@Nullable
  private Node parseSelector() {
    TextMateSelectorToken token = getToken();
    if (token == TextMateSelectorToken.LPAREN) {
      advance();
      Node result = parseSelectorList();
      if (getToken() == TextMateSelectorToken.RPAREN) {
        advance();
      }
      return result;
    }
    if (token instanceof TextMateSelectorLexer.SelectorToken) {
      advance();
      return new Selector(((TextMateSelectorLexer.SelectorToken)token).getText());
    }
    return null;
  }
@Nullable
  private Node parseSelector()