In this recipe, we will use the same concept used in the first recipe, but we will add a counter for each type of received message. We will introduce states!
To get started, let's create a module named messages_with_state.ex with the following code:
defmodule MessagesWithState do
def start_link do
{:ok, spawn_link(fn -> wait_for_messages(0,0,0) end)}
end
defp wait_for_messages(pings, pongs, unknown) do
receive do
{"ping", caller} ->
send caller, "pong"
IO.puts "Received #{pings + 1} ping messages!"
wait_for_messages(pings + 1, pongs, unknown)
{"pong", caller} ->
send caller, "pong"
IO.puts "Received #{pongs + 1} pong messages!"
wait_for_messages(pings, pongs + 1, unknown)
{:status, _caller} ->
IO.puts "Current status: #{pings} pings, #{pongs} pongs and #{unknown} unknown messages."
{_, caller} ->
IO...