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Re: Disimproved definition of literals in Concepts; close ISSUE-94?

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 14 Nov 2012 15:33:35 +0000
Message-ID: <50A3B9CF.5000200@epimorphics.com>
To: public-rdf-wg@w3.org

On 14/11/12 15:04, Markus Lanthaler wrote:
> Sorry for the late reply. I have been (and unfortunately am still) very
> busy.
> On Wednesday, November 07, 2012 2:19 PM, Ivan Herman wrote:
>> On Nov 7, 2012, at 05:54 , Richard Cyganiak wrote:
>>> On 6 Nov 2012, at 22:38, Markus Lanthaler wrote:
>>>> Was it considered that also literals with datatypes other
>>>> than rdf:langString can be language-tagged? I'm specifically
>> thinking of
>>>> rdf:html for example..
>>> Language tags don't make sense for the vast majority of datatypes.
>> Asking existing implementations to change in order to be able to store
>> language tags for integers and dates is a non-starter.
>>> This leaves the option of adding language tags to only a limited set
>> of datatypes, like rdf:HTML. The objection there is that this would add
>> *more* exceptions to the design of RDF literals (where our goal was to
>> make the handling of literals more uniform), and also rdf:HTML doesn't
>> need it because it already has a mechanism for language annotation
>> (<span lang="xx">).
> I see, but I still don't understand why that single exception exists then!?
> For historic reasons? To avoid blank nodes?
>> I would be, actually, a little bit stronger than Richard on this one. I
>> think it would be wrong to add a language tag to HTML (or to XML, for
>> that matter): having two different tools (the XML/HTML provided tools
>> as well as an RDF provided tool) would lead to confusion. Eg, when
>> comparing two HTML literals (which is based on a DOM function), one
>> where the language tag is set by RDF and the other where the language
>> tag is set via the HTML attribute, would two such HTML literals be
>> equal? (Provided the rest of the DOM is identical.)
> Yes, it's true that rdf:HTML has a mechanisms for language annotation. The
> problem is that if you want to filter such values based on language you have
> to parse each value which is a quite costly operation.

[ rdf:value "....."^^rdf:HTML ;
   ex:language   "en"

c.f. units.

(Not that is makes sense for rdf:HTML to have "a" language if parts of 
it do not and difefrent languages are used in the same rdf:HTML.)

> There are certainly a lot of other data types that could profit from
> language tags, just think of Markdown, Textile, all the Wiki syntaxes, etc.
> yet there's no way language-tag them. That's exactly what triggered my
> question.
> Thanks,
> Markus
> --
> Markus Lanthaler
> @markuslanthaler
Received on Wednesday, 14 November 2012 15:34:13 UTC

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