>
> I think ISO/IEC 19757-4 NVDL is the mechanism by which we can safely
> look at XML instances using the view that sets of labeled information
> found in a single instance *each have their own model* ... those sets
> identified unambiguously through the use of namespace-rich
> labels.  This is not achievable with the traditional view that the
> entire instance *has a single model* that is sacrosanct.  The real
> world does not accommodate this traditional view well when trying to
> accommodate different users' needs.

I'm actually having some problems with NVDL, because I was having a
hard time reading in the available documentation how one would handle
specific common situations. These are:

1. Namespace qualified attributes on an element of another element.
I really can't think of any way one could handle that in a reasonable
manner, and I suspect that in most scenarios this would be one
namespace extending another, not a mix of two data sets. But I don't
this for a fact, just a suspicion.

2. propogation of text nodes up from elements in namespace y to
elements in namespace x, example:

<x:x>
<y:y>text node</y:y>
</x:x>

in this scenario y:y is extending x:x, and conceptually we assume that
they share the text node. so when split they should be

<x:x>text node</x:x>
and <y:y>text node</y:y>

I think this is a reasonably common usage but I'm not sure if NVDL
handles it.  I suppose the argument could be made that this is an
extremely dangerous and dirty usage, and we would not want to automate
that kind of splitting of data.

Cheers,
Bryan Rasmussen