require 'eventmachine'

class Actor
    def initialize(&cb)
        @channel = EM::Channel.new
        @sid = @channel.subscribe &cb
    end
    def << message
        @channel.push message
    end
    def die
        @channel.unsubscribe(@sid)
    end
end

class Player < Actor
    def initialize(output)
        cb = lambda do |message|
            if message == "play"
               puts "playing #{output}"
            end
        end
        super &cb
    end
end





EM::run {
    rock_n_roll = Player.new("AC/DC")
    classical = Player.new("Mozart")
    rock_n_roll << "play"
    classical << "play"
    EM::stop_event_loop
}