Undefined is self-explanatory: it does no operation when it is invoked.Keys can be divided into three categories: undefined, prefix key, or complete key. Most Emacs users will never interact with keymaps aside from indirectly assigning keys to them.Įvery buffer and most major and minor modes have a keymap, and that keymap defines what the keys do when key sequences are sent to that buffer. Keymaps are rarely modified directly instead, you modify them through a set of functions that manipulate the data structure for you. What is a Keymap?Ī keymap is an internal data structure used by Emacs to store keys and their associated actions. As you can see, every keypress – even basic ones like typing a character on the screen – has an associated key binding that you can modify or even remove. So if you type C-u 10 f you will see ffffffffff printed on your screen. For instance, the key f is bound to self-insert-command, a special command that repeats the last typed key N times. Layer upon layer - or keymap upon keymap!Įven elementary things like inserting characters – called self-insertion – is amenable to change. Every function in Emacs in turn builds on smaller functions, and so on, right through all the strata of elisp until you reach the C core.Įmacs’s key engine works in much the same way. Almost all of Emacs is written in Emacs Lisp. What makes up a key bind?Įmacs is “self-hosting” and, depending on who you ask, close to achieving sentience. I’ve included a selection of handy templates near the end that you can customize and put in your init file. And the best thing about this guide is that you don’t need to know any elisp to get started! To save you the time of reading all of that, I’ve written a guide that covers what you need to know to bind keys to even complex commands, and a set of templates you can use in your own code. But there’s a reason why the Emacs manual has dedicated 30-odd pages to describing, in great detail, all the subtleties and nuances of how to bind keys. Altering the key bindings in Emacs should not, on the face of it, be a difficult task.

Emacs page down shortcut