How can I dynamically list only fields with values on a topic?

%STARTSECTION{"example"}%

%FORMAT{
  "%QUERY{
    "'%URLPARAM{"qtopic" default="%WEB%.%TOPIC%"}%'/fields.name"
  }%"
  type="string"
  format="$percntIF{
    \"'%URLPARAM{"qtopic" default="%WEB%.%TOPIC%"}%'/$item =~ '\w'\"
    then=\"   $ $item: $percntQUERY{'%URLPARAM{"qtopic" default="%WEB%.%TOPIC%"}%'/$item}$percnt\"
  }$percnt"
}%

%ENDSECTION{"example"}%

TopicTitle

How can I dynamically list only fields with values on a topic?

TopicClassification

FrequentlyAskedQuestion

Subject

Data forms, Search