XQuery recursive descent copy

recursive-descent-copy.xquery

(:~
 : Template for the recursive descent copy.
 :
 : This function does not actually modify anything as such.  Modify it as needed,
 : this version does by default, for each node, a recursive exact same copy.
 :
 : Note that in addition to typeswitch cases, you can also have regular if/else
 : statements, for more complex conditions, but conditions that can be expressed
 : as typeswitch cases will be more efficient.
 :)
declare function local:modify($node as node())
{
   typeswitch($node)
      (: recursively copy documents and elements :)
      case document-node() return
         document {
            $node/node() => local:modify()
         }
      case element() return
         element { fn:node-name($node) } {
            $node/(@*|node()) => local:modify()
         }
      (: copy attributes, text nodes, comments and PIs :)
      case attribute() return
         $node
      case text() return
         $node
      case comment() return
         $node
      case processing-instruction() return
         $node
      (: in MarkLogic, you can have other node types, like binary() and object() :)
      default return
         fn:error((), 'Unexpected node type')
};