class="anchor"></a><code><span class="keyword">val</span> join : <span>[&lt; <a href="index.html#type-t">t</a> ]</span> <span>&#45;&gt;</span> <span>[&lt; <a href="index.html#type-t">t</a> ]</span> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a></code></dt></dl><dl><dt class="spec type" id="type-xcompare"><a href="#type-xcompare" class="anchor"></a><code><span class="keyword">type</span> <span>'a xcompare</span></code><code> = <span>lhs:<span class="type-var">'a</span></span> <span>&#45;&gt;</span>