Split a string without using regex

split.ex

defmodule Split do
  @moduledoc """
      iex(2)> Split.split("this,is,1,way,to,do_it")
      ["this", "is", "1", "way", "to", "do", "it"]
  """
  @spec split(bitstring) :: [bitstring]
  def split(s) do
    do_split(s, [], [])
    |> Enum.map(&List.to_string/1)
    |> Enum.map(&String.reverse/1)
    |> Enum.reverse()
  end
  @spec do_split(bitstring, charlist, [charlist]) :: [charlist]
  def do_split("", [], list) do
    list
  end
  def do_split("", cur, list) do
    [cur | list]
  end
  def do_split(<<hd :: rest>>, cur, list) when (hd >= 97 and hd <= 122) or (hd >= 48 and hd <= 57) do
    do_split(rest, [hd | cur], list)
  end
  def do_split(<<_ :: rest>>, cur, list) do
    do_split(rest, [], [cur | list])
  end
end