br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Pcl_open</span>&nbsp;<span class="keyword">of</span>&nbsp;<span class="constructor">Parsetree</span>.open_description&nbsp;*&nbsp;<span class="constructor">Parsetree</span>.class_expr<br>
&nbsp;&nbsp;<span class="keyword">and</span>&nbsp;class_structure&nbsp;=&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;pcstr_self&nbsp;:&nbsp;<span class="constructor">Parsetree</span>.pattern;<br>
&nbsp;&nbsp;&nbsp;&nbsp;pcstr_fields&nbsp;: