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Re: Shadow DOM: Hat and Cat -- if that's your real name.

From: Edward O'Connor <eoconnor@apple.com>
Date: Tue, 04 Feb 2014 10:02:19 -0800
To: www-style@w3.org
Message-id: <m2ob2mdadw.fsf@eoconnor.apple.com>
Hi Dimitri,

You wrote:

> As indicated by Tab at the F2F, Blink currently implements the cat/hat
> combinators proposed by yours truly [3].
> FWIW, I don't fully understand why it would be so terrible to leave
> cat and hat alone (in talking with Tab, there's only a weak precedent
> for preferring pseudo element functions to combinators with
> ::content), but I am okay with renaming them. Ultimately, it's this
> WG's shed, I just store my bike there.

I don't think host documents should be able to select arbitrary elements
in the shadow DOM. A much better model, which IIRC was in one of your
documents at one point, is to let the component author explicitly export
certain shadow elements as pseudos. Something like:

# In shadow tree

    <div pseudo=foo>...</div>

# in CSS, if that shadow tree is attached to el with id bar

    #bar::pseudo(foo) { ... }

In this model, the component author is only signing up for a contract
for which they know the terms.

Also, given the several open threads on public-webapps about various
foundational components issues, I think it would be a mistake to ship an
implementation without either prefixing it or putting it behind a
disabled-by-default runtime flag. That said, I'm sure you guys
understand Blink's policy for exposing features to the Web better than I

Received on Tuesday, 4 February 2014 18:02:41 UTC

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