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Re: Bugs in CSS parsing

From: Jo Rabin <jrabin@mtld.mobi>
Date: Thu, 10 Jul 2008 17:12:49 +0100
Message-ID: <48763501.2010307@mtld.mobi>
To: Francois Daoust <fd@w3.org>
CC: public-mobileok-checker <public-mobileok-checker@w3.org>

 > Actually, not willing to open a big can of worms and to trigger, but...
 > why did we decide to link to the CSS1 Grammar and not the CSS2 Grammar
 > (they are mostly the same anyway)?

Because the DDC supports CSS Level 1 of course :-)

On 10/07/2008 17:07, Francois Daoust wrote:
> Jo Rabin wrote:
>> Interesting point. Apparently everything that CSS defines is case 
>> insensitive: property names values and units in particular. But I 
>> suppose selectors, font-names, URIs, classes, ids and so on are not. I 
>> don't think that the latter affects mobileOK processing, though, since 
>> we make no attempt to match any of these to the document that the CSS 
>> is applied to
> 
> I haven't checked the latter point into details because we don't really 
> care here indeed (there are interesting exceptions to the 
> case-insentivity in practice [also triggered by the fact that HTML is 
> case-insensitive whereas XHTML is not and this kind of things]).
> 
> But the former point still holds: property name, values, and units are 
> case-insensitive. And spaces may be defined almost anywhere.
> 
> 
> 
>> - though perhaps we ought to have done in the case of CSS in <style> 
>> elements. I think we did discuss it and dropped it as an idea, another 
>> version, maybe.
> 
> Already having some new ideas for a future version of the mobileOK Basic 
> Tests document? I see you're a bit sad to let it go... ;-)
> 
> 
>>
>> Space sensitivity is another matter though. In some cases spaces are 
>> required, in some cases they are optional and in other cases they are 
>> prohibited ... so is the treatment of space in the way we do a defect 
>> in the CSS parser, or is it an artefact of using regex to extract some 
>> parts of the CSS Style?
> 
> The bug is just an artefact of using regex. Nothing too hard to fix, I 
> was mostly willing to make sure that we agreed on the need to relax the 
> way the parsing is done in the checker.
> 
> In practice, the changes affect, I think:
> - MeasuresTest.java: to extract absolute values, and match CSS1 properties
> - CSSUtils.java: there may be spaces before the ":" (i.e.: 
> "background-image:" and "background-image   :" are both correct)
> - StyleSheetsSupport.java
> 
> I just committed a first patch to MeasuresTest.java.
> I say "first patch" as it's not entirely enough, because:
>   "font-size:
>     12pt;"
> ... is valid as well, and we're parsing the CSS line after line AFAICT.
> I guess we may list this last case in the "bug for later" category though.
> 
> The same needs to be done to CSSUtils.java and StyleSheetsSupport.java.
> (Note I'm off tomorrow, and Monday is a blank holiday in France)
> 
> 
> Actually, not willing to open a big can of worms and to trigger, but... 
> why did we decide to link to the CSS1 Grammar and not the CSS2 Grammar 
> (they are mostly the same anyway)?
> 
> Francois.
Received on Thursday, 10 July 2008 16:13:41 GMT

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