HXQ-0.17.0: data/q5.xq

declare function local:copy($element as element()) as element() {
   element {name($element)}
      {$element/@*,
          for $child in $element/node()
              return
               if ($child instance of element())
                 then local:copy($child)
                 else $child
      }
};

local:copy(doc('data/cs.xml')/*)