Haskell Design Patterns

Summary

This chapter started with a high-level discussion of the patterns of generic programming.

In the remainder of the chapter, we explored three variations of datatype-generic programming, that is, three techniques of parameterizing generic functions by data shape rather than by contents.

Underlying these varied approaches were some common threads:

• To achieve generic functions, we need "generic data" (in the form of a universal type representation)
• Datatype-generic programming mixes well with more rudimentary meta-programming (for example, when we autoderived Typeable instances in the process of writing generic functions)
• using "shallow recursion" on a lower layer allows us to express all manner of recursive functions on the higher level

Generic ...