Re: [css-selectors] Proposal: Logical Combinators / Sets

On Wed, Mar 13, 2013 at 2:25 PM, Liam R E Quin <liam@w3.org> wrote:

> On Wed, 2013-03-13 at 12:20 -0400, Brian Kardell wrote:
> [...]
> > .person:allOf( [occupation='designers'] *, [country='US'] *).unemployed{
> > .... }
>
>
> Your example shows that it's going to be easy to simulate look-ahead,
> which stalls progressive rendering. People do that today anyway, using
> jQuery or other libraries, but providing the common cases in forms that
> are easily optimized seems to be a win, so I think some more work would
> be needed here.
>


I'm not sure why - I think perhaps you've misunderstand my proposal.

In my example the splats represent person, a better way to illustrate it
might have been:

*:allOf( [occupation='designers'] *, [country='US'] *).person.unemployed

Selects descendants of elements that meet both of those criteria,
regardless of where (this also makes them more resilient to minor changes
in the structure).  Since parsing is recursive, it seems impossible that
you could construct a situation where there is an unknown like there would
in the case of something like :has() (sigh, or the subject token if we must
;)).

 Of course, the whole idea of a proposal is that it can have counter
proposals and I think perhaps you might have just made one - personally I
care much more about a good discussion and competition of ideas than I do
getting specifically this, but this seems very doable to me.

-Brian