
cts.indexOrder( index as cts.reference, [options as String[]] ) as cts.order
  Creates a index-based ordering clause, for use as an option to
  
  cts.search.
Only one of "ascending" or "descending" may be specified in the options parameter. If neither "ascending" nor "descending" is specified, then the default is "ascending".
cts.indexOrder(cts.elementReference(xs.QName("TITLE")));
// returns the following:
// cts.indexOrder(cts.elementReference(fn.QName("","TITLE"),
//   ["type=string","collation=http://marklogic.com/collation/"]), "ascending")