Re:All i have to say is: (Score 2, Interesting)

Another fun one is the REX shallow XML parser algorithm that's been around for some time. Check out http://www.cs.sfu.ca/~cameron/REX.html and scroll to appendix A for a Perl implementation. I recently had to reverse-engineer this approach and write a stack-based parser to run in an environment where Perl's :?$foo construct was broken. Much fun...