a href="index.html#type-t">t</a></span></code></dt><dt class="spec value" id="val-all_unit"><a href="#val-all_unit" class="anchor"></a><code><span class="keyword">val</span> all_unit : <span><span>unit <a href="index.html#type-t">t</a></span> list</span> <span>&#45;&gt;</span> <span>unit <a href="index.html#type-t">t</a></span></code></dt></dl><div class="spec module" id="module-Let_syntax"><a href="#module-Let_syntax" class="anchor"></a><code><span class="keyword">module</span> <a href="Let_syntax/index.ht