"VALfold"><span class="keyword">val</span> fold</span> : <code class="type">('b -&gt; 'a -&gt; 'b) -&gt; 'b -&gt; 'a <a href="Stack.html#TYPEt">t</a> -&gt; 'b</code></pre><div class="info ">
<code class="code">fold f accu s</code> is <code class="code">(f (... (f (f accu x1) x2) ...) xn)</code>
    where <code class="code">x1</code> is the top of the stack, <code class="code">x2</code> the second element,
    and <code class="code">xn</code> the bottom element. The stack is unchanged.<br>
<b>Since</b> 4.03<