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Re: SWC out of sync on rdf:PlainLiteral

From: Stella Mitchell <stellamit@gmail.com>
Date: Thu, 4 Mar 2010 19:28:56 -0500
Message-ID: <d64b0f2c1003041628w71267d0ew57b9e517c28358d4@mail.gmail.com>
To: Sandro Hawke <sandro@w3.org>
Cc: Jos de Bruijn <jos.debruijn@gmail.com>, RIF <public-rif-wg@w3.org>
That RIF PS-->XML translator follows the documentation in BLD and
DTB section 2.2.2, and so will interpret "mystring" in the RIF PS as
shorthand for "mystring"^^xs:string.

 I thought the proposed change to table 1 in SWC that Jos described would
mean that "mystring" in the RDF part of a RIF-RDF combination would
correspond to "mystring@"^^rdf:PlainLiteral in RIF.  (but not that the
SWC table is specifying what "mystring" means in RIF PS).

Stella



On Thu, Mar 4, 2010 at 12:30 PM, Sandro Hawke <sandro@w3.org> wrote:

> > So, do you propose to change (in Table 1):
> >
> > Constant in the xs:string symbol space        "literal string"^^xs:string
> >
> > to:
> >
> > Constant in the rdf:PlainLiteral symbol space         "literal
> > string@"^^rdf:PlainLiteral
> >
> > ?
>
> Exactly.   Also, a few lines down, there's a bullet:
>
>   * Strings, i.e., constants of the form "my string"^^xs:string may be
>     written as "my string".
>
> which would be changed to:
>
>   * Plain literals without language tags, i.e., constants of the form
>     "my string@"^^rdf:PlainLiteral may be written as "my string".
>
> Which makes me wonder what other specs, if any, that affects, and what
> Hassan & Stella's code does.  Basically, that affects the mapping from
> Presentation Syntax to XML Syntax.
>
> > That would be fine for me.
>
> Good...
>
>     -- Sandro
>
> > Cheers, Jos
> >
> > On 2010-03-04 14:11, Sandro Hawke wrote:
> > >> SWC doesn't map plain literals to anything. According to the RDF
> > >> semantics, plain literals without language tags are always mapped to
> > >> themselves, i.e., strings of unicode characters. Now, XSD specifies
> that
> > >> xs:string literals are also mapped to themselves, and thus they
> > >> correspond 1-to-1 to plain literals w/o language tags.
> > >> Now, it happens to and be the case that the value space of
> > >> rdf:PlainLiteral also includes all strings. Therefore, there is a
> > >> one-to-one correspondence between RDF plain literals and xs:strings of
> > >> the form "xyz", on the one hand, and rdf:PlainLiterals of the form
> > >> "xyz@", on the other.
> > >
> > > I'm not talking about the value spaces or the semantics, just the
> > > syntactic correspondence in Table 1.  (In terms of the semantics, yes,
> I
> > > agree with everything you say above.)
> > >
> > >     -- Sandro
> > >
> > >>
> > >> Best, Jos
> > >>
> > >> On 2010-03-02 20:06, Sandro Hawke wrote:
> > >>> During the telecon today we looked at
> > >>>
> > >>>
> http://www.w3.org/2005/rules/wiki/RDF_Combination_Constant_Equivalence
> > _2
> > >>>
> > >>> and it seems that while that example is supported by the SWC, SWC
> isn't
> > >>> saying quite the right thing, here.  It says plain literals without
> > >>> language tags map to xs:string constants, but I think it would be
> better
> > >>> to map to rdf:PlainLiteral constants.  The difference is actually
> > >>> invisible to any entailment test (I think?  maybe it depends on the
> > >>> entailment regime?), so in a sense RIF doesn't care, but for
> interchange
> > >>> purposes is does matter.  In particular, SPARQL, when not doing
> > >>> entailment, will notice the difference.
> > >>>
> > >>> Do you remember why it's xs:string now?
> > >>>
> > >>> This isn't a huge problem, but if there's no compelling reason not to
> > >>> change it, I think it's more correct to map to rdf:PlainLiterals.
> > >>>
> > >>>      -- Sandro
> > >>
> > >> --
> > >> Jos de Bruijn
> > >>   Web:          http://www.debruijn.net/
> > >>   LinkedIn:     http://it.linkedin.com/in/josdebruijn
> > >>   Skype:        josdebruijn
> > >>   Google Talk:  jos.debruijn@gmail.com
> > >>   Mobile phone: +43 660 313 5733
> >
> > --
> > Jos de Bruijn
> >   Web:          http://www.debruijn.net/
> >   LinkedIn:     http://it.linkedin.com/in/josdebruijn
> >   Skype:        josdebruijn
> >   Google Talk:  jos.debruijn@gmail.com
> >   Mobile phone: +43 660 313 5733
>
>
Received on Friday, 5 March 2010 00:29:38 GMT

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