This is a talk I gave to the PDXPython user group on 2014-04-23. It covers the concepts involved in building parsers for domain-specific languages. If you want to follow along with the slides, they're shared as a Google Docs presentation.
I'm sorry about the way the video cuts out in the midst of the Q&A. My camera apparently only records 25 minutes of video at one go. I'm told this is more about tariff categories than technological limits, which is frustrating.
If you're interested in learning more about the parser-generator libraries available in python, I prepared some supplemental material that you might find interesting.