ble path has a shape that corresponds to a statically known set of field labels, folds over those field labels.</p><p>Otherwise, calls the <code>fallback</code> function on <code>init</code>.</p><p>If the summary is <code>None</code>, will always fallback.</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-as_field_label_singleton"><a href="#val-as_field_label_singleton" class="anchor"></a><code><span><span class="keyword">val</span> as_field_label_singleton : <span><span><a href