fiber-enumerable.rb

require 'fiber'
require 'pp'

class MyWrapper
  include Enumerable

  def initialize
    @fiber = fiber
    @results = []
  end

  def each
    @results.each { |obj| yield obj }
    
    while @fiber.alive?
      obj = @fiber.resume
      @results << obj
      yield obj
    end
  end

  private

  def fiber
    Fiber.new do
      10.times do |i|
        puts "CREATING #{i}"
        Fiber.yield(i)
      end
    end
  end

end

e = MyWrapper.new

pp e.take(3)
# CREATING 0
# CREATING 1
# CREATING 2
#=> [0, 1, 2]

pp e.take(5)
# CREATING 3
# CREATING 4
#=> [0, 1, 2, 3, 4]

pp e.take(10)
# CREATING 5
# CREATING 6
# CREATING 7
# CREATING 8
# CREATING 9
#=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]