sbool ai_tripleToTripleRef_debug;

static TripleRef<Symbol> ai_tripleToTripleRef(TripleWeb w, Symbol searchTerm, int occurrence) {
  if (ai_tripleToTripleRef_debug) {
    print("ai_tripleToTripleRef: " + w + " " + searchTerm + " " + occurrence);
    //print("a: " + symbolToStringFull(w.a));
    //print("searchTerm: " + symbolToStringFull(searchTerm));
    print("eq: "+ eqic(w.a, searchTerm) + " " + eqic(w.b, searchTerm) + " " + eqic(w.c, searchTerm));
  }
  
  if (w == null) null;
  // occurrence count magic
  if (occurrence < 3)
    for (int i = 0; i < 3; i++)
      if (eqic(tripleGet(w, i), searchTerm)) {
        if (occurrence-- == 0) {
          if (ai_tripleToTripleRef_debug)
            print("ai_tripleToTripleRef returning: " + i);
          ret tripleRef(w, i);
        }
      }
  null;
}