Mixing Metaphors: Actors as Channels and Channels as Actors

Channel- and actor-based programming languages are both used in practice, but the two are often confused. Languages such as Go provide anonymous processes which communicate using buffers or rendezvous points---known as channels---while languages such as Erlang provide addressable processes---known as actors---each with a single incoming message queue. The lack of a common representation makes it difficult to reason about translations that exist in the folklore. We define a calculus lambda-ch for typed asynchronous channels, and a calculus lambda-act for typed actors. We define translations from lambda-act into lambda-ch and lambda-ch into lambda-act and prove that both are type- and semantics-preserving. We show that our approach accounts for synchronisation and selective receive in actor systems and discuss future extensions to support guarded choice and behavioural types.