Infinite generator

gistfile1.rb

#!/usr/bin/env ruby
# Return given number of even Integers
# that have number '4' within them

even_numbers = Enumerator.new do |yielder|
  number = 0
  count = 1
  loop do
    number += count
    count += 1
    yielder.yield number
  end
end

class Enumerator
  def infinite_selector(&block)
    Enumerator.new do |yielder|
      self.each do |value|
        yielder.yield(value) if block.call(value)
      end
    end
  end
end

p even_numbers
  .infinite_selector {|val| val % 2 == 0}
  .infinite_selector {|val| val.to_s =~ /4/}
  .first(10)