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Date: Wed, 10 Dec 2014 17:50:33 +0100
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Subject: AW: [PHP-DEV] [RFC] Nullsafe calls
From: php@tutteli.ch ("Robert Stoll")



> -----Urspr=FCngliche Nachricht-----
> Von: Robert Stoll [mailto:php@tutteli.ch]
> Gesendet: Mittwoch, 10. Dezember 2014 17:20
> An: 'Josh Watzman'; 'PHP internals'
> Betreff: AW: [PHP-DEV] [RFC] Nullsafe calls
>=20
> > -----Urspr=FCngliche Nachricht-----
> > Von: Robert Stoll [mailto:php@tutteli.ch]
> > Gesendet: Mittwoch, 10. Dezember 2014 17:17
> > An: 'Josh Watzman'; 'PHP internals'
> > Betreff: AW: [PHP-DEV] [RFC] Nullsafe calls
> >
> > Hi,
> >
> > > -----Urspr=FCngliche Nachricht-----
> > > Von: Josh Watzman [mailto:jwatzman@fb.com]
> > > Gesendet: Mittwoch, 10. Dezember 2014 00:08
> > > An: PHP internals
> > > Betreff: [PHP-DEV] [RFC] Nullsafe calls
> > >
> > > Hey internals! A useful feature that Hack picked up in the last =
few
> > > months are "nullsafe calls", a way of propagating
> > failure
> > > forward in a series of chained method calls to the end of the =
whole
> > > computation, getting rid of a lot of the
> > boilerplate in the
> > > middle. I think the feature would be a good one for PHP as well, =
so
> > > I'm submitting this RFC to add it -- you can see
> > the RFC
> > > itself for a full discussion of the motivation for the feature, as =
well as the feature itself:
> > >
> > > https://wiki.php.net/rfc/nullsafe_calls
> > >
> > > Josh Watzman
> > >
> > >
> > > --
> > > PHP Internals - PHP Runtime Development Mailing List To =
unsubscribe,
> > > visit: http://www.php.net/unsub.php
> >
> > First of all, I like the RFC, I think as well that it is a useful
> > feature for PHP and I already have it on my wish
> list
> > ;)
> >
> > Yet, either I misunderstand the section about short circuiting or I =
propose to change the behaviour.
> >
> > "If $obj is null, when $obj?->foo(..) executes, the arguments will =
still be evaluated."
> >
> > IMO that is wrong. It should not evaluate the arguments since the
> > nullsafe operator (sometimes called "safe
> navigation"
> > operator in other languages - which is the better wording IMO, maybe
> > change it? But that is just a detail) is just
> syntactic
> > sugar for making the call only if $bj is not null. So the following:
> >
> > $obj =3D null;
> > $obj?->foo($a, $b);
> >
> > should be the same as
> >
> > $obj =3D null;
> > If($obj !=3D=3D null){
> >  $obj->foo($a, $b);
> > }
> >
> > hence PHP will not complain that $a and $b where not defined.
> >
> >
> > --
> > PHP Internals - PHP Runtime Development Mailing List To unsubscribe,
> > visit: http://www.php.net/unsub.php
>=20
> Appendum: I somehow skipped the section "Prior Art". So I see, that =
the different behaviour was on purpose. I do not
> think it is a clever idea to implement a common concept differently. =
In this sense -1 Changing the RFC and
implementing it
> the same way others do +1
>=20
>=20
>=20
> --
> PHP Internals - PHP Runtime Development Mailing List To unsubscribe, =
visit: http://www.php.net/unsub.php

Appendum 2:

hm... my example was wrong as well, I was too quick. It should have been =
like this of course:
$obj =3D null;
$obj !=3D=3D null ? $obj->foo($a, $b) : null;

=20