+ for(Sequence s : (Union)e)
+ walk(s, hs);
+ }
+ private void walk(Sequence s, HashSet<Element> hs) {
+ hs.add(s);
+ for(Position p = s.firstp(); p != null; p = p.next())
+ walk(p.element(), hs);
+ for(Sequence ss : s.needs()) walk(ss, hs);
+ for(Sequence ss : s.hates()) walk(ss, hs);