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[Fwd: GRDDL Going to Last Call]

From: Harry Halpin <hhalpin@ibiblio.org>
Date: Thu, 08 Feb 2007 22:14:21 -0500
Message-ID: <45CBE70D.3030108@ibiblio.org>
To: www-archive@w3.org

-- 
		-harry

Harry Halpin,  University of Edinburgh 
http://www.ibiblio.org/hhalpin 6B522426


attached mail follows:


I'm Harry Halpin, the Chair of the GRDDL WG [1] which links XML and XHTML(including "microformats") to the Semantic Web in order to facilitate the deployment of the Semantic Web.  It is obviously a much lighter-weight spec than XQuery.

 In order to prevent a "surprise" Last Call, I'd like for your WG to know  that we are going to go, barring any final comments or problems, to  request move to Last Call on or shortly after Feb 15th for the following three documents:

 1) GRDDL Specification [2]
 2) GRDDL Primer [3]
 3) GRDDL Use Cases [4]
 
 We believe this technology is related to the XML Processing Model WG as a GRDDL can be considered a type of function or "process" from XML to RDF, and that GRDDL transformations may be implemented using XPROC, and  we'd appreciate if this message was forwarded to either your listserv or to interested parties in your list if you think needed. In fact, when the Spec settles down, if someone wants to make a XPROC GRDDL transformation (our current test suite using XSLT), I would be happy to add it to our test suite. 

  In particular, I would personally be interested if you believe our definition of XML documents in terms XPath nodes in [2] is correct, and our relationship between XPath and Infosets we draw is correct. We are unaware if XML Processing Group takes a particular stand on issues like resolving XIncludes in order to get a standard "elaborated infoset"  and pragmatically we have decided that responsibility issue should be in hands of the publishers of the transform. We include the following informative warning in [2] (drafted by Murray Maloney, edited by Dan Connolly):

"When an information resource is represented by an XML document, the corresponding XPath data model is somewhat under-determined, depending on, for example, whether an agent elaborates inclusions, parameter entities, fixed and default attributes, or checks digital signatures. Put another way, if an author takes responsibility for the information in an XML document, for what information exactly is the author taking responsibility? And how can the author ensure that a GRDDL transformation is able to meet GRDDL's Faithful Rendition assurance?

This specification is purposely silent on the question of which XML processors are employed by or for GRDDL-aware agents. Whether or not processing of XInclude, XML Validity, XML Schema Validity, XML Signatures or XML Decryption take place is implementation-defined. There is no universal expectation that an XSLT processor will call on such processing before executing a GRDDL transformation. Therefore, it is suggested that GRDDL transformations be written so that they perform all expected pre-processing, including processing of related DTDs, Schemas and namespaces. Such measure can be avoided for documents which do not require such pre-processing to yield an infoset that is faithful. That is, for documents which do not reference XInclude, DTDs, XML Schemas and so on.

XProc: An XML Pipeline Language[XPROC], a language for describing operations to be performed on XML documents, has recently been published as a W3C Working Draft. It merits consideration for expressing more complex or sophisticated transformations which require control over the flow of processing through a variety of XML processing tools. Using XProc, one could apply a sequence of operations such XInclude, validation, and transformation to a document, aborting if the result of an intermediate stage is not valid, for example."
 
 [1]http://www.w3.org/2001/sw/grddl-wg/
 [2] http://www.w3.org/2004/01/rdxh/spec
 [3] http://www.w3.org/2001/sw/grddl-wg/doc29/primer.html
 [4] http://www.w3.org/2001/sw/grddl-wg/doc43/scenario-gallery.htm



Murray Maloney (wordsmithing via Dan Connolly) drafted us this text:

"When an information resource is represented by an XML document, the
corresponding XPath data model is somewhat under-determined, depending
on, for example, whether an agent elaborates inclusions, parameter
entities, fixed and default attributes, or checks digital signatures.
Put another way, if an author takes responsibility for the information
in an XML document, for what information exactly is the author taking
responsibility? And how can the author ensure that a GRDDL
transformation is able to meet GRDDL's Faithful Rendition assurance?

This specification is purposely silent on the question of which XML
processors are employed by or for GRDDL-aware agents. Whether or not
processing of XInclude, XML Validity, XML Schema Validity, XML
Signatures or XML Decryption take place is implementation-defined. There
is no universal expectation that an XSLT processor will call on such
processing before executing a GRDDL transformation. Therefore, it is
suggested that GRDDL transformations be written so that they perform all
expected pre-processing, including processing of related DTDs, Schemas
and namespaces. Such measure can be avoided for documents which do not
require such pre-processing to yield an infoset that is faithful. That
is, for documents which do not reference XInclude, DTDs, XML Schemas and
so on."

-- 
		-harry

Harry Halpin,  University of Edinburgh 
http://www.ibiblio.org/hhalpin 6B522426
Received on Friday, 9 February 2007 03:14:27 GMT

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