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Date: Wed, 10 Dec 2014 19:20:52 +0000
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To: Josh Watzman <jwatzman@fb.com>
Subject: Re: [PHP-DEV] [RFC] Nullsafe calls
From: ajf@ajf.me (Andrea Faulds)

Hi again.

> On 10 Dec 2014, at 19:11, Josh Watzman <jwatzman@fb.com> wrote:
>=20
> On Dec 10, 2014, at 9:19 AM, Andrea Faulds <ajf@ajf.me> wrote:
>=20
>> First, how is this substantially different from catching an =
exception? With Nikita=92s Exceptions in the Engine RFC, something like =
this would be possible:
>>=20
>>   try {
>>       return $foo->bar()->qux()->elePHPant()->dance();
>>   } catch (EngineException $e) {
>>       return NULL;
>>   }
>>=20
>> That would essentially do the same as what you=92re proposing:
>>=20
>>   return $foo?->bar()?->qux()?->elePHPant()?->dance();
>>=20
>> Are there many instances where there=92d be a substantial benefit to =
using ?-> versus catching an exception?
>=20
> It's an API decision up to the implementors of the object. If you like =
using exceptions for *every* failure, then go for it, this syntax won't =
cost you anything or get in your way :)
>=20
> However, for a lot of failures, I don't feel that exceptions are =
appropriate. I tend to only use them for exceptional behavior -- =
usually, some failure that needs to be propagated up a few levels up the =
stack, to an appropriate error boundary. This doesn't necessarily mean a =
completely unrecoverable error, but it's *locally* unrecoverable. For =
things that are completely recoverable, returning null might be more =
appropriate and more lightweight, and then this nullsafe operator would =
be useful at that point.

=85huh? I=92m not talking about exceptions the object itself throws. In =
PHP 7, if Nikita=92s RFC passes, trying to call a method on NULL will =
throw an exception. That largely negates the need for a special =
operator, since you can just catch the exception.

Thanks.
--
Andrea Faulds
http://ajf.me/