 class="code">[]]</code> matches a <code class="code">]</code> character and
      <code class="code">[^]]</code> matches any character that is not <code class="code">]</code>.
      Use <code class="code">%%</code> and <code class="code">%@</code> to include a <code class="code">%</code> or a <code class="code">@</code> in a range.</li>
<li><code class="code">r</code>: user-defined reader. Takes the next <code class="code">ri</code> formatted input
      function and applies it to the scanning buffer <code