Stack sort using elixir

stack_sort.ex

defmodule StackSort do
  @moduledoc """
  Documentation for StackSort.

  Recursively pops and compares all values with top
  of the stack value and pushes it else keeps
  popping out until invariant satisfied.

  You will find only comments in docstrings.
  I(t's a no brainer.

  l = [2,300, -100, -1, 0, 1000]
  StackSort.sort_stack(l) |> IO.inspect
  [-100, -1, 0, 2, 300, 1000]
  """


  defp top_stack(stack, top_val), do: [top_val] ++ stack


  def sort_stack([]), do: []

  @doc """
  Pushes greater value i.e. top_val to stack;
  """
  def sort_stack([ h | t ]) do
    sort_stack(t) |> _insert(h)
  end

  defp _insert([], top_val), do: [top_val]

  defp _insert([ h | t ], top_val) when top_val > h do
    t |> _insert(top_val) |> top_stack(h)
  end

  defp _insert(stack, top_val), do: stack |> top_stack(top_val)

end

l = [2,300, -100, -1, 0, 1000]
StackSort.sort_stack(l) |> IO.inspect