nbsp;}<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;encode_pair&nbsp;:&nbsp;<span class="constructor">Build_path_prefix_map</span>.pair&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;string<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;decode_pair&nbsp;:<br>
&nbsp;&nbsp;&nbsp;&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;(<span class="constructor">Build_path_prefix_map</span>.pair,&nbsp;<span class="constructor">Build_path_prefix_map</span>.error_mes