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Date: Thu, 23 Jul 2020 10:26:21 -0500
Message-ID: <CAESVnVq0ocUWTMSbbhumrYSC-97jqsOBGi+T3-Wtk9n9uxitFg@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Ternary associativity
From: pollita@php.net (Sara Golemon)

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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

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