t></td>
     <td headers="matches">A word boundary</td></tr>
 <tr><td valign="top" headers="construct bounds"><tt>\B</tt></td>
     <td headers="matches">A non-word boundary</td></tr>
 <tr><td valign="top" headers="construct bounds"><tt>\A</tt></td>

     <td headers="matches">The beginning of the input</td></tr>
 <tr><td valign="top" headers="construct bounds"><tt>\G</tt></td>
     <td headers="matches">The end of the previous match</td></tr>
 <tr><td valign="top" headers="construct bounds"><tt>\Z</tt></td