async_uci_interaction.rb

require 'open3'
require 'io/wait'
require 'thread'

class Uci
	attr_accessor :to
	attr_accessor :from

	def initialize path_to_engine
		@to, @from = Open3.popen2e "/usr/local/bin/stockfish"
	end

	def send command
		puts ">#{command}"
		to.puts command
	end 
end

uci = Uci.new "/usr/local/bin/stockfish"

queue = Queue.new
Thread.new do
	while true do
		if uci.from.ready?
			queue.enq uci.from.readline
		end
		sleep 0.25
	end  
end

loop do
  res = queue.deq      # this function blocks.
  puts "=>#{res}"
  if res =~ /^Stockfish/
  	uci.send "uci"
  end
end