require 'generator'

module Prime
  extend Enumerable

  def each()
    h = {}
    yield(2)
    n = 1
    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
        yield(h[m] = n)
      end
    end
    h
  end
  module_function :each

  class PrimeGenerator
    def initialize()
      @h = []
      @g = Generator.new{|g| Prime.each{|n| g.yield(n) } }
    end

    def succ()
      @g.next()
    end
    alias next succ
  end
end # module Prime