e><span><span class="keyword">val</span> reduce : 
  <span>init:<span class="type-var">'a</span> <span class="arrow">&#45;&gt;</span></span>
  <span>case:<span>( <span><span>( <span><a href="#type-term">term</a> <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'a</span> )</span> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-term">term</a> <span class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> <span class="xref-unresolved">Base</span>.option</s