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Re: Linking 'location' and 'technique': models and examples

From: Shadi Abou-Zahra <shadi@w3.org>
Date: Mon, 04 Dec 2006 15:28:32 +0100
Message-ID: <45743090.5030305@w3.org>
To: Carlos Iglesias <carlos.iglesias@fundacionctic.org>
Cc: public-wai-ert-tsdtf@w3.org

Hi Carlos,

Using ID and IDREF attributes seems much more difficult to process. Also 
more difficult to read and so more prone to bugs. Unless there is a case 
for significant benefits, then I suggest we don't complicate things.

For this group our primary target is to describe the relationship of a 
sample to the respective technique. So nesting (different types of) 
location pointers under each technique makes most sense (option A).

However, since option A is quite restricted to the (current draft) WCAG 
2.0 model, we may choose to go for a less technique-oriented approach. 
Option B is probably more verbose since the technique would be repeated 
in each (different type of) location pointer but I could live with it.

What is your opinion?

Regards,
   Shadi


Carlos Iglesias wrote:
> Hi Shadi,
> 
>> Thanks for this summary and the opportunity to comment. I 
>> strongly prefer option B, can live with option C, and dislike 
>> option A.
> 
> Could you elaborate on why you dislike option A?
> 
> Regards,
>  CI.
>  
>> cstrobbe wrote:
>>> Hi,
>>>
>>> I had an action item to provide examples of two ways to link a 
>>> 'location' with one or more 'technique' elements. This 
>> issue has been 
>>> discussed a few times before [1] [2], and there was another 
>> discussion 
>>> on the last conference call. We did not reach consensus, so 
>> here's a 
>>> description of the three models that were discussed.
>>> (Note that we need to allow references to more than one 
>> technique for 
>>> some success criteria [3], so the first proposal in [1] is not
>>> appropriate.)
>>>
>>>
>>> Model A: using ID and IDREFS
>>>
>>> Keep the sequence 'locations' (containing one or more instances of
>>> 'location') and 'techniques' (containing one or more instances if
>>> 'technique') as in the current schema, but link them by means of ID 
>>> and IDREFS type attributes.
>>> (And rename the 'id' attribute on the 'rule' element to 
>> 'xlink:href'.) 
>>> In practice, this would mean that we add an 'id' attribute to 
>>> 'technique' (do we need a naming convention for this ID?) and a 
>>> 'techrefs' attribute to 'location'. (These new attributes would be 
>>> optional in TCDL 2.0, but we can make them obligatory in our usage
>>> document.)
>>> The attachment sc3.1.1_l1_001_20061129_modelA.xml illustrates this 
>>> model.
>>>
>>>
>>> Model B: nesting 'locations' inside 'technique'
>>>
>>> The rationale for this change is that locations can be seen as 
>>> properties of a technique.
>>> Compared to model C (nesting 'techniques' inside 
>> 'location'), model B 
>>> also has the advantage that it is not necessary to repeat the 
>>> 'technique' element for each location where the technique 
>> is used. It 
>>> was also pointed out however, that there should be only one 
>> instance 
>>> of each technique or failure, because test samples should be atomic.
>>> The attachment sc3.1.1_l1_001_20061129_modelB.xml illustrates this 
>>> model.
>>>
>>>
>>> Model C: nesting 'techniques' inside 'location'
>>>
>>> The rationale for this model is that locations identify 
>> where barriers 
>>> occur and that 'techniques' provides additional (outside TSD TF:
>>> optional) information about these locations. Outside TSD 
>> TF, not very 
>>> location or barrier will map to a technique or failure 
>> documented by 
>>> WCAG 2.0, so other users may not want to nest 'locations' inside 
>>> 'technique'.
>>> (I have not created an example for this model.)
>>>
>>>
>>> [1] 
>> http://lists.w3.org/Archives/Public/public-wai-ert-tsdtf/2006Nov/
>>> 0029.html
>>> [2] 
>> http://lists.w3.org/Archives/Public/public-wai-ert-tsdtf/2006Oct/
>>> 0024.html
>>> [3] "Re: Minimum number of techniques in metadata": 
>>> http://lists.w3.org/ 
>>> Archives/Public/public-wai-ert-tsdtf/2006Oct/0072.html
>>>
>>> Best regards,
>>>
>>> Christophe Strobbe
>>>
>> -- 
>> Shadi Abou-Zahra     Web Accessibility Specialist for Europe |
>> Chair & Staff Contact for the Evaluation and Repair Tools WG |
>> World Wide Web Consortium (W3C)           http://www.w3.org/ |
>> Web Accessibility Initiative (WAI),   http://www.w3.org/WAI/ |
>> WAI-TIES Project,                http://www.w3.org/WAI/TIES/ |
>> Evaluation and Repair Tools WG,    http://www.w3.org/WAI/ER/ |
>> 2004, Route des Lucioles - 06560,  Sophia-Antipolis - France |
>> Voice: +33(0)4 92 38 50 64          Fax: +33(0)4 92 38 78 22 |
>>
>>
> 
> 

-- 
Shadi Abou-Zahra     Web Accessibility Specialist for Europe |
Chair & Staff Contact for the Evaluation and Repair Tools WG |
World Wide Web Consortium (W3C)           http://www.w3.org/ |
Web Accessibility Initiative (WAI),   http://www.w3.org/WAI/ |
WAI-TIES Project,                http://www.w3.org/WAI/TIES/ |
Evaluation and Repair Tools WG,    http://www.w3.org/WAI/ER/ |
2004, Route des Lucioles - 06560,  Sophia-Antipolis - France |
Voice: +33(0)4 92 38 50 64          Fax: +33(0)4 92 38 78 22 |
Received on Monday, 4 December 2006 14:28:37 GMT

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