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

Re: [selectors] Previous-sibling combinator?

From: Benjamin Poulain <benjamin@webkit.org>
Date: Wed, 11 Feb 2015 15:05:27 -0800
Message-ID: <54DBE037.5060609@webkit.org>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: Liam R E Quin <liam@w3.org>, Marat Tanalin <mtanalin@yandex.ru>, Clive Chan <doobahead@gmail.com>, Brad Kemper <brad.kemper@gmail.com>, Henrik Andersson <henke@henke37.cjb.net>, www-style list <www-style@w3.org>
On 2/11/15 2:57 PM, Tab Atkins Jr. wrote:
> On Thu, Feb 12, 2015 at 9:52 AM, Benjamin Poulain <benjamin@webkit.org> wrote:
>> On 2/11/15 2:47 PM, Tab Atkins Jr. wrote:
>>> The problem with "giving people enough rope to hang themselves" is
>>> when the mere existence of the feature slows down or complexifies the
>>> engine as a whole, regardless of whether it's used.
>>
>> Can you explain this? Why is that the case?
>
> Because being able to handle style invalidations from arbitrarily high
> up in the tree prevents simplifications that assume that can't happen;
> at minimum, it probably adds branches in the code which can have
> measurable perf effects.

There is nothing special about this case. Such invalidation already 
happen for :valid/:invalid and soon for :focus-within.

Benjamin
Received on Wednesday, 11 February 2015 23:07:32 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:52:01 UTC