Why does D not have generics?

[Ola Fosheim Grøstad]

On Tuesday, 12 January 2021 at 16:57:43 UTC, Q. Schroll wrote:
> Yes. But I'm not saying: Do exactly as Java does. I'm saying: 
> Java has this very interesting concept that D might want to 
> learn, too.

Right. D has to chose something that blends well with what is 
already there. :-)

But I actually think that the semantics for this are there, but 
the syntax is lacking, but maybe I misunderstand what you want.

> For example, if you call T.method(), but no constraint says 
> that T.method() exists, the compiler rejects the code. On the 
> other hand, in C++ or D, if you call T.method() in a template 
> and only test types that happen to have method(), everything is 
> good between friends (Andrei's quote).

But I don't quite see how this is different from C++ concepts, 
which basically is better syntax for testing traits of types 
provided through parameters/methods.


> I'm not arguing you *always* want static checks, obviously DbI 
> hardly works that way. All I'm saying is, the big thing 
> generics would bring to D is **statically ensuring** that the 
> requirements put on type parameters suffice for the 
> implementation to be valid.

Yes, I certainly agree that this is desirable. I just don't 
understand what semantics are missing. I think D has this? Just 
not the syntax?