lass="keyword">auto</span>&amp;&amp; else_) -&gt; decltype(<span class="keyword">auto</span>) {</div>
<div class="line">        <span class="keywordflow">return</span> tag-dispatched;</div>
<div class="line">    }</div>
</div><!-- fragment -->
<p>Conditionally execute one of two branches based on a condition. </p>
<p>Given a condition and two branches in the form of lambdas or <code><a class="el" href="structboost_1_1hana_1_1lazy.html" title="hana::lazy implements superficial laziness via a monadic interfac