fp

Section

list = [1, 2, 3, 4]
List.delete_at(list, -1)

Enum.map(["dogs", "cats", "flowers"], &String.upcase/1)

defmodule StringList do
  def upcase([]), do: []
  def upcase([first | rest]), do: [String.upcase(first) | upcase(rest)]
end

StringList.upcase(["dogs", "cats", "flowers"])

Body recursion

defmodule FactorialBR do
  def of(0), do: 1
  def of(n) when n > 0, do: n * of(n - 1)
end

FactorialBR.of(5)

Tail Recursion

defmodule FactorialTR do
  def of(n), do: factorial_of(n, 1)
  defp factorial_of(0, acc), do: acc
  defp factorial_of(n, acc) when n > 0, do: factorial_of(n - 1, n * acc)
end

FactorialTR.of(5)

Screw Factory

defmodule ScrewFactory do
  def run(pieces) do
    pieces
    |> Stream.chunk_every(50)
    |> Stream.flat_map(&add_thread/1)
    |> Stream.chunk_every(100)
    |> Stream.flat_map(&add_head/1)
    |> Enum.each(&output/1)
  end

  defp add_thread(pieces) do
    Process.sleep(50)
    Enum.map(pieces, &amp;(&amp;1 <> "--"))
  end

  defp add_head(pieces) do
    Process.sleep(100)
    Enum.map(pieces, &amp;("0" <> &amp;1))
  end

  defp output(screw) do
    IO.inspect(screw)
  end
end

metal_pieces = Enum.take(Stream.cycle(["-"]), 1000)
ScrewFactory.run(metal_pieces)

metal_pieces = Enum.take(Stream.cycle(["-"]), 1000)
ScrewFactory.run(metal_pieces)