> what about using saxon:discard-document()?
> 
> i guess it hard to persist id in this case

There was a discussion a whil eback on th esaxon list as to whether that
was really conformant. I think it is but you need to say that it is
(essentially) like xsl:copy-of

so if you call a document twice using discard-document you get (or might
get) copies of the original document node. But it's all in the exact
semantics of discard-document, which is out of scope for the xsl spec
itself. 

But generate-id() is clear you always get the same id if it is the same
node, but whether or not an extension function returns the same node or
a copy is another question...

David


________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is
powered by MessageLabs. 
________________________________________________________________________