e>x</code>. Useful for chaining matchers where the first returning non-<code>None</code> determines the result.</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-if_none_eval"><a href="#val-if_none_eval" class="anchor"></a><code><span><span class="keyword">val</span> if_none_eval : <span>f:<span>(<span>unit <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'a</span>)</span> <span class="arrow">&#45;&gt;</span></span> <span><span><span class="type-var">'a</span> 