This is probably an imperfect solution, but isn't this kind of what Actors provide? Syntax and concurrency aside, passing a message is equivalent to calling a

This is probably an imperfect solution, but isn't this kind of what Actors provide? Syntax and concurrency aside, passing a message is equivalent to calling a method. The biggest annoyance I can foresee is discoverability. Object-orinented classes make it pretty clear what a given object's interface is (just look at its public methods). This is not true of actors in the languages I've used (not many), but in theory it should be a fairly trivial question of syntax.