Generate a list of ranges from a list of characters

list_to_range.ex

defmodule ListToRange do

  def generate(list) do
    generate(list, [])
  end

  def generate([_], accumulator) do
    accumulator
  end

  def generate([head | tail], accumulator) do
    [next | _] = tail
    generate(tail, accumulator ++ ["#{head} - #{next}"])
  end

end

# ListToRange.generate([0, 10, 20, 30]) -> ["0 - 10", "10 - 20", "20 -30"]