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Date: Wed, 10 Dec 2014 21:19:50 +0100
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Subject: AW: [PHP-DEV] [RFC] Nullsafe calls
From: php@tutteli.ch ("Robert Stoll")



> -----Urspr=FCngliche Nachricht-----
> Von: Andrea Faulds [mailto:ajf@ajf.me]
> Gesendet: Mittwoch, 10. Dezember 2014 20:21
> An: Josh Watzman
> Cc: PHP internals
> Betreff: Re: [PHP-DEV] [RFC] Nullsafe calls
>=20
> Hi again.
>=20
> > On 10 Dec 2014, at 19:11, Josh Watzman <jwatzman@fb.com> wrote:
> >
> > On Dec 10, 2014, at 9:19 AM, Andrea Faulds <ajf@ajf.me> wrote:
> >
> >> First, how is this substantially different from catching an =
exception? With Nikita=92s Exceptions in the Engine RFC,
> something like this would be possible:
> >>
> >>   try {
> >>       return $foo->bar()->qux()->elePHPant()->dance();
> >>   } catch (EngineException $e) {
> >>       return NULL;
> >>   }
> >>
> >> That would essentially do the same as what you=92re proposing:
> >>
> >>   return $foo?->bar()?->qux()?->elePHPant()?->dance();
> >>
> >> Are there many instances where there=92d be a substantial benefit =
to using ?-> versus catching an exception?
> >
> > 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 :)
> >
> > 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.
>=20
> =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.
>=20
> Thanks.
> --
> Andrea Faulds
> http://ajf.me/
> > --
> PHP Internals - PHP Runtime Development Mailing List To unsubscribe, =
visit: http://www.php.net/unsub.php

I think it is a matter of taste whether you use try/catch as control =
structure or only as exception handling. I for
myself usually try to avoid using it as control structure and thus would =
write something like:
if($a !=3D=3D null){
   $a->foo(bar());
}

And for this case the ?-> operator seems perfect for me - as long as it =
does not evaluate bar().=20