if (children != null) { ret.children = children.clone(stylesheet); } if (next != null) { ret.next = next.clone(stylesheet); } return ret;
  TemplateNode clone(Stylesheet stylesheet)  {    return new NumberNode((children == null) ? null :                          children.clone(stylesheet),                          (next == null) ? null :                          next.clone(stylesheet),                          value.clone(stylesheet),                          format, lang, letterValue,                          groupingSeparator, groupingSize);  }