b>Since</b> 4.06.0</li>
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">len&nbsp;&lt;&nbsp;0</code>.</li>
</ul>
</div>

<pre><span id="VALappend"><span class="keyword">val</span> append</span> : <code class="type">'a list -&gt; 'a list -&gt; 'a list</code></pre><div class="info ">
<div class="info-desc">
<p>Catenate two lists.  Same function as the infix operator <code class="code">@</code>.
   Not tail-recursive (length of the first argument).  The <code class="code">@</code>
   opera