W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > September 2009

Re: XMLLiterals and c14n

From: Ivan Herman <ivan@w3.org>
Date: Thu, 17 Sep 2009 06:58:23 +0200
Message-ID: <4AB1C1EF.305@w3.org>
To: Ben Adida <ben@adida.net>
CC: Philip Taylor <pjt47@cam.ac.uk>, public-rdf-in-xhtml-tf@w3.org
Ben,

In my view:

- RDFa per se does not have to change anywhere, the spec is good is as 
is. Simply because RDFa just defines the way literals are mapped on RDF. 
"2.00"^^xsd:float is a perfectly valid lexical form for a float per the 
XSD specification, so there is no canonicalization issue there 
whatsoever. The special case of RDF XML Literals is that their lexical 
form is, well, unexpected for an outsider because of the c14n issue. 
That _may_ (I say 'may') deserve some extra clarification. That is it.

- The issue is, in fact, in the test cases; the way the corresponding 
SPARQL code is defined is, strictly speaking, wrong. That is all the 
changes that I think is necessary.

Ivan

Ben Adida wrote:
> Ivan, Philip,
> 
> I had an action to follow up on this issue, but looking at this thread
> I'm a little bit confused.
> 
>> The bottomline is that you are right. Neither N3/Turtle nor SPARQL
>> includes any automatic canonicalization of XML Literals (in contrast to
>> RDF/XML), nor will the new version of SPARQL do it.
> 
> So, this is a bit disconcerting. As I mentioned on the call, does RDFa
> need to worry about float canonicalization, too? Does SPARQL consider
> "2.0"^^xsd:float different from "2.00"^^xsd:float?
> 
> If SPARQL indeed considers these to be different and effectively only
> does string comparisons, then what is the point of datatyping?
> 
> And if SPARQL *does* canonicalize floats, then why wouldn't it also
> canonicalize XMLLiterals?
> 
> My action was to express the sentiment that this is not part of the RDFa
> scope: we're just parsing a syntax and creating and RDF graph with typed
> values. I still think that's the case.
> 
> Thoughts?
> 
> -Ben

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
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Received on Thursday, 17 September 2009 04:55:39 GMT

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