@John: In a way, yes. Basically, I have a bunch of classes that represent the various ‘bits’ that make up a CSS file: Selectors, Properties, and what I’m calling “Parts” (comma separated values for properties). So the way my system works is that it basically parses the CSS file into a bunch of these classes — selectors have properties, and properties have parts. This means that, unlike YUI, I’m not looking at the ENTIRE file when I’m minifying — rather, I’m dealing with it on a much smaller scale. Regular expressions are still used within the parts themselves, and I also do some basic pre-formatting before I actually parse the file, like removing comments and tabs, newlines and carriage returns.