Implement ractor by Thread

ractor-by-thread.rb

using Module.new {
  refine ThreadGroup do
    attr_accessor :fake_ractor
  end
}

class FakeRactor
  def initialize(*args, name: nil, &block)
    @name = name
    @incoming = Thread::Queue.new
    @outgoing = Thread::Queue.new

    Thread.new do
      ThreadGroup.new.tap do |g|
        g.add Thread.current
        g.fake_ractor = self
      end
      instance_exec(*args, &block)
    end
  end

  attr_reader :incoming
  attr_reader :outgoing

  def self.current
    Thread.current.group.fake_ractor
  end

  def self.count
    raise NotImplementedError
  end

  def self.select(*ractors, yield_value: true, move: false)
    raise NotImplementedError
  end

  def self.recv
    current.incoming.deq
  end

  def send(obj, move: false)
    @incoming << obj
    self
  end

  def self.yield obj, move: false
    current.outgoing << obj
  end

  def take
    @outgoing.deq
  end

  alias << send

  def inspect
    super
  end

  def name
    @name
  end

  class RemoteError
    attr_reader :ractor
  end

  def close_incoming
    @incoming.close
  end

  def close_outgoing
    @outgoing.close
  end

  def close
    close_incoming
    close_outgoing
  end
end

r = FakeRactor.new do
  FakeRactor.yield FakeRactor.recv
end

r.send 42
p r.take