I'm embarrassed by how long I've let this program go without a single comment, let alone some proper documentation. We'll add documentation in 3 layers: external (README.markdown), top-level (Haddock), and narrative (comments). By the end, our redo implementation will look like a proper program, ready for use. Haddock: http://www.haskell.org/haddock/ Links from this video: http://jekor.com/article/what-gets-documented-gets-improved http://en.wikipedia.org/wiki/TeX Follow along on GitHub at https://github.com/jekor/redo Notices and updates on Twitter at @jekor https://twitter.com/jekor All Haskell from Scratch videos:    • Haskell from Scratch