W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > June 1997

Re: Update on namespaces

From: David G. Durand <dgd@cs.bu.edu>
Date: Wed, 18 Jun 1997 14:31:40 -0500
Message-Id: <v03007805afcddf59fd77@[205.181.197.104]>
To: w3c-sgml-wg@w3.org
At 11:28 AM -0500 6/18/97, Matthew Fuchs wrote:
>> For now, I lean to #3, with AF's a fallback position if there's a really
>> good reason for not doing #3.  Andrew Layman and have agreed to cook
>> up a formal proposal along these lines, which will be forthcoming.
>>
>>-- End of excerpt from Tim Bray
>
>Occam's razor would indicate going with #2, since we need add nothing.  #3 is
>certainly cool syntactic sugar, but it opens the door to messing with the
>structure of the GI.  I've also suggested a different extension for error
>recovery.

And the notion that XML should not have any syntax it does not need also
argues for #2. In fact, I have yet to see an answer to the arguments of
myself and others that there is _no_ positive argument for #3, if #2 can
meet the need.

The only argument that I can think of is a knee-jerk opposition to any form
of markup declaration by those members of the web community who _lack_ any
experience with structured markup other than HTML. Parsing the entity and
attribute declarations in the DTD subset provides more notational power
than any the hacked-up GI formats that have been proposed, and will be
required for reliable operation of XML-link anyway.

Needless to say (as you might guess from my presentation of the argument),
I am not convinced. However, I'd like to see the argument presented in
rational terms, or another better argument presented. I did reread all of
Andrew Layman's posts to look for the namespace requirements and the
original post that posed the problem. I did see aan assumption that the use
of architectural forms inherently involves a model of inheritance, but
nothing that showed a need that could not be met.

>The next step will be defining regular expressions for parsing the GI to
>determine which extensions are being used.  I don't say  that's good or bad,
>but I suggest it will now be inevitable.

This is one potential consequence of accepting solution #3, and I agree
that it's not very attractive.

Even worse is the creation of a DTD escape hatch that makes validation
impossible under current rules. Furthermore, it is proposed that we make
this change without an analysis of the underlying semantics of the
syntactic implications of the change. This would be foolhardy and
irresponsible. You can't create syntax before you analyze the semantics
you're looking for and hope to get it right.

WF documents are acceptable because they meet a variety of needs, but so
does the notion of valid documents. Re-casting XML so that DTDs are
essentially meaningless, because another namespace can dump aribtrary crap
into any document anywhere, without declaration, is a bad idea in
relatively objective terms. It trashes the utility of the DTD for those
purposes that it (imperfectly) meets.

I remain opposed to the whole notion of special namespace syntax absent a
clear justification of its absolute necessity. Rereading Andrew's posts has
only reconfirmed my impression that no such requirements have been
articulated so far. I also think that if it _is_ necessary we must know
what effects the new feature will have on validity. Validity does not solve
all problems, but it alleviates many, and making an instance syntax that
cannot be validated against some formal syntactic description throws those
benefits away.

Sorry to be a bit redundant, but I'm tired of seeing posts like Tim's that
started:

>The original statement of the requirement by Andrew Layman seems to have
>stood up pretty well under pressure of discussion here, and external talk
>with various interested groups here and there in the W3C and engineering
>groups around the web.

I think the only thing that we've seen is that some people need
architectures but don't care for the syntax. I don't think that that's a
reason to trash a significant part of the work we've already done, based on
concrete experience (over the whole group) of multiple decades (probably
more than a century) or markup experience.

Why did we waste time arguing about content models if we were going to add
the equivalent of a universal "Include #ANY" inclusion exception at the
11th hour without even considering its effect on the DTD?

   -- David


_________________________________________
David Durand              dgd@cs.bu.edu  \  david@dynamicDiagrams.com
Boston University Computer Science        \  Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/   \  Dynamic Diagrams
--------------------------------------------\  http://dynamicDiagrams.com/
MAPA: mapping for the WWW                    \__________________________
Received on Wednesday, 18 June 1997 14:37:08 EDT

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