static L<TripleRef<Symbol>> ai_triplesToCRefs(final L<TripleWeb> l) {
  if (l == null) null;
  class TTCR extends LazyList<TripleRef<Symbol>> {
    final int n = l(l);
    public int size() { ret n; }
    public TripleRef<Symbol> get(int i) {
      ret TripleC(syncGet(l, i));
    }
  }
  ret new TTCR;
}