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Re: UPDATED: Pointers changes and issues

From: Shadi Abou-Zahra <shadi@w3.org>
Date: Wed, 18 Jul 2007 17:40:00 +0200
Message-ID: <469E3450.4080609@w3.org>
To: Carlos Iglesias <carlos.iglesias@fundacionctic.org>
CC: public-wai-ert@w3.org

Hi,

Carlos Iglesias wrote:
>> COMMENT 3:
>> Issue #9: I don't think I understand the problem, my 
>> understanding so far was that a CSS Selector is something 
>> like "h2" or "#id" etc.
> 
> Yes, the probem is how are you going to use this kind of pointers.
> I can imagine two possible scenarios:
> 
> A - Use css pointers (css selectors) to point into a css document
> 
> In this case you can have a CSS document like:
> 
> #1 h1 {
> #2   whatever;
> #3 } 
> #4
> #5 h2, h3 {
> #6   whatever else;
> #7 }
> #8
> #9 h1 {
> #10  something more;
> #11}
> ...
> 
> If you use "h1" as a selector pointer within this document you have 
> to lead with the ambiguity that is presented.
> Is h1 single pointer always to the first occurrence? Line #1
> Is h1 a multiple pointer to all the occurrences? Lines #1 and #9
> IS h1 a single pointer to just an occurrence? Then, which one? Line 
> #1 or #9? --> need something more
> 
> B - Use css pointer (css selectors) to point into a html document
> 
> In this case let's say we have something like:
> 
> ...
> <h1>Hello World</h1>
> ...
> <h2>First attempt</h2>
> ...
> <h2>Second attempt</h2>
> ...
> 
> In this case if you use "h2" as a selector pointer we have more or less 
> the same problems as before.
> 
> IMO we should have a well defined model that avoids these ambiguities, 
> for example with a new ptr:occurrence property.

Thanks for clarifying. I think a "CSS Selector" has a specific meaning 
and it is what you highlight in B -to point into HTML, XHTML, and XML. 
So unless someone has an objection, I propose that we use this meaning 
for the CSSSelectorPointer.

As to pointing into a CSS document, we can create a different pointer as 
needed. I'm not sure how this would work, I think most editors I've seen 
so far use a plain line/char to describe errors in a CSS document.


>> COMMENT 7:
>> 2.4 CompoundPointer: how about we have a simple 
>> SnippetPointer that can be used with the RangePointer to 
>> replace 2.4.2 CharSnippetRangePointer and 2.4.4 
>> ByteSnippetRangePointer (as in the comment above)?
> 
> If we use base64 for ByteSnippets ptr:snippet will need different 
> ranges  in each case.

No, ptr:snippet will be a Literal in both cases. It will just contain 
different stuff depending if it is used in a CharSnippet or ByteSnippet 
class.


Regards,
   Shadi


-- 
Shadi Abou-Zahra     Web Accessibility Specialist for Europe |
Chair & Staff Contact for the Evaluation and Repair Tools WG |
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Received on Wednesday, 18 July 2007 15:43:10 GMT

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