Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:102264
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain librelamp.com designates 45.79.96.192 as permitted sender)
To: internals@lists.php.net
References: <CAESVnVqm3tVt53bQfxOpQcOMf_2fXhnu9y+42trTfv7zNMONHw@mail.gmail.com>
 <CAF+90c-HGB-2MbdrCYuQNrNYR4EJ9hAeFaKTW-sh1kwboDd0Kg@mail.gmail.com>
 <20180614155730.2C8BC1A8027C@dd1730.kasserver.com>
Message-ID: <53d1a1f6-10b8-3aec-c2ac-a005d6041f15@librelamp.com>
Date: Thu, 14 Jun 2018 09:16:58 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.8.0
MIME-Version: 1.0
In-Reply-To: <20180614155730.2C8BC1A8027C@dd1730.kasserver.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] Strict switch statements
From: alice@librelamp.com (Alice Wonder)

On 06/14/2018 08:57 AM, Thomas Bley wrote:
> Nikita Popov wrote on 14.06.2018 10:35:
>
>> On Thu, Jun 14, 2018 at 6:53 AM, Sara Golemon <pollita@php.net> wrote:
>>
>>> Just for casual discussion at this point:
>>> https://github.com/php/php-src/pull/3297
>>>
>>> switch ($a) {
>>>   case FOO:
>>>       // Works exactly as current behavior.
>>>       break;
>>>   case == FOO:
>>>      // Nearly identical, though not using the ZEND_CASE optimization.
>>>      // Can probably make this equivalent to `case FOO`, but it felt
>>> like an interesting direction.
>>>      break;
>>>   case === FOO:
>>>      // Only triggers if `$a === FOO`, no type juggling
>>>      break;
>>> }
>>>
>>> Love it? Hate it? See obvious flaws?  The implementation is just a
>>> rushed proof of concept, not something I've labored over, it may well
>>> have bugs.  Certainly wouldn't target anything earlier than 7.4, if at
>>> all.
>>>
>>
>> I like the general idea here (switch with strict type comparison), but not
>> super fond of the particular syntax and implementation.
>>
>> I think if people want to use strict matching, they'll quite likely want to
>> have it on all cases. Something like "strict switch ($expr) {}" or "switch
>> strict ($expr) {}" or "switch (strict $expr) {}" or "switch ($expr) strict
>> {}" or "switch ($expr) { strict; }" or whatever would be preferable in that
>> case.
>>
>> Additionally, switch has the issue of fall-through behavior, which is
>> somewhat unexpected and error prone to many people. It might make sense to
>> introduce an entirely new "match" statement that conforms a bit more with
>> how switch-like strictures are implemented nowadays. That is, something like
>>
>> match ($expr) {
>>    "foo" => {...},
>>    "bar" | "baz" => {...},
>> }
>>
>> or similar. This might need some more design work to ensure forward
>> compatibility with potential future algebraic datatypes etc.
>>
>> Nikita
>>
>
> for simplicity I would use an extra parameter to have a strict comparison (similar to the extra parameter in in_array()):
>
> switch ($a, true) { // strict comparison
> switch ($a) { // loose comparison
>
> Regards
> Thomas
>

Should declare(strict_types = 1) do that?

I haven't tried, but I would think it should.