enum.ex

defmodule Enum do
  def map([], _fun), do: []

  def map([head | tail], fun) do
    [fun.(head) | map(tail)]
  end
  
  def reduce([], acc, _fun), do: acc
  
  def reduce([head | tail], acc, fun) do
    reduce(tail, fun.(head, acc), fun)
  end
end