Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:67667
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain zend.com from 209.85.215.47 cause and error)
References: <CAF+90c_PPTajBqs636f373DKF=hotrK1ObTojddxx=bxC3g16w@mail.gmail.com>
	<CA+9eiLvnV-i7Zp15oQ1EAzu2u8v_sc_Og8_bqHPBYWH9TyJ9cQ@mail.gmail.com>
	<CAF+90c_KfGWc7U5qA2Ey7FDqscvsRijAF16mqr+aG+561=WT9w@mail.gmail.com>
	<CA+9eiLuiDLYJtwxuUE8_1Het-S-NqaqDC_6gLm8scU253DTidw@mail.gmail.com>
	<CAF+90c9YV4P4MAHe8u2bq3FjVS0LxUtV9mfpni+4j0brvX7yNw@mail.gmail.com>
	<CA+9eiLtF3H=iu87udX8DNm87fWy3oofU1NyZOk7ALeKivRJiTg@mail.gmail.com>
	<CAF+90c9eTPM2ctqj9vGkBxsPSB+ommQnx2bT7e9aZ5VY_N+43A@mail.gmail.com>
	<CA+9eiLuqCLhM_5fDkL_7Cdk64oVbwPBMNhFAtixmca3mWWX8VA@mail.gmail.com>
	<CAF+90c_fS_+euRE6+7HpOci8aUs5yqZWmXEhiK0gu6oyS7PTfg@mail.gmail.com>
	<CA+9eiLvTEKngseTeQWE_=fHO0vkCZ8tw23UyxoYytV8DrqaAiQ@mail.gmail.com>
	<CAF+90c_OdYiTm7eViwnmzFpmg4GNBZMwU6Pc3nzcwJ+6HThU8g@mail.gmail.com>
	<e71357aa48f925454afa1392fa137666@mail.gmail.com>	<CAF+90c8fqYvMjrR5hHe_2G8_AaU-t0YsgN=vu76eA7i66LH=DA@mail.gmail.com>
	<056e6e6464af1227f4238a50f562bc29@mail.gmail.com>	<CAF+90c9jLc_55d8mEH+zBoi-P0wbstbSuf6UR=REgU9q8fBxkQ@mail.gmail.com>
	<9e 7fd04d05a632a38dd306d056eae6e8@mail.gmail.com> <CAF+90c_wSHUZvDFKrK2KHzyDCAPkKNCXcUwdnfEK2qt+a+WKLA@mail.gmail.com>
In-Reply-To: <CAF+90c_wSHUZvDFKrK2KHzyDCAPkKNCXcUwdnfEK2qt+a+WKLA@mail.gmail.com>
MIME-Version: 1.0
Thread-Index: AQJbRrTwu75xlJaupAGVjny9GR4KPgIHESCtAXBChYUBvMxDrwEtlwtYArRtSGkCFRs9mQG+KBpdAz9tlb8CCKvR4QEPaE7cAkfUr7MCYWcKaQFKc6R9Amx5N8kBjNbjIwGVXu2Slx2Qt1A=
Date: Sun, 9 Jun 2013 17:34:17 +0300
Message-ID: <9f01c72b4a81355bf087d602b21d3d28@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: RE: [PHP-DEV] [RFC] Internal operator overloading and GMP improvements
From: zeev@zend.com (Zeev Suraski)

From: Nikita Popov [mailto:nikita.ppv@gmail.com]
Sent: Sunday, June 09, 2013 5:15 PM
To: Zeev Suraski
Cc: PHP internals
Subject: Re: [PHP-DEV] [RFC] Internal operator overloading and GMP
improvements

On Sun, Jun 9, 2013 at 3:37 PM, Zeev Suraski <zeev@zend.com> wrote:
>> What I meant by cumulativity in that context is really commutativity =E2=
=98=BA
>> Fixed (and also added transitivity).
>>
>> In other words, operands that are commutative in PHP (like addition,
>> multiplication, etc.) =E2=80=93 one should not overload for domains wher=
e they=E2=80=99re
>> not commutative.
>
> Why?

Mostly because I don't want us to have to worry about this when implementin=
g
the engine.  It might side effects on optimizations that are valid when
dealing with standard values - but not when dealing with these complex
values.  That said, you brought up a couple of examples where we already
have different behaviors for $a+$b and $b+$a, so this point might be moot
(mostly referring to the array part, I have a harder time accepting the
floating point assertion although I understand why you're saying it...)

> That's why I'm not sure it makes sense to have "too strict" definitions
> for what is a valid overload and what isn't. I think "limited to cases
> where there are clear definitions to > the behavior of all overloaded
> operators" and "should be for mathematical use cases only" are enough as
> guidelines :)

I guess I can live with that (if nobody has any other additional thoughts o=
n
what we might be missing here).  I can say that I mostly heard horror
stories about operator overloading from my old C++ days - which is why I
want us to do our best to avoid creating the same pitfalls in PHP.  I do
think that clear extension-level operator overloading support can be quite
useful in some cases though (like gmp/bcmath).

Zeev