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Re: RDF-ISSUE-80 (rdf:PlainLiteral): Ask OWL and RIF WGs to update the rdf:PlainLiteral spec [RDF General]

From: Alex Hall <alexhall@revelytix.com>
Date: Thu, 17 Nov 2011 12:10:02 -0500
Message-ID: <CAFq2biyv_HN-5ifV-E-Yy1=dx472XbAGaiGxjzynVk+yYcmG8Q@mail.gmail.com>
To: Richard Cyganiak <richard@cyganiak.de>
Cc: Sandro Hawke <sandro@w3.org>, Ivan Herman <ivan@w3.org>, RDF Working Group WG <public-rdf-wg@w3.org>
On Thu, Nov 17, 2011 at 10:55 AM, Richard Cyganiak <richard@cyganiak.de>wrote:

> On 17 Nov 2011, at 14:58, Sandro Hawke wrote:
> > Are we really breaking backward compatibility that much?
>
> The design and terminology of the rdf:PlainLiteral spec make no sense at
> all when read with RDF 1.1 goggles.


This is only partly true. I think there were two motivations for the
rdf:PlainLiteral datatype:

1. Give a name to the class of untyped literals in RDF, for use in
domain/range statements and in data models that require a datatype IRI for
all literals.
2. Allow values from the RDF data model, which has 3 slots (lexical,
language, datatype) to be expressed in OWL and RIF data models which only
have 2 slots (lexical, datatype) by mashing together the lexical and
language parts of the RDF model.

The first issue might no longer be a concern with the addition of
rdf:LanguageString, but the second issue is still relevant. Short of
modifying the OWL and RIF data models to align with RDF, they'll still
require something along the lines of rdf:PlainLiteral, even if it's no
longer called rdf:PlainLiteral.

That said, I agree that rdf:PlainLiteral will need a rewrite to accurately
reflect changes in RDF 1.1

-Alex



> *I* don't have a problem with that. I don't think rdf:PlainLiteral made
> sense in the first place. But the OWL and RIF people might care that one of
> their documents no longer has any foundation in the RDF data model.
>
> And I *do* slightly care that they're squatting in the RDF namespace. Why
> were they allowed to do that? This could be fixed as part of the update of
> the rdf:PlainLiteral document.
>
> > Let's just
> > include some "Historical Notes" in RDF 1.1 that explains what terms like
> > "Plain Literal" meant, and how they should now be understood.
>
> Well, we currently have this:
>
> [[
> In earlier versions of RDF, literals with a language tag did not have a
> datatype IRI, and simple literals could appear directly in the abstract
> syntax. Simple literals and literals with a language tag were collectively
> known as plain literals.
> ]]
>
> http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#dfn-plain-literal
>
> I would rather not clutter the spec too much with “Historical Notes” that
> no one will care about five years down the road. The spec already had way
> too many notes in 2004, and the need to point out every change between 2004
> and 1.1 doesn't help.
>
> Best,
> Richard
>
>
>
> > Then, I
> > think, existing systems will be fine.     (Or... perhaps I'm missing
> > something.)
> >
> >    -- Sandro
> >
> >> Thanks
> >>
> >> Ivan
> >>
> >> On Nov 10, 2011, at 18:06 , RDF Working Group Issue Tracker wrote:
> >>
> >>>
> >>> RDF-ISSUE-80 (rdf:PlainLiteral): Ask OWL and RIF WGs to update the
> rdf:PlainLiteral spec [RDF General]
> >>>
> >>> http://www.w3.org/2011/rdf-wg/track/issues/80
> >>>
> >>> Raised by: Richard Cyganiak
> >>> On product: RDF General
> >>>
> >>> The ISSUE-12 and ISSUE-71 resolutions, which are now implemented in
> the RDF Concepts ED [1], have removed the distinction between plain and
> typed literals from the RDF abstract syntax.
> >>>
> >>> This has a major effect on the rdf:PlainLiteral spec [2]. Parts of it
> are now obsolete, and the rest needs updating.
> >>>
> >>> RDF-WG should ask OWL-WG and RIF-WG to update the document.
> >>>
> >>> [1] http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html
> >>> [2] http://www.w3.org/TR/rdf-plain-literal/
> >>>
> >>>
> >>>
> >>
> >>
> >> ----
> >> Ivan Herman, W3C Semantic Web Activity Lead
> >> Home: http://www.w3.org/People/Ivan/
> >> mobile: +31-641044153
> >> FOAF: http://www.ivan-herman.net/foaf.rdf
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
>
>
>
Received on Thursday, 17 November 2011 17:11:02 GMT

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