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Date: Tue, 26 Nov 2013 10:48:56 -0700
Message-ID: <CAAjMSDPLEe_vugnQNOzLOKe9Q7bM8NYUs8PM9=SBhBdMOeWaRQ@mail.gmail.com>
To: Paul Dragoonis <dragoonis@gmail.com>
Cc: Mats Lindh <mats.lindh@gmail.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=f46d043c81ba3dee6c04ec18189b
Subject: Re: [PHP-DEV] [Proposal] Modification to ?: functionality
From: me@chrislondon.co (Chris London)

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On Tue, Nov 26, 2013 at 10:41 AM, Paul Dragoonis <dragoonis@gmail.com>wrote:

>
>
>
> On Tue, Nov 26, 2013 at 4:58 PM, Chris London <me@chrislondon.co> wrote:
>
>> On Tue, Nov 26, 2013 at 8:15 AM, Mats Lindh <mats.lindh@gmail.com> wrote:
>>
>> > On Tue, Nov 26, 2013 at 3:43 PM, Chris London <me@chrislondon.co>
>> wrote:
>> >
>> >> I believe these two statements are functionally equivalent:
>> >>
>> >> $foo = $foo ? $foo : 'default';
>> >>
>> >> $foo = $foo ?: 'default';
>> >>
>> >
>> > They are.
>> >
>> >
>> > I would like to change it so it also checks for isset() so I propose the
>> >> following would be functionally equivalent:
>> >>
>> >> $foo = isset($foo) && $foo ? $foo : 'default';
>> >>
>> >> $foo = $foo ?: 'default';
>> >>
>>
>
> We can't change the behaviour of ?: that ship has already sailed, we'll
> just be hurting existing codebases on upgrading and more user education is
> required to understand non-visual changes in syntax like this, lets try to
> learn from our mistakes by not changing 'behaviour' anymore.
>
> An alternative syntax that is similar and not ugly would be good since the
> ?: behaviour was broken from the start since you still need to run isset()
> before running ?: which was the problem we tried to solve in the first
> place but it just didn't happen.
>
> I don't like the @ symbol it's too different from what's already there on
> the ternary logic.
>

My reason for the @ symbol was that it's already used to suppress errors so
to me it seems like it could be interpreted as a suppressed ternary but I'm
open to other suggestions.


>
> Proposal:   $foo = $arr['value'] ?:: "";
>

I'd be fine with this choice.


>
> Thoughts?
>
> >
>> > The would break the assumption that a reference to an uninitialized
>> value
>> > would generate a notice, unless explicitly handled in the logic.
>> >
>> > While I also would like to have something similar to ?: to handle
>> default
>> > values for array keys, etc., this would change a fundamental assumption
>> > that as been in place for many years now. I'm not sure if that's a BC
>> break
>> > that would be acceptable this late. An alternative operator may be more
>> > suitable.
>> >
>>
>> What do you think about using:
>>
>> $foo = $foo @: 'default';
>>
>> and possibly
>>
>> $foo @= 'default';
>>
>>
>>
>> >
>> > The change proposed has also been discussed several times since the
>> > implementation of ?:. See the ifsetor-RFC:
>> >
>> > https://wiki.php.net/rfc/ifsetor
>> >
>> > It also contains links to the discussion around the feature back then.
>> >
>> > --mats
>> >
>>
>
>

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