 enum instances <code>a</code> and <code>b</code> by value.</p>
<p>Unlike <code>a == b</code>, this function performs a deep equality check on the
arguments of the constructors, if exists.</p>
<p>If <code>a</code> or <code>b</code> are null, the result is unspecified.</p></div></div><div class="field "><a name="enumIndex"></a><h3 class="anchor"><code><span class="label label-static">static</span><a href="#enumIndex"><span class="identifier">enumIndex</span></a>(<span style="white-space:nowrap">e:<a class="t