First of all great work, great tokenizer, really funny grammar...
I have added support for links and refs (see also my project https://github.com/dotmaster/jsonToYaml for the oposite direction). So now we can serialize Objects to YAML and back, maintaining the complete structure, which IMHO is really cool ;)))
I created some test cases and everything seems to work as expected.
Let me know your comments.
added support for links and refs
removed useless lines
I like the additions of &refs and *links!
You can add https://gist.github.com/779245 as an additional passing test case,
or even better the YAML spec Full Length Example http://yaml.org/spec/1.2/spec.html#id2761803
as a (currently) failing test case for future js-yaml feature development.