tardy v0.0.1 - Runtime polymorphism without inheritance

[Atila Neves]

On Tuesday, 16 June 2020 at 15:50:07 UTC, jmh530 wrote:
> On Tuesday, 16 June 2020 at 13:31:49 UTC, Atila Neves wrote:
>> [snip]
>
> Pretty cool, thanks for the fixups.
>
> It may make for a good documentation example, in that it may 
> help make clear that you need to pass the module in somehow 
> when dealing with non-member functions (AFAICT). You could 
> include a comment about how it would be different if it were 
> split into separate files.

Good point.


> In your original example, is there any issue if we then make 
> transform a templated non-member function that is generic over 
> types like Adder (maybe there is an enum hasAddableMember that 
> is true for Adder and false for Plus1)?

I was going to say "it should work" but instead I wrote the code 
and... it does. It all falls out of how UFCS works and usual 
language rules.

https://github.com/atilaneves/tardy/blob/feb26282608081098134c8846be87d398772ccb0/tests/ut/polymorphic.d#L102
https://github.com/atilaneves/tardy/blob/feb26282608081098134c8846be87d398772ccb0/tests/modules/ufcs/template_.d


> Am I right that the shared static constructor in vtable means 
> that there is one vtable for all the instances?

All instances of the same concrete type share the same vtable 
pointer, yes. Originally I built the vtable on the spot with 
`new` and assigned to each function pointer but then I realised 
that was a waste of time and allocations - the vtable is unique 
per concrete type.

> Are there any technical issues preventing Polymorphism from 
> accepting a class in addition to an interface?

None. It could even accept a struct, really.