Coactor

C++20 actor framework using coroutines.

Design

Actors

• An actor has an inbox that contains a list of messages.
• An actor has a unique address.
• An actor can send messages to actors that it has the address to.
• Actors have state, i.e. stored data.
• Actors are isolated, in the sense that they can not access the data stored in other actors.
• Actors process the messages in the inbox in the same order as they were received.
• When a message is processed, the message and the actor state decides what the actor does.
• Actors can spawn new actors.

Coroutines

A coroutine is a function that can be suspended, and then resumed later. A suspended coroutine saves its local variables, and restores them when it is resumed.

We can implement actors using coroutines by creating a mechanism for receiving and sending messages between coroutines.

Actor addresses

TODO

Sending messages

TODO

Receiving messages

TODO

Spawning actors

TODO

Messages

A message can contain: TODO

Processing messages

TODO