@Override
  public IMatchable findObject(MatchNode matchNode, int index) {
    IMatchable object = super.findObject(matchNode, index);
    if (object != null) {
      return object;
    }

    if (matchNode.getType() == MatchNode.MATCHNODE_EXPRENT) {
      String position = (String)matchNode.getRuleValue(MatchProperties.EXPRENT_POSITION);
      if ("head".equals(position)) {
        return getHeadexprent();
      }
    }

    return null;
  }
@Override
  public IMatchable findObject(MatchNode matchNode, int index)