fibers as generators

generators.rb

module Generators

  def generator(&blk)
    Fiber.new do
      loop { Fiber.yield(blk.call) }
    end
  end

end

tokenizer.rb

require "generators"

class Tokenizer
  include Generators

  def initialize
    @tokens = [:a, :b, :c].each # File.open, Socket.new, ...
    @generator = generator { @tokens.next }
  end

  def emit
    @generator.resume
  end
end

t = Tokenizer.new
t.emit
# => :a
t.emit
# => :b
t.emit
# => :c
t.emit
# => nil

# PS: http://ruby-doc.org/core/Enumerator.html