[$arg as String]
) as complexType()?
Returns the complex type of item, as a schema component, if any.
If the item has a simple type rather than a complex type, the empty
sequence is returned.
The context item is used if no argument is given.
If the item is a document node, the result is the complex type of its
If the item is an element node, the result is the complex type of its
If the item is a schema component, the result is the associated
complex type schema component.