Learning one real text editor is a life investment. So you’d like that investment to be really worth it and applicable to everything you do. This article is for Mac users for whom the text editor choice fell on Emacs.

Assumptions

• You’re on Mac OS X 10.9 Mavericks
• You like to have your left alt key configured as Meta

Out of the box: Basic movement

Shells usually come with keybindings for Emacs (and vi) so cursor movement, copy, paste, etc. work without any effort. Meta is bound to Esc by default, you should change that in your terminal app[1] to enable things like kill-word or backward-kill-word.

The basic text panes (as in TextEdit, Mail, etc.) of Mac OS X also suport some Emacs keybindings¹ without custom configuration but keybindings involving alt- (alt-f, alt-b, etc.) will produce glyphs instead. This is useful if you’re often using characters that are not available in your basic keyboard layout but not if you’re trying to get ubiquitous Emacs bliss.

The magic of DefaultKeyBinding.dict

Mac OS X provides a mechanism to override default key bindings system wide on a per-user basis. The file is called DefaultKeyBinding.dict and has to live in Library/KeyBindings below your home directory. The format is described here.

This is my basic version of the file, also found on GitHub. It enables deletions with alt-, movements with ctrl- and alt-, undo and word completion with familiar Emacs key bindings.

/* emacsify Mac OS X, see http://youtrack.jetbrains.com/issue/IDEA-17392 */
{
 /* Kill alt-bindings that keep me from using emacs-style operations */
  "~f" = "moveWordForward:";
  "~b" = "moveWordBackward:";
  "~d" = "deleteWordForward:";

 /* add some missing emacs features */
  "~<" = "moveToBeginningOfDocument:";
  "~>" = "moveToEndOfDocument:";
  "~v" = "pageUp:";
  "^v" = "pageDown:";
  "^/" = "undo:";
  "~/" = "complete:";
  "^j" = "insertNewline:";
}

Fixing IntelliJ IDEA

My main motivation for this key binding hack was that I couldn’t get alt-f and alt-b to work with IntelliJ IDEA’s Emacs key bindings. Jetbrains provides a reasonable² Emacs keymap but most bindings involving alt- do not work on a Mac (which lead to a bunch of unfixed issues in their tracker; one of which contains the solution given here).

The use of DefaultKeyBinding.dict fixes IDEA’s behaviour! You might have to extend the alt-bindings further if you want to use more of them in IntelliJ but be aware that this disables the glyphs produced by the respective keys.

Bonus: Mark-point everywhere!

As suggested in IDEA’s YouTrack issue you can even enable Emacs’ mark-point behaviour for cutting and pasting of regions system-wide.

Footnotes