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Re: [selectors4] Features to Defer

From: Daniel Glazman <daniel.glazman@disruptive-innovations.com>
Date: Wed, 22 Jul 2015 09:41:52 +0200
To: www-style@w3.org
Message-ID: <55AF4940.8000103@disruptive-innovations.com>
On 22/07/2015 02:54, Benjamin Poulain wrote:

> Getting it into the JIT compiler would be significantly harder. The JIT
> only knows how to traverse trees upward.
> :has() is the kind of selector that greatly benefits from the JIT.

(w/o my co-chairman's hat and with my former editorship/authorship
 of Selectors L3)

That's exactly, precisely, the reason that already blocked some
extensions of Selectors some oh... fourteen to fifteen years ago.
"the code only knows how to traverse the tree upward". I find it
extremely disturbing for our WG reputation to discover only now it
must be postponed because implementors - who pushed the feature forward
in the draft - won't/can't implement it for that same reason.

So I have the feeling this is not only a technical decision. This is
also a decision about managing this document and not holding a feature
forever. Maybe we should stop adding to this document things that have,
from the start, a too high probability of not making it, despite of
potentially immense usefulness to our users. Selectors are the very
first thing Web authors learn and manipulate; I bet a cookie they will
eventually become the only selecting mechanism in Web Standards, just
like XSL-FOs are out of the game on the Web in favor of CSS. We must be
extra-careful with that spec, because it's one the cornerstones of CSS.
The draft is too much an idea sink instead of being a list of things
that are in hyper-vast majority on path to implementation.

As said earlier in this thread, :has() has a long history. A long
history of never making it, unfortunately. The subject selector was
probably far easier to implement, including in a JIT compiler, ahem,
and I feel, as a WG member, totally ridiculous to postpone :has() again
for the n-th time in more than fifteen years.

Maybe we need to make a choice now about either keeping in L4 but only
in static profile or dropping the feature. And if the former means
giving priority to this feature during next weeks and confcalls, let's
do that instead of deferring to a L5. The WG has a face-to-face meeting
in a month from now; this is the right moment to make a final decision
and that gives us some time to do cleanup. Giving Web authors false
expectations over 15 years seems to me counter-productive for the
Working Group. That way of doing, with a deadline, seems to me better
than moving immediately to CR with no clear decision on :has().

</Daniel>
Received on Wednesday, 22 July 2015 07:42:19 UTC

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