W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > May 2003

RE: Languageless Typed Literals

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 5 May 2003 15:01:55 -0500
Message-Id: <p0521063fbadc7272e5c6@[10.0.100.12]>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: <Patrick.Stickler@nokia.com>, w3c-rdfcore-wg@w3.org

>Jeremy:
>>  Option 1:
>>  XMLLiteral ceases to be a typed literal but we revert to the old
>>  treatment  where it was simply a special.
>
>
>Patrick:
>>  My strong preference is then for option 1, reverting (in a sense)
>>  XML literals to the M&S definition.
>>
>>  This has the additional benefit that lexical forms can be left
>>  as-is in the graph per the RDF/XML serialization and only need be
>>  canonicalized when testing for equality.
>>
>>  Thus, plain and XML literals both may take lang tags and neither
>>  are typed literals nor fall within the scope of RDF datatyping.
>>
>>  Typed literals do not take lang tags, period.
>>
>>  This avoids all the headaches relating to the bizzare datatype
>>  rdf:XMLLiteral.
>>
>>  Patrick
>>
>>
>
>The old treatment was in say:
>http://www.w3.org/TR/2002/WD-rdf-concepts-20020829/
>
>I think that the reagle issue resolutions would in the main stay, and the
>canonicalization would still be specified in the syntax, but with the
>implementation note that makes it clear that they "only **need** be
>canonicalized when testing for equality."
>
>I have three concerns about this option:
>
>a) we had comments
>http://lists.w3.org/Archives/Public/www-rdf-comments/2002JulSep/0092.html
>linking to
>http://www.w3.org/2002/07/29-rdfcadm-tbl.html#xtocid103643
>
>and
>
>http://lists.w3.org/Archives/Public/www-rdf-comments/2002JulSep/0165.html
>
>both of which would need resurrecting, since we have followed up saying that
>we have changed in the way they sort of wanted.
>
>
>b) how difficult would it be for Pat to go back and rework

Not very difficult.  I am ready for almost any decision we make, I 
think. I have the relevant changes scoped out for them all, and will 
do the edits once we decide.

But...

>
>c) impact on OWL support for XML Literals - webont are generally negative
>about them, the more work they have to do, the less support there will be in
>OWL for these.

...right. BUt then, Webont are free to rule out this part of RDF from 
OWL, and take the resulting heat from their user community.

I think it would be easier for OWL if it were presented with XML 
literals as a distinct syntactic category, since that would enable 
them to deny equality substitution inside XML literals without 
compromising their semantics.

Pat
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Received on Monday, 5 May 2003 16:01:58 EDT

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