Re: simple fix

> >> Can't we just say, as strongly as we need to, that rdf:text is NOT  
> >> for use in RDF?
> 
> Too strong. All we need is that its not for use as the datatype URI in  
> an RDF typed literal. It would be fine to allow RDFS to reason about  
> the class, for example. Yes, that is pretty much what my earlier  
> suggestion amounts to, in practice.

Yes, I didn't think of that case, but indeed, I did mean that rdf:text
is not for use in RDF as an RDF datatype URI.

I'm hoping that by explaining what rdf:text is *for* we can make this
more obvious.  I'm imaging text in the intro like:

    Systems which support XML datatypes but do not directly support RDF
    can use rdf:text to represent RDF Plain Literals.  The mapping is
    1-to-1, so such systems can do their processing of XML data values
    and effectively be processing RDF data values.

> On another topic, the more I think about it, the better the idea gets  
> of sticking to xsd:string for untagged literals and using rdf:text  
> only for tagged ones. This seems to lead to a simplification in the  
> spec for handling all the alternative function definitions as well.

I find that very appealing, but I think there's a fatal problem with it,
which is that these two RDF graphs are not the same:
     <a> <b> "Hello".
and
     <a> <b> "Hello"^^xs:string.

If we did this simplification you're suggesting, then in the rdf:text
form we could no longer distinguish between the above two triples, and
if we converted back to RDF, we'd have altered the graph.  The mapping
would not longer be 1-to-1.  Not a huge pain for users, but still, I
think, and unnecessary incompatibility.

(Of course I *wish* those two RDF graphs were the same, but, alas.  I
rather think xs:string should have been banned as a datatype from RDF,
for the same reason we're banning rdf:text.  But I guess it's too late
to do that now.  Maybe someone, somehow, can make a Best Practice
declaration against using xs:string?  Hmmm.  I wonder if the reason some
people use xs:string is because they want to process their RDF without
implementing Plain Literals, and they don't have any language tags....
In that case, it's germaine for rdf:text spec to mention that there is
now one less reason to use xs:string at all, and maybe people should
just avoid it in RDF.  I know that's a stretch.  xs:string probably has
some big fans out there, and it's best for rdf:text not to anger them.)

     -- Sandro

Received on Friday, 22 May 2009 00:19:35 UTC