Scalable Component Abstractions

Abstract. We identify three programming language abstractions for the construction of re-usable components: abstract type members, explicit selftypes and symmetric mixin composition. Together, these abstractions enable us to transform an arbitrary assembly of static program parts with hard references between them into a system of re-usable components. The transformation maintains the structure of the original system. We demonstrate this approach in two case studies, a subject/observer framework and a compiler front-end.