Elixir Pipes

General Discussion
5

The syntax in Elixir is a bit different than in some other common languages. It gets a lot more readable if you move the anonymous functions into separate functions.

Anonymous functions get called with a dot:

# define an anonymous function
f = fn x, y -> x + y end

# the dot is required
f.(3, 4)
#=> 7

The &1 part is explained here. It’s just capturing the first argument, which is the sum of black + white.

You can make it more readable by moving the anonymous functions into the private section. Then the piped section reads more like English.

defmodule Game do
  @doc """A more readable example."""
  def total_pieces_on(board) do
    board
    |> count_pieces_by_color()
    |> sum_all_pieces()
    |> format_sum()
  end

  # private functions
  defp count_pieces_by_color(_board), do: { 10, 11 } # skipping the computing of pieces
  defp sum_all_pieces({ black, white }), do: black + white
  defp format_sum(total_pieces), do: "Total pieces: #{total_pieces}"
end

Game.total_pieces_on("In a real program, this could be game board data.")
#=> "Total pieces: 21"

His Elixir course is pretty good.

Edit: fixed mistakes in the code example.