\@primitives{url}%
\def\@urlttstyle{\def\UrlFont{\ttfamily}}%
\def\@urlsfstyle{\def\UrlFont{\sffamily}}%
\def\@urlrmstyle{\def\UrlFont{\rmfamily}}%
\def\urlstyle#1{\csname @url#1style\endcsname}%
\urlstyle{tt}%
\def\url{\begingroup\urlstyle{tt}\Url}%
\let\UrlLeft\relax\let\UrlRight\relax%

