proto_test.ex

defmodule Impl do
  defstruct value: 100

  def runImpl(%Impl{value: value}, x, y) do
    value + x + y
  end
end

defprotocol Runnable do
  def run(r, x, y)
end

defimpl Runnable, for: Impl do
  def run(r, x, y) do
    Impl.runImpl(r, x, y)
  end
end


defmodule ProtoTest do
  use ExUnit.Case

  @count 1000_000

  defmacrop measure(name, block) do
    quote do
      {micros, _} = :timer.tc fn ->
        Enum.each 1..@count, fn _ ->
          unquote(block)
        end
      end
      micros = micros / @count
      IO.write "Execution of #{unquote(name)} took #{inspect micros} microseconds\n"
    end
  end

  test "how fast?" do
    r = %Impl{}

    measure "protocol" do
      Runnable.run(r, 10, 20)
    end

    f = &(Impl.runImpl(r, &1, &2))
    measure "closure" do
      f.(10, 20)
    end

    measure "direct" do
      Impl.runImpl(r, 10, 20)
    end

  end
end