W3C home > Mailing lists > Public > xml-uri@w3.org > May 2000

Re: Use cases

From: Simon St.Laurent <simonstl@simonstl.com>
Date: Wed, 17 May 2000 11:07:02 -0400
Message-Id: <200005171505.LAA27410@hesketh.net>
To: Michael Rys <mrys@microsoft.com>, "'xml-uri@w3.org'" <xml-uri@w3.org>
At 06:29 PM 5/16/00 -0700, Michael Rys wrote:
>The main scenarios that I am aware of is to refer to inline XDR schemas and
>inline XSLT function extension mechanisms. The schema references may be
>hand-authored or generated by some of the XML and ADO XML database tools.
>Both scenarios do not care about the actual string value but are used for
>resolution. However, see below!

The generated documents are what interest me most, as hand-authored
documents might be easier to fix if such a fix was necessary.

>The issue is not really an MS issue. The issue is that a relatively old rec
>exists that requires literal interpretation of namespaces for equality. Any
>change to this interpretation, in particular introducing additional
>processing of namespace uris to determine equality will break current
>documents and their processing. While we as tool implementors have control
>over the tools we write, we do not have control over our customers'
>documents.

15 months is old?  That's okay, you're right.

So let me double-check this.  Microsoft is currently using relative URIs to
support various XML operations.  This usage works just fine under the
namespaces rec as currently interpreted - equality by string comparison -
but may break should relative URIs be absolutized.

>In general retroactive spec changes would be acceptable "if possible",
>namely: 
>
>1. retroactive changes have virtually no impact on the conformance of
>existing documents (e.g. loosen constraints, not tighten), 
>2. retroactive changes can be introduced by vendors with minimal customer
>disruption, 
>3. that changes larger than these employ a versioning mechanism, 
>4. that a new version have compelling feature benefits to drive adoption by
>vendors and customers. 
>
>In the specific case being considered, none of these conditions appear to
>obtain, and thus changes to the NS recommendation should not be considered
>as a possible option.

That's a nice concise statement.

>Note that a versioning of the XML Namespace spec may be acceptable if done
>right. However, there are other issues associated with that.

I think it's fair to say that there are issues involved in any versioning
of XML-based specs, many of them thorny.

>Best regards
>Michael "Weenie" Rys 

Thanks for your patience, and for the clear direct answers.

At least I feel like I have a grasp on the backward-compatibility issues now.

Simon St.Laurent
XML Elements of Style / XML: A Primer, 2nd Ed.
Building XML Applications
Inside XML DTDs: Scientific and Technical
Cookies / Sharing Bandwidth
http://www.simonstl.com
Received on Wednesday, 17 May 2000 11:05:07 UTC

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