Idris, a general-purpose dependently typed programming language: Design and implementation

Many components of a dependently-typed programming language are by now well understood, for example the underlying type theory, type checking, unification and evaluation. How to combine these components into a realistic and usable high-level language is, however, folklore, discovered anew by successive language implementators. In this paper, I describe the implementation of IDRIS, a new dependently-typed functional programming language. IDRIS is intended to be a general purpose programming language and as such provides high-level concepts such as implicit syntax, type classes and do notation. I describe the high-level language and the underlying type theory, and present a tactic-based method for elaborating concrete high-level syntax with implicit arguments and type classes into a fully explicit type theory. Furthermore, I show how this method facilitates the implementation of new high-level language constructs.