static L<IfThen> nlLogic_applyMetaRules(L<IfThen> rules) {
  final L<IfThen> metaRules = nlLogic_filterByRHSConstructs(rules, 'construct);
  if (empty(metaRules)) ret rules;
  
  new L<IfThen> newRules;
  for (IfThen rule : rules)
    newRules.add(nlLogic_transformShallow(rule, func(Exp e) -> Exp {
      if (!e instanceof Sentence2) ret e;
      final new NLLogic_ConstructChecker c;
      S original = e.text();
      c.construct = original;
      applyNLLogicFacts_v3(c, voidfunc(Exp e) {
        if (e cast Func)
          if (eq(e.name, 'construct))
            c.construct = e.arg.text();
      }, metaRules);
      ret eq(c.construct, original) ? e : nlLogic_parseExpression(c.construct);
    }));
  ret newRules;   
}