- From: Charles McCathieNevile <charles@w3.org>
- Date: Wed, 29 Nov 2000 15:43:10 -0500 (EST)
- To: "Sean B. Palmer" <sean@mysterylights.com>
- cc: <w3c-wai-er-ig@w3.org>, "Leonard R. Kasday" <kasday@acm.org>, Wendy A Chisholm <wendy@w3.org>
Hi Sean (and all) I have writtena description of the language that Danbri and I worked on last year for doing this - it is a rough page at http://www.w3.org/1999/11/conforms - if you look at it in Amaya or some Mozilla versions you will see the graphic as an SVG, but at the moment most tools will present the text embedded in the SVG. (So this is also a demo of how SVG can be used...) In fact the image is not really brilliant in terms of drawing, but I thought the idea was valuable cheers Charles On Tue, 28 Nov 2000, Sean B. Palmer wrote: Accessibility Description Language (ADL) A Summary of the Points Raised so far. This is also available at http://www.mysterylights.com/xhtml/adl/, but has points that will probably want to be discussed on the list...I shall make all updates to that file (and try to keep it up to date). Abstract: This is an "IMHO/FYI" overview of the points raised, in depth. I hope that it will prove a very useful foundation document, but it really a double edged sword in that I intend it to be used for both reference and discussion. 1 Introduction 1.1 What Is ADL? Accessibility Description Language is a description format for making assertions about the accessibility of different formats. It could also be extended to be processed to the extent where it actually parses and repairs the aforementioned files. Also, an element of logic could be applied to the system, increasing it's potential power enormously. Although it covers a wide scope of technologies, this is useful because it makes ADL holistic in the sense that it should enable us to make assertions any repairs about any aspect of accessibility. 1.2 What formats would it describe? Uncertain. Len pointed out the following: XML, XHTML, CSS, ECMAScript, HTML, Invalid HTML, etc. Some consensus within the ERT group was reached that any UI medium should be able to have accessibility assertions made about it. ADL will have great benefits in describing and repairing accessibility problems in valid XML, but is *should not* be limited to that alone. 2 Aims 2.1 The abstract aim. In general we want to create a metadata description language that can describe the accessibility of languages, and also point into these languages specifically if possible. (N.B. It may only be possible to do that in valid/cleaned up XHTML and XML applications). Not only that, but we also want it to be a widely used, recognisable and interoperable format for people to use. In other words it has to be easy to generate, and easy to use. People should be able to make accessibility assertions about their documents, and accessibility tools authors should be able to utilise ADL for pointing out accessibility errors and repairing them. 2.2 The process aim. WC asked what kind of process we are looking at for ADL. It seems that there are three options. 1. Just an unofficial note published by the ERT group. This would mean we can update it whenever we want, and we don't have to go through W3C process, but it may make the language less acceptable, and possibly even inadequate if not looked at carefully. 2. A W3C Note. Has the advantage of finality, and also of sub-endorsement by the W3C. The disadvantage is that a note is just that: only a note. 3. A W3C Recommendation. The disadvantages are the length of process we'd need to go through, but there are huge benefits: endorsement by the W3C, full development including implementation to get through CR, a published versioning system, and publicity: people will know about it when it goes to recommendation. 3. Format 3.1 What format will ADL take on? This is the hottest topic. There seem to be many advantages in using XML/RDF, not least of which is the tool support and the W3C backing. It may not be viable to extend it to assert accessibility claims for all types of documents, but it should cover most. In my *opinion*, the current likelihood looks like:- RDF - 50% XML - 30% Other - 20% The fear in using RDF is that we don't have control over the actual framework, but that is also the major benefit: the framework already exists. The question of what tools RDF offers is the main one. 3.2 Implementation What implementations will ADL take on? It could be used for asserting things in documents, specifically pointing at them, applying logic to them, and ultimately repairing them. One great example that was brought up was ensuring that XML Schemas have the required accessibility features in them. 4 The Next Step 4.1 What is the next step? We have to decide on what the process aims are of ADL, so that we can get started if need be. Also, from the recent teleconference:- SP: May attend by phone. What is needed by me? WC: Example of what RDF buys us. LK: Please put URIs on mailing list. Should we brainstorm ideas on what ADF will be like? [I presume that means ADL] WC: Useful and instructive. LK: Future discussion on list. WC: Ask people to provide test pages. LK: Break into 2 or 3 groups and compare results. Therefore it seems that we need to address what advantages RDF will buy us, and provide testable examples of sites for ADL to apply to. I would also like to comment on how open-minded and productive this group actually is. Is ADL had been suggested anywhere else, it would have been doomed to failure due to it's complexity: it encompasses XML, RDF, XHTML, WCAG, CSS, and so on, and that is a lot of technologies for people to have backgrounds in. In a way we need to be experts in every single field, so that we can provide an ADL language that actually asserts how accessible each of these formats are in the best possible manner. A good example of how open-minded this group is comes from discussion in the Telecons. For example, Daniel said that XHTML should be written in XML Schemas, and that everything we do should be based on Schemas. Coming form the XHTML world that is quite astounding, and I had to remind everyone that for now XHTML is a document format, and that we need to recognise the legacy aspects of it. The fact of the matter is, if we did let politics get in the way, and we didn't look as far into the future as possible, we couldn't follow the aims of ERT! For example, if I suggest that we need to use Namespaces for RDF Schema validation purposes, most people would agree, but some would ask "why?". If I then pointed out that 1. It is a useful practise, and 2. It is endorsed by TimBL and the RDF community, then you would say fine, use namespaces for validating Schemas. Now, try posting the phrase "use namespaces for Schema validation" onto any XML list and prepare for some serious argumentative discussion... It seems that this list appreciates the finer points of cutting edge technology, and that is an incredible achievement. Because of that, ADL will be a cohesive, interoperable, and approachable language: it's going to work! IMHO etc. P.S. BTW: There is already an "ADL" out there somewhere, so maybe is is a taken abbreviation. I'll try to find out what it is again, but try typing "ADL" into Google. Kindest Regards, Sean B. Palmer http://xhtml.waptechinfo.com/swr/ http://www.w3.org/WAI/ER/ http://www.w3.org/WAI/GL/ "Perhaps, but let's not get bogged down in semantics." - Homer J. Simpson, BABF07. -- Charles McCathieNevile mailto:charles@w3.org phone: +61 (0) 409 134 136 W3C Web Accessibility Initiative http://www.w3.org/WAI Location: I-cubed, 110 Victoria Street, Carlton VIC 3053, Australia September - November 2000: W3C INRIA, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France
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