Deriving class instances for datatypes

We provide a framework for registering automatic methods to derive class instances of datatypes, as it is possible using Haskell’s “deriving Ord, Show, . . . ” feature. We further implemented such automatic methods to derive (linear) orders or hash-functions which are required in the Isabelle Collection Framework [1] and the Container Framework [2]. Moreover, for the tactic of Huffman and Krauss to show that a datatype is countable, we implemented a wrapper so that this tactic becomes accessible in our framework. Our formalization was performed as part of the IsaFoR/CeTA project [3]. With our new tactic we could completely remove tedious proofs for linear orders of two datatypes.