It would be useful to have a <query:emtpy /> and a <query:notEmpty /> tags

It would be useful to have a <query:emtpy /> and a <query:notEmpty /> tags, based on the "empty" jstl operator. It would avoid the template developer to have to do some specific developments, depending the type of the filtered field.

Currently, we have to use <greaterThan value="0" /> for a date field, <notEqual value ="" /> for a textField, ...