&gt;</span> <span class=comment>// the key is the entire element</span>
    <span class=special>&gt;</span>
  <span class=special>&gt;</span>
<span class=special>&gt;</span> <span class=identifier>cont</span><span class=special>;</span>
</pre></blockquote>

<h3><a name="member"><code>member</code></a></h3>

<p>
<a href="../reference/key_extraction.html#member"><code>member</code></a>
key extractors return a reference to a specified
data field of the base object. For instance, in the following version of our