<code><span class="keyword">type</span> <a name="TYPEorder"></a><code class="type"></code>order = </code><table class="typetable">
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span class="constructor">PreOrder</span></code></td>

</tr>
<tr>
<td align="left" valign="top" >
<code><span class="keyword">|</span></code></td>
<td align="left" valign="top" >
<code><span class="constructor">PostOrder</span></code></td>

</tr></table>


