Functional Actors

This project aims to implement actors from the actor model using pure functional programming with Cats-Effect.

The interface for creating and interacting with actors is heavily inspired by Akka actors, particularly with Behaviours being used as the main way to define message handling functionality.

Example

sealed trait Command
case class Ping[F[_]](sender: ActorRef[F, Command]) extends Command
case object Pong extends Command

def msgHandler[F[_]: Sync: Console]: Behaviour[F, Command] = Behaviour.receive { (context, message) =>
  message match {
    case Pong =>
      for {
        _ <- Console[F].println("Pong")
      } yield ()
    case Ping(sender: ActorRef[F, Command]) =>
      for {
        _ <- Console[F].println("Ping")
        self <- context.self
        _ <- sender ! Pong
      } yield ()
  }
  msgHandler
}

val program = for {
  actorSystem <- ActorSystem[IO, Command](Behaviour.empty, "system")
  pinger <- actorSystem.spawn[Command](msgHandler, "pinger")
  ponger <- actorSystem.spawn[Command](msgHandler, "ponger")
  _ <- pinger ! Ping(ponger)
  _ <- actorSystem.cancel
} yield ()

TODO

• Implement the ask pattern found in Akka.
• Implement support for communication between actors on different JVMs.
• Implement additional failure recovery of actors.