>Contact</a></p></td><td id="content"><p><b>Implementer Page: </b><a href="date.sum.html">date.sum.html</a><br/><b>Function Package: </b><a href="date.sum.zip">date.sum.zip</a></p><h4>Function Syntax</h4><pre><var>string</var> <b>date:sum</b>(<var>node-set</var>)</pre><div><p>
         The <code>date:sum</code> function adds a set of durations together.  The string values of the nodes in the node set passed as an argument are interpreted as durations and added together as if using the <a href="/date/functio