sclass GazelleContextCache {
  transient Lock lock = lock();
  transient GazelleEvalContext cachedCtx;
  
  GazelleEvalContext get() {
    lock lock;
    GazelleEvalContext ctx = cachedCtx;
    if (ctx == null) {
      GazelleEvalContext _cachedCtx = dm_gazelle_stdEvalContext(dm_gazelle_allRulesWithComment("discord"));
      cachedCtx = _cachedCtx;
      ctx = gazelle_cloneCtx(_cachedCtx);
    }
    ret ctx;
  }

  AutoCloseable listenToMessages() {
    ret vmBus_onMessages(r { cachedCtx = null },
      'gazelleRulesChanged, 'gazelleFeedbackChanged);
  }
}