This came up in the thread about the book @joshuacc is writing (see the Prose for Programmers thread here). I wrote a tool for my book, Effective Python, which has a lot of similarities to Donald Knuth’s Literate programming. Someone requested the tool on the thread with joshuacc. I’ve gotten a few other requests for it from new authors, too. So I finally open sourced the thing! Feedback, patches, constructive criticism welcome.