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To: Sara Golemon <pollita@php.net>, Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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 <CAESVnVq0ocUWTMSbbhumrYSC-97jqsOBGi+T3-Wtk9n9uxitFg@mail.gmail.com>
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Date: Thu, 23 Jul 2020 19:36:18 +0200
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Subject: Re: [PHP-DEV] Ternary associativity
From: bjorn.x.larsson@telia.com (=?UTF-8?Q?Bj=c3=b6rn_Larsson?=)

Den 2020-07-23 kl. 17:26, skrev Sara Golemon:

> On Thu, Jul 23, 2020 at 7:26 AM Nikita Popov <nikita.ppv@gmail.com> wrote:
>
>> PHP currently has an incorrect right-associative ternary operator. In
>> https://wiki.php.net/rfc/ternary_associativity the use of nested ternaries
>> was deprecated, and was supposed to become an error in PHP 8.0.
>>
>> Concurrently with that proposal
>> https://wiki.php.net/rfc/concatenation_precedence made a very similar
>> change to the concatenation operator precedence. The difference here is
>> that this throws a deprecation notice in PHP 7.4 (same), but changes the
>> behavior in PHP 8.0 (rather than making it an error).
>>
>> This is a pretty nonsensical outcome, in that the same type of change is
>> implemented in two different ways. I think it would be good to handle the
>> ternary change the same way as the concatenation change, i.e. make
>> ternaries use the correct left-associative behavior in PHP 8.0, rather than
>> throwing an error.
>>
>> Disagree.  Consistency is valuable, but the overlap of misusage is
> different.
>
> A stacked right-associative ternary will still give a "good" result in the
> sense that it's reliably reproducible and meaningful in its output based on
> being written for right-associativity.
> A concat mixed with other binary ops (e.g. math ops) will NOT typically
> give a "good" result since the string being contacted to the numeric then
> having its math op applied will result in a nonsense answer at best.
>
> It made sense for the concat change to favor "fixing" old code in ways that
> doesn't apply to stacked-ternaries since a similar "fix" there will more
> likely be a break.
>
> Strong -1 from me.
> -Sara

Would it then make sense to have it as compile time error in 8.0 and
make it right-associativein in e.g. 8.1?

OTOH, when looking in RFC on top 1000 affected composer packages
it looks like having the change in 8.0 might be a way forward...

r//Björn L