[xquery-talk] XQuery treatment of xs:positiveInteger?

[David Sewell]

Given the following XQuery code:

  declare namespace my = "uri:foo";

  declare function my:simple-add($x as xs:positiveInteger,
                                 $y as xs:positiveInteger) as xs:positiveInteger
      { $x + $y };

  my:simple-add(2, 3)

Shouldn't this happily produce '5' for output, as it would if the data
types were all xs:integer?

I get complaints about argument type when I run this on three different
XQuery processors. For example, Saxon 8:

"Required type of first argument of my:simple-add()
  is xs:positiveInteger; supplied value has type xs:integer"

How can '2' not be interpreted as xs:positiveInteger?  (Adding a "+"
before the arguments doesn't make a difference.)

Am I missing something totally obvious about use of derived data types,
or is this a parser bug?

David

-- 
David Sewell, Editorial and Technical Manager
Electronic Imprint, The University of Virginia Press
PO Box 400318, Charlottesville, VA 22904-4318 USA
Courier: 310 Old Ivy Way, Suite 302, Charlottesville VA 22903
Email: dsewell at virginia.edu   Tel: +1 434 924 9973