https://www.youtube.com/watch?v=QuoKNZjr8_U


WARNING: This post is exceedingly cool, and so if you're winding down
for the evening or due to take a nap, or if you have been advised by
your doctor to avoid intense mental stimulation, then postpone reading
to another time.

As an ode to my twin I absorbed in the womb, I shared my idea of a
"chimeric pointer" three years ago on this mailing list:

    https://lists.isocpp.org/std-proposals/2022/11/5033.php

Here is the paper I shared at the time:

    https://www.virjacode.com/papers/chimeric_pointer3.pdf

Soon afterward, Arthur O'Dwyer then went on to write a blog post about it:

    https://quuxplusone.github.io/blog/2022/12/01/chimeric-ptr/

Now . . . three years on . . . I pay homage to my absorbed twin . . .
I've written 'std::chimeric_ptr' into the GNU g++ compiler. Here's my
compiler patch:

    https://github.com/healytpk/gcc-thomas-healy/commit/tag_chimeric_ptr

Specifically here's what it does:

    When you apply the operator -> to an object of type
'chimeric_ptr', followed by the name of a member, a search is
performed through all of the Base classes in order to find the member
(i.e. you don't need to specifically identify the correct Base class).

Here it is tested and working up on GodBolt:

     https://godbolt.org/z/vdf5Gz871

This is the coolest new feature since C++11, I think I can argue.
There's a few cool things that have been added in C++14, C++17, C++20,
C++23 and the upcoming C++26, but 'std::chimeric_ptr' might be the
cream. Possibly.

And here's the GodBolt copy-pasted:

#include <cstdio> // puts
#include <memory> // chimeric_ptr
using std::puts;

struct Widget {
    virtual ~Widget(void) noexcept = default;
};

struct Text : virtual Widget {
    virtual void set_text(void) noexcept = 0;
};

struct Colorful : virtual Widget {
    virtual void set_color(void) noexcept = 0;
};

struct Placard : Colorful, Text {
    void set_color(void) noexcept override { puts("Placard SetColor"); }
    void set_text (void) noexcept override { puts("Placard SetText" ); }
};

struct Billboard : Text, Colorful {
    void set_color(void) noexcept override { puts("Billboard SetColor"); }
    void set_text (void) noexcept override { puts("Billboard SetText" ); }
};

void set_text_and_color( std::chimeric_ptr<Colorful,Text> p )
{
    p->set_color();
    p->set_text ();
}

int main(void)
{
    Placard placard;
    set_text_and_color(&placard);
}