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Date: Sun, 12 Dec 2021 16:01:48 -0600
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] User Defined Operator Overloads (v0.6)
From: larry@garfieldtech.com ("Larry Garfield")

On Sun, Dec 12, 2021, at 12:56 PM, Dan Ackroyd wrote:
> On Sat, 11 Dec 2021 at 17:46, Larry Garfield <larry@garfieldtech.com> =
wrote:
>>
>> Using symbols, however, would (with some future extension to make it =
extensible) allow for:
>
> I don't get how it's easier, other than being able to skip naming the
> symbol name. e.g. adding union and intersection operators
>
> function __union(...){}
> function __intersection(...){}
>
> vs
>
> operator  =E2=88=AA(...){}
> operator =E2=88=A9(...){}
>
> In fact, I find one of those quite a bit easier to read...

If the list of operators is expanded by the engine, yes.  The point is t=
hat IF it were decided in the future to allow user-space defined operato=
rs, that would be considerably easier with a separate keyword.  Eg:

class Matrix {
  operator dot(Matrix $other, bool $left) {
    // ...
  }
}

$result =3D $m1 dot $m2;

Whether that is something we want to do is another question, but the ope=
rator keyword makes that logistically easy, while using __mul or __astri=
sk makes it logistically hard.

Using an attribute instead to bind a method to an operator, as previousl=
y suggested, would also have that flexibility if we ever wanted it.  The=
re seems to be a lot of backpressure against using attributes for such t=
hings, though, and it wouldn't cleanly self-resolve the issue of keyword=
s that make sense on methods being nonsensical on operators.  (public, s=
tatic, etc.).  I'd probably be fine with it myself, but I cannot speak f=
or others.

--Larry Garfield