hmm interesting, just read another article on Grok yesterday posted by a previous intern of that team.
(sadly it's in Chinese, but it covered the detail of Python Indexer's implementation)
http://blog.sina.com.cn/s/blog_5d90e82f010191rh.html
Thanks for sharing. The first article is really interesting. The author worked 3 months as an intern at Google, and his much under-appreciated works saved Steve Yegge's Grok team that has been struggling for years.
> Today I found that I forgot how to derive the defintion of the Y combinator. I learned it several years ago from an online article, but now the search term “Y combinator” gives me all the news about startups (sigh).
EDIT: Another article on the analyzer by this author, in English. http://yinwang0.wordpress.com/2010/09/12/pysonar/