W3C home > Mailing lists > Public > www-style@w3.org > February 2015

Re: [css-scoping] Shadow Cascading

From: Hayato Ito <hayato@google.com>
Date: Wed, 04 Feb 2015 22:38:19 +0000
Message-ID: <CAFpjS_1eBGnR6+_00JpnMwq=FS+SKn9ELU9bfpCbnWoqoG3Saw@mail.gmail.com>
To: Rune Lillesveen <rune@opera.com>, "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: www-style list <www-style@w3.org>
On Wed Feb 04 2015 at 8:49:06 PM Rune Lillesveen <rune@opera.com> wrote:

> On Wed, Feb 4, 2015 at 10:00 AM, Tab Atkins Jr. <jackalmage@gmail.com>
> wrote:
> >
> > On Feb 4, 2015 7:24 PM, "Rune Lillesveen" <rune@opera.com> wrote:
> >>
> >> On Wed, Feb 4, 2015 at 5:48 AM, Tab Atkins Jr. <jackalmage@gmail.com>
> >> wrote:
> >> > On Tue, Feb 3, 2015 at 5:51 AM, Rune Lillesveen <rune@opera.com>
> wrote:
> >>
> >> >> If so, using "tree of trees" might mislead to think otherwise.
> >> >
> >> > Eh, if you just follow the algorithm it's impossible to screw up.  And
> >> > "tree of trees" is the term I want, as it applies between sibling
> >> > shadow trees.
> >>
> >> OK, I'm fine with using "tree of trees", but aren't sibling shadow
> >> trees also different scopes? That is, the scoping root is the shadow
> >> root and sibling shadow trees each have a separate shadow root? They
> >> currently are in Blink fwiw.
> >
> > Not quite. You can, via `:host >>> .foo`, select into sibling shadows
> from
> > inside one of the shadows.
>
> Sure, but that's a scope crossing rule. My point was that the
> cascading order between rules in different shadow trees for the same
> host is still governed by:
>
> "When comparing two declarations, if one of them is in a shadow tree
> and the other is in a document that contains that shadow tree, then
> for normal rules the declaration from the outer document wins, and for
> important rules the declaration from the shadow tree wins."
>
> as order of appearance is further down the list in [1]. So, perhaps
> that statement should mention a tree-of-trees order instead of
> inner/outer.
>
> [1] http://www.w3.org/TR/css-cascade-3/#cascading
>
>
That would change the order of precedence, wouldn't that?

Looks like the current spec wants to say:

1. The Origin and Importance matters
2. [Shadow Tree] The outer wins the inner (only when there is an
ancestor/descendant relationship between two node trees)
3. [Shadow Tree] The younger wins the older (only when they are hosted by
the same shadow host)
4. Specificity matters
5. Order of Appearance in tree-of-trees matters


> --
> Rune Lillesveen
>
>
Received on Wednesday, 4 February 2015 22:38:47 UTC

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