bsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">String</span>&nbsp;<span class="keyword">of</span>&nbsp;(string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit)
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Set_string</span>&nbsp;<span class="keyword">of</span>&nbsp;string&nbsp;<span class="constructor">Pervasives</span>.ref
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Int</span>&