>val</span>&nbsp;record&nbsp;:&nbsp;?accumulate:bool&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;(<span class="keywordsign">'</span>a&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>b)&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>a&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>b<br>
&nbsp;&nbsp;<span class="keyword">type</span>&nbsp;column