kkallio@8: class gui t = t -> xbody
kkallio@8: 
kkallio@8: fun toXml [t ::: Type] (xmlize : gui t) = xmlize
kkallio@8: 
kkallio@8: fun gui_xbody x = x
kkallio@8: 
kkallio@8: fun mkGui [t ::: Type] (toXml : t -> xbody) = toXml