Futures

futures.rb

class Future
  def initialize &future
    @thread = Thread.new { @value = future.call }
  end
  
  def ready?
    !!@value
  end
  
  def value
    @thread.value
  end
end

# See http://tx.pignata.com/2012/11/concurrency-patterns-in-ruby-futures.html

future = Future.new do
  sleep 1
  puts 'Cooking...'
  sleep 5
  puts '5 more seconds in the oven...'
  sleep 5
  puts 'Ready.'
  %w[Cookies! Cake. Pie! Brownies!].sample
end
#=> #<Future:0x007fe1fc76b840 @thread=%<2ac22334Thread:0x007fe1fc76b778 sleep>>

future.ready?
#=> false

sleep 6
#=> 6
# Cooking...
# 5 more seconds in the oven...

future.ready?
#=> false

sleep 5
#=> 5
# Ready.

future.ready?
#=> true

future.value
#=> "Cookies!"