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Date: Tue, 26 Nov 2013 17:41:09 +0000
Message-ID: <CAKxcST_SzQ95AB9_1Rv6O54vJUVwwzW8G4dws99X_Z55+HidkQ@mail.gmail.com>
To: Chris London <me@chrislondon.co>
Cc: Mats Lindh <mats.lindh@gmail.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a11c2b762694a5f04ec17fc7e
Subject: Re: [PHP-DEV] [Proposal] Modification to ?: functionality
From: dragoonis@gmail.com (Paul Dragoonis)

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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
> >
>

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