Fun with Elixir

max.ex

defmodule Fun do
  def max([x]), do: x
  
  def max([ head | tail ]), do: Kernel.max(head, max(tail))
end  

slice.ex

defmodule Fun do
  def slice(x, start, length), do: x
end

swap.ex

defmodule Fun do
  def swap([head | tail], _, 1, carry, rest), do: [head] ++ List.delete_at(rest, -1) ++ [carry] ++ tail

  def swap([head | tail], 1, second, carry, rest), do: swap(tail, 1, second - 1, carry, rest ++ [hd(tail)])

  def swap([head | tail], first, second, _, rest), do: [head] ++ swap(tail, first - 1, second - 1, hd(tail), rest)

  def swap(x, first, second), do: swap(x, first, second, hd(x), [])
end