Crude Recursion

AEM_Step1.exs

"""
238 - 128 = 110
110 - 64 = 46
46 - 32 = 14
14 - 8 = 6
6 - 4 = 2
2 - 2 = 0

"""

defmodule AncientEgyptianMultiplication do
  require Integer

  def of(0.0, state), do: state
  def of(238.0, state) do
    of(238 - :math.pow(2, 7), concat( state, :math.pow(2, 7) ))
  end

  def of(110.0, state) do
    of(110 - :math.pow(2, 6), concat( state, :math.pow(2, 6) ))
  end

  def of(46.0, state) do
    of(46 - :math.pow(2, 5), concat(state, :math.pow(2, 5)))
  end

  def of(14.0, state) do
    of(14 - :math.pow(2, 3), concat(state, :math.pow(2, 3)))
  end

  def of(6.0, state) do
    of(6 - :math.pow(2, 2), concat(state, :math.pow(2, 2)))
  end

  def of(2.0, state) do
    of(2 - :math.pow(2, 1), concat(state, :math.pow(2, 1)))
  end

  def of(_, _L), do: "Incorrect Input"

  defp concat(first, second) do
    Enum.concat(first, [second])
  end

end