C++ Metaclasses proposal

[Nicholas Wilson via Digitalmars-d]

On Tuesday, 27 June 2017 at 15:57:01 UTC, Enamex wrote:
> PDF: 
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0707r0.pdf
> Reddit: 
> https://www.reddit.com/r/programming/comments/6js4uv/metaclasses_in_c/
>
> I thought a bit on possible patterns in D to accomplish the 
> same without string mixins.
>
> For example, defining the prototype `Foo_` then mixing in 
> `mixin MyMetaclass!Foo_ Foo`.
>
> Got stuck trying to 'forward' (or copy the implementation of) 
> functions in `Foo_` into `Foo` after modifying them, though.
>
> Besides trying to do it in D (please try still!), what do you 
> think of the idea? In general and say versus a robust macro 
> system with some level of access to CTFE? Or even just a good 
> macro system (someone began discussing this on the reddit 
> thread; talking about Racket macros).

Quite a lot of it seems doable with mixin templates and UDA 
reflection.
Ethan Watson's dconf talk is a good point of comparison.