// preds return a MapSO or Bool
// (null is false)
// returns pairs (sublist, mapping)
static <A> LPair<L<A>, MapSO> ai_scanOverListWithMatchFunctions(L<A> l, IF1<A, O>... preds) {
  new LPair<L<A>, MapSO> out;
  search: for (L<A> sub : allSubListsOfLength_iterator(l(preds), l)) {
    MapSO map = ciMap();
    for i over sub: {
      O o = preds[i].get(sub.get(i));
      if (o cast Map) {
        if (!putAllStrictly(map, o)) continue search;
      } else if (o cast Bool) {
        if (!o) continue search;
      } else if (o == null) continue search;
      else { warn("Unknown predicate result: " + o); continue search; }
    }
    out.add(pair(sub, map));
  }
  ret out;
}