x.html#val-op"><code>op</code></a>.</p></dd></dl><dl><dt class="spec value" id="val-concat"><a href="#val-concat" class="anchor"></a><code><span class="keyword">val</span> concat : <span><a href="index.html#type-t">t</a> <a href="../../../../Alg_structs/NonEmptyList/index.html#type-t">Alg_structs.NonEmptyList.t</a></span> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a></code></dt><dd><p><code>concat xs</code> is the concatenation of all elements of <code>xs</code> into a single value using <code>op