get("messages");
    $status[] = array($msg, $severity);
    $session->set("messages", $status);
  }
  public function get() {
    $messages = Session::instance()->get_once("messages", array());
    if ($messages) {
      $buf = "
";
      foreach ($messages as $msg) {
        $buf .= "- $msg[0]";
      }
      return $buf .= "
";
    }
  }
  public function severity_class($severity) {
    switch($severity) {
    case log::INFO:
      return "gInfo";
    case log::WARNING:
      return "gWarning";
    case log::ERROR:
      return "gError";
    }
  }
}