Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:81249
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain zend.com designates 209.85.220.173 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <20150122103807.DD8255F8EE@mx.zeyon.net>
References: <20150122103807.DD8255F8EE@mx.zeyon.net>
Date: Tue, 27 Jan 2015 20:55:44 +0400
Message-ID: <CA+9eiLvLSK3m1PBfS_WY3dQsxbmBHCQ_X6_gh0ynCdOMSypySA@mail.gmail.com>
To: Benjamin Coutu <ben.coutu@zeyos.com>
Cc: Nikita Popov <nikita.ppv@gmail.com>, Xinchen Hui <xinchen.h@zend.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a11339f8a344726050da52073
Subject: Re: [PHP-DEV] Improvements to for-each implementation
From: dmitry@zend.com (Dmitry Stogov)

--001a11339f8a344726050da52073
Content-Type: text/plain; charset=UTF-8

Hi,

I'm working on a PoC, implementing the proposed behavior -
https://gist.github.com/dstogov/a311e8b0b2cabee4dab4

Only few PHPT tests had to be changed to confirm new behavior and actually
they started to behave as HHVM.
2 tests are still unfixed XFAILed. Foreach by reference is still need to be
improved to support different array modifications.

The patch makes ~1% improvement on Wordpress-3.6 (saving duplication and
destruction of 200 arrays on each request)

Thanks. Dmitry.



On Thu, Jan 22, 2015 at 1:38 PM, Benjamin Coutu <ben.coutu@zeyos.com> wrote:

> Hi Nikita,
>
> I would suggest using the proposal for the by-value case and sticking with
> the current behavior for the by-reference case as you suggested. Granted,
> we then cannot remove the internal pointer all together, but we would just
> use it for the less common by-reference case as well as for the legacy
> reset/next functions, of course. This would still improve most for-each
> traversals. At least we then wouldn't have to find a replacement solution
> for rest/prev/next/end. Moreover we can then move the internal position
> pointer out of the hashtable structure into zend_array because it is only
> used for userland arrays, not other hash tables (such as object properties
> or internal structures that build upon the hashtable struct).
>
> Thanks,
>
> Ben
>
> ========== Original ==========
> From: Nikita Popov <nikita.ppv@gmail.com>
> To: Benjamin Coutu <ben.coutu@zeyos.com>
> Date: Thu, 22 Jan 2015 10:53:19 +0100
> Subject: Re: [PHP-DEV] Improvements to for-each implementation
>
> Doing this was the idea I had in mind as well, i.e. change the semantics of
> foreach to say that it will always work on a copy for by-value iteration
> (which ironically avoids having to actually copy it). Note that this will
> differ from the current behavior in a number of ways. In particular it
> means that changes to arrays that were references prior to iteration will
> not influence the iteration.
>
> The real question is what we should do in the by-reference case. Given that
> we need to acquire references to elements of the original array we can't
> reasonably work with copy-semantics (at least I don't see how). So would we
> just stick with the previous behavior (using the hash position hack) for
> that?
>
> Nikita
>
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>

--001a11339f8a344726050da52073--