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Re: [css3-mediaqueries] grammar unspecified?

From: Andrey Mikhalev <amikhal@abisoft.spb.ru>
Date: Wed, 25 Feb 2009 19:36:22 +0300 (MSK)
To: Anne van Kesteren <annevk@opera.com>
cc: www-style@w3.org
Message-ID: <Pine.LNX.4.63.0902251911360.7663@master.abisoft.spb.ru>
On Wed, 25 Feb 2009, Anne van Kesteren wrote:

> On Wed, 25 Feb 2009 05:41:49 +0900, Andrey Mikhalev <amikhal@abisoft.spb.ru> 
> wrote:
>> in WD-css3-mediaqueries-20081015 part '3. Syntax' contain mix of references 
>> both to generic grammar and CSS2 appendix G grammar, which makes it 
>> unusable:
>> 1. "media_query_list production defined below replaces the medium
>>    production from CSS2"
>>    - appendix G grammar has 'medium' but does not define 'value'
>>      production which used in syntax.
>>    - generic grammar has 'value' but does not contain 'medium' production.
>> 2. "RESOLUTION is to be added to the CSS2 term  production and NOT, ONLY,
>>    AND, and ',' are to be added to the CSS2 value production"
>>    - again, weird unclean mix of statements from two different grammars
>>      (generic has no 'term', app.G has no 'value')
>>    - 'value' defined in generic grammar. for me, statement above claim
>>      mediaquery syntax broken (i.e. mediaquery cannot be parsed in generic
>>      grammar w/o modification).
> This is mostly because CSS grammar is a mix of productions, prose and magic. 
> (Ok, no magic.) This seemed like a good approximation, though if you have 
> suggestions on how to improve things that'd be cool.

"good approximation" which produce yacc syntax error?
suggest only one basic grammar should be used to define syntax, not both.
  : '(' S* media_feature S* [':' S* expr]? ')' S*

>> btw, generic value ("[ any | block | ATKEYWORD S* ]+") looks like overkill 
>> for mediaquery expressions listed in spec.
> We could restrict it I suppose, it does not really matter either way as far 
> as I can tell...

thin ice of another issue.
css generic grammar allow only one [nested] block per at-rule...

Received on Wednesday, 25 February 2009 16:37:03 UTC

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