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Re: QSA, the problem with ":scope", and naming

From: Alex Russell <slightlyoff@google.com>
Date: Wed, 19 Oct 2011 09:22:46 +0100
Message-ID: <CANr5HFWQgi57vdMKKQXESJxT37+seBtWGwJ6BkQ0-O+kDx4o8w@mail.gmail.com>
To: Boris Zbarsky <bzbarsky@mit.edu>
Cc: public-webapps@w3.org
On Wed, Oct 19, 2011 at 2:26 AM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
> On 10/18/11 8:08 PM, Alex Russell wrote:
>>>
>>> The other "excuse" is that adding special cases (which is what you're
>>> asking
>>> for) slows down all the non-special-case codepaths.  That may be fine for
>>> _your_ usage of querySelectorAll, where you use it with a particular
>>> limited
>>> set of selectors, but it's not obvious that this is always a win.
>>
>> Most browsers try to optimize what is common.
>
> Yes, but what is common for Yehuda may well not be globally common.

Yehuda is representing jQuery. I'll take his opinion as the global
view unless he choses to say he's representing a personal opinion.

> There's also the question of premature optimization.  Again, I'd love to see
> a non-synthetic situation where any of this matters.  That would be a much
> more useful point to reason from than some sort of hypothetical faith-based
> optimization.

The jQuery team did look to see what selector are "hottest" against
their engine at some point and explicitly optimize short selectors as
a result. The simple forms seem to be the most common.

Regards
Received on Wednesday, 19 October 2011 08:23:49 GMT

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