getHeader(Enum) :-
        exhausted(Enum),
        []
        ;
  getHeader(Enum) :-
        Elem = eValue(Enum),
        isHeader(getXName(Elem)),
        [getXText(Elem) | getHeader(eNext(Enum))]
        ;
  getHeader(Enum) :-
        getHeader(eNext(Enum))
        ;

  isHeader("h1");
  isHeader("h2");
  isHeader("h3");
  isHeader("h4");
  isHeader("h5");
  isHeader("h6");

  main(HTML) :- getHeader(eXElem(HTML));