 a closing bracket appears in a range, it must occur as the
      first character of the range (or just after the <code class="code">^</code> in case of
      range negation); hence <code 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