sclass WaitForName {
  S question;
  
  persistently swappable S answer(S s) {
    if (isCancelCommand(s)) ret cancel();
    S name = nameFromInput(s);
    if (name != null) {
      cancelSilently();
      print("Processing name: " + quote(name));
      ret processName(s);
    }
    ret otherInput(s);
  }
  
  persistently swappable S nameFromInput(S s) { ret s; }
  persistently swappable S otherInput(S s) { ret "I don't understand. " + question; }
  persistently swappable S processName(S name) { ret "You said: " + name; }
  persistently swappable bool isCancelCommand(S s) { ret match("cancel", s); }
  persistently swappable void cancelSilently() { print("Cancelling"); }
  persistently swappable S cancel() { cancelSilently(); ret "Action cancelled"; }
}