Prepro

This module currently does the following:

• Picks all files from the drupal stylesheets/javascript list and offers to preprocess them (based on filetype) to registered preprocessors (such as Sassy or Coffeescript-PHP)
• Caches the files on production servers, with the option to recompile on mtime change
• Wraps the settings stuff neatly into one page.
• Makes it easy to move between multiple compilers if required (eg Sassy and a Ruby parser link for SASS/SCSS)

How it works

The module gets access to the list of JS/CSS files added, and picks files from the array based on file syntax (eg .sass) and offers them to registered preprocessor modules (such as Sassy). The output file gets cached and is available on future page requests and thereby doesn't cause any additional performance loss. Drupal Core CSS/JS aggregation still works as expected.

Implementing modules:

• Sassy: SASS/SCSS => CSS
• Coffeescript-PHP: Coffeescript => Javascript