Delegates methods to "imported" module on Elixir

import_and_extend.exs

defmodule Father do
  def sing() do
    IO.puts "Lalalalalala"
  end

  def song(a, b) do
    turn_bass_on()
    IO.puts "Lelelelelele #{a} #{b}"
  end

  defp turn_bass_on do
    IO.puts "Du Du Dum Du Du Dum"
  end

  # Delegate functions to Father module based on public Father functions
  defmacro __using__(_) do
    IO.puts "Functions to define:"
    IO.inspect Father.__info__(:functions)

    for {name, arity} <- Father.__info__(:functions) do
      quote do
        defdelegate unquote(name)(unquote_splicing(Macro.generate_arguments(arity, __MODULE__))), to: Father
      end
    end
  end
end

defmodule Son do
  use Father

  def sing_and_dance  do
    sing()
    IO.puts "Dance...."
  end
end

IO.puts String.duplicate("-", 70)
IO.puts "Call sing:"
Son.sing()

IO.puts String.duplicate("-", 70)
IO.puts "Call song:"
Son.song(1,2)

IO.puts String.duplicate("-", 70)

IO.puts String.duplicate("-", 70)
IO.puts "Call sing_and_dance:"
Son.sing_and_dance
IO.puts String.duplicate("-", 70)