override_def.ex

defmodule Overrider do
  defmacro __using__(_) do
    quote do
      import Kernel, except: [def: 2]
      import Overrider
    end
  end

  defmacro def(fun_def, opts) do
    quote do
      Kernel.def unquote(fun_def) do
        IO.puts "Calling #{inspect unquote(Macro.escape(fun_def))}"
        unquote(opts[:do])
      end
    end
  end
end


defmodule Test do
  use Overrider

  def add(x, y) do
    x + y
  end
end

Test.add(2, 3)
|> IO.inspect