fillcode

[![gnu.jpg](/space/gnu.jpg)](/space/fillcode)

For the impatient:  
  [Download fillcode.el 0.7.1](/space/fillcode.el)  
  [Download fillcode.tar.gz](/space/fillcode.tar.gz) (includes
[elunit](http://www.lostway.org/~tko/elisp/elunit/) unit tests)  

_Updated 2007/08/24._

Fillcode is an [Emacs](http://gnu.org/software/emacs/) minor mode that fills, or
wraps, some parts of source code. It's best described by example. Fillcode fills
this:

    public static void foo(int i, float f, String s) {

to this:

    public static void foo(int i, float f,
                           String s) {

The motivation is described in my original [call for filling
code](/space/filling code in emacs).

Fillcode can fill any parenthesized expression, including function prototypes,
function calls, and conditional expressions. It only breaks lines at commas and
binary operators, and correctly preserves embedded comments and string literals.
It also normalizes existing whitespace and line breaks.

Fillcode is supported in [Emacs](http://gnu.org/software/emacs/) 21 and 22
and [XEmacs](http://xemacs.org/), and works with most programming language
major modes, including Java, C, C++, Objective C, Perl, Python, shell, and SQL
modes.

Fillcode fills when `fill-paragraph` (usually `M-q`) is called. If the major
mode itself attempts to fill - inside a comment, for example - fillcode
graciously steps back and does nothing.

If you provide a prefix argument, e.g. `C-u M-q`, fillcode will automatically
insert a line break at the first open parenthesis or other appropriate point.
This can be useful when the first open parenthesis is near `fill-column`.

You can load fillcode automatically by copying
[fillcode.el](/space/fillcode.el) into `/usr/share/emacs/site-lisp/`,
or any other directory in Emacs' `load-path`. Then, add this to your .emacs
file:

    (require 'fillcode)

`M-x fillcode-mode` toggles fillcode on and off in the current buffer. To turn
it on automatically whenever you open source code, add these lines to your
.emacs file.

    (add-hook 'c-mode-common-hook 'fillcode-mode)
    (add-hook 'perl-mode-hook 'fillcode-mode)
    (add-hook 'python-mode-hook 'fillcode-mode)
    (add-hook 'shell-script-mode-hook 'fillcode-mode)
    (add-hook 'sql-mode-hook 'fillcode-mode)

Fillcode is a work in progress. Here's a list of issues:

  * It depends on the major mode's indentation and parsing engines. These are
less than perfect in some major modes.
  * It's not entirely compatible with
[auto-fill-mode](http://www.gnu.org/software/emacs/manual/emacs.html#Auto%20Fill)
or [filladapt-mode](http://www.wonderworks.com/#filladapt)...yet.
  * It doesn't break lines at `=`, the assignment operator.

Fillcode is copyright 2005-2007 [Ryan Barrett](http://snarfed.org/), and
is distributed under the [GPL](http://www.gnu.org/licenses/gpl.html).