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Re: Please declare in GRDDL spec that XML validation is not required

From: Dan Connolly <connolly@w3.org>
Date: Sat, 10 Feb 2007 01:17:27 -0600
To: Dave Beckett <dave@dajobe.org>
Cc: public-grddl-comments@w3.org
Message-Id: <1171091847.7497.802.camel@dirk>

On Fri, 2007-02-09 at 22:13 -0800, Dave Beckett wrote:
> http://chatlogs.planetrdf.com/swig/2007-02-10#T03-28-23
> onwards:
> 
> <chimezie> .grddl
> http://www.ibiblio.org/hhalpin/homepage/notes/vcardtable.html "SELECT
> ?homeSyn WHERE { ?homeSyn owl:equivalentProperty foaf:homePage }"
> 
> <Emeka> Querying against 98 triples
> ...
> 
> Raptor failed on this document.
> 
> Checking I found:
> 
> $ xmllint --valid --noout
> http://www.ibiblio.org/hhalpin/homepage/notes/vcardtable.html
> http://www.ibiblio.org/hhalpin/homepage/notes/vcardtable.html:29: element
> div: validity error : ID v.Address already defined
> w3.org/2006/vcard/ns#Address">v:Address</a></td><td></td><td><div id="v.Address"
>                                                                                ^
> http://www.ibiblio.org/hhalpin/homepage/notes/vcardtable.html:48: element
> tr: validity error : Element tr content does not follow the DTD, expecting
> (th | td)+, got (td td a td td )
> </tr><tr id="v.url">
>      ^
> http://www.ibiblio.org/hhalpin/homepage/notes/vcardtable.html:134: element
> tr: validity error : ID v.role already defined
> </tr><tr id="v.role">
> 
> 
> However GRDDL.py was generating triples.   It was not obvious to me
> that you are assuming the GRDDL process runs in WF-only XML mode.
> 
> I shall change Raptor's use of libxml accordingly, if this is
> the case.

Let's see... I think the WG did consider a relevant issue
recently...

what infoset to use as the input to GRDDL transformations? do XInclude?
http://www.w3.org/2004/01/rdxh/spec#issue-faithful-infoset

Perhaps the resolution we came up with addresses your request?

"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.
... "
 http://www.w3.org/2004/01/rdxh/spec#issue-faithful-infoset 1.206

(I argued for a more conservative resolution to the issue, but
unsuccessfully.)

> Is XML validation of the profile/namespace URIs, XSLT documents
> also ignored?  I would assume not, since they are somebody else's
> mime type, spec.  

The spec defines GRDDL results without using
terms like "ignored"; the definitions are declarative rules,
rather than specifying how implementations work. I think
an implementation that allows well-formed-but-invalid
profile and namespace documents is consistent with the spec.

> RDF/XML aka application/rdf+xml does use validation.

I don't understand what you mean by that. In what way
does RDF/XML use validation?

I suppose it would be possible to distinguish not only
valid documents from well-formed documents but als
documents with no DTD from those that have a DTD but
don't match it. So far, we haven't bothered with those
details, but only referred to XPath nodes.

I do hope we'll find time to add tests for the cases you're
asking about.


> Dave
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Saturday, 10 February 2007 07:17:38 GMT

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