[xsl] order by in XPath 2.0 expression?

["Darcy Parker" <darcyparker@xxxxxxxxx>]

Hi,

I was just reading a document about XML databases and saw this
interesting XPath expression:

for $i in /bead order by $i/text/@lang return $i

(Source: http://www.oracle.com/technology/products/berkeley-db/pdf/overview-of-berkeley-database-xml.pdf)

The meaning of it seems obvious - and useful.  But I have never seen
"order by" in an XPath expression before.  I had a look online. I
don't see anything about it in http://www.w3.org/TR/xpath20/ or in
Michael Kay's XSLT 2.0 and XPath 2.0 Programmer's Reference (4th
edition).  As well, I tested using it in saxon and see that it is not
recognized...

Perhaps this is an Oracle extension...?  Has anyone seen this in an
XPath implementation before?

Thanks

Darcy