+ $r = preg_replace_callback('@(ftp|http|https|mms|rtsp|gopher|news|nntp|telnet|wais|file|prospero|webcal|xmpp|irc)://[^\]>\s]+@', 'common_render_uri_thingy', $r);
+ $r = preg_replace_callback('@(mailto|aim|tel):[^\]>\s]+@', 'common_render_uri_thingy', $r); // Pseudo-protocols don't require '//' after ':'.