int docContext = dtm.getDocumentRoot(context);
XObject arg = (XObject) this.getArg0().execute(xctxt);
String base = "";
Expression arg1Expr = this.getArg1();
if (null != arg1Expr)
{
// The URI reference may be relative. The base URI (see [3.2 Base URI])
// of the node in the second argument node-set that is first in document
// order is used as the base URI for resolving the
// relative URI into an absolute URI.
XObject arg2 = arg1Expr.execute(xctxt);
if (XObject.CLASS_NODESET == arg2.getType())
{
int baseNode = arg2.iter().nextNode();