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Date: Mon, 2 Mar 2020 17:23:19 +0000 (UTC)
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Subject: Re: [RFC] Userspace operator overloading
From: terje.slettebo@sandefjordbredband.net (=?iso-8859-1?Q?Terje=20Sletteb=f8?=)

> On 15/02/2020 22:05, jan.h.boehmer@gmx.de wrote:
> 
> How many of you would prefer a interface solution for operator
> overloading?
> I wonder if the RFC voting should include the option to choose between
> either the magic method approach (with the syntax proposed in the
> current
> RFC version) or using interfaces.
> For an interface version I would suggest these interfaces:
> ArithmeticOperators (implements +, -, *, /), PowOperator (**),
> ModuloOperator (%), ConcatOperator (.) and BitwiseOperators (~, &, |,
> ^, <<, >>> ).

+1 for magic methods.

There's too many domains where only a few of the operators makes sense and 
groupings like ArithmeticOperators would not make sense, not at least one 
of the motivating examples of this proposal: Being able to write a Money 
class and associated functionality.

Adding and subtracting money makes sense, but it makes no sense to multiply 
or divide them, and this is just *one* domain.

Please, let's not go there and artificially limit the possibilities of future 
developers.

For example, for me, it's quite natural to be able to write code like this:

$total_discount = $total * $discount;

Here, $total_discount and $total is Money, while $discount is a Percentage, 
so we should be able to define a method that allows you to multiply Money 
with Percentage, and return a Money object. Adding Money and Percentage would 
make no sense, but multiplying them does.

Regards,

Terje