Re: Overriding GMP objects
Hi Rob,
>> On Thu, Jun 27, 2024, at 06:07, Saki Takamachi wrote:
>>
>> I agree with Gina. Being able to change the class of a computed result of an inherited
>> child class causes several problems.
>>
>> The points raised in the BCMath\Number discussion can be summarized as
>> follows.
>>
>> - If it is possible to perform calculations on parent Class and child Class, what should
>> the resulting class be?
>
> Ask the class what it wants to be?
>
>> - Multiplying the distance class and the speed class should give you the time class.
>
> That would depend on the library’s implementation.
>
>> - Similarly, multiplying two distance classes together should yield an area class.
>
> See above.
>
>> - If only child classes have a property that should be specified in the constructor, how do
>> you determine the value of this property in the result class? Perhaps it is possible to determine
>> the value of the property, but in that case the commutativity of the computation should be lost.
>
> This can be handled via the child class in static methods, per the library specifications.
>
>>
>> These problems cannot be solved without significant complexity. And there is a possibility
>> that it cannot be resolved in the first place.
>
> I very much disagree; there is very little complications in the extension. It’s actually
> quite simple:
>
> If one value is scalar and the other an instance of GMP, for binary ops, ask the GMP class to
> perform the operation. (This is a one-linish change)
>
> If both are GMP instances, in a binary op, ask the left-most one to perform the op. The default
> GMP implementation will delegate to the right-side if the right side isn’t a base-GMP instance,
> otherwise, business as usual.
>
> And that’s pretty much it, other than defining the base-type ops. From there, you can
> implement any units library you want, with whatever behavior makes sense — so long as the base
> representation is a number.
>
> If I remember the original operator overloading RFC, this is exactly what was asked for by the
> people who voted no. In theory, it should pass if brought as an RFC.
>
> — Rob
I see.
All of what I wrote are problems that arise when php doesn't provide a way to control them in
userland.
Your proposal implicitly allows operator overloading in userland.
So your proposal essentially amounts to allowing operator overloading only for GMP classes.
If I understand correctly, this discussion is not centered on GMP, but on the topic of limited
exposure of operator overloading functionality.
I believe this is something that requires some very careful discussion.
Regards,
Saki
Thread (11 messages)