new function `mailcap-file-name-to-mime-type' has been added. It's a simple convenience function for looking up MIME types based on file name extensions. +++ ** The new function 'read-answer' accepts either long or short answers depending on the new customizable variable 'read-answer-short'. ** The function 'load' now behaves correctly when loading modules. Specifically, it puts the module name into 'load-history', prints loading messages if requested, and protects against recursive loads. * Changes in Emacs 27.1 on Non-Free Operating Systems --- ** Battery status is now supported in all Cygwin builds. Previously it was supported only in the Cygwin-w32 build. ---------------------------------------------------------------------- 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 . Local variables: coding: utf-8 mode: outline paragraph-separate: "[ ]*$" end: