>         The only way I see a graph traversal possible in XSLT that
> can keep track of the nodes it has already tried is if the

If you use Saxon, you could use the extension saxon:set-attribute on the
node to mark it.
 
>         I hope someone else has a better answer; it's a really good
> question: How powerful is this XSLT?

Very powerful, but there are forces both in nature and in computer
science that it needs a little help in order to master them completely.

The help is easy to provide with Java extensions in Saxon; much easier
than in XT in my experience.

 Steve


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