在dede:list标签中怎样使用if判断

{dede:list pagesize='10'}        <ul>            <li><a href="[field:arcurl/]" target="_blank">[field:array runphp='yes']@me = (empty(@me['litpic']) ? "" : "<img src='{@me['litpic']}' width='217' height='167' border='0' />"); [/field:array]</a></li>            <li class="ht"><a href="[field:arcurl/]" target="_blank">[field:title/]</a></li>            <li><a href="[field:arcurl/]" target="_blank"><img src="/img/bw.jpg" width="154" height="32" border="0" /></a></li>        </ul>{/dede:list}