1. Frank Fischer
  2. evil

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An extensible vi layer for Emacs

Evil is an extensible vi layer for Emacs. It emulates the main features of Vim, and provides facilities for writing custom extensions. Also see our page on EmacsWiki.

Build Status

Download

Evil lives in a Mercurial repository. To download Evil, do

hg clone https://bitbucket.org/lyro/evil

Alternatively, download a zip of default (extract with unzip lyro-evil-*.zip).

Install

Move Evil to ~/.emacs.d/evil. Then add the following lines to ~/.emacs:

(add-to-list 'load-path "~/.emacs.d/evil")
(require 'evil)
(evil-mode 1)

Evil requires undo-tree.el in the load-path for linear undo and undo branches.

Documentation

A brief PDF manual is available.

Mailing list

Evil is discussed at the gmane.emacs.vim-emulation mailing list.

IRC

Visit us on irc.freenode.net #evil-mode

Wiki

Development goals and discussions are found at the Development page. The wiki is open to anyone with a Bitbucket account.

Evil also has a page at EmacsWiki.

Bug reports

Bug reports and feature requests should be made on the Issue Tracker here on bitbucket.org.

Before sending a bug report, please take note of the following comments.

  1. Please provide a full description of the configuration of your system. This includes
    • Emacs version,
    • Evil version (e.g., the hash in the git repository),
    • Whether you use Emacs/Evil in X mode or in terminal mode,
    • Whether you use Emacs/Evil in terminal mode with some terminal multiplexer like tmux or screen (and see below).
  2. Test the bug in a clean Emacs environment without any additional packages loaded (besides Evil itself). You can easily get such an environment by executing either make emacs (for X) or make terminal (for terminal mode) in Evil's source directory. If your bug is related to some other packages, try to load only this package directly from the clean environment.
  3. If you've just updated your Evil from the repository, do not forget to recompile Evil by executing make in Evil's source directory.
  4. If possible, try to give a minimal example how to reproduce the error starting from a fresh Emacs. The minimal example could be some buffer content and a sequence of key-strokes that show up the error.
  5. If the bug you want to report is related to the behavior of some commands or motions, please note the following. One goal of Evil is to get a behavior as close to Vim as possible unless there is a good reason not to do so. The reason is that many users come from Vim or use both, Vim and Evil, and we want to keep the number of annoying differences between both as small as possible, especially in common commands. In case you get an unexpected behavior, please
    • compare the behavior with plain Vim (i.e., without any customization), if there's a difference please file the bug with a description of this difference (and possibly a reference to Vim's documentation)
    • if you realize that both, Vim and Evil, behave the same but you want a different behavior, you may make a feature request for some customization option (but the default behavior will probably not be changed in favor for Vim compatibility). Evil already contains several customization options and sometimes the desired changes can be achieved as easily as redefining some key-bindings.

FAQ

Problems with the Escape key in terminal mode.

A common problem when using Evil in terminal mode is a certain delay after pressing the Escape key. Even more, when pressing the Escape key followed quickly by another key the command is recognized as M-<key> instead of two separate command ESC followed by <key>. In fact, it is perfectly valid to simulate M-<key> by pressing ESC <key> quickly (but see below).

The reason for this is that in terminal mode a key sequence involving the Meta-key (or Alt-key) always generates a so called "escape sequence", i.e., a sequence of two events sent to Emacs, the first being ESC the second the key pressed simultaneously. The problem is that pressing the Escape-key itself also generates the ESC event. Thus, if Emacs (and therefore Evil) receives an ESC event there is no way to tell whether the Escape key has been pressed (and no further event will arrive) or a M-<key> combination has been pressed (and the <key> event will arrive soon). In order to distinguish both situations Evil does the following. After receiving an ESC event Evil waits for a short time period (specified by the variable evil-esc-delay which defaults to 0.01 seconds) for another event. If no other event arrives Evil assumes that the plain Escape key has been pressed, otherwise it assumes a M-<key> combination has been pressed and combines the ESC event with the second one. Because a M-<key> sequence usually generates both events in very quick succession, 0.01 seconds are usually enough and the delay is hardly noticeable by the user.

But if you use a terminal multiplexer like tmux or screen the situation may be worse. Those multiplexers have exactly the same problem recognizing M-<key> sequences and often introduce their own delay for the ESC key. There is no way for evil to influence this delay. In order to reduce it you must reconfigure your terminal multiplexer.

Note that this problem should not arise when using Evil in X mode. The reason is that in this case the Escape key itself generates a different command, namely 'escape (a symbol) and hence Evil can distinguish whether the Escape key or a M-<key> combination has been pressed. But this also implies that pressing ESC followed by <key> cannot be used to simulate M-<key> in X mode!

Underscore "_" is not a word character

An underscore "_" is a word character in Vim. This means that word-motions like w skip over underlines in a sequence of letters as if it was a letter itself. In contrast, in Evil the underscore is often a non-word character like operators, e.g. +.

The reason is that Evil uses Emacs' definition of a word and this definition does often not include the underscore. In Emacs word characters are determined by the syntax-class of the buffer. The syntax-class usually depends on the major-mode of this buffer. This has the advantage that the definition of a "word" may be adapted to the particular type of document being edited. Evil uses Emacs' definition and does not simply use Vim's definition in order to be consistent with other Emacs functions. For example, word characters are exactly those characters that are matched by the regular expression character class [:word:].

If you want the underscore to be recognised as word character, you can modify its entry in the syntax-table:

(modify-syntax-entry ?_ "w")

This gives the underscore the word syntax-class. You can use a mode-hook to modify the syntax-table in all buffers of some mode, e.g.:

(add-hook 'c-mode-common-hook #'(lambda () (modify-syntax-entry ?_ "w")))

This gives the underscore the word syntax-class in all C-like buffers.

Updated