elixir function for splitting lists into equal sized chunks, written using recursion

partition.ex

# `partition/2` splits a list into smaller lists of a given size, using recursion!
#
# usage:
# list = [:one, :two, :three, :four, :five]
# partition(list, 2)
# > [[:one, :two], [:three, :four], [:five]]

def partition(list, partition_size) 
  when is_list(list) 
  and is_integer(partition_size) 
  and partition_size > 0 
  do Enum.reverse(part(list, partition_size))
end

defp part(list, p_size, acc \\ [])

defp part([], _, acc) do
  acc
end

defp part(list, p_size, acc) do
  [current | rest] = list
  case acc do
    [] -> part(rest, p_size, [current])
    [head | tail] when is_list(head) ->
      chunk = part([current], p_size, head)
      case chunk do
        [h | _] when is_list(h) -> part(rest, p_size, chunk ++ tail)
        _ -> part(rest, p_size, [chunk | tail])
      end
    p when length(p) < p_size -> part(rest, p_size, p ++ [current])
    p -> part(rest, p_size, [[current], p])
  end
end