As a continuation of our previous topic of indenting a buffer or a region, this time around I’ll show you how to indent a single defun1. So here’s the magic bit of code:

(defun er-indent-defun ()
  "Indent the current defun."
    (indent-region (region-beginning) (region-end))))

This function should work in all properly written major programming modes.

Why would you want to use er-indent-defun instead of er-indent-region-or-buffer? Pretty simple - indenting huge buffers can take quite a while and you might want to save a bit of time if you know that a buffer’s indentation is correct pretty much everywhere else.

I’d suggest binding the command to C-M-z (since it kind of resembles the keybinding for function evaluation in major modes for dynamic programming languages C-M-x).

(global-set-key (kbd "C-M-z") #'er-indent-defun)

Special thanks to Fuco 2 who suggested that command in the previous post.

er-indent-defun is available in crux (but with a crux- prefix).

  1. Emacs slang/terminology for a function/procedure/method definition, originating from the way functions are defined in Emacs Lisp and a few other Lisp dialects. 

  2. Who I assume is Matus Goljer, of smartparens fame.