r>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;weaken_map&nbsp;:&nbsp;<span class="constructor">String</span>.<span class="constructor">Set</span>.t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">Depend</span>.map_tree&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">Depend</span>.map_tree<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;free_structure_names&nbsp;:&nbsp;<span class="constructor">String</span>.<span class="constructor">Set</spa