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Re: [RDFa] rdf:XMLLiteral (was RE: Missing issue on the list: identification of RDFa content)

From: Elias Torres <elias@torrez.us>
Date: Sun, 18 Mar 2007 22:57:24 -0400
Message-ID: <45FDFC14.60805@torrez.us>
To: mark.birbeck@x-port.net
CC: Dan Brickley <danbri@danbri.org>, Ian Davis <iand@internetalchemy.org>, Ben Adida <ben@adida.net>, public-rdf-in-xhtml-tf@w3.org



Mark Birbeck wrote:
> Hi Dan,
> 
> 
> So for me, the question remains, what do we *lose* on the RDF side,
> given that on the XHTML side we *gain* the ability to mark-up text
> without having to resort to using the datatype attribute and the RDF
> namespace.

I just want to make sure we remember that this is not about losing an
ability but choosing the default. Your benefit is ability to mark-up
*mark-up* not text (this would just be a plain literal) w/o adding a
datatype attribute. My benefit is having the ability to mark-up text w/o
adding a datatype attribute. Which one happens more often? Isn't this
how defaults should be chosen?

BTW, I also have a problem with @content. It violates DRY and I'm not
sure why it couldn't be done with a meta element somewhere else, if the
content cannot be parsed deterministically and we are not maintaining a
relationship to the original user input in the model.

-Elias

> 
> Regards,
> 
> Mark
> 
> On 18/03/07, Dan Brickley <danbri@danbri.org> wrote:
>> Mark Birbeck wrote:
>> >
>> > Hi Elias/Ian,
>> >
>> > I'm afraid I'm missing from this discussion, first what we *lose* by
>> > using rdf:XMLLiteral, and second, some clear-cut explanation of why
>> > plain literals are *logically* the correct default, rather than just
>> > simply someone's 'preference'.
>>
>> One brief but hopefully simple point: if RDFa generates literals that
>> are typed XMLLiteral, ... RDFa document authors need to choose RDF
>> vocabularies whose properties have that has a range.
>>
>> Actually I'm not sure. They certainly need to consider the range.
>>
>> http://www.w3.org/TR/rdf-schema/#ch_xmlliteral
>>
>> "The class rdf:XMLLiteral is the class of XML literal values.
>> rdf:XMLLiteral is an instance of rdfs:Datatype and a subclass of
>> rdfs:Literal."
>>
>> If we define a property to have a range rdfs:Literal, and it is
>> generally used with plain literals... does anything get tricky if we
>> start using it with rdf:XMLLiteral?
>>
>> I have to admit, to date, I had assumed without scrutiny that this was
>> problematic. I guess I had been confusing the superclass rdfs:Literal
>> with the notion of a "plain Literal",
>> http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-plain-literal
>> ... but it seems (unless I'm missing something; sorry I forget the
>> design discussions! it was a while back now...) ...seems that we don't
>> define a class for plain literals.
>>
>> So, for example, we say foaf:name has a range
>> http://www.w3.org/2000/01/rdf-schema#Literal
>>
>> I had previously thought this made use of XMLLiteral in names
>> problematic, eg. for ruby markup in names. But perhaps not.
>>
>> A question (for the OWL folk here): if we have a property sometimes
>> taking plain literals as values, and sometimes taking XMLLiteral, ...
>> does this put the property (and hence vocab) into OWL Full?
>>
>> cheers,
>>
>> Dan
>>
>>
>>
>>
>>
>>
>>
>>
>>
> 
> 
Received on Monday, 19 March 2007 02:57:38 GMT

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