or">List</span>.rev_map2&nbsp;f&nbsp;l1&nbsp;l2</code> gives the same result as
   <a href="List.html#VALrev"><code class="code"><span class="constructor">List</span>.rev</code></a><code class="code">&nbsp;(</code><a href="List.html#VALmap2"><code class="code"><span class="constructor">List</span>.map2</code></a><code class="code">&nbsp;f&nbsp;l1&nbsp;l2)</code>, but is tail-recursive and
   more efficient.</p>
</div>
</div>

<pre><span id="VALfold_left2"><span class="keyword">val</span> fold_left2</span> :