// rulesMechListName = "<default>" => default rules & facts
static Steppable nlLogic_processInputOrFact_steppable(S input, bool inputAsFact, S rulesMechListName, Collector<ExecutedRule> out) {
  ret nlLogic_processInputOrFact_steppable(input, inputAsFact,
    eq(rulesMechListName, "<default>")
      ? ai_activeRulesAndFacts()
      : pair(ai_rulesFromMechLists(tok_splitAtComma(rulesMechListName)), emptyList(S)), out);
}

static new ThreadLocal<Bool> nlLogic_processInputOrFact_steppable_allowUnsafeEvals;

static Steppable nlLogic_processInputOrFact_steppable(S input, bool inputAsFact, Pair<L<IfThen>, LS> rulesAndFacts, final Collector<ExecutedRule> out) {
  new NLLogicChecker_v3 c;
  if (!inputAsFact) c.input = input;
  c.facts = reversed(rulesAndFacts.b);
  if (inputAsFact) c.facts = concatLists(ll(input), c.facts);
  c.rules = reversed(rulesAndFacts.a); // latest rules first!
  if (!inputAsFact)
    c.rules = [IfThen r : c.rules | ai_ruleAccessesInput(r)];
  c.allowUnsafeEvals = isTrue(nlLogic_processInputOrFact_steppable_allowUnsafeEvals!);
  print("Have " + n2(rulesAndFacts.a, "rule"));
  c.useIterate = true;
  //c.staticVerbose = true;
  ret nlLogic_fillBattleSpace_steppable(c, new Collector<RuleWithParams>() {
    bool add(RuleWithParams r) {
      ret false with out.add(nlLogic_executedRuleFromRuleWithParams(r));
    }
  }, false);
}