Lisp editing
Tips on how to edit lisp code efficiently.
Built-in modes
With evil-mode
Lispy, a vi-like paredit
Lispy makes it easier to edit lisp code when we use evil-mode.
It offers very short keybindings. For example, going to the next parenthesis is bound to j, s moves down the current expression, e to eval and xe to edebug, xd turns current lambda into a defun, etc
The price to pay is that the bindings are only active when:
- the point is before an open paren: (, [ or {
- the point is after a close paren: ), ] or }
- the region is active
Installation
Via MELPA:
M-x package-install RET lispy RET
(you might want to M-x package-refresh-content beforehand).
Tips and tricks
Integrate expand-region
expand-region is handy because it permits to expand the region by semantic units. For example, in the string (hello "foo | oo"), calling it the first will select "foo", then "\"foo\"", then "hello \"foooo\"", then the whole expression with the parenthesis.
The following snippet binds "v" to expand-region when the region is active.
;; https://emacs.stackexchange.com/questions/16614/make-evil-mode-more-lisp-friendly
(defun evil-visual-char-or-expand-region ()
(interactive)
(if (region-active-p)
(call-interactively 'er/expand-region)
(evil-visual-char)))
(define-key evil-normal-state-map "v" 'evil-visual-char-or-expand-region)
(define-key evil-visual-state-map "v" 'evil-visual-char-or-expand-region)
(define-key evil-visual-state-map [escape] 'evil-visual-char)
Make "dd" delete an expression
di( or da( isn't specific to lisp, they are just evil text objects.
See also
The emacs lisp page.