 class="spec value" id="val-fold_map"><a href="#val-fold_map" class="anchor"></a><code><span class="keyword">val</span> fold_map : <span>m:<span>(<span class="keyword">module</span> <a href="../../../alg_structs/Alg_structs/Monoid/module-type-S/index.html">Alg_structs.Monoid.S</a> <span class="keyword">with</span> <span class="keyword">type</span> <a href="../../../alg_structs/Alg_structs/Monoid/module-type-S/index.html#type-t">t</a> = <span class="type-var">'m</span>)</span></span> <span>&#45;&gt;</span> <