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Re: Test cases for literal equality?

From: Dan Connolly <connolly@w3.org>
Date: 01 Apr 2003 08:58:16 -0600
To: Dave Beckett <dave.beckett@bristol.ac.uk>
Cc: Graham Klyne <gk@ninebynine.org>, w3c-rdfcore-wg@w3.org
Message-Id: <1049209096.23308.70.camel@dirk.dm93.org>

On Thu, 2003-03-13 at 05:32, Dave Beckett wrote:
> >>>Graham Klyne said:
> > 
> > Do we have any test cases for dealing with literal equality?
> > 
> > In particular, I'm wondering if the recent discussion of XML literals and 
> > canonicalization will have any effect of the interpretation of language 
> > tags for typed literals.  Currently, if I have the details right, typed 
> > literals with different language tags are distinct values in the abstract 
> > graph, but always denote the same thing, with the exception of XML 
> > literals.  Plain literals are language-tag sensitive.  What about xsd:string?
> xsd:string is a datatype in the XSD specification and from what I
> recall, RDF doesn't use it - no RDF literal is an xsd:string nor has
> one as a part,

If people are going to continue to say things like this about
literals in RDF vs. XML Schemas, I guess I'll have to take
a much stronger position on 

On the contrary, *every* RDF literal is either an xsd:string
or has one in part.

Proof: "The ˇvalue spaceˇ of string is the set of finite-length
sequences of characters"
 -- http://www.w3.org/TR/xmlschema-2/#string

"A literal in an RDF graph contains three components called:

      * The lexical form being a Unicode [UNICODE] string in Normal Form
        C [NFC]."
 -- http://www.w3.org/TR/rdf-concepts/#section-Literals

>  although the lexical form definition is compatible
> with it.  A quick grep in the concepts WD confirms this as far
> as I can tell.  So we don't need to test xsd:string comparisons.

I think that's a counter-productive direction to take.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 1 April 2003 09:58:26 UTC

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