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Date: Mon, 11 May 2020 12:53:51 +0200
To: "Nikita Popov" <nikita.ppv@gmail.com>
Cc: "Rowan Tommins" <rowan.collins@gmail.com>,
	"internals" <internals@lists.php.net>
Message-ID: <172035e5f2e.dac3608e708777.4548425207243262176@manuelcanga.dev>
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Subject: Re: [PHP-DEV] [RFC] Keep type of reference params
From: php@manuelcanga.dev (Manuel Canga)

Hi, Nikita and internals,


 ---- En lun, 11 may 2020 11:34:22 +0200 Nikita Popov <nikita.ppv@gmail.com=
> escribi=C3=B3 ----
 > On Fri, May 8, 2020 at 8:49 AM Manuel Canga <php@manuelcanga.dev> wrote =
to this RFC, could someone give me(manuelcanga user ) karma in order to cre=
ate wiki page ?.
 >=20
 > I'm finding it hard to follow what is actually being proposed here at th=
is point (as many different ideas seems to be discussed at the same time). =
I've granted you RFC karma on the wiki in case you want to write down somet=
hing.
 > As other's have mentioned, this is not a simple topic from the implement=
ation side, so it's good to have a firm idea of how things would work on a =
technical level. If you want to pursue the "inout" idea, I would recommend =
reading through https://externals.io/message/101254 in its entirety, becaus=
e there is quite a bit of inout related discussion in there. My current ass=
essment is that I do not see any way to implement inout in a way that both =
does not use references and has acceptable performance. (Implementing inout=
 on top of references is possible, but has impact on its behavior, e.g. the=
 fact that the reference will be initialized to null by default, even if th=
e function throws.)
 > One of the core problems is that any naive approach to inout (i.e. liter=
ally implementing it as a read before the call and a write after the call) =
will necessitate a copy of the modified value, precluding rc=3D1 cow avoida=
nce. Implementing array_push() as an inout operation would copy the array e=
very time a value is pushed. Maybe this is actually a fundamental implement=
ation-independent property of inout, if it has the semantics that the origi=
nal value is not changed on exception (a copy would be necessary in case co=
de later in the function throws.)


Thanks, Nikita. I will read that thread.=20

I don't have know about PHP core so it's possible I will say a silly thing =
but... is possible using Hack implementation ?. Maybe They found the best w=
ay of implementation.

Regards

--
Manuel Canga