index order) and stores the resulting bytes in a new sequence
    that is returned as the result.</p>
</div>
</div>

<pre id="VALmapi">val mapi : f:(int -&gt; char -&gt; char) -&gt; bytes -&gt; bytes</pre><div class="info ">
<div class="info-desc">
<p><code class="code">mapi&nbsp;~f&nbsp;s</code> calls <code class="code">f</code> with each character of <code class="code">s</code> and its
    index (in increasing index order) and stores the resulting bytes
    in a new sequence that is returned as the result