Re: HTML 4 Profile for RDFa

On May 24, 2009, at 15:59, Shelley Powers wrote:

> Henri Sivonen wrote:
>> On May 23, 2009, at 19:49, Philip Taylor wrote:
>>
>>> * Use some other prefix-binding mechanism (in both XHTML in HTML)  
>>> like prefix="t=... T=..." instead of xmlns:t="..." (breaking  
>>> current implementations and deployed content, but avoiding the  
>>> mess of parsing differences between XHTML and HTML).
>>>
>>> I can't think of any other solutions, so something is going to  
>>> break no matter what is chosen.
>>
>>
>> * Use a mechanism other than CURIEs to turn attribute values into  
>> absolute IRIs.
>>
>> As it happens, the microdata to RDF conversion already has a  
>> mechanism for mapping itemprop values to absolute IRIs without  
>> prefix-based indirection. (And itemprop works nicely with  
>> Selectors, too, allowing styling based on microdata, while  
>> Selectors don't support matching on expanded CURIEs, so styling on  
>> RDFa would need to depend on the prefixes that aren't supposed to  
>> be significant.) In fact, even RDFa itself has a non-CURIE-based  
>> mapping from attribute values onto IRIs for traditional rel tokens.
>>
> I wouldn't make an assumption that the microdata section will exist  
> going into the future. Regardless, discussions of Microdata are  
> irrelevant to discussions of RDFa, don't you think?

Microdata shows that it's possible to formulate a non-CURIE mapping  
from attribute values onto RDF properties. The proof of possibility  
wouldn't go away even if the section in the spec went away.

>> http://rdfa.info/wiki/Rdfa-in-html-issues currently has 12 issues.
>
> And how many of these are related to bugs in the processors, and how  
> many are actually issues with RDFa?

Since RDFa isn't defined for text/html, one might take a position that  
it's a bug for a processor to try to process text/html resource  
representations as having embedded RDFa. Alternatively, one might say  
that the failure to cover text/html is an issue with RDFa.

> And how many of these are related to underlying problems with the  
> DOM, not directly with RDFa?

The underlying problems of the DOM are a given (especially when part  
of the RDFa community have taken a position that no browser changes  
are needed). It is then a major flaw of RDFa that it has been written  
in such a way that the problems of the DOM end up being touched and  
haven't been properly avoided.

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/

Received on Sunday, 24 May 2009 13:17:14 UTC