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Date: Tue, 10 Jul 2018 10:36:49 -0400
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To: ocramius@gmail.com
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Content-Type: multipart/alternative; boundary="000000000000168a060570a610b0"
Subject: Re: [PHP-DEV] Re: [RFC] [VOTE] User-defined object comparison
From: rudolf.theunissen@gmail.com (Rudolf Theunissen)

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Thanks for explaining your vote Marco.

I realise it's probably too late but I'd like to respond anyway.

1. I was hoping that this proposal would reduce those edge cases and make
`==` on objects something useful.
2. That's true, but there are so many gotchas with the current behaviour
that I wouldn't say it works *well*. Also no strict comparison.
3. We shouldn't need to ever use `method_exists()`? Everything can be
compared, so tests for implementation are effectively useless. If this is
not the case in the future we can introduce interfaces for Comparable and
Equatable that abstract and implied by the presence of the methods (Golang
style). I don't foresee this to ever happen though.
4. "Equal ordering implies equality" is primarily to keep consistent with
current behaviour - PHP doesn't treat them as separate things today.
5. This was a difficult trade-off between flexibility and consistency. I
opted for a wider approach that can be narrowed later if we really want to.

Happy to discuss further.

Rudi

On Tue, 10 Jul 2018 at 05:35, Marco Pivetta <ocramius@gmail.com> wrote:

> Heya!
>
> Just some background on my -1 vote:
>
>  1. the `==` operator is already riddled with edge cases and complexity,
> and it is overall advisable to stay away from it
>  2. comparison of value objects already works correctly with `==` (if we
> don't consider edge cases like `'0.' == '0.0'`)
>  3. the suggested approach is to add more interface-less reserved/magic
> methods: an `Eq` and an `Ord` class would have solved this much more
> elegantly and with clear type declarations that can be re-used in userland.
> With this patch, we have to rely on `method_exists()` instead.
>  4. It would also be much clearer to enforce that `Ord extends Eq`, rather
> than adding implicit "sorting implies equality" rules
>  5. "the methods are not restricted to instances of the same class" - this
> is something I disagree with, but we lack the type system facilities to
> declare the variance of the `Eq` and `Ord` operations for a specific class.
>
>
> Marco Pivetta
>
> http://twitter.com/Ocramius
>
> http://ocramius.github.com/
>
> On Mon, Jul 9, 2018 at 8:57 PM, Rudolf Theunissen <
> rudolf.theunissen@gmail.com> wrote:
>
>> Apologies for that middle discussion link, it was a bad hyperlink from a
>> bad paste if you look at source.
>>
>> Here are the correct ones:
>>
>> *Discussion:*
>>   - https://externals.io/message/102337
>>   - https://externals.io/message/102473
>>
>>
>>
>> On Mon, 9 Jul 2018 at 13:57, Rudolf Theunissen <
>> rudolf.theunissen@gmail.com>
>> wrote:
>>
>> > Hi everyone,
>> >
>> > With no further discussion and no objection to start voting on this
>> RFC, I
>> > would like to move forward with the vote, which requires a 2/3 majority
>> to
>> > pass.
>> >
>> > *RFC*: https://wiki.php.net/rfc/object-comparison
>> >
>> > Discussions:
>> >   - https://externals.io/message/102337
>> > <https://externals.io/message/102389> (June 21)
>> >   - https://externals.io/message/102473 (June 26)
>> >
>> > The vote will be open until 2018-07-16.
>> >
>> > Thank you,
>> > Rudi
>> >
>> >
>>
>
>

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