h>
                    <p>
                      Expression
                    </p>
                  </th>
<th>
                    <p>
                      Semantics
                    </p>
                  </th>
</tr></thead>
<tbody>
<tr>
<td>
                    <p>
                      <code class="computeroutput"><span class="identifier">columns</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code>
                    </p>
                  </t