lass="mendoza-code">(not patt)</code> </td> <td> Matches only if patt does not match. Will not produce captures or advance any characters. </td></tr>
    <tr><td><code class="mendoza-code">(! patt)</code>   </td> <td> Alias for <code class="mendoza-code">(not patt)</code> </td></tr>
    <tr><td><code class="mendoza-code">(look offset patt)</code> </td> <td> Matches only if patt matches at a fixed offset. offset can be any integer. patt will not produce captures and the peg will not advance any characters. <