
fn:doc( [$uri as xs:string*] ) as document-node()*
Returns the document(s) stored in the database at the specified URI(s).
document-node() returned for each item in the result
  contains an element() root node for XML documents, a
  text() root node for text documents, an 
  object-node(), array-node(), or another JSON node
  for a JSON document, and a binary() root node for binary 
  documents.
fn:doc("/mydocs/doc.xml")
=> returns the document at the URI /mydocs/doc.xml