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Re: A few things I noticed about w3c's xml-schema
- From: Murali Mani <mani@CS.UCLA.EDU>
- To: Rick Jelliffe <email@example.com>
- Date: Wed, 30 May 2001 21:15:42 -0700 (PDT)
thanks -- I agree that i seem to be interested in only *one* aspect --
supporting operations. I consider it very important, though.
i fully agree that most specifications are based on speculative analysis
-- how much can be speculated is always an issue. The final convergence
point is not clear at least to me.
I will hope that finally the schema will be good -- i am doubtful, but i
am quite sure that the only solution will be to revert back to the rich
literature on regular tree languages -- also hope that we can satisfy all
the requirements. I will request the schema people to try to read the
material on regular tree/hedge languages -- i think it mostly will turn
out to be important.
thanks and regards - murali.
On Thu, 31 May 2001, Rick Jelliffe wrote:
> From: "Murali Mani" <mani@CS.UCLA.EDU>
> > I also *fully* agree that RELAX NG is the most important thing that is
> > happening at present.
> But the point is that it is _still_ happening: the different flavours of
> RELAX were not good enough for James' criteria so he made TREX; TREX is not
> good enough for Murata-san so they are co-operating on developing it
> further, over at OASIS.
> If James, one of the keenest technocrats around, is still working on a
> language after more than a decade experience with DTDs, with reviewing the
> efforts of the XML Schemas WG, and after consideration of the seminal DSD
> and RELAX, what does that suggest?
> It suggests to me that _any_ standard for schemas must be considered either
> premature or interim, at the current time. And this is exactly the approach
> that the XML Schema WG has taken: XML Schemas 1.0 is provisional both in
> small matters (because of the work of XML Schemas 1.1) and in larger
> matters (the mooted XML Schemas 2.0).
> Murali carpets W3C XML Schemas as bad, but he is in fact only interested in
> one area of them. The areas of datatyping, schema construction, keyrefs,
> name handling have all been pretty well received: even though they are all
> amenable improvement (respectively localizable datatypes, modules, better
> keyrefs, status of schemaLocation). (These are things I hope XML Schemas
> 1.1 will improve.)
> The areas that have not been well received are
> -- perceived complexity of the spec (though complexity of the spec and
> complexity of the technology are not at all the same thing: looking at the
> two diagrams in the specs shows there is not spaghetti at the top-levels)
> -- type derivation (is it very useful for non-databases?)
> -- the details of the grammar (is it overly
> I don't see RELAX NG as a competitor to XML Schemas; to the contrary, I
> think we can only ascend to XML Schemas 2.0 when there are credible
> alternative languages developed and deployed, by which we can judge XML
> Schemas 1.n. (It is dialectic development.)
> So RELAX NG is the best friend of the XML Schema WG, in the long run: it is
> their unofficial research lab. I don't know if Murata-san works on company
> time on RELAX-NG, but I were his manager at IBM I would allot him spend as
> much time as possible on it, because of IBM's commitment to XML Schema. If
> he is working on company time, then IBM should be congratulated.
> RELAX NG may be just as important for XML Schemas 2.0 as the XML Schemas 1.1
> standards work. But I hope deployment experience from XML Schemas 1.n will
> be much more influential than any speculative analysis: I think speculative
> analysis is the methodology used both in XML Schemas and RELAX NG and
> ultimately it provides no guarantee of producing a productive result. When
> a spec is made by committees sitting around the globe making up user
> requirements on the spot as needed to justify their technological and
> aesthetic predelictions, with no regard for how humans think and act, the
> emperor has no clothes, no matter how relaxing he may find it.
> An alternative take on all this would be that, if grammars (one of the most
> exhaustively studied abstractions) introduce problems (such as the problem
> adding or substracting schemas from each other) that are still (after 16+
> years of schema language development) then perhaps they are dense and
> compelling distractions which are actively preventing us from adopting more
> schema paradigms.
> Rick Jelliffe
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