Finalizers, Destructors, RAII, GC

[Ola Fosheim Grøstad]

On Friday, 30 April 2021 at 10:44:07 UTC, Ola Fosheim Grøstad 
wrote:
> On Thursday, 29 April 2021 at 15:11:06 UTC, Imperatorn wrote:
>> 1. What's bad about the implementation (haven't looked)?
>
> From the ABI:
>
>>An interface is a pointer to a pointer to a vtbl[]. The vtbl[0] 
>>entry is a pointer to the corresponding instance of the 
>>object.Interface class. The rest of the vtbl[1..$] entries are 
>>pointers to the virtual functions implemented by that 
>>interface, in the order that they were declared.

The bad part is made more explicit here:

https://dlang.org/spec/abi.html#classes

As you can see, every object wastes 8 bytes per interface it 
supports. Ok if you only have 100 instances, not good if you have 
one million instances (would waste 8 megabytes per interface you 
support).