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Specificity of :any (was Re: [css3-selectors] Grouping)

From: L. David Baron <dbaron@dbaron.org>
Date: Thu, 25 Feb 2010 15:16:09 -0800
To: www-style@w3.org
Message-ID: <20100225231609.GB9097@pickering.dbaron.org>
On Thursday 2010-02-25 17:58 -0500, Boris Zbarsky wrote:
> At least in Gecko's case, what you wrote above would indeed be more
> or less just syntax sugar.  But this:
> 
>   :any(#authors, #publications) div
> 
> would probably be faster to match than:
> 
>   #authors div, #publications div
> 
> In fact, we're looking into implementing this right now (as
> :-moz-any()) to more efficiently deal with the numerous rules of
> this form that appear in our UA stylesheet.

So the one thing that I just realized I'm not sure how to implement
is specificity.  (What I actually have implemented is treating :any
as a pseudo-class and ignoring its arguments, which probably isn't
what we want.)

So given a selector like:

p:any(:hover,#mypara)

Should this selector have:

 specificity 11 (p + :any)
 specificity 111 (p + :hover + #mypara)
 specificity 121 (p + :any + :hover + #mypara)
 specificity 11 (p + :hover) or 101 (p + #mypara) depending on how it
   matches (with 101 if it matches both ways)?
 one of 11 or 101, not depending on how it matches (just always the
   lowest or highest)

I'd note that the next-to-last seems like it might be best, but I
can't think of an obvious way to implement it in our code.

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/
Received on Thursday, 25 February 2010 23:16:37 GMT

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