t><span class="paramLabel">Parameters:</span></dt>
<dd><code>context</code> - The context of this evaluation.</dd>
<dd><code>base</code> - The base object whose set of valid properties is to be enumerated, or <code>null</code> to enumerate the
 set of top-level variables that this resolver can evaluate.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>An <code>Iterator</code> containing zero or more (possibly infinitely more) <code>FeatureDescriptor</code>
 objects, or <code>null</code> if this r