So the issue is that you want inheritance, but you don't want a vtable to
be generated for your runtime code because it won't have inheritance there?

Sounds like your interface should be a template, kind-of like how
std::allocator works. You don't need virtual dispatch... just the types to
line up.

This has other trade-offs, but might suit your needs better than virtual
function calls.

I could also be completely misunderstanding, of course.

On Thu, Nov 9, 2023 at 8:22 PM Smith, Jim via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> Hi All,
>
> Test-driven development (TDD) is my de facto standard for writing
> software. On some projects I can't use TDD because interfaces introduce
> VTBL operation into the code. For me this is a serious issue.
>
> I've always used C++ interfaces i.e., classes with all pure virtual
> functions for TDD, especially when implementing a design patterns like
> Factory.
>
> I'm proposing a compiler option that will turn a virtual call through an
> interface, to a direct call on the object. For example,
>
> interface* i = Factory::Create();
>
> i->someVirtualFunc();
>
> In cases where single inheritance is used i->someVirtualFunc() would be
> optimized to a direct call on the object without any VTBL operation.
>
> This way the TDD code can use the standard VTBL operations, and in
> production builds a flag can be set to optimize it away. I can't do this
> myself without mentioning the concrete type created by the factory but the
> compiler can make the optimization.
>
>
> --James S.
>
>
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