binary_parse_slow.exs

defmodule BinaryParseSlow do
  def parse(bin) do
    parse(bin, 0)
  end

  def parse(bin, acc) do
    case do_parse(bin) do
      {:nofin, x, rest} ->
        parse(rest, acc + x)
      {:fin, x} ->
        acc + x
    end
  end

  def do_parse(<<0::1, x::7, _::bits>>) do
    {:fin, x}
  end
  def do_parse(<<1::1, x::7, rest::bits>>) do
    {:nofin, x, rest}
  end
end