module Prime
  extend Enumerable
  
  class PrimeGenerator
    def initialize()
      @h = {}
      @n = nil
    end

    def primes()
      @h.values().unshift(2)
    end

    def succ()
      @n = 1
      class << self
      def succ()
        n = @n
        while true
          m = n += 1
          if (b = @h[n])
            while(@h[m += b]); end
            @h[m] = b
            @h.delete(n)
          end
          m = n += 1
          if (b = @h[n])
            while(@h[m += b]); end
            @h[m] = b
            @h.delete(n)
          else
            while(@h[m += n]); end
            return @n = @h[m] = n
          end
        end
      end
      alias next succ
      end
      2
    end
    alias next succ

    def self.each()
    end
  end

  def self.each()
    g = PrimeGenerator.new()
    while (n = g.succ())
      yield(n)
    end
  end
end # module Prime