Emacs Lisp
Emacs Lisp is a dialect of the Lisp programming language used by GNU Emacs. Most of the editing functionality built into Emacs is written in Emacs Lisp, with the remainder being written in C (as is the Lisp interpreter itself). Users of Emacs commonly write Emacs Lisp code to customize and extend Emacs.
Emacs Lisp is also commonly referred to as "elisp" or "Elisp". Files containing Emacs Lisp code use the .el filename suffix; when byte-compiled, the same filename prefix is used but with the .elc filename suffix.
Basic setup
You can customize the way Emacs edits and displays this and all other lisp languages with M-x customize-group RET lisp RET.
Helpful keybindings
- <span title="Try `C-h k M-<tab>' for more information." style="border-bottom
- 1px dotted">[M-<tab>]
- Complete at point
- [C-M-x]
- Evaluate the
defunat point
Common customizations
Outlining
For Org-style outlining, add the following snippet to your Emacs configuration file.
;; Turn on outline minor mode
(add-hook 'emacs-lisp-mode-hook 'outline-minor-mode)
;; Add key bindings for Org-style outline cycling
(add-hook 'outline-minor-mode-hook
(lambda ()
(define-key outline-minor-mode-map [(control tab)] 'org-cycle)
(define-key outline-minor-mode-map [(shift tab)] 'org-global-cycle)))
Now visit any elisp file (say M-x find-library RET outline) and keep pressing [S-TAB] and see what happens. Experiment similarly with [C-TAB].
Indentation
Add the following snippet to your Emacs configuration file, so that you don't have to indent deliberately. See M-x reindent-then-newline-and-indent.
(add-hook 'emacs-lisp-mode-hook
(lambda nil
(local-set-key [(return)] 'reindent-then-newline-and-indent)))
Always keep parenthesis balanced
See Skeleton#Keep some chars always balanced
Scope
By default elisp uses dynamic scope. Since Emacs 24 lexical scope has been added.
To use lexical binding, an Emacs-lisp source file must set a file-variable lexical-binding to t in the file header, e.g., by using a first line like:
;;; -*- lexical-binding: t -*-