LambdaConf 2015 - A Practical Introduction to Haskell GADTs Richard Eisenberg

A burgeoning Haskeller soon discovers that proper use of descriptive types helps to capture real-world ideas, catches errors, aids in refactoring, speeds development, and indeed makes programming more fun. But, once that Haskeller has drunk the well-typed Kool-Aid, where to go from there? The answer: even more types! A Generalized Algebraic Datatype (GADT), at its core, allows a compiler to make different assumptions about types within different branches of a pattern match. Leveraging this power allows a pr