Simple Elixir Calculator Server

simple_calculator_server.ex

defmodule Calculator do

  def start do
    spawn( fn -> loop(0) end)
  end

  defp loop(current_value) do
    new_value = receive do
      {sender_pid, :value} ->
        IO.puts("current value is #{current_value}")
        current_value
      {sender_pid, :add, value} ->
        #send(sender_pid,{:new_value, current_value + value})
        current_value + value
      {sender_pid, :deduct, value} ->
        #send(sender_pid,{:new_value, current_value - value})
        current_value - value
      {sender_pid, :multiply, value} ->
        #send(sender_pid,{:new_value, current_value * value})
        current_value * value
    end
    loop(new_value)
  end
end


# Refactored Version
defmodule Calculator do

  def start do
    spawn( fn -> loop(0) end)
  end

  defp loop(current_value) do
    new_value = receive do
      message ->
        process_message(current_value, message)
    end
    loop(new_value)
  end

  def process_message(current_value, {:value}) do
    IO.puts("current value is #{current_value}")
    current_value
  end

  def process_message(current_value, {:add, value}) do
    current_value + value
  end

  def process_message(current_value, {:deduct, value}) do
    current_value - value
  end

  def process_message(current_value, {:multiply, value}) do
    current_value * value
  end

  def process_message(current_value, {:divide, value}) do
    current_value / value
  end

end