concept Conversation {
  bool authed;
  S cookie, ip;
  new LL<Msg> oldDialogs;
  new L<Msg> msgs;

  void add(Msg m) {
    syncAdd(msgs, m);
    change();
    vmBus_send chatBot_messageAdded(mc(), this, m);
  }
  
  int allCount() { ret lengthLevel2(oldDialogs) + l(msgs); }
  int archiveSize() { ret lengthLevel2(oldDialogs); }
  
  L<Msg> allMsgs() { ret concatLists(listPlus(oldDialogs, msgs)); }
}