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Re: Comments on GRDDL (using 3rd-party XML schemas with GRDDL) [OK?]

From: Jonathan Robie <jonathan.robie@redhat.com>
Date: Thu, 19 Jul 2007 11:25:23 -0400
Message-ID: <469F8263.7060707@redhat.com>
To: Harry Halpin <hhalpin@ibiblio.org>, Dan Connolly <connolly@w3.org>
CC: "C. M. Sperberg-McQueen" <cmsmcq@acm.org>, Jim Melton <jim.melton@acm.org>, Andrew Eisenberg <andrew.eisenberg@us.ibm.com>, public-grddl-comments@w3.org, w3c-xsl-query@w3.org

Let me ask a few questions to try to understand the basic design.

As I read http://www.w3.org/2004/01/rdxh/spec#ns-bind, I have two 
choices: I can either associate a transformation with individual 
documents, or with all documents for a given namespace. If I want to do 
the latter, I can only do so if I am able to create a resource at the 
address corresponding to the namespace URL. Did I get that right?

Does the term "3rd-party XML schemas" have a technical meaning, or could 
we change the title to "Using XML Schemas with GRDDL" without changing 
the meaning? (I'm sure you're aware that most XML Schemas in use today 
are not available using HTTP and the associated namespace URL.)

Are you avoiding the XML Schema mechanisms because you want to avoid XML 
Schema processing, or because you need an explicit mechanism to specify 
the relationship between a namespace and the associated schema, or for 
some other reason?

What's important to me is that the "interesting" semantics of a document 
depend on who is processing the document. Suppose I'm a regulatory 
agency or the Department of Homeland Security and I am looking for 
patterns in FIX documents or SOAP documents, which are created by people 
completely ignorant of what I am doing, and which may be in a stream. I 
can't easily modify those documents. I don't own the namespace. What do 
I do?


C. M. Sperberg-McQueen wrote:
> On 18 Jul 2007, at 16:08 , Harry Halpin wrote:
>> An aside, although the official response will come from Dan himself.
>> The reason GRDDL does not use third-party schemas is because it 
>> already has a mechanism (for both XHTML and XML) for pointing to 
>> third-party transformations. Since the only reason GRDDL uses a 
>> schema at the namespace URI is to find a transformation (as it uses 
>> no other part of the schema), it seems reasonable to assume that if a 
>> schema is somewhere else rather than at a namespace URI, then the 
>> user can simply directly point to the transformation given by the 
>> "third-party" schema. This keeps indirection to minimum.
> So if I have a few thousand, or a few hundred thousand, documents
> in the same vocabulary, and use a schema for that vocabulary which
> is not at the namespace name but which is accessible to my processes,
> the advice of the GRDDL group is not to document the transformation
> in the schema document, but to edit each document and add an
> explicit link to the GRDDL transformation for that vocabulary?
> Given that the semantics are associated with the vocabulary,
> and the annotations for the vocabulary are documented in the
> schema document I use -- and given that there's no particular
> technical difficulty involved here, that I can see -- why would
> I as a document owner want to incur that kind of cost and
> introduce that kind of redundancy?
> --C. M. Sperberg-McQueen
Received on Thursday, 19 July 2007 15:26:29 UTC

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