class Integer < Value
  Word digit( int rest )
    if_zero( rest == 5 )
      return "5"
    end
    if_zero( rest == 1 )
      return "1"
    end
    if_zero( rest == 2 )
      return "2"
    end
    if_zero( rest == 3 )
      return "3"
    end
    if_zero( rest == 4 )
      return "4"
    end
  end
  Word add_string(Word str)
    int div
    div = self / 10
    int rest
    rest = self - div
    if_notzero( rest )
      rest = self.digit( rest )
    else
      str = div.add_string(str)
    end
    return str
  end
  Word to_string()
    Word start = " "
    return add_string( start )
  end
end