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Date: Tue, 26 Nov 2013 18:47:54 +0100
Message-ID: <CACQesk6=wrmQgK4poCbTOiggmShV0T23wd0bG2xZYbyz1CFxWQ@mail.gmail.com>
To: Paul Dragoonis <dragoonis@gmail.com>
Cc: Chris London <me@chrislondon.co>, Mats Lindh <mats.lindh@gmail.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=047d7b5d8d45b6042804ec181587
Subject: Re: [PHP-DEV] [Proposal] Modification to ?: functionality
From: colder@php.net (Etienne Kneuss)

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On Tue, Nov 26, 2013 at 6:41 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.
>

I disagree, I think removing a case for a Notice is the kind of BC break we
can allow, especially in major versions.

We should aim at making the language easier to use for day to day cases,
and I think this change goes in that direction.


>
> 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
> > >
> >
>



-- 
Etienne Kneuss
http://www.colder.ch

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