Elixir Ping Pong

ping_pong.ex

defmodule PingPong do
  def start do
    ping_process = spawn(Ping, :loop, [])
    pong_process = spawn(Pong, :loop, [])
    send(ping_process, {:pong, pong_process})
  end

  def ping do
    Ping
  end
end

defmodule Ping do
  def loop(n \\ []) do
    receive do
      {:pong, sender_pid} ->
        :timer.sleep(1_000)
        send(sender_pid, {:ping, self()})
        IO.puts("ping ----")

        loop()

      _ ->
        loop()
    end
  end
end

defmodule Pong do
  def loop(n \\ []) do
    receive do
      {:ping, sender_pid} ->
        :timer.sleep(1_000)
        send(sender_pid, {:pong, self()})
        IO.puts("---- pong")

        loop()

      _ ->
        loop()
    end
  end
end