tter factory provided by the library out of the box. For example,
          let's assume we have the following user-defined type that we want to use
          as an attribute value:
        </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">point</span>
<span class="special">{</span>
    <span class="keyword">float</span> <span class="identifier">m_x</span><span class="special">,</span> <span class="identifier">m_y</span><span class="special">;</span>

   