We're moving towards writing all our styles using Sass. Since we have a lot of styles already in place in different themes and plugins this means a lot of copy-rewrite-test. Compiling and deploying a theme each time you write a new rule to test it is taking a lot of time which was why we tried to get a quicker roundtrip.
This is a write-up of how we got Liferay Portal to work with an external Sass/Compass compiler, giving us auto deployment of a Theme. Our enviroment is OSX but any *NIX should work. Windows is largely dependent on a proper shell.
First out: Liferay/portal-developer.properties
To bypass caching, thus enabling reloads from disk, we have to include the properties listed in the portal-developer.properties. Either by including this file or by copying some (or all) of the properties into your properties-ext.properties.
Second: Install a Sass/Compass compiler
Install a compiler that automatically compiles your Sass/Compass code whenever a change occurs.
Third: Configure Compass and tell it to watch the theme directory
Compass watches a directory for changes and automatically compiles the .scss files. The output directory should be your plugin installation directory. That is, /liferay-portal-6.1.30-ee-ga3/tomcat-7.0.40/webapps/my-theme/css.
Generate a configuration file in your plugin root:
http_path = "/"
css_path = "/.../liferay-portal-6.1.30-ee-ga3/tomcat-7.0.40/webapps/UU-universal-theme/css"
sass_dir = "src/main/webapp/css"
Run compass and tell it to watch this directory.
NOTE! The Compass compiler only reacts to files named .scss or .sass!
Liferay on the other hand only compiles files that end with .css! This is a big issue for developers without a proper shell. In my case I created a link with the ln command. I would really like to see a way for Liferay to process the .scss files in the compile stage in a future release and not just .css.
In my case, whenever a change is detected in the sass_common.scss-file (or any file it imports) a compiled version will be installed in my tomcat/webapps/plugin/css directory. Since Liferay is running with developer settings this change will be loaded at the next browser reload.
With this setup we're able to quickly add new rules from an old theme, rewrite them into Sass-style and easily verify that they are correct. It doesn't sound like much but this literally saves us hours per week!