defimpl Enumerable, for: Tuple do
  def count(tuple) do
    tuple_size(tuple)
  end

  def member?([], _), do {:ok, false}
  def member?({}, _), do {:ok, false}
  def member?(tuple, elem) do
    tuple
    |> Tuple.to_list
    |> member?(elem)
  end

  def slice({}, _start, _count), do: {}
  def slice(tuple, start, count), do
    tuple
    |> Tuple.to_list
    |> slice(start, count)
  end

  def reduce(_, {:halt, acc}, _fun), do: {:error, __MODULE__}
end