Re: ISSUE-41/ACTION-97 decentralized-extensibility

On Oct 6, 2009, at 2:38 AM, Julian Reschke wrote:

> Maciej Stachowiak wrote:
>>> I do not believe that anybody involved in this discussion had  
>>> problems understanding how namespaces work. It was just confusion  
>>> about a specific API.
>> I got the impression that at least some RDFa advocates thought it  
>> was acceptable and desirable to base semantics on nodeName (or  
>> indeed how an attribute was spelled in the source text) instead of  
>> on the {namespaceURI, localName} ordered pair. And indeed, that is  
>> how a number of RDFa implementations seem to work in practice. I'm  
>> not sure how much of the seeming confusion in the discussion was  
>> genuine and how much was the result of trying to justify a hacky  
>> solution.
>
> Using nodeName + prefix mappings obtained separately instead of  
> namespaceURI/localName is a workaround for environments where DOM L2  
> either isn't there (IE), or doesn't work as desired (HTML5 for now).

Prefix mapping obtained separately how? There's no obtaining of a  
prefix mapping involved when you look at nodeName in order to treat  
{null}xmlns:foo as {http://www.w3.org/2000/xmlns/}foo.

> It has nothing to do with not understanding how namespaces work.  
> Otherwise those implementations wouldn't pass tests, right?

The RDFa text/html tests are written to expect checks of nodeName  
rather than namespaceURI/localName. The implementations do  checks of  
nodeName rather than namespaceURI/localName. That is why the tests  
pass. A test case that used script to insert {null}xmlns:foo into an  
XML document would give results that show the mapping in effect, in JS- 
based implementations (I haven't tested, but I'm pretty sure, given  
how they are coded). A test that resulted in {null}xmlns:foo and {http://www.w3.org/2000/xmlns/ 
}foo attributes on the same element would give unpredictable results.

I think this shows either a failure to understand namespaces on the  
part of the test writers and implementors, or a deliberate decision to  
go against the Namespaces in XML model.


>> ...
>>> But that's an API choice. A single function would have been  
>>> sufficient by using the right syntax. (Again, Clark notation)
>> What advantage would Clark notation have over simply allowing URIs  
>> to be event names?
>> ...
>
> I don't know the event API sufficiently to answer that. If a simple  
> URI works as identification, then no, there's no point in making it  
> a (URI,localName) tuple instead.

A simple URI does work as identification (but non-URI names are also  
allowed, as for the existing standard events like "click").

Regards,
Maciej