Concepts like c++20 with specialized overload resolution.

[vushu]

On Saturday, 27 May 2023 at 18:41:47 UTC, ryuukk_ wrote:
> On Saturday, 27 May 2023 at 17:49:27 UTC, vushu wrote:
>> On Saturday, 27 May 2023 at 16:38:43 UTC, Steven Schveighoffer 
>> wrote:
>>> On 5/27/23 9:50 AM, vushu wrote:
>>>> On Saturday, 27 May 2023 at 13:42:29 UTC, Basile B. wrote:
>>>>> [...]
>>>> 
>>>> Yes I know there is template constraint, but not with 
>>>> specialized overloading right?
>>>> 
>>>> so you need to use static if for checking if it hasmagma.
>>>
>>> What is missing is an "else" thing.
>>>
>>> So you have to repeat the constraint (as a negation) 
>>> unfortunately.
>>>
>>> e.g.:
>>>
>>> ```d
>>> struct LavaMan {
>>>   void magma() { writeln(" LavaMan is throwing LAVA"); }
>>> }
>>>
>>> struct FakeVulcano {
>>>   void try_making_lava() { writeln(" Making fake lava"); }
>>> };
>>>
>>> void make_lava(T)(ref T lava) if (hasMagma!T) {
>>>     lava.magma();
>>> }
>>>
>>> void make_lava(T)(ref T lava_thing) if (!hasMagma!T){
>>>     lava_thing.try_making_lava();
>>> }
>>> ```
>>>
>>> -Steve
>>
>>
>> I see thanks for the example :), I think this probably the 
>> closest equivalent i dlang.
>
> I feel like overload in that case make things harder to read
>
> My example has less context switch, and hte logic is correctly 
> understandable at first sight
>
> Only one make_lava function

It depends this example is quite small and a `static if` is 
sufficient, if you have a lot of cases it would make sense to 
split thing up into overloaded functions.
imagine you are writing a library for handling vector or matrices 
that has a common
`add` function. I just want to know the equivalent thing in dlang 
vs c++.