Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:127560
Date: Tue, 03 Jun 2025 15:20:48 +0000
To: Anton Smirnov <sandfox@sandfox.me>
Cc: internals@lists.php.net
Subject: Re: [PHP-DEV] [RFC] Transform void into an alias for null
Message-ID: <9CMD5Mjh0unmR6G9NjfMonV9S7q8KQ9F29o8OdcndyaZ4_sOMOGuQU8chWKRdz6LYwslYWnuWM069sWhWt8ZTFRiQluEWqjZOXME0UZ2Zrc=@gpb.moe>
In-Reply-To: <0ac00d42-7584-4de2-bca4-9099f3d4cbb5@sandfox.me>
References: <6Z2Ysh6MjYp1nyzuB0bTPJc5srObIcMRqt731JaQeXUJk1f_V_Yo2nRn8WvjI7er7pp7pIUE6WYl5pRwvYrtcrd07nCutyAqKPSsZHmrS-Y=@gpb.moe> <7f7dc3dc-bb9a-4f6e-9b77-055c4a8801d1@rwec.co.uk> <0ac00d42-7584-4de2-bca4-9099f3d4cbb5@sandfox.me>
Feedback-ID: 96993444:user:proton
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
From: internals@gpb.moe ("Gina P. Banyard")

On Tuesday, 3 June 2025 at 02:36, Anton Smirnov <sandfox@sandfox.me> wrote:

> On 02/06/2025 23:50, Rowan Tommins [IMSoP] wrote:
>=20
> > I agree the type hierarchy you describe is weird, but rather than
> > throwing away the functionality completely, I wonder if we can make it
> > more consistent:
> >=20
> > - Make "no return type declared" and "mixed" equivalent
> > - Make "void" a sub-type of "null", and therefore a sub-type of "mixed"
>=20
>=20
> I think that null and void are semantically very different so I'd like
> to suggest just making void subtype of mixed. This will both keep the
> semantic meaning of void and make mixed and undeclared mean the same thin=
g.

You are going to need to expand on why you think those two are semantically=
 very different.
PHP does not have the concept of "execution control is returned to the call=
ing scope, but no concrete value is returned".
And this is a good thing IMHO, as it means you can always take the result o=
f a function.

Moreover, "just making void subtype of mixed" can mean everything and nothi=
ng.
Do you mean for void to live on its own island like the int or string types=
?
Make it a subtype of null like Roman suggested?
Have void be a super type of some weird union of types representing scalars=
 int|string|float|bool?
Something else altogether?

Best regards,

Gina P. Banyard