s that compare equal are kept in their original order) and
   not guaranteed to run in constant heap space.</p>

<p>The current implementation uses Merge Sort. It uses <code class="code">n/2</code>
   words of heap space, where <code class="code">n</code> is the length of the array.
   It is usually faster than the current implementation of <a href="Array.html#VALsort"><code class="code"><span class="constructor">Array</span>.sort</code></a>.</p>
</div>
</div>

<pre><span id="VALfast_sort"><span class="keyw