Samples of some uses in the browser with an input text area in which you can paste CSS and see what it parses into...
- Less.css Parser Samples https://rawgit.com/bkardell/research/master/less-parser.html
- Daniel Glazman's Parser Samples https://rawgit.com/bkardell/research/master/glazou-parser.html
- Rework/Myth.io Parser Samples https://rawgit.com/bkardell/research/master/rework-parser.html
- Tab Atkin's Parser Samples https://rawgit.com/tabatkins/parse-css/master/example.html
Projects I don't have working samples for but have some kind of documentation for what they parse to
- Gonzales/CSSP Parser (ES/Node) https://github.com/css/gonzales/blob/master/doc/AST.CSSP.en.md#11-cssp-ast
- Tiny CSS Parser (Python) https://pythonhosted.org/tinycss2/#ast-nodes
- Crass Parser (Ruby) https://github.com/rgrove/crass/#examples