Dominik Charousset: Towards Type-safe Composition of Actors

Available actor systems either use dynamic typing or object-oriented abstractions. The former burdens the programmers with correctness checking, while the latter tightly couples callers and callees. Further, object-oriented software designs lack powerful facilities for behavior reuse and composition. Combining services offered by two or more actors or building message pipelines takes place outside of the type system. Custom code for interconnecting serial or parallel communication patterns is repetitive and written sequentially. In CAF, we want to follow the functional programming (FP) example, where functions are first-class citizens that can be combined into new functions with ease, thus enabling a declarative, clean, and concise programming style. By treating actor interfaces as first-class citizen, we want to enable compositions in a similar way FP does. Instead of sequentially describing messaging sequences, programmer should express communication patterns at a high level of abstraction. Naturally, the result of such a composition is an actor itself, has its own messaging interface, and can be composed further.

In this talk, we give insights into the design of the type system of CAF and discuss ongoing work on type-safe actor compositions based on this type system.

Slides