static Collection<S> nlLogic_certainOperatorArgsFromRuleWithParams(RuleWithParams r, S operator) {
  new LinkedHashSet<S> out;
  for (Exp e : nlLogic_unrollAnd(r.rule.out)) {
    e = nlLogic_applyMatches(e, r.matches);
    if (e cast Func)
      if (eq(e.name, operator))
        out.add(nlLogic_text(e.arg));
    nlLogic_checkHelper(e, r.matches); // changes matches e.g. for newID()
  }
  ret out;
}