p;&nbsp;<span class="keyword">val</span>&nbsp;map&nbsp;:&nbsp;(elt&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;elt)&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;t<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;choose_one&nbsp;:&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;elt<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;of_list