static L<SS> ai_iterateExpressionOnFacts(Exp exp, LS facts) {
  final new NLLogicChecker_v3 c;
  c.facts = facts;
  final new NLLogicChecker_v2.Matching m;
  final new L<SS> matches;
  c.iterate(exp, m, r { matches.add(m.matches) });
  ret matches;
}