I'm pretty sure it is Turning-Complete, and it's something they were heralding a few weeks back. Their goal is to be a programming language.<p>Wikipedia: <i>After its initial versions, Nathan Weizenbaum and Chris Eppstein have continued to extend Sass with SassScript, a Turing Complete scripting language used in Sass files.</i><p>and <a href="http://wiseheartdesign.com/articles/2010/01/18/the-demise-of-css-why-sass-and-languages-like-it-will-triumph/" rel="nofollow">http://wiseheartdesign.com/articles/2010/01/18/the-demise-of...</a>