ex.html#type-t">t</a> <span>&#45;&gt;</span> int <span>&#45;&gt;</span> unit</code></dt><dt class="spec value" id="val-is_visited"><a href="#val-is_visited" class="anchor"></a><code><span class="keyword">val</span> is_visited : <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> int <span>&#45;&gt;</span> bool</code></dt><dt class="spec value" id="val-update"><a href="#val-update" class="anchor"></a><code><span class="keyword">val</span> update : <span>?&#8288;add_symops:int</span> <span>&#45;&gt;</spa