Re: [Themis-dev] CSS

[<Ar...@co...>]

> I'm currently doing a more in-depth analysis of the CSS grammar
> (currently trying to determine if the CSS3 grammar is LL(1)), so I can
> better judge the available parsers.  There is a number of really odd
Not sure how much this helps:

CSS 2.1 Revision 1 Parsing rules:
http://www.w3.org/TR/2007/CR-CSS21-20070719/syndata.html#syntax
All futures versions of CSS will conform to these parsing rules (including CSS 3 -- so says the spec at least :) )
This page has some additional notes about the grammar:
http://www.w3.org/TR/2007/CR-CSS21-20070719/grammar.html
It is in LALR(1) but suggests not to use it in the real world, since it doesn't conform perfectly to the parsing standards.

For CSS3 selectors, the specs has an LL(1) sample here:
http://www.w3.org/TR/css3-selectors/#w3cselgrammar
Again it states: "but note that most UA's should not use it directly, since it doesn't express the parsing conventions"

Also, here's something interesting....  An older working draft of CSS 2 has a sample using LL1:
http://www.w3.org/TR/2002/WD-CSS21-20020802/grammar.html


>From what I can make out, it needs to follow the parsing conventions for CSS and that part will never change on any version of CSS.  However, beyond that I don't really know what's going on.  Does the spec require the browser to use LALR(1) for CSS 2.1 or is that merely there as an example?

If you could help explain a few things to me, maybe I could ask around for you.

Thanks,
Kevin
 -------------- Original message ----------------------
From: Maxwell Collins <ma...@um...>
> Yes, I've been following the mailing list.
> 
> I'm currently doing a more in-depth analysis of the CSS grammar
> (currently trying to determine if the CSS3 grammar is LL(1)), so I can
> better judge the available parsers.  There is a number of really odd
> properties of the CSS grammar, and one of the most important properties
> of a CSS parser is how it handles these.  I'm going to completely
> analyze all of the oddities of the CSS 2.1 grammar (which I'm familiar
> with), then try to see if I can anticipate any similar issues that may
> have arisen with some of the new CSS3 stuff.
> 
> Once I've completed that, I'll send my thoughts on all of the available
> CSS Parsers/CSSOM packages (including some beyond the three you listed).
> 
> On Fri, 2007-09-14 at 06:32 +0000, Ar...@co... wrote:
> > Hey,
> > Are you still following the mailing list?
> > I posted something about a person working on a project called UZI....  Have 
> you looked at any of the stuff he has to see if it might be something worth 
> considering for Themis?
> > 
> > Anyways, what's your thoughts on CSS (if you've gotten a chance to look)?  
> Does the current CSS look like it's a good start, does it look like the 
> foundation is bad and that it would just be better to start with a new CSS 
> parser (like yours).  I know you were interested in the particular area of CSS, 
> but the reason I'm contacting you is to see how UZI mixes into things.  In 
> comparing the 3: Themis' CSS, your CSS, or UZI's CSS, which appears to have the 
> more solid foundation (regardless of whether it's even close to feature 
> complete)... and which is closer to feature complete?
> > Of course, what involvement UZI might have in the Themis project is uncertain 
> at this point, but I didn't want their to be a conflict between what you were 
> interested in and that project (since that project also include CSS stuff).
> > 
> > Kevin
> 
> 
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