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Date: Fri, 16 Oct 2015 11:04:07 +0200
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Subject: =?iso-8859-1?Q?AW:_=5BPHP-DEV=5D_Re:_=5BRFC=5D_Void_Return_Type_=28v0.2?=
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From: php@tutteli.ch ("Robert Stoll")

Hi Andrea

> -----Urspr=FCngliche Nachricht-----
> Von: Andrea Faulds [mailto:ajf@ajf.me]
> Gesendet: Donnerstag, 15. Oktober 2015 23:04
> An: internals@lists.php.net
> Betreff: [PHP-DEV] Re: [RFC] Void Return Type (v0.2, re=F6pening)
>=20
> Hi everyone,
>=20
> Andrea Faulds wrote:
> > I'm reviving my Void Return Type RFC, this time for PHP 7.1:
> >
> > https://wiki.php.net/rfc/void_return_type
> >
> > Please read it and tell me your thoughts!
>=20
> Since the void/null naming issue has been a frequently-asked question, =
I've added a subsection to the RFC explaining
why I
> chose this name. It doesn't really say anything I haven't said =
already, it just summarises it. In particular, it lists
a bunch of
> languages using `void`, some of which do what PHP does.
>=20
> The new section is here:
> =
https://wiki.php.net/rfc/void_return_type#why_call_it_void_and_not_null
>=20
> Thanks.
>=20
> --
> Andrea Faulds
> http://ajf.me/
>=20
> --
> PHP Internals - PHP Runtime Development Mailing List To unsubscribe, =
visit: http://www.php.net/unsub.php

You write in your RFC "others do allow void functions in expressions, =
just as PHP does, by making them implicitly return
some unit type."
You mentioned TypeScript -- unit type =3D null -- ActionScript -- unit =
type =3D undefined -- and Swift -- unit type =3D empty
tuple, ergo ().
TypeScript [1] allows to return null, ActionScript does not allow to =
return undefined, and Swift allows to return an
empty tuple explicitly [2].

I agree with others that is seems inconsistent to use the name void but =
allow to use void functions in expression
(return implicitly a unit type) and in the same time forbid to return =
the unit type explicitly in such functions.
IMO ActionScript should have allowed to return the unit type explicitly =
as well and so should PHP.
At first I did not like the idea of introducing void in PHP at all if it =
has not the same behaviour as in C -- meaning
it should be forbidden to use void functions in expressions -- but now I =
think it better suits PHP if void stands for
return nothing (hence null implicitly) or null explicitly. I think you =
should change your RFC to allow returning
explicitly null for two reasons:

1. Implicit and explicit behaviour should be consistent. If a function =
returns null implicitly then it should be allowed
to return null explicitly.
2. Not everyone might be aware of the implicit behaviour and some code =
conventions might want to be explicit on this
part and dictate that one needs to express the behaviour in code.=20

To conclude, personally I want that the following are all equivalent:
function foo() : void {}
function foo() : void { return; }
function foo() : void { return null; }

To go a step further, I kind of like the idea that using the return =
value of a void function results (at least) in an
E_NOTICE. But maybe that is something for PHP 8.=20

Another random thought, why not treat void like Void [3] in Java where =
null is the only valid value of this type? Nah...
bad idea, would be too heavy to use an object everywhere and secondly it =
would force to write "return null;" all the
time, so forget about it.

[1] =
http://www.typescriptlang.org/Playground#src=3Dfunction%20foo()%3Avoid%7B=
return%20null%3B%7D%0A=20
[2] http://swiftstub.com/114266460/?v=3Dgm
[3] http://docs.oracle.com/javase/7/docs/api/java/lang/Void.html=20