Re: RDFa and Web Directions North 2009

Henri Sivonen wrote:
> ...
> Although this looks like a non-problem in browsers because the 
> Namespace-unaware DOM Level 1 view is available, it is a technical 
> problem with APIs that only provide a Namespace-aware representation. 
> For example, XOM doesn't allow attributes called xmlns:foo in the data 
> model. Non-browser consumers are important, and it should be perfectly 
> reasonable to use XOM in such a consumer.
> ...

Could you elaborate what exactly the problem with XOM is? I didn't get 
it from this paragraph.

> There's also a technical issue for browsers: For resolving a prefix in a 
> namespace mapping context on the XML side in a browser, it would make 
> sense to intern the prefix being queried and then do pointer compares 
> against interned local names of attributes in the 
> "http://www.w3.org/2000/xmlns/" namespace as traversing up the tree. If 
> you ever wanted browsers to implement any RDFa features natively, being 
> sensitive to xmlns:foo attributes set with setAttribute() would preclude 
> a pointer compare-based lookup and would require actually inspecting 
> string data unless the internal data structures of browsers were 
> changed. (But see point #13 in my previous email on the topic of 
> changing the data structures.)

That doesn't seem to be true. An implementation of setAttribute (L1) 
would just need to know that an attribute named "xmlns:*" is something 
special, and internally map it.

> ...
> Let's see if it's robust when a script mutates a parser-inserted attribute:
> http://hsivonen.iki.fi/test/moz/xmlns-dom-setter-cc.xhtml
> 
> Not robust in Opera.
> ...

"A bug in Opera"?

> ...

BR, Julian