Subtyping first-class polymorphic components

Abstract

We present a statically typed, class-based object oriented language where classes are first class polymorphic values. A main contribution of this work is the design of a type system that combines first class polymorphic values with structural equirecursive types and admits a subtyping algorithm which is arguably much simpler than existing alternatives. Our development is modular and can be easily instantiated for either a Kernel-Fun or a F≤T style of subtyping discipline. © Springer-Verlag Berlin Heidelberg 2005.