Newsgroups: php.internals
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Xref: news.php.net php.internals:112544
Date: Thu, 17 Dec 2020 22:11:37 +0000
To: Aaron Piotrowski <aaron@trowski.com>
Cc: Peter Stalman <sarkedev@gmail.com>, php internals <internals@lists.php.net>
Reply-To: Saif Eddin Gmati <azjezz@protonmail.com>
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In-Reply-To: <461ED1D8-45CF-431C-91BA-959EF511CBBD@trowski.com>
References: <E4BE4688-3CD1-4CE8-A818-5A862F0293F5@trowski.com> <CAPrKfG5fQCb4MMHrZzsu2c8UJ+GGmsbM5eO90t4O-QTq5wTQOg@mail.gmail.com> <461ED1D8-45CF-431C-91BA-959EF511CBBD@trowski.com>
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Subject: Re: [PHP-DEV] [RFC] Fibers
From: azjezz@protonmail.com (Saif Eddin Gmati)

Hello Aaron,

First, I want to say that I love this proposal and would love to see it lan=
d in the next PHP release, but I have one question regarding this:


> Promises result in the =E2=80=9CWhat color is your function=E2=80=9D prob=
lem as described in the introduction of the RFC. Returning promises from fu=
nctions means that functions calling those functions must also return promi=
ses, resulting in the entire call stack needing to return promises.

Hack-Lang provides `HH\Asio\join` function which allows awaiting Awaitables=
 in sync code, so you are capable of running multiple async tasks concurren=
tly without having to declare the entire call stack as "async" or with an "=
Awaitable" return type, isn't this possible?

```
use namespace HH\Asio;

async function async_task(): Awaitable<void> {
  await Asio\usleep(1000000);
}

<<__EntryPoint>>
function main(): void {
  $start =3D microtime(true);

  $async =3D async {
    concurrent {
      await async_task();
      await async_task();
    };

    return 'hello';
  };

  $result =3D Asio\join($async);

  printf('Result: %s ( %f )', $result, microtime(true) - $start); // output=
 "Result: hello ( 1.010382 )"
}

```

Regards,

Saif.


=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original Me=
ssage =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90
On Thursday, December 17, 2020 8:43 PM, Aaron Piotrowski <aaron@trowski.com=
> wrote:

> Hi Peter,
>
> > On Dec 17, 2020, at 1:23 PM, Peter Stalman sarkedev@gmail.com wrote:
> > Hi Aaron, this is very interesting to me. Can I ask why this approach a=
s
> > opposed to other paradigms like promises, coroutines, etc? You mentione=
d
> > async/await in the future scope, and I assume most of these patterns ca=
n be
> > implemented once there is an underlying functionality. Basically, why
> > fibers instead of x?
>
> Promises result in the =E2=80=9CWhat color is your function=E2=80=9D prob=
lem as described in the introduction of the RFC. Returning promises from fu=
nctions means that functions calling those functions must also return promi=
ses, resulting in the entire call stack needing to return promises.
>
> Fibers are a method of implementing coroutines or interruptible functions=
. Promises likely would still be used as placeholders in libraries using fi=
bers, but coroutines written using fibers do not have to return another pla=
ceholder. Fibers allow async code to be indistinguishable from sync code, a=
s opposed to an approach where async functions must return a promise.
>
> > You also mentioned this isn't really intended to be used directly, but =
with
> > a library such as AMPHP. IS the expectation that non-blocking I/O
> > functionality like database drivers and file operation be provided by
> > libraries as well?
>
> Since most code written for PHP is blocking, yes, such libraries/framewor=
ks would need to provide functionality such as database drivers. Both AMPHP=
 and ReactPHP already have existing async drivers available for several dif=
ferent popular database systems. AMPHP=E2=80=99s postgres, mysql, and redis=
 drivers already have a version using fibers.
>
> > I hope I don't come off as critical, I am merely curious. Thank you for
> > pushing this forward, as async is something PHP has been lacking and sh=
ould
> > have IMO to compare favourably to other alternatives that do.
>
> You didn=E2=80=99t com off as critical at all! These were good questions =
to ask. I too think if PHP is to add support for async code it should compa=
re favorably to other languages. I think fibers offer a distinct advantage =
to using promise for async code.
>
> Cheers,
> Aaron Piotrowski
>
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