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Re: [css-regions] ::region() or ::fragment() pseudo-element

From: Alan Stearns <stearns@adobe.com>
Date: Fri, 14 Jun 2013 14:51:49 -0700
To: Brad Kemper <brad.kemper@gmail.com>
CC: W3C WWW Style <www-style@w3.org>, Tab Atkins <jackalmage@gmail.com>
Message-ID: <CDE0DB6B.2C225%stearns@adobe.com>


On 6/14/13 12:53 PM, "Brad Kemper" <brad.kemper@gmail.com> wrote:

>On Jun 13, 2013, at 12:01 PM, Alan Stearns <stearns@adobe.com> wrote:
>
>> An earlier discussion [1] of the region styling syntax ended with a
>>choice
>> between what's currently in the draft
>> 
>> 
>> <region-selector>::region(<content-selector>) {}
>> 
>> 
>> 
>> And a reversal of the selectors, with a change to ::fragment()
>> 
>> 
>> <content-selector>::fragment(<region-selector>) {}
>> 
>> 
>> 
>> I think the latter might be useful for other fragment containers, but
>>I'm
>> a bit worried about grouping. One problem with ::region() that©ös been
>> noted is that you may want to style a number of <content-selector>s for
>>a
>> given region, which will require some duplication to express. Am I
>>correct
>> in assuming that some future grouping solution would probably be limited
>> to grouping on the left side of the pseudo-element? If that's the case,
>>we
>> should probably stick with the current syntax.
>> 
>> [1] http://lists.w3.org/Archives/Public/www-style/2013May/0632.html

>
>I think it is far from clear whether or not "some future grouping
>solution" would be able to make a difference here, by splitting the
>parentheses of a pseudo-element onto two lines in order to group multiple
>different selectors within the parentheses into their own lines between
>the parentheses. This is the only case where that would be needed, isn't
>it?

That's my point. I don't think that the change to ::fragment lets us use
future grouping solutions. All of the grouping examples I've seen (and the
Hierarchies proposal) split similar selectors and create a group out of
the left side of the split. So if you have the current region styling
syntax:

<region-selector>::region(<content-selector-A>) {}
<region-selector>::region(<content-selector-B>) {}


Then you could use a left-side grouping mechanism to do what we want,
which is define a set of region styles for a particular region:

Group<region-selector>
{
  ::region(<content-selector-A>) {}
  ::region(<content-selector-B>) {}
}


But if we have the proposed change to region styling:

<content-selector-A>::region(<region-selector>) {}
<content-selector-B>::region(<region-selector>) {}

Then a left-side grouping mechanism would not be able to express a set of
region styles for a particular region. The only grouping you'd be able to
do is define different region styles for a particular content selector,
which isn't a use case I've encountered. And I don't expect to see a
grouping solution that groups on a pseudo-element parameter.


Thanks,

Alan

Received on Friday, 14 June 2013 21:52:17 UTC

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