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In-Reply-To: <95A581EE-A062-4926-BE44-BCA87FC9B356@fb.com>
Date: Tue, 9 Dec 2014 23:18:13 +0000
Cc: PHP internals <internals@lists.php.net>
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To: Josh Watzman <jwatzman@fb.com>
Subject: Re: [PHP-DEV] [RFC] Nullsafe calls
From: ajf@ajf.me (Andrea Faulds)


> On 9 Dec 2014, at 23:07, Josh Watzman <jwatzman@fb.com> wrote:
>=20
> 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:
>=20
> https://wiki.php.net/rfc/nullsafe_calls

Hi!

In a way, this would complement the ?? null coalescing operator we=E2=80=99=
re adding. :)

Two thoughts, though:

1) Wouldn=E2=80=99t it be useful to also have this for properties? If =
you=E2=80=99re going down a long list of property accesses, =
$foo?->bar?->qux is probably nicer than if ($foo !=3D=3D NULL && =
$foo->bar !=3D=3D NULL) { $foo->bar->qux; =E2=80=A6 } - on the other =
hand, the ?? operator partly covers this and even handles arrays, as you =
can do $foo->bar[=E2=80=98elePHPant']->qux[=E2=80=98boop=E2=80=99] ?? =
NULL already. We also couldn=E2=80=99t add something like ?-> for =
arrays, as the ?[] syntax is ambiguous (looks like ternary with short =
array syntax).

2) It=E2=80=99d probably be better if you made a language specification =
patch before, not after, the RFC is accepted. Having to specify the =
syntax and semantics formally can make what the operator does clearer =
and help to spot issues. Plus, going forward, the language specification =
should not be an afterthought.

Otherwise, though, I=E2=80=99m in favour of this change.

Thanks!

--
Andrea Faulds
http://ajf.me/