No, neither.  That behavior is implemented in the same way as in the Lisp in Dart (<a href="http:&#x2F;&#x2F;www.oki-osk.jp&#x2F;esc&#x2F;dart&#x2F;lisp-en.html#4" rel="nofollow">http:&#x2F;&#x2F;www.oki-osk.jp&#x2F;esc&#x2F;dart&#x2F;lisp-en.html#4</a>).