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Date: Tue, 26 Nov 2013 11:12:50 -0700
Message-ID: <CAAjMSDOCkf+hy8raRR3ATV+_HUXV4TrGAGYf4nEB=DMbh74PRQ@mail.gmail.com>
To: Etienne Kneuss <colder@php.net>
Cc: Philip Sturgeon <pjsturgeon@gmail.com>, Paul Dragoonis <dragoonis@gmail.com>, 
	Mats Lindh <mats.lindh@gmail.com>, "internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=f46d043c81bab599b004ec186d75
Subject: Re: [PHP-DEV] [Proposal] Modification to ?: functionality
From: me@chrislondon.co (Chris London)

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On Tue, Nov 26, 2013 at 11:08 AM, Etienne Kneuss <colder@php.net> wrote:

>
>
>
> On Tue, Nov 26, 2013 at 6:57 PM, Philip Sturgeon <pjsturgeon@gmail.com>wrote:
>
>> On Tue, Nov 26, 2013 at 12:41 PM, 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.
>> >
>> > Proposal:   $foo = $arr['value'] ?:: "";
>> >
>> > 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
>> >> >
>> >>
>>
>> This seems like a cracking time to suggest:
>>
>>    $x ||= $y;
>>
>> The difference? Anything left of the ? SHOULD fail if it is not set,
>> because you are using it in a condition which is dangerous and odd for
>> other types of condition, but adding in this new syntax (similar to
>> Ruby) would essentially evaluate to this:
>
>
>>    empty($x) ? $y : $x;
>>
>> This gives keeps the behavior of ternary operators working in the same
>> way, but adds what we want: the ability to nicely set defaults for
>> variables and array keys that may not be set.
>>
>
> To me this reads as $x = $x || $y like all the <OP>= binary operators. So
> it would definitely feel weird to use that syntax for something else...
>


I really like that. I do stuff like that in Javascript right now.



>
>
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>>
>
>
> --
> Etienne Kneuss
> http://www.colder.ch
>

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