lass="arrow">&#45;&gt;</span></span> <a href="#type-attr">attr</a></span></code></div><div class="spec-doc"><p><code>attr_of s q</code> returns the attribute of state <code>q</code> in <code>s</code>. Raise <code>Not_found</code> if there is no state <code>q</code> in <code>s</code></p></div></div><h2 id="building-functions"><a href="#building-functions" class="anchor"></a>Building functions</h2><div class="odoc-spec"><div class="spec value anchored" id="val-empty"><a href="#val-empty" class="anchor"></a><c