Generic Programming on the Structure of Homogeneously Nested Arrays

In this paper we propose a new means to model and operate on nested arrays that allows for a high level of abstraction without introducing a performance penalty. We achieve this by using a nesting structure on array types which allows us to shift the nesting information of arrays from the runtime representation level to the type system level. This information can then be exploited for generic function definitions on the nesting structure of arrays which, as we show, neatly integrates with subtyping based function overloading. Finally, we demonstrate for an example how nested arrays and generic function definitions can be fully stripped out using existing optimisation techniques.