是C#写的
原文地址：http://www.codeproject.com/KB/recipes/CSSParser.aspx
A Quick Note on the Downloads
If you have previously seen this article, the v2 downloads contain a complete rewrite of the parser, which required a completely new model. The v1 downloads are provided for those who are dependant on the previous model (the v1 parser was last updated on 11/25/2008). If this is the first time you are seeing this article, use the v2 downloads that this article now describes.
Introduction
My motivation for this project came from an interest in importing color information. I needed to import from CSS files into an application I was working on for managing color sets of Web and other projects. However, on import I didn't just want the color, but the elements it is associated with as well. So, Regex was out. This left me with the need for a full CSS parser that could be used for lots of things, not just my nutty little color manager. So all I need is a grammar that describes the structure of the CSS 2.1 language. Unfortunately, the only grammar definition for CSS I could find was the W3C grammar written for Lex/Yacc. Due to my inexperience with Yacc, and my apathy towards learning it, I had to write a grammar from scratch. Ultimately, I chose to write a Coco/R attributed grammar. With version 2, the parser is now based on the 2.1 spec, with support for some 3.0 elements. Because it now handles "@" rules generically, most browser specific extensions should also now be supported. The object model was changed completely for the 2nd version of this parser. Hopefully this will cover most uses you may have for a CSS parser. If you have further requirements, it may be a good base to work from.
Parsers
I don't claim to be an expert in the fine arts of deterministic finite automaton. Having said that, the basic concept of parsing text, interpreting the contents and building some useful result from it can be understood without a deep understanding of the nitty gritty of how it is accomplished. When working with a parser generator like Coco, it's important to understand the basic concepts.