Comparing approaches to generic programming in Haskell

The last decade has seen a number of approaches to data- type-generic programming: PolyP, Functorial ML, `Scrap Your Boiler- plate', Generic Haskell, `Generics for the Masses', etc. The approaches vary in sophistication and target audience: some propose full-blown pro- gramming languages, some suggest libraries, some can be seen as cat- egorical programming methods. In these lecture notes we compare the various approaches to datatype-generic programming in Haskell. We in- troduce each approach by means of example, and we evaluate it along different dimensions (expressivity, ease of use, etc)