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Re: XQuery types was Re: Yet another plea for XUpdat

• To: Jonathan Borden <jborden@a...>
• Subject: Re: XQuery types was Re: Yet another plea for XUpdate...
• From: Dare Obasanjo <kpako@y...>
• Date: Sun, 5 May 2002 09:10:53 -0700 (PDT)
• Cc: xml-dev@l...
• In-reply-to: <000b01c1f49b$7ea90980$0301a8c0@n...>

This thread is a waste of my time. Obviously you have
refused to understand my point w.r.t. XQuery & updates
but instead are trying to flaunt some sort of
classical education and resorting to personal attacks.


Funny thing is I know people on the XQuery WG and I'm
sure they'd agree with me before they'd agree with
you. However, I have better things to do than slam my
head against a brick wall so I'll leave you to
continue your fawning fanboy adoration of the
fantastic XQuery "type system" on your own. 


--- Jonathan Borden <jborden@a...> wrote:
> Dare Obasanjo wrote:
> 
> > What you just stated doesn't jibe with any formal
> > knowledge I have about types and language systems
> but
> > since my background in formal computer science
> theory
> > is weak I won't attempt to correct your claims.
> 
> What I am talking about: _logic_ and its foundation
> in set theory, was
> formulated long before computers existed (e.g.
> starting perhaps with
> Aristotle, and codified by Geog Cantor) and remains
> apropos today. In any
> case, run, do not walk, to the bookstore, get
> yourself a copy of Tarski, and
> read it. It has nothing to do with computers but
> everything to do with
> classes and types and how you view the world.
> 
> >
> > So I'll try to explain my point in lay terms. The
> main
> > benefit of a type system is so that things can be
> done
> > *statically* at compile time instead dynamically
> at
> > run time. Validation is a dynamic process.
> 
> No. The main benefit of a "type system" is that
> individuals (e.g. individual
> documents or fragments of documents) can be
> collected into sets based on
> constraints. This is so simple and basic a concept
> that it should hit you
> right between the eyes. No formal mumbo jumbo
> needed.
> 
> I think you mean "static types" but I've not used
> that term, and think that
> is largely irrelevent to XML. It is a far too common
> mistake to conflate XML
> which is about _data_ with programming languages
> which are most often about
> algorithms and processes. The term "static type" has
> no meaning that I can
> see for an XML document.
> 
> Types or classes are a basic concept, indeed if you
> _start_ with just
> classes and a few details (e.g. cardinality) you can
> derive all of
> mathematics, and hence all of computer science.
> "Validation" is a process,
> an algorithm, that determines whether or not an
> individual is a member of
> the class. That's all.
> 
> >
> > Thus a "type system" based on validation isn't
> really
> > type system especially to people with a
> programming or
> > database background.
> 
> Let's just get this straight, the XQuery (or any
> other) "type system" is not
> "based on" validation, no matter what you read or
> how you interpret what you
> read, see above. This concept is really important so
> I will harp on it.
> Logic is so central to computer science that this
> needs to be understood. I
> don't mean to be condescending, but it is hard to
> have a meaningful
> converstation unless we agree on a few principles.
> 
> >
> > Bottom Line: The XQuery type system although
> onerous
> > and complex does not forestall the need for
> > post-update validation if/when XQuery becomes a
> DML
> > and not just a query language. Therefore claims
> that a
> > "type system" is necessary before update semantics
> can
> > be added to XQuery are ill-considered.
> 
> It is _impossible_ to define the term _semantics_
> without a "type system".
> Every piece of software which works correctly has an
> _implicit_
> understanding of this. The XQuery, or any other,
> formal semantics, is merely
> an explicit, longhand, way of writing this down. The
> benefit of writing this
> down is that there is a document that implementors
> and test suite developers
> can go to, to decide, e.g. when two different
> implementations give differing
> results, which is correct. In many, but not all,
> software applications,
> correctness is desired. In such cases a formal
> semantics is a good thing. I
> doubt these folks think they are wasting their time.
> 
> Jonathan
> 
> 
> 


=====
THINGS TO DO IF I BECOME AN EVIL OVERLORD #145
My dungeon cell decor will not feature exposed pipes. 
While they add to the gloomy atmosphere, they are good conductors of vibrations and a lot of prisoners know Morse code.

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