sp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;iteri&nbsp;:&nbsp;(int&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;char&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit)&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;map&nbsp;:&nbsp;(char&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;char)&nbsp;<span class="key