- From: Mark Birbeck <mark.birbeck@webbackplane.com>
- Date: Wed, 4 Jun 2008 11:20:26 +0100
- To: "Charles McCathieNevile" <chaals@opera.com>
- Cc: "Robert J Burns" <rob@robburns.com>, elharo@metalab.unc.edu, "Al Gilman" <Alfred.S.Gilman@ieee.org>, "Henry S.Thompson" <ht@inf.ed.ac.uk>, "www-tag@w3.org List" <www-tag@w3.org>, "public-html@w3.org WG" <public-html@w3.org>, "public-xhtml2@w3.org WG" <public-xhtml2@w3.org>, "wai-xtech@w3.org WAI-XTECH" <wai-xtech@w3.org>
Hi Charles, > Saying that the attributes in HTML are in the null namespace does not > anticipate anything that some future spec might say, nor does it conflict > with any current draft I know of, with regard to XML - it is in fact > perfectly in line with the specs and implementations that have emerged in > the 10 years of XML. > > It *also* simplifies the process of building applications, and the process > of explaining how to add aria to a new XML or non-XML spec. > > These two reasons are why I believe the PFWG will adopt the solution I > suggested above as its preferred model for both HTML and XML languages. You've made a leap again. :) I think this is what Robert is getting at. To say that you don't want to use an XML technique (namespaces) in HTML is one thing, but to then have some kind of reverse feedback loop where you say that this is therefore the preferred technique for XML (i.e., to not use XML namespaces) is dubious. In particular, the foundation for ARIA is the @role attribute module, which was created precisely for solutions like ARIA, to be used in XML-based languages. So dropping namespaces completely from ARIA is not a good idea. (I get a sense that people think that @role was sitting around doing nothing until some clever soul thought of using it for ARIA--quite the contrary...it was designed first and foremost as an accessibility hook.) That's not to say that XML namespaces need to be taken 'as is'. I do agree that they are a bit of a mess, but I think that this is mainly because everyone is posturing on the subject; the W3C is defensive about the technology, not seeming to want to admit any flaws, whilst those who don't like it simply rubbish it without any real reference to the problems that it tries to solve. But there are many different ways that namespaces could evolve for the 21st century...if we have the will to sort them out. The first thing I would do is prise apart the syntax and the infoset. I don't see any reason why the underlying representation of a DOM can't be taken as given, even if we fiddle around to remove the need for prefix-explosion in the mark-up. The second thing I'd do is make XHTML a special case; there is no reason why XHTML as an XML-based language needs to have all of the features, power and flexibility that 'generic XML' has. For example, why do we care if 'xf:' is hard-coded to always refer to the XForms namespace? Likewise, what's the big deal if 'aria:' always points to the same namespace, too? In fact, I wouldn't lose any sleep if we said that: <span @aria-banana="foo"> is a shorthand for: <span @aria:banana="foo" xmlns:aria="http://..."> I'm not particularly wedded to that approach either...I'm just trying to stress that if we have the will to solve the problem, then we can look for solutions that both maintain compatibility with the architecture (e.g., by defining things in terms of the infoset), but still create better and easier to use solutions for the future. An example of this is in the latest CURIEs draft [1]; myself and Shane added a small and probably unnoticed feature that permits host languages that want to make use of CURIEs, to define their own values. These strings must still 'map' to full URIs (since CURIEs are generally used to carry RDF information), but the effect is to allow a language to remove the need for namespaced prefixes, whilst still being a 'good citizen' in the namespace world. This was needed in RDFa to allow legacy mark-up like @rel="next" to work correctly, without requiring @rel="xh:next". But it's also the mechanism that allows @role="widget" to be defined, too. In other words, a language can make use of a large part of @role functionality without requiring namespace-prefixed values, simply because it uses CURIEs. In short, XML is very powerful, and very flexible, but it seems to me that we could hide a lot of its complexity if we stopped polarising the discussion. XHTML needs a lot of this power, but not all of it, and recognising that might help us to unlock this seemingly intractable problem. Regards, Mark [1] <http://www.w3.org/TR/curie/> -- Mark Birbeck, webBackplane mark.birbeck@webBackplane.com http://webBackplane.com/mark-birbeck webBackplane is a trading name of Backplane Ltd. (company number 05972288, registered office: 2nd Floor, 69/85 Tabernacle Street, London, EC2A 4RR)
Received on Wednesday, 4 June 2008 10:21:03 UTC