# Demonstration of tail recursion in recursive parallel calls
#
# Paul Griffioen 2012

module message_loop_bound

include channel

public procedure main(args) = 
  let 
      channel_A := open_channel("channel A");
      channel_B := open_channel("channel B");
      channel_C := open_channel("channel C") 
  in
      sender(channel_A, 99999) |
      buffer(channel_A, channel_B) |
      buffer(channel_B, channel_C) |
      receiver_rec(channel_C)
  end
  
procedure sender(channel, count) =
  let i := count in
      while i != 0 do
          i := i-1;
          send(channel, "Hello World!");
	  sleep(0.001)
      end
  end;
  send(channel, "end")

procedure buffer(input, output) =
  let m := receive([input]) in
      send(output, m.message) | 
      if m.message != "end" then 
          buffer(input, output)
      end
  end

procedure receiver(channel) =
  let m := receive([channel]) in
      while m.message != "end" do
          print_message(m);
          m := receive([channel])
      end
  end

procedure receiver_rec(channel) =
  let m := receive([channel]) in
      if m.message != "end" then
          print_message(m);
          receiver_rec(channel)
      end
  end

procedure print_message(m) = 
  print_line(format("$message from $channel",
                    message := m.message;
                    channel := channel_name(m.channel)))