Re: simple fix

On May 21, 2009, at 5:07 PM, Axel Polleres wrote:

> Sandro Hawke wrote:
>> Can't we just say, as strongly as we need to, that rdf:text is NOT  
>> for
>> use in RDF?  Instead it is for use in *non-RDF* systems which use XML
>> datatypes and want interoperability with RDF's language-tagged  
>> literals?
>> I know that hasn't been made very clear, to date.   New title:
>>  rdf:text -- an equivalent to RDF Plain Literals for non-RDF systems
>> We can be more precise about this in the body -- I like Dave  
>> Reynold's
>> description of how RIF is not an RDF system, but is still  
>> compatible --
>> but mostly this just seems like a PR problem.
>> I think there's also an open question of whether to allow empty  
>> language
>> tags, and whether RDF plain literals without language tags should be
>> mapped to xs:strings instead of rdf:text, but I bet we can solve  
>> those a
>> lot more easily after we're clear about rdf:text's place in the  
>> world.
>>       -- Sandro
>
> All,
>
> I am personally fine with this and/or Andy's suggested wording:
> Maybe doing both the title change and adding the respective  
> paragraph is no harm...

Can I urge that we adopt the weaker prohibition I suggested?  
Prohibiting the use of an URi *at all* really is a rather drastic  
condition to impose on RDF, and its not necessary. In fact, having  
this as (eg) a class name in RDFS would be generally useful.

Ive done a quick redraft of the note with my suggested version of  
Sandro's idea,  and your renaming, incorporated into it, here:

http://www.ihmc.us/users/phayes/RDFPlainLIteral.html

The changes are highlighted in yellow. As you can see, the actual  
datatype has not been changed at all, only the 'convnetion' about how  
to encode it in RDF.

Please consider this change carefully, as I really think it will give  
the best compromise between expressivity and interoperability. It  
requires NO change at all to current RDF syntax, and allows RIF and  
OWL to proceed as they currently plan to, without interruption.

>
> One last proposal (if you think changing this is at all feasible):
>
> Wouldn't it make things MUCH clearer than if we change the name to  
> the datatype to just
>
>   rdf:PlainLiteral

Excellent idea, and it fits perfectly with the phrase "plain literal  
typing convention".

>
> I have the feeling that with that name the intention is much clearer  
> than rdf:text and somewhat it even "hints" why it is not a good idea  
> to use it in RDF systems, since in RDF systems there is already a  
> unique standard syntax  for plain literals.
>
> E.g. (modifying Andy's proposed text accordinglt:)
> """
> Systems that employ SPARQL with entailment regimes that cover D- 
> entailment of rdf:PlainLiteral, MUST expose their results in the RDF  
> forms.  This condition is met when the scoping graph contains  
> literals in the RDF forms plain literals and xsd:string and does not  
> mention rdf:PlainLiteral as a datatype.

. ..and does not use rdf:PlainLiteral as a datatype URI in typed  
literals.

OR

...does not contain typed literals with the datatype rdf:PlainLiteral

>


> """
>
> Opinions?
>

> One thing I am not sure still: It was pointed out that we cannot  
> prevent people from writing graphs using rdf:text as a datatype  
> explicitly.
> Is that a problem?

Well, I think we can very actively discourage them from doing so, and  
warning them to expect trouble, and exactly what to expect, if they  
do. In fact, nothing will actually break if they do, unless they  
expect these things to mean the same as plain literals without using  
datatype entailment. Its more likely that they, the publishers. won't  
have any problems, but some poor schmuk the other side of the world  
won't get their queries answered properly. But if the spec has plainly  
said this using rdf:text (or whatever) as a dataype will cause these  
problems, and it does, then its going to be easy for people to find  
the culprit, which I think is all that we really need to do. Social  
pressure will do the rest: blogs will immediately point out that XXX's  
RDF is corrupted with the forbidden datatype, etc..

Pat



>
> Axel
>
>
> -- 
> Dr. Axel Polleres
> Digital Enterprise Research Institute, National University of  
> Ireland, Galway
> email: axel.polleres@deri.org  url: http://www.polleres.net/
>
>
>

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Received on Friday, 22 May 2009 00:16:10 UTC