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Re: RDF-ISSUE-12 (String Literals): Reconcile various forms of string literals (time permitting) [Cleanup tasks]

From: Ivan Herman <ivan@w3.org>
Date: Sat, 5 Mar 2011 17:33:48 +0100
Cc: RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <5C88B838-7862-472C-B9AF-5E0EC0E3AF58@w3.org>
To: Pat Hayes <phayes@ihmc.us>

On Mar 5, 2011, at 16:24 , Pat Hayes wrote:

> 
> On Mar 5, 2011, at 5:35 AM, RDF Working Group Issue Tracker wrote:
> 
>> 
>> RDF-ISSUE-12 (String Literals): Reconcile various forms of string literals (time permitting) [Cleanup tasks]
>> 
>> http://www.w3.org/2011/rdf-wg/track/issues/12
>> 
>> Raised by: Ivan Herman
>> On product: Cleanup tasks
>> 
>> At the moment we have plain literals, rdf:plainLiteral, and xsd:string literals. They are very very close to one another but they are officially different. In practice this means that, eg, SPARQL queries have to have a three branch UNION to handle all of these. Worth looking at some sort of a reconciliation of these.
> 
> +100 

:-)

> 
> We really should clean up this mess. I suggest a draconian solution: deprecate all but xsd:string. Untyped literals were just a mistake, it seems clear from hindsight. rdf:plainLiteral was a brave attempt to clean up the mess, but it is a crock because it had to work within the existing specs. We have a chance to put all this right. 
> 
> We can allow language tags on xsd:string literals and we can even allow the plain literal syntax to stay, but treat it as syntactic sugar for an xsd:string literal. And we can incorporate xsd:string datatyping into plain RDF entailment. All of this is inelegant at the theoretical level (but no more than having XMLLIteral in there) but supremely practical, since the entire world knows what xsd:string means and uses xsd typing. 

Well, the entire world does not use xsd typing, they tend not to use typing at all:-) But yes, just as the string 123.456 is a syntactic sugar in Turtle, for example, for a float literal, we could do the same.

I would like to spend some time to check that we do not break existing systems. Ie, old queries should still work, stuff like that. I do not really believe there is a problem, but due diligence would require to look at that.

Ivan


> 
> Pat
> 
>> 
>> 
>> 
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> 
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Ivan Herman, W3C Semantic Web Activity Lead
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Received on Saturday, 5 March 2011 16:32:11 UTC

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