Implementing #each with Ractor- and Async-based concurrency for fun

enumerable.rb

require 'async'

module Enumerable
  module Async
    [Array, Hash, Range, Struct].each do |collection|
      refine collection do
        def each(&block)
          super do |value|
            Async do
              block.call(value)
            end
          end

          self
        end
      end
    end
  end

  module Parallel
    [Array, Hash, Range, Struct].each do |collection|
      refine collection do
        def each(&block)
          pipe = Ractor.new do
            loop do
              Ractor.yield Ractor.receive
            end
          end

          pool_size = size&.clamp(..16) || 16
          workers = (1..pool_size).map do
            Ractor.new pipe, Ractor.make_shareable(block) do |pipe, shareable_block|
              while value = pipe.take
                Ractor.yield shareable_block.call(value)
              end
            end
          end

          super do |value|
            pipe << value
          end
        end
      end
    end
  end
end

# A hack until Procs are shareable, see: https://bugs.ruby-lang.org/issues/18243
module Kernel def Parallel(&) = nil.instance_eval(&) end

example_async.rb

require_relative 'enumerable'

using Enumerable::Async

Async do
  (1..3).each do |number|
    sleep 3
    puts "#{number}\n"
  end
end
# Three seconds later...
#>> 2
#>> 3
#>> 1
#=> 1..3

example_parallel.rb

require_relative 'enumerable'

using Enumerable::Parallel

Parallel do
  (1..3).each do |number|
    sleep 3
    puts "#{number}\n"
  end
end
#=> 1..3
# Three seconds later...
#>> 1
#>> 3
#>> 2