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Date: Mon, 11 Jun 2012 17:12:03 -0400
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To: ab@php.net
Cc: Laruence <laruence@php.net>, Nikita Popov <nikita.ppv@googlemail.com>, 
	PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Generators in PHP
From: tom@punkave.com (Tom Boutell)

Can you really use setjmp and longjmp in that way safely? I thought it
was only safe to longjmp "back," not "forward" - you can use them to
fake exception support but that's it because you'll smash the stack
otherwise. Something like that...

OK, I'm thinking of this:

"Similarly, C99 does not require that longjmp preserve the current
stack frame. This means that jumping into a function which was exited
via a call to longjmp is undefined.[6] However, most implementations
of longjmp leave the stack frame intact, allowing setjmp and longjmp
to be used to jump back-and-forth between two or more functions=97a
feature exploited for multitasking."

It does not sound like something that can be done in portable C.

On Mon, Jun 11, 2012 at 4:13 PM, Anatoliy Belsky <ab@php.net> wrote:
> Hi,
>
> it'd be really cool if the implementation would do the "real" context
> switch in c, which would be the true basis for spl_coroutine. The current
> implementation seems not to do that.
>
> Context switch in c would be comparable with threads. In fact coroutines
> would be a comensation for lacking threads functionality in php, as they
> are already implemented on most popular platforms. However, it would
> require some platform specific libs (fibers on windows, setjmp and longjm=
p
> on unix(like)).
>
> Coroutines in c are per se thread safe, so implementing them once would
> not hurt both ts and nts. Additionally, in some cases coroutines can even
> have advantages over the "usual" preemptive threads.
>
> Regards
>
> Anatoliy
>
> Am Mi, 6.06.2012, 04:42 schrieb Laruence:
>> On Wed, Jun 6, 2012 at 10:27 AM, Laruence <laruence@php.net> wrote:
>>> On Wed, Jun 6, 2012 at 10:15 AM, Laruence <laruence@php.net> wrote:
>>>> Hi Nikita:
>>>>
>>>> =A0 =A0the most important part to me is how did you implemented `yield=
`
>>>> keyword, =A0 is there a whole patch file I can look into?
>>> Nervermind, =A0I will check the branch out later
>>>
>>> thanks
>>
>> After a quick look, =A0I think the main idea should goes to two parts:
>>
>> 1. implement yield (Zend)
>> 2. implement spl_generators but not generator class (Spl)
>>
>> then we can implement spl_coroutine later base on this. =A0what do you
>> think?
>>
>> thanks
>>>>
>>>> =A0 =A0what will happen if you use a `yield` in a normal function?
>>>>
>>>> =A0 =A0actually, =A0I tried to implemented coroutine, but since I coul=
d not
>>>> find a way to make zend_execute interruptable, then I didn't make it.
>>>>
>>>> =A0 =A0so, I am really interesting of this tech-specific :)
>>>>
>>>> thanks
>>>>
>>>> On Wed, Jun 6, 2012 at 1:35 AM, Nikita Popov
>>>> <nikita.ppv@googlemail.com> wrote:
>>>>> Hi internals!
>>>>>
>>>>> In the last few days I've created a proof of concept implementation
>>>>> for generators in PHP. It's not yet complete, but the basic
>>>>> functionality is there:
>>>>> https://github.com/nikic/php-src/tree/addGeneratorsSupport
>>>>>
>>>>> The implementation is outlined in the RFC-stub here:
>>>>> https://wiki.php.net/rfc/generators
>>>>>
>>>>> Before going any further I'd like to get some comments about what you
>>>>> think of adding generator support to PHP.
>>>>>
>>>>> If you don't know what generators are you should have a look at the
>>>>> "Introduction" section in the above RFC or in the Python documentatio=
n
>>>>> at http://wiki.python.org/moin/Generators.
>>>>>
>>>>> Nikita
>>>>>
>>>>> --
>>>>> PHP Internals - PHP Runtime Development Mailing List
>>>>> To unsubscribe, visit: http://www.php.net/unsub.php
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Laruence =A0Xinchen Hui
>>>> http://www.laruence.com/
>>>
>>>
>>>
>>> --
>>> Laruence =A0Xinchen Hui
>>> http://www.laruence.com/
>>
>>
>>
>> --
>> Laruence =A0Xinchen Hui
>> http://www.laruence.com/
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>>
>
>
>
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>



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