l-exists"><a href="#val-exists" class="anchor"></a><code><span class="keyword">val</span> exists : <span>(<a href="../Loc/index.html#type-t">Loc.t</a> <span>&#45;&gt;</span> bool)</span> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> bool</code></dt><dt class="spec value" id="val-mem"><a href="#val-mem" class="anchor"></a><code><span class="keyword">val</span> mem : <a href="../Loc/index.html#type-t">Loc.t</a> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <span>&#