sclass GazelleContextCache_v2 {
  transient Lock lock = lock();
  transient GazelleEvalContext cachedCtx;
  DynModule module;
  bool debug = true;
  
  *(DynModule *module) {}
  
  void fill {
    lock lock;
    cachedCtx = dm_gazelle_stdEvalContext(dm_gazelle_allRulesWithComment("discord")); 
    gazelle_addHelpers(cachedCtx);
  }
  
  
  GazelleEvalContext get() {
    lock lock;
    ret gazelle_cloneCtx(_cachedCtx);
  }

  AutoCloseable listenToMessages() {
    ret combineAutoCloseables(
      vmBus_onMessage('gazelleRuleChanged, voidfunc(O rule) {
        temp module.enter();
        lock lock;
        if (cachedCtx == null) ret;
        S ruleID = getString globalID(rule);
        print("GazelleContextCache_v2: processing rule update " + ruleID);
        RuleEngine2 engine = cachedCtx.engine;
        RuleEngine2.Rule rule = engine.getRule(ruleID);
        if (rule == null) ret;
        engine.rules.remove(rule);
        PairS p = dm_textAndCommentForRule(ruleID);
        if (p == null) ret;
        engine.addRules2(ll(t3(p.a, p.b, ruleID)));
        rule = cachedCtx.engine.getRule(ruleID);
        if (rule == null) ret;
        gazelle_addHelpers(gazelle_dummyEngineWithRule(rule));
        print("GazelleContextCache_v2: rule update complete");
      }),
      vmBus_onMessage('gazelleRuleDeleted, voidfunc(O rule) {
        temp module.enter();
        lock lock;
        if (cachedCtx == null) ret;
        S ruleID = getString globalID(rule);
        cachedCtx.engine.deleteRule(ruleID);
        print("GazelleContextCache_v2: rule " + ruleID + " deleted");
      }));
  }
}