code: public double num() throws javax.xml.transform.TransformerException
    {
  
      error(XPATHErrorResources.ER_CANT_CONVERT_TO_NUMBER,
            new Object[]{ getTypeString() });  //"Can not convert "+getTypeString()+" to a number");
  
      return 0.0;
    }
docs: Cast result object to a number. Always issues an error.
  
  @return 0.0
  
  @throws javax.xml.transform.TransformerException