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I don't agree that when people talk about the complexity of W3C schemas they
are referring to the formalism, at least in my case I'm not.
After all, SQL has an underlying formalism yet this doesn't prevent relatively
untrained programmers from using it to write VB-front ends to DB apps, mySQL
backed weblogs, and Microsoft Access applications without having to understand
relational algebra, set theory, cartesian products, etc. because when it boils
down to it the essence of SQL is relatively simple and straightforward.
On the other hand, W3C XML schemas are not simple to use and are definitely
not straightforward. No one completely grasps all of its nuances even amongst
the experts in the field and even the W3C puts out buggy test cases.
Unfortunately it is beginning to look like most people are going to end up
using GUI tools to create them, I've lost count of the amount of newsgroup
posts about schemas and also that we'll have interoperability issues when
people try to move schemas from one validating parser to the other due to
incompatibilities between parser implementations even over concepts that
should be fairly basic (my personal favorite is anything involving
THINGS TO DO IF I BECOME AN EVIL OVERLORD #41
Once my power is secure, I will destroy all those pesky time-travel devices.
----- Original Message -----
From: "Jonathan Robie" <firstname.lastname@example.org>
To: "Sean McGrath" <email@example.com>; <firstname.lastname@example.org>
Sent: Wednesday, January 02, 2002 7:33 AM
Subject: RE: [xml-dev] W3C's five new XQuery/Xpath2 working drafts - Still
> At 02:24 PM 1/2/2002 +0000, Sean McGrath wrote:
> >>[Michael Champion]
> >>The larger issues that Mike Kay raises are critical: All this committee
> >>is for nothing if the result is too complex or expensive to actually use.
> >>am not all that much dumber than the average software developer, I have
> >>followed the XML world full-time for 5 years now, and this
> >>schema/PSVI/strongly-typed XQuery stuff makes my head spin. I can't
> >>what ordinary developers who don't focus on XML will think of it.
> >>Actually, come to think of it, I can ... it will be C++ and the Windows
> >>all over again; few developers go anywhere near it without GUI tools and
> >>wizards to hide the complexity behind a proprietary front end.
> Formalisms are a helpful way to design something that is simple and
> consistent. For most users, formalisms are not easy to grasp, so they are
> not a good way to present a language to a user. Languages quite commonly
> are designed using tools that the user is not exposed to - relatively few
> users read the EBNF description of the languages they use, learn the formal
> type system, or understand precisely how polymorphism is implemented. In a
> well-designed language, this does not prevent them from using the syntax,
> the types, polymorphism, etc based on an informal understanding.
> RELAX-NG is a simple and straightforward language, but it is defined with
> formalisms quite similar to those of the XML Query Formal Semantics. XML
> Schema is not as simple and straightforward as RELAX-NG, and this may be
> partly due to the fact that its formal semantics were defined after the
> language itself - had it been done earlier, I think XML Schema would be
> simpler for end users.
> I think XQuery is pretty easy and straightforward for end users.
> >Thus playing right into the hands of those who would make lock us in
> >to their tools. As data owners, we need to fight this. When really smart
> >people start talking about needing GUIs to grok what some notation really
> >*means*, they are wittingly or otherwise heading down the vendor-lockin
> >fork in the road.
> I disagree - the formalisms ensure that the language is unambiguously
> specified, which ensures interoperability.
> Most programmers work perfectly well with a somewhat vague understanding of
> what their languages do - adequate for programming, but not adequate for
> implementing the language. I doubt very much that people will learn XQuery
> by reading the Formal Semantics. The language specification itself is also
> becoming more oriented toward implementors.
> >I fully expect to get flamed for that statement but what the heck.
> >I'm trying to grok some vendor locked in XML at the moment and consequently
> >I'm not in a very good humour.
> XQuery is being widely implemented - surely you are not claiming that it is
> a proprietary vendor scheme? If so, which vendor are you accusing? Since
> the original language, Quilt, was created by people from Software AG, IBM,
> and Crossgain, I assume one or more of these companies must have hatched
> the plot....
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