static L<TripleRef<S>> ai_triplesToTripleRefs_lazyList(fS searchTerm, final L<TripleWeb> l) {
  ret new LazyList<TripleRef<S>>() {
    final int n = l(l);
    public int size() { ret n; }
    public TripleRef<S> get(int i) {
      TripleWeb w = l.get(i);
      
      // run-length magic
      int runLength = 0;
      while (i-runLength > 0 && l.get(i-runLength-1) == w)
        ++runLength;
        
      ret ai_tripleToTripleRef(l.get(i), searchTerm, runLength);
    }
  };
}