>&nbsp;<span class="keyword">of</span>&nbsp;<span class="constructor">Dir</span>.t&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">F</span>&nbsp;<span class="keyword">of</span>&nbsp;t<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;create&nbsp;:&nbsp;<span class="constructor">Dir</span>.t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">Base</span>.t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;t<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp