xml-dev - Re: Namespaces problems (SOAP, ...) and general problem of standard sim

[Miloslav Nic <nicmila@idoox.com>]

Andrew Layman wrote:
> 
> Per the W3C specification for namespaces, the "price" element name in the
> example you cite is an unqualified name.  The XML Schemas specification
> provides for locally scoped names, and also provides that an unqualified
> name may be the expression of a locally scoped name.
> 
> In short, the example is valid per XML 1.0, valid per the namespaces
> specification and valid per the schemas specification.  Per the namespaces
> specification alone, the price element does not have a universally-qualified
> name, so additional context is needed for its unambiguous interpretation.
> XML Schemas provide one way to give that additional context.
> 

I did not object the syntax but meaning. I know that the syntax is O.K.
from standard point of view.
But the example was evidently written with human readable assumption
that Price belongs to
GetLastTradePriceResponse. But machine does not understand this meaning.
As long as recipients of
the message just check for the presence of <Price> element, that's O.K.
and with simple applications I suspect nobody 
will bother to be really thorough. But what if you combine several
answers to the SOAP message and then what if you
build some reasoning into your code. Then something like this will break
your software. 
According to my view namespaces are an excellent tool but the more
people will say with them something else than they
intended the less useful they become. 

 <m:GetLastTradePriceResponse  xmlns:m="Some-URI">
      <Price>34.5</Price>
</m:GetLastTradePriceResponse>


> I hope this is helpful.  You might also want to take a look at the very nice
> XML Schemas Primer editted by David Fallside, at
> http://www.w3.org/TR/xmlschema-0/.
>

<my-original-mail>
But to master them you must
master namespaces, regular expression, object oriented technologies,
XPath, ...
</my-original-mail>

I read it about 5 times and I read the standard a few times.
I wrote tutorials about XML, DTD, regular expressions
(http://zvon.vscht.cz/ZvonHTML/Zvon/zvonTutorials_en.html).
While I am amateur and very average programmer but I did object
programming in Lisp, Java and C++.
Recently I read quite a few papers about RDF and about ontology. 

Equipped with this and with strong feeling that it is really useful it
took me quite a long time to get mental picture of the standard. When I
saw Rick Jeliffe Schematron a few months ago I could use it in a few
minutes and I still consider 
it an intellectual master piece. According to my view he found a nice
balance between power and simplicity.
And of course I am a great admirer of XPath.

Saying that, please do not take the previous paragraph as a claim of
intellectual inefficiency of the XML Schema authors, after all Rick
Jeliffe  is one of them and there are others listed I admire their work.
But I cannot help my feeling is that standards become larger and larger.
Would it be somehow possible to bring OO to standard work? In the
current way we will have plenty of 90% standard implementations and the
last 10% will always differ one implementation from another.  

And mainly, XML based methodologies and tools could be very useful in
domains outside computer science and comp. applications.
But to achieve this you must have  experts in XML, experts in the given
domain and some means how to communicate between them. I am afraid this
communication becomes more and more difficult.




 
> Best wishes,
> Andrew Layman
> 
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*** Miloslav Nic                    ***
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