Yet Another Ruby FizzBuzz その2

class Fixnum
  def self.fizzbuzzize
    alias org_to_s to_s
    def to_s
      if    self%15 == 0 then "FizzBuzz"
      elsif self%3  == 0 then "Fizz"
      elsif self%5  == 0 then "Buzz"
      else self.org_to_s
      end
    end
  end

  def self.unfizzbuzzize
    undef to_s
    alias to_s org_to_s
  end
end

Fixnum.fizzbuzzize
(1..100).each { |i| print "#{i} " }
puts
Fixnum.unfizzbuzzize
(1..100).each { |i| print "#{i} " }

Yet Another Ruby FizzBuzz - hp12c