Adding structure to monoids: thus hopefully ending Haskell's string type confusion

Abstract

This paper presents the rationale and design of monoid-subclasses. This Haskell library consists of a collection of type classes that generalize the interface of several common data types, most importantly those used to represent strings. We demonstrate that the mathematical theory behind monoid-subclasses can bring substantial practical benefits to the Haskell library ecosystem by generalizing attoparsec, one of the most popular Haskell parsing libraries.