Dynamic templated virtuals - I still often want them

[Arafel]

On 23/7/20 17:00, Max Samukha wrote:
> WIW, a more general way to initialize an object with static type data 
> would be (currently it fails for indirectly derived classes due to a 
> compiler bug):
> 
> class Base {
>      this(this This)() {
>          _serialize = function(Base base) {
>              // base can be safely reinterpreted into This here if needed
> 
>              return This.stringof; // just for example
>          };
>      }
> 
>      final string serialize() {
>          return _serialize(this);
>      }
> 
>      private string function(Base) _serialize;
> }
> 
> class Derived: Base {
> }
> 
> void main() {
>      Base b = new Derived;
>      assert(b.serialize() == "Derived");
> }
> 

Good that I read all the replies before hitting "send", because I was 
going to propose exactly this :-)

My only doubt is how it would interact with constructors defined in the 
derived classes. I think I tried doing something like this some time 
ago, but I couldn't make it work in the end because the `super` 
constructor wasn't being called.

Being able to register classes when there are first instantiated would 
be a useful workaround.

> Also, there seems to be no good reason "this T" should not work for any 
> class member, including class static constructors.

This seems to be regularly reported as a bug, I posted earlier some of 
them. I would really love to see this work, and not just for static 
functions, also for enums, aliases or actually any other kind of template.