Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:102559
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 74.125.83.54 as permitted sender)
To: Dan Ackroyd <danack@basereality.com>,
 Rudi Theunissen <rtheunissen@php.net>
Cc: PHP internals <internals@lists.php.net>
References: <CAHFNTwccchXDWnpy=rmxRJ+r6rJrr_gs3ojxim+rPQPsKPVvLA@mail.gmail.com>
 <CA+kxMuR7d5GmVxC0v+=+W_TAMLawunsKSCF73cawMbU5jKffQQ@mail.gmail.com>
Openpgp: preference=signencrypt
Autocrypt: addr=smalyshev@gmail.com; prefer-encrypt=mutual; keydata=
 xsJuBE9mqaARCACFSqcGmNunkjQQu3X+yXnTmFeEkvM4JXZTOBdR8aEevNGmmFEfyvjaDjWi
 9hcwp4E/lYtC+P7VsVjM1OSX9eq0jC/lGL0ZyRXek+mNy0n5H1NSuTpf9Y18LMqhc4G+RU+L
 cNiZ9K0DJuOOvNLPxW7OHZguxb3wdKPXNVa2jyRfJAKm2uaJJMT1mTmFT9a0Q8SKr+mUrrJk
 uG0H2o6SzrKt8Wwoint1eh67zVsJaJtQFchnEZnlawIcqP2yC4nLGR3MkubowxoEBYCZet18
 aHVVRbvpG2Qtob8Lu5xrsGbmXymTkHTdpvkfcJFADa8MzOL90zOxXwbGfbIZOlh5En8jAQCX
 lfnx2eQL3BSW/6XANa51dbWiEp1d1BAkpGKtZvlk0Qf+M9WAi+9aXMe3xP5krxtgnRNUf2WN
 6Zdy2MxL1RRJCFbytLhl0ronC49BsGYVGshdEH8xhBbiIOJKuVZ/DTl9bEm7P9c7CC7iJyVC
 khUAhouH6xzZQNLR+RU+QebYzXypVfl99Qk7EdMmr/WAZCHLuvanyqepC5EBsa3VnAfQemSN
 oBeGBKWWLiOsPjvS72+y1z4RUMAfXHn4l/sFMt8zt7/74AmJPwZquV41p4mPO12V4+xPyc6R
 sB84sfsk2QVivU8w8AkvGQeYjXoz7Iwao95+fWteVzZ36KRQvUckP8pGjHlDXnHxJ0HI1I/k
 OBZSjwRwUf0dd73y6erPhbLk+gf+NdI3H9KGJBzG5/rVyWKwUeQ9d5ud4jTJRkQGvAP5pg76
 vEa9dogbpe4W5Z+0BfbiJSnQmQWSHiZddj/t33ptbup44Ck6ZTgdlmFYMLF1hR47PIZTDKER
 EuKYGci/vq8snZvEJP9YCw/TtiHcMdrMKcY/+Lp8lQO0GHLPB9glVhnC0db6l1Xpg1CMI8/R
 ozBMcij30EgATggC/y2zbiqAFoS9FN9nXPbe4phStqABEyeZ+nXudt7PUYTjVgcrqo8bHZCi
 sBobWC7OnKyUzxVxzUeuPkIfmZuzkLaMw2McQdvwwsNvQ0DzaLP30c1Xsm/7EIYJcOWpzlVJ
 5QrdmE0/Bc0yU3RhbmlzbGF2IE1hbHlzaGV2IChQSFAga2V5KSA8c21hbHlzaGV2QGdtYWls
 LmNvbT7CegQTEQgAIgUCT2aqtAIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQL3lW
 vF2gS12XMwD9HuRIolSwIK77u8EY461y2u6sbX36n5/uo/LDQuxoi3sA/0MvpnvzOhv9Iufv
 vsZEj3E7i3h+iD5648YMwfTFCij+zsFNBE9mqaAQCADfZPMpjZkkGZj3BY/7ApoLq4mwqzbh
 +CpLXwNn20tFNvSXfb8RdeXvVEb7Scx+W9qYpiaun2iXJgCVH8fgpZpR856ulT1q6uCG++CX
 ubEvip/eJkZl93/84h04KQJwsgOrAh0Om3OePRn8Pr+++0LNS0EL8uX/YHeTOGOnnmTqYTey
 SBVFdov6L4mepddfjekicKQqhL7mZh/xuq29JijT0uNNX8v4vDWQDu5dlAcdd+uB3gcXMD/P
 ginD11zp+6wtrWCm/+yBqpvDwXQX5PGUnwvbRfl7Ay3MmwmoXiecZMg0dwTSc7e0lhB4HGRH
 ZdBMJB4rHUVGdzqujK/ctOvrAAMFB/0Utb76Qe6sCMlHxVAmeE/fbo7Pi05btZ/x01r67dHf
 aMSP0riCKJ7M0OW+jAXtu9+z/BVnYisW67WWfxl2cS5tZDgiHgJARXWUOO72+sScHP8KQmTl
 1z16gyKbwY3SmyBkwcpOL35nhUWNLy93syPoY6sZUTikr2bZYukHDQ33XBPs4e6MbWKfsa9q
 aVmnlOF3k5UqChjutfHaEa4Q7VP4wBIpphHBi9MI16oJIzzBPbGl2uoedjwiZ6QeQZnSuOVY
 ZxU2d3lRA8PrtfFN1VSlpEm/VcAvtieHUYWHN0wOu+cp3Slr5XJVNjTjJhl28SlinMME54mK
 AGf2Ldr/dRwXwmEEGBEIAAkFAk9mqaACGwwACgkQL3lWvF2gS126EQD/VVd3FgjLKglClRQP
 zdfU847tqDK4zJjbmRv5vLLwoE0A+wbrQs7jVGU3NrS0AIl5vUmewpp2BKzSkepy23nWmejw
Message-ID: <400c6be3-c4b4-192b-d76e-2dc70cdaf30f@gmail.com>
Date: Tue, 3 Jul 2018 11:51:03 -0700
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0)
 Gecko/20100101 Thunderbird/60.0
MIME-Version: 1.0
In-Reply-To: <CA+kxMuR7d5GmVxC0v+=+W_TAMLawunsKSCF73cawMbU5jKffQQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] Equality and relative ordering of objects
From: smalyshev@gmail.com (Stanislav Malyshev)

Hi!

> I think if you want to push the RFC forward, a really quite strong
> case needs to be made for why having it be a language level feature is
> so much better (or even at all better) than having it be implemented
> in userland.

I tend to agree here. There are not that many cases where < and > are
natural for objects - mostly for implementation of extended numeric
types like complex numbers, but that's not a very common thing people do
in PHP. And when they do, they usually come with custom methods, since
these types work different from scalar types.

Sorting may be a major use case, but there I think using custom sort
functions have it covered. So I'd like to see more specifically on the
case why it's important to have operators and not specialized methods
for objects in the RFC. Especially for </> kind - I can see some case
for non-strict equality, but ordering seems to be a bit exotic (I may be
missing some cases though).

There are also some complications there. I.e., if you implement both
__compare and __equals, you essentially have two functions that do
"equals" - you probably won't want to call both for something like >=?
But that creates an opening for very weird bugs.

Also note: Python had __cmp__ in Python 2, but they moved away from it
to specialized comparison methods in Python 3. It would be a good idea
to look into why they did it, so we could learn from their experience.
Doesn't mean our decision would be the same, but it looks like they had
something that made them change it, so I think we should at least
consider what it was.
-- 
Stas Malyshev
smalyshev@gmail.com