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

From: Dan Brickley <danbri@danbri.org>
Date: Mon, 19 Mar 2007 00:05:34 +0000
Message-ID: <45FDD3CE.6060604@danbri.org>
To: mark.birbeck@x-port.net
Cc: Elias Torres <elias@torrez.us>, Ian Davis <iand@internetalchemy.org>, Ben Adida <ben@adida.net>, public-rdf-in-xhtml-tf@w3.org

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 00:05:42 GMT

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