="computeroutput"><span class="identifier">matches</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code>
                    </p>
                  </td>
<td>
                    <p>
                      Execute the subject parser <code class="computeroutput"><span class="identifier">a</span></code>,
                      and return as its attribute whether it succeeded. The directive
                      itself does always succeed.
                    