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Re: Literals and turning off datatype/language

From: Niklas Lindström <lindstream@gmail.com>
Date: Thu, 14 Jun 2007 15:22:29 +0200
Message-ID: <cf8107640706140622l698fd7a9h580159cf185d51c0@mail.gmail.com>
To: "Hausenblas, Michael" <michael.hausenblas@joanneum.at>
Cc: public-rdf-in-xhtml-tf@w3.org

[I'm sorry, Michael, I meant to reply-all.]

Ah, now I remember. Thank you, I had forgotten to check it out again.
In general I find the hybrid approach fine for all the needs I have
come upon. And my concerns are clearly mentioned in "Issues".


1. This I hope to be a part of the resolution:

  * _always_ use the language when establishing plain literals

Which (it seems) would involve updating the process flow chart, in the
case of "literal -> no @content -> no @datatype -> no markup" to
explicitly say "and evaluate xml:lang".

For completeness - would it be useful to explicitly state:

    * xml:lang="" to indicate no language

? To make clear that it is intentionally allowed (of course, as per
<http://www.w3.org/TR/REC-xml/#sec-lang-tag>).


2. Less obvious (and I will not argue this further if the current
resolution goes against it):

    * datatype="" to indicate no type

Would this also mean that the following:

    <tr about="..." property="foaf:name" datatype="" xml:lang="">
        <td>Some</td>
        <td>Body</td>
    </tr>

will yield:

    <...> foaf:name "Some Body" .

? I.e. meaning that "@datatype is present -> @datatype is empty"
would always yield a plain, stripped literal. If this is the case, it
seems the flow chart should to be updated for that too (since no
hybrid-mode check for contained markup should be done if
@datatype="").


Best regards,
Niklas


On 6/14/07, Hausenblas, Michael <michael.hausenblas@joanneum.at> wrote:
>
> Niklas,
>
> Thanks for sharing your concerns. Just a quick check:
> Did you have a look at [1], already?
>
> Cheers,
>         Michael
>
> [1] http://www.w3.org/2006/07/SWD/wiki/RDFa/LiteralObject
>
> ----------------------------------------------------------
>  Michael Hausenblas, MSc.
>  Institute of Information Systems & Information Management
>  JOANNEUM RESEARCH Forschungsgesellschaft mbH
>
>  http://www.joanneum.at/iis/
> ----------------------------------------------------------
>
>
> >-----Original Message-----
> >From: public-rdf-in-xhtml-tf-request@w3.org
> >[mailto:public-rdf-in-xhtml-tf-request@w3.org] On Behalf Of
> >Niklas Lindström
> >Sent: Wednesday, June 13, 2007 11:16 PM
> >To: public-rdf-in-xhtml-tf@w3.org
> >Subject: Literals and turning off datatype/language
> >
> >
> >Hello all!
> >
> >The telecon for this Thursday (June 14th) aims to make official the
> >resolution to ISSUE-25 - Default Datatype for Literals. This is not an
> >attempt to re-raise the long-running debate. I do however have two
> >concerns I'd like to voice before the issue is resolved. (I must admit
> >I wasn't sure that a consensus had been reached..) Hopefully this is
> >already as things are intended to work.
> >
> >
> >My concerns are:
> >
> >1) It should be possible to "turn off" datatyping, regardless of
> >whether rdf:XMLLiteral is the default or not. *Requiring* the author
> >to resort to @content could IMO discourage adoption of RDFa in
> >some/many cases. The reasons are:
> >
> >    - A datatyped literal has no language information.
> >    - Given the same string values, a datatyped literal is not the
> >same as a plain literal.
> >
> >Turning off datatyping should be done with an empty @datatype. Thus:
> >
> >    <html ... xml:lang="en">
> >        <head>
> >            <title property="dc:title" datatype="">The Story
> >Of Language</title>
> >
> >should yield:
> >
> >    <> dc:title "The Story Of Language"@en .
> >
> >
> >2) It should be possible to "turn off" language scope. The reason is:
> >
> >    - Given the same string values, a literal with language is not the
> >same as a plain literal.
> >
> >Turning off language scope should be done with an empty @xml:lang.
> >Thus (combined with turning off datatype):
> >
> >    <p property="foaf:name" datatype="" xml:lang="">Some Body</p>
> >
> >should yield:
> >
> >    <> foaf:name "Some Body" .
> >
> >
> >That is all. As said, this may already be the default behaviour,
> >either implicitly or because I have failed to see it in the
> >specification (this *is* how xml:lang is supposed to work as described
> >at <http://www.w3.org/TR/REC-xml/#sec-lang-tag>). If not, I hope that
> >this can be agreed upon and possibly added explicitly to avoid
> >misunderstandings.
> >
> >
> >Best regards,
> >Niklas Lindström
> >
> >
> >
>
Received on Thursday, 14 June 2007 13:22:32 UTC

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