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Re: [closed] xmlsch-11 layering on xml

From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
Date: 03 Oct 2003 22:22:18 +0200
To: Dave Beckett <dave.beckett@bristol.ac.uk>
Cc: W3C XML Schema IG <w3c-xml-schema-ig@w3.org>, www-rdf-comments@w3.org
Message-Id: <1065212537.5800.488.camel@michael.hit.uib.no>

Colleagues,

thank you for your response to our comment.  A full account
of our formal responses to your responses is attached to
http://lists.w3.org/Archives/Public/www-rdf-comments/2003OctDec/0011.html
For the sake of those who are trying to track this particular issue
using the email archives, our response on this topic is given 
below.

-C. M. Sperberg-McQueen
 for the XML Schema WG

On Tue, 2003-04-29 at 21:05, Dave Beckett wrote:
> Dear Colleagues
> 
> The RDF Core WG has considered your last call comment captured in
> 
>    http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-11
> 
> (raised in section
>  "4.4. Normative specification of XML grammar (policy, substantive)" of
> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0489.html )
> 
> The main points you raised in this comment are:
> 
> 1) RDF/XML is defined in "what is very nearly a character-level BNF
>   [which] is at best a missed opportunity and at worst a serious
>   mistake." 
>     - obscuring important parts of the document type
>     - making it very difficult for the reader to actually
>       understand what is and isn't actually allowed.
>     - confusing layers
> 
> RDF/XML is entirely layered on the XML Infoset as defined in
>   Syntax Data Model
>   http://www.w3.org/TR/rdf-syntax-grammar/#section-Data-Model
> and is not defined at the character-level.
> 
> All XML detail is handled by the XML specifications, not this
> document - deployed RDF/XML applications are entirely built on
> standard XML tools.  In layering on the XML infoset, we leave only
> the important parts of RDF/XML that users and application writers
> need be concerned about - elements, attributes, whitespace and text.
> 
> It would have been a mistake to gloss over where, say, the whitespace
> was significant and where it was ignored - which was one problem with
> the original RDF M&S specification.
> 
> 
> 2) Rules out XML documents not parsed from character streams (such as DOM)
> 
> This was explicitly called out:
>   [[
>     This model illustrates one way to create a representation of an
>     RDF Graph from an RDF/XML document. It does not mandate any
>     implementation method - any other method that results in a
>     representation of the same RDF Graph may be used.
> 
>     In particular:
>     ...
> 	* This specification does not require the use of [XPATH] or [SAX2]
>   ]]
>   http://www.w3.org/TR/rdf-syntax-grammar/#section-Data-Model
> 
> If a DOM interface can provide the very few (4) XML Infoset Infoitems
> that are needed here, it is not ruled out.
> 
> 
> 3) Suggests a two-step approach first mapping to canonical RDF form
>    constrained by DTD or XML Schema
> 
> An approach using a mapping to a canonical RDF written in XML is
> related to issue xmslch-10 where we explain why we didn't feel we
> could do this under the current charter.  It certainly would have
> been useful and helped.
> 
> The model and grammar used here closely matches how many RDF/XML apps
> were written, in a token matching style that can be used with
> standard syntax lexers and grammar generators.  This approach has
> proved suitable after other implementor feedback.
> 
> 
> 
> The RDF Core Working Group has decided:
> 
>     http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Apr/0361.html
> 
> that the explanation above answers your comment as a clarification.
> 
> Please reply to this email, copying www-rdf-comments@w3.org indicating
> whether this decision is acceptable.
> 
> Thanks
> 
> Dave

Thank you.

We realize that this is a difficult area, but we believe that it would
be  a  mistake  for  W3C to move forward with a new version of the RDF
specifications  without  undertaking  the  work  of  a revision of the
syntax.

We  regret  that we must dissent formally from your resolution of this
issue.  The  current mismatch between RDF syntax and off-the-shelf XML
tools  has  not  become  easier to bear as time goes on; we believe it
must be addressed.
Received on Friday, 3 October 2003 16:23:22 GMT

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