###############################################################
#
# Demonstration of the Actor Model using Icon's co-expressions
#  as coroutines.  (Well not really a full blown Actor Model)
#  As stated in the Icon Book, this is not a tremendously
#  effecient use of Icon features.  A simple generator would
#  suffice for this contrived example.
#
###############################################################
global actor1, actor2

# main procedure, create the coroutines and start up the actors
#   note; @actor is a shortcut equivalent of  &null @ actor
procedure main()
    local datum
    &trace := -1
    datum := [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

    #  summing using two co-expressions
    write("create 1")
    actor1 := create sumall()
    write("create 2")
    actor2 := create sumodd()

    # for intial activation of co-expression, transmitted data is ignored
    #   as there is nothing yet suspended to receive the data
    #   we will use this opportunity to set the running (local) totals to zero
    @actor2

    # now to generate all the data and transmit to the sumall coroutine
    every !datum @ actor1
end

# the sum procedure; locals are captured in the co-expression
procedure sumall()
    local val, total
    /total := 0
    repeat {
        # result transmitted is result of expression that called co-routine
        val := @&main
        # transmit odd values to the odd total coroutine
        if val % 2 == 1 then val @ actor2
        total +:= val
        write("all total = ", total)
    }
end

# the sumodd procedure
procedure sumodd()
    local odd, total
    /total := 0
    repeat {
        odd := @actor1
        total +:= odd
        write("odd total = ", total)
    }
end

create 1
create 2
actor.icn    :   28  | main; co-expression_1 : &null @ co-expression_3
actor.icn    :   23  | sumodd()
actor.icn    :   53  | | sumodd; co-expression_3 : &null @ co-expression_2
actor.icn    :   21  | | sumall()
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 1) @ co-expression_2
actor.icn    :   42  | | | sumall; co-expression_2 : 1 @ co-expression_3
odd total = 1
actor.icn    :   53  | | | sumodd; co-expression_3 : &null @ co-expression_2
all total = 1
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 2) @ co-expression_2
all total = 3
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 3) @ co-expression_2
actor.icn    :   42  | | | sumall; co-expression_2 : 3 @ co-expression_3
odd total = 4
actor.icn    :   53  | | | sumodd; co-expression_3 : &null @ co-expression_2
all total = 6
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 4) @ co-expression_2
all total = 10
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 5) @ co-expression_2
actor.icn    :   42  | | | sumall; co-expression_2 : 5 @ co-expression_3
odd total = 9
actor.icn    :   53  | | | sumodd; co-expression_3 : &null @ co-expression_2
all total = 15
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 6) @ co-expression_2
all total = 21
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 7) @ co-expression_2
actor.icn    :   42  | | | sumall; co-expression_2 : 7 @ co-expression_3
odd total = 16
actor.icn    :   53  | | | sumodd; co-expression_3 : &null @ co-expression_2
all total = 28
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 8) @ co-expression_2
all total = 36
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 9) @ co-expression_2
actor.icn    :   42  | | | sumall; co-expression_2 : 9 @ co-expression_3
odd total = 25
actor.icn    :   53  | | | sumodd; co-expression_3 : &null @ co-expression_2
all total = 45
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   31  | | | main; co-expression_1 : (variable = 10) @ co-expression_2
all total = 55
actor.icn    :   40  | | | sumall; co-expression_2 : &null @ co-expression_1
actor.icn    :   32  | | main failed

import scala.actors._

object ActorTest extends Application {
    object PING { override def toString = "PING" }
    object PONG { override def toString = "PONG" }
    object STOP { override def toString = "STOP" }
   
    val pinger : Actor = new Actor {
        def act = while (true) receive {
            case PONG => { // upon receiving message PONG
                Console println PONG
                Thread sleep 1000
                ponger ! PING // Send message PING to actor ponger
            }
            case STOP => exit // Exits actor
        }
    };
   
    val ponger : Actor = new Actor {
        def act = while (true) receive {
            case PING => {
                Console println PING
                Thread sleep 1000
                pinger ! PONG
            }
            case STOP => exit
        }
    }
   
    // Start the actors
    pinger.start
    ponger.start
   
    // The two actors are in receiving mode at this point. So fire a message to either one to get them to play.
    pinger ! PONG

    // We use a separte actor here to pause for 5s and then stop these two above,
    // Note: We are NOT allowed to call Thread.sleep on the executing thread when using actors.
    // Also note: Using the following alternative method of creating actors, implicitly starts them as well.
    Actor actor {
        Thread sleep 5000
        pinger ! STOP
        ponger ! STOP
        exit
    }

    // All actors must `exit` for the program to terminate.
}