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Re: [std-proposals] Derived class's function invokes base class's function

From: Jason McKesson <jmckesson_at_[hidden]>
Date: Mon, 11 Apr 2022 12:19:18 -0400
On Mon, Apr 11, 2022 at 11:32 AM Frederick Virchanza Gotham via
Std-Proposals <std-proposals_at_[hidden]> wrote:
>
> On Mon, Apr 11, 2022 at 10:34 AM Marcin Jaczewski wrote:
>
> > ```
> > template<typename... Modifiers>
> > class Laser
> > {
> > std::tuple<Modifiers...> _mod; //could be base classes
> > void trigger()
> > {
> > (get<Modifiers>(_mod).apply(), ...);
> > }
> > };
> > ```
>
>
> I see how that would work, however then you wouldn't be able to deal
> with a simple "Laser &" or "Laser *".
>
> Instead of having simple non-template functions like:
>
> void DoSomething(Laser &arg) { . . . }
>
> void DoSomethingElse(Laser &arg) { . . . }
>
> You would have to complicate it as follows:
>
> template<typename... Modifiers>
> void DoSomething(Laser<Modifiers...> &arg) { . . . }
>
> template<typename... Modifiers>
> void DoSomethingElse(Laser<Modifiers...> &arg) { . . . }

You say that as though your version is *less* complicated. It's just
complex in a different way. Indeed, the only complexity that template
functions require is that... you know that it's a template.

Containment is typically a better, more maintainable alternative in a
lot of cases compared to inheritance. This has been demonstrated
repeatedly over the past 20+ years of the prominence of OOP-based
designs. Component-based designs typically beat inheritance-based
designs for large-scale systems, particularly on extensibility and
maintenance. They are better able to compartmentalize distinct
systems.

In short, your overall language feature seems to be "let's make it
easier for people to write bad code", not "let's encourage people to
write good code."

Received on 2022-04-11 16:20:12