Why namespaces?

Simon St.Laurent simonstl at simonstl.com
Wed Sep 1 16:54:04 BST 1999

At 04:19 PM 9/1/99 +0200, Oren Ben-Kiki wrote:
>Paul Prescod <paul at prescod.net> wrote:
>> If the validation layer sees two things as distinct then any layer built
>> on top of the validation layer should continue to see them as distinct.
>> To me that is a no-brainer. In this case the validation layer sees
>> htmlloose:P and htmlstrict:P as completely different documents. To the
>> validator they are as distinct as Docbook:article and xsl:stylesheet!
>I think this is the source of our disagreement (I hope it is!), and -
>obviously - I disagree.

Oren goes on to make some excellent points about the relationships between
parsers, DTDs, and namespaces.

The general problem seems to me to be that XML (and namespaces as well)
were written without a clear processing model in mind.  XML is a big ol'
block of rules, with no real suggestion of how those rules might be broken
down into smaller parts.  The distinction between well-formed and
validating parsers doesn't really create a 'validation' module with
well-defined functions, and when you throw in the other things that can
happen during XML processing - attribute defaulting, entity expansions,
etc. - it's pretty difficult to see where one set of functions ends and
another begins.

Add namespaces to that large block, and the potential complexity grows
exponentially. (2 specs -> 4x complexity).  It isn't clear how namespaces
is supposed to fit with the rest of what we already have - all that's clear
is what namespaces do: provide unique identifiers.  The rest of it remains
completely up in the air.

While I'm looking forward to the Infoset WG defining lots of these parts,
I'm not sure they'll be able to get us out of the woods on these kinds of
issues where how XML is processed is just as important as what it contains.

Frustrating, to say the least.

Simon St.Laurent
XML: A Primer (2nd Ed - September)
Building XML Applications
Inside XML DTDs: Scientific and Technical
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