structure inheritance and polymorphism

[Paul Backus]

On Monday, 4 January 2021 at 01:06:20 UTC, zjh wrote:
> Can d be added with support for structure inheritance and 
> polymorphism?
> I like D, but I don't like GC, so I can't use classes. I can 
> only use betterC. But I want d to have c++ structure 
> inheritance and polymorphism. In this way, I think the 
> competition with c++, the odds are better.

You can use classes without the GC. You just have to allocate and 
free them manually, either with malloc/free or something like 
std.experimental.allocator. You may also find a smart-pointer 
library like automem useful for this:

https://code.dlang.org/packages/automem

If you want to avoid the D runtime completely, you cannot use 
"normal" D classes, but extern(C++) classes will still work.

If you absolutely must use structs, you can use "alias this" to 
achieve something very similar to inheritance:

https://dlang.org/spec/class.html#alias-this