A Generic Programming Extension for Clean

1 Introduction The standard library of a programming language normally defines functions like equality, pretty printers and parsers for standard data types. For each new user defined data type the programmer often has to provide similar functions for that data type. This is a monotone, error-prone and boring work that can take lots of time. Moreover, when such a data type is changed, the functions for that data type have to be changed as well. Generic programming enables the user to define a function once and specialize it to the data types he or she needs. The idea is to define the functions by induction on the structure of types. This idea is based on the fact that a data type in many functional programming languages, including Clean, can be represented as a sum of products of types