Functional Programming: A PragPub Anthology

A Final Example

Let’s use our knowledge of actors to write one final example program. This is a library that implements the map function. (The map function takes a collection and applies a function to each element, returning a new collection containing the results of each function call.) However, we’ll make this example more interesting by running each computation in a separate process. Without further ado, here’s the code:

elixir/pmap.exs

defmodule Parallel do

  import Enum, only: [map: 2]

  # Parallel map
  def pmap(collection, fun) do
    collection |> spawn_children(fun) |> collect_results
  end

  defp spawn_children(collection, fun), do: collection |> map(&spawn_child(&1, fun))

  def spawn_child(item, fun), ...