[whatwg] foreign attributes Re: several messages about XML syntax and HTML5

Ian Hickson ian at hixie.ch
Mon Dec 4 23:27:09 PST 2006

On Tue, 5 Dec 2006, Elias Torres wrote:
> In one of the products, we need two things: one to specify our own piece
> of structure data (call it microformat, call it RDFa data).

Could you give an example of the kind of data you're talking about and how 
you'd use it? Obviously I don't mean to ask you for details that would 
compromise an NDA or customer information, but I'm curious what level of 
structure you're talking about. Are we talking about inline data that you 
want to annotate, like a list of tracks on a CD album which needs artist 
information and beats-per-minute? Are we talking about manufacturing 
parameters like instructions for an automated lathe? What's the kind of 
schema that the data needs? Is it just a list of strings? Strings with 
associated flags? A two-dimensional row/column deal? Arbitrary tuples with 
arbitrarily deep nested data?

> Our first problem is parsing microformats. We must somehow explain in 
> prose how to parse our specific microformats just like hCard/hEvent do 
> or do it via GRDDL (XSLT transform) or custom JavaScript parsing code. 
> If you can read in the uF wiki [1] there's really not much guidance on 
> how to parse one or all of them.

"Parse" is the wrong word here. How to process the data is not well 
defined; I and others have sent this feedback to the Microformats 
community several times in the past.

_Parsing_ of Microformats is actually well defined; you end up with a DOM, 
as described by the HTML5 parser spec, and the DOM is a tree, each node 
of which can have attributes, certain of which -- class, rel, title, id, 
e.g. -- are especially relevant.

> RDFa on the other hand gives a generic parsing mechanism to extract 
> properties (hopefully as a JSON object) for our [...] JS libraries to 
> enhance the UI of our applications.

RDFa gives you no more than HTML5's parsing algorithm does -- you still 
just end up with an arbitrary blob of data, the meaning of which you have 
to define.

> Secondly, we need our customers to safely express details about objects 
> also via HTML using a metadata approach that allows this, currently 
> RDFa, without worrying about class names collisions.

While this sounds interesting, I am very skeptical (sorry) that this 
actually happens, and even more skeptical that if it does, that it should.

Obviously within a walled garden it doesn't matter what the 
industry-standard specifications say, since interoperability isn't 
required. And similarly, once you're on the wide Web, proprietary 
extensions are undesirable, since the end user wouldn't be able to make 
user of them. I'm not sure which case this is.

> I hope this gets a bit more concrete, but as I check around tomorrow at 
> work, I'll try to get more details. Thanks.

More details would be very useful, yes please.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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