aggressive-indent-mode
electric-indent-mode
is enough to keep your code nicely aligned when
all you do is type. However, once you start shifting blocks around,
transposing lines, or slurping and barfing sexps, indentation is bound
to go wrong.
aggressive-indent-mode
is a minor mode that keeps your code always
indented. It reindents after every change, making it more reliable
than electric-indent-mode
.
Demonstration
Instructions
This package is available from Melpa, you may install it by calling
M-x package-install RET aggressive-indent
Then activate it with
(add-hook 'emacs-lisp-mode-hook #'aggressive-indent-mode)
(add-hook 'css-mode-hook #'aggressive-indent-mode)
You can use this hook on any mode you want, aggressive-indent
is not
exclusive to emacs-lisp code. In fact, if you want to turn it on for
every programming mode, you can do something like:
(global-aggressive-indent-mode 1)
(add-to-list 'aggressive-indent-excluded-modes 'html-mode)
Manual Installation
If you don't want to install from Melpa, you can download it manually,
place it in your load-path
along with its dependency cl-lib
(which
you should already have if your emacs-version
is at least 24.3).
Then require it with:
(require 'aggressive-indent)
Customization
The variable aggressive-indent-dont-indent-if
lets you customize
when you don't want indentation to happen.
For instance, if you think it's annoying that lines jump around in
c++-mode
because you haven't typed the ;
yet, you could add the
following clause:
(add-to-list
'aggressive-indent-dont-indent-if
'(and (derived-mode-p 'c++-mode)
(null (string-match "\\([;{}]\\|\\b\\(if\\|for\\|while\\)\\b\\)"
(thing-at-point 'line)))))