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On Thu, 12 Jun 2003, Michael Kay wrote:
> > Thanks for the clarification, these are the things I was
> > hoping someone could tell me, using for iterator etc, have we
> > introduced more non-closed operators?? Has someone looked at
> > them closely..?? I suspect there will be some more operators
> > of this nature in XPath 2.0..
> The input and output of XPath operations are constrained to be values
> described by the XPath data model. In that sense the language is closed.
> Whether the data model has the particular mathematical properties you
> are looking for is something I can't easily judge.
That is right, with respect to values they are closed. But the question is
with respect to schema.. I think this might be useful to know these
Anyways, if someone does study all the operations of XPath, XQuery etc,
and see under what they are closed (w.r.to schema), I think it might be
cheers and regards - murali.
> There are a few glitches in terms of closure, for example I'm not very
> comfortable with the fact that the semantics of FLWR expressions in
> XQuery are defined using a notion of "tuples" which are objects that
> can't be represented directly in the data model, but overall I think
> it's pretty clean.
> Michael Kay