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   RE: simple question on namespaces. Last one.

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  • From: Andrew Layman <andrewl@microsoft.com>
  • To: xml-dev@lists.xml.org
  • Date: Thu, 28 Dec 2000 14:34:28 -0800

The XML Namespaces specification says certain things and not others.  It is
an improper use of the specification to cite it to mean things that it does
not say or that are in contradiction to what it does say.  This holds
equally true whether one approves or disapproves of what it says. 

1.	a. The URI of a namespace is not a mere string.  Per the namespaces
in XML specification, it is a URI.
	b. I do not know what you mean by "No hidden benefits for any XML
processing tool."

2.	a.	Retrieval of a document or other resource based on the URI
of the namespace is not "abuse" of the specification.  The specification
states "It is not a goal that it be directly usable for retrieval of a
schema (if any exists)."  Had it been the intention of the specification's
authors to prohibit retrieval of a resource, the wording would have said
that, instead.  As it is, the specification is simply neutral on the matter
of whether retrieval is possible or not, desirable or not.
	b.	I do not know what documents you refer to by the definite
article in "the documents".

3.	I do not understand what you are saying in this point.

4.	I do not understand what you are saying in this point.

I do not understand the somewhat conspiracy-theory like discussions of "tool

One last point: During the namespaces specification design and also during
the design of schemas, it was lengthily debated whether a namespace and a
schema are coextensive, that is, whether there is only one schema associated
with a namespace and visa versa.  In both cases, the conclusion after much
consideration was that namespaces and schemas are distinct.  Elements etc.
within a namespace may be associated, at the processing applications
convenience, with any schema.  Further, there may be named items in a
namespace that are not associated with any schema.  (This is a separate
matter from whether the owner of a namespace may wish to publish a
definitive schema and state its association.)

-----Original Message-----
From: Paul Tchistopolskii [mailto:paul@qub.com]
Sent: Wednesday, December 27, 2000 9:35 PM
To: xml-dev@lists.xml.org
Subject: Re: simple question on namespaces. Last one.

----- Original Message ----- 
From: Paul Tchistopolskii <paul@qub.com>

> When something is *not* a URL it should *not* look like a URL. My
> just cleans up the mess, I think.  And I still think I'm right because I
see not 
> too much rationale in your arguments.

I'm wrong.  Somehow.

After reading the letter 
From: Andrew Layman <andrewl@microsoft.com>
I'm making a bit different statement.

1. Current semantics of namespace declaration is to 
attach some hidden string to every element/attribute
in the document. The value of the string does not matter, 
the only restriction is to be unique. No hidden benefits 
for any XML processing tool.

2. Some company makes some tool ( tool X ) which 
starts abusing the namespace declaration, using URLs 
to retrieve the documents. It *is* abusing the namespace 
declaration ( because the semantics of the namespace 
declaration is (1)) , but who cares, right ?

3. I'm  XML developer. I have to design some schema 
and I also want my documents to be processed by tool X. 
Of course - I'll use URLs for my namespaces , so that tool 
X can work with my 'namespaces'. Why should I take 
something *other* than URL ? URL is fine with  
W3C paper. URL is fine with 'tool X'. - very good.

4. That's it. Now it does not matter to me  what 
is actually written in some paper on W3C website. 
Also because that paper explicitly says that 
"URLs could be used"  -  there is no contradiction. 
Just another 'de facto' standard of tool X which 

"namespaces are URLs and please : 
make this and that information accessible by URL". 

That's it. I'm doomed. See - how easy. I should now 
configure my webserver in some way that will be 
good *only* for  'tool X' .

We should just wait for first tool X to appear. I also think 
I know what will be the first company producing tool X.

I was wrong. 

Those namespaces things should be URLs, because they 
will *be*  URLs anyway. 

What is your problem with URLs PaulT ?

My problem is that the scenario  described above 
works only for *one*  company producing 'tool X'.  

If there are 2 companies, and 2 tools X and I want to 
process my documents with both of the tools, I can 
not do that. One tool may expect one thing at the 
end of URL, another tool may expect another thing at 
the end of the *same* URL , and I have URLs hardcoded 
in every document I have, because they are not my URLs!
They are my *namespaces*. Just 'tuned' a but for the sake 
of 'tool X'.

If some tool starts abusing namespaces declaration 
( using URL for retrieval ) I'm locked to that tool.

The only way to avoid this situation is to have the current 
semantics of the namespace declaration  ( see (1) - above )
and to make it hard to abuse it. 

That's why I tried to remove the http: from the URL. It makes 
a bit harder  to abuse namespaces declaration and it has all the 
current benefits of uniqueness.

Nevermind. I'm waiting for  tool X to appear. 



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