@Nullable
  private Node parseConjunction() {
    Node node = parseScopeSelector();
    if (node == null || getToken() != TextMateSelectorToken.PIPE) {
      return node;
    }
    List<Node> children = new ArrayList<>();
    children.add(node);
    while (getToken() == TextMateSelectorToken.PIPE) {
      advance();
      Node child = parseScopeSelector();
      if (child == null) break;
      children.add(child);
    }
    return new Conjunction(children);
  }
@Nullable
  private Node parseConjunction()