Procedure calls are the assembly language of software interconnection: Connectors deserve first-class status

Software designers compose systems from components written in some programming language. They regularly describe systems using abstract patterns and sophisticated relations among components. However, the configuration tools at their disposal restrict them to composition mechanisms directly supported by the programming language. To remedy this lack of expressiveness, we must elevate the relations among components to first-class entities of the system, entitled to their own specifications and abstractions.