parallel_map.cr

module Enumerable
  def parallel_map(&block : T -> U)
    channel = Channel(U).new(20)

    count = 0
    each do |e|
      spawn parallel_map_task(channel, block, e)
      count += 1
    end

    Array(U).new(count) { channel.receive }
  end

  private def parallel_map_task(channel, block, element)
    channel.send block.call(element)
  end
end