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Re: A plea for Sanity

From: Norman Walsh <Norman.Walsh@Sun.COM>
Date: Wed, 21 Aug 2002 17:27:29 -0400
To: jenglish@flightlab.com
CC: xml-names-editor@w3.org, w3c-xml-core-wg@w3.org
Message-ID: <87fzx7dhry.fsf@nwalsh.com>

Joe,

The Core WG has considered your comments[3] on XML Namespaces 1.1.

> But the new requirement implies that the *exact set of in-scope
> namespaces at each node* is an essential part of the Infoset.
> This is the part that I think is ill-considered.  This property
> should be deemed inessential, just as whitespace in tags and the
> order of attribute value specifications are deemed inessential.
> XML-related specifications should not expect or demand that it be 
> preserved; any set of namespace declarations that produce the same 
> {URI+localname} pairs after namespace processing should be considered 
> equivalent.
> 
> In particular, "additional namespace information items which
> serve no useful purpose" -- and hence do not affect the interpretation
> of QNames in markup or content -- should not matter.  Applications
> should be free to insert or discard them as they see fit without
> changing the meaning of the Infoset.

In the best of all possible worlds, you're right. The set of namespace
declarations and in-scope namespaces should be irrelevant. But in
point of fact, the existence of QNames in content adds great
complexity to task of determining the semantics of an XML document.
Some of these complexities are discussed in the TAG[1] finding "Using
Qualified Names (QNames) as Identifiers in Content"[2].

In particular, changing the set of in-scope namespaces for a given
element may effect a change in the semantics of that element, its
attributes, or its descendants to some down-stream processor. As much
as we might wish that that were not the case, it appears impossible to
circumvent at this time.

Therefore the XML Core WG still supports the requirement to be able to
undeclare namespaces.

On behalf of the W3C XML Core WG,
Norman Walsh

[1] http://www.w3.org/2001/tag
[2] http://www.w3.org/2001/tag/doc/qnameids
[3] http://lists.w3.org/Archives/Public/xml-names-editor/2002May/0009

-- 
Norman.Walsh@Sun.COM    | We measure the excellency of other men, by
XML Standards Architect | some excellency we conceive to be in
Sun Microsystems, Inc.  | ourselves.--John Selden
Received on Wednesday, 21 August 2002 17:29:55 UTC

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