"val-union"><a href="#val-union" class="anchor"></a><code><span><span class="keyword">val</span> union : <span><span>(<span><a href="../index.html#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-value">value</a> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-value">value</a> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-value">value</a> option</span>)</span> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-t">t</a> <span cla