Re: Can change vtbl record at runtime ?

[frame via Digitalmars-d-learn]

On Wednesday, 3 February 2021 at 05:30:37 UTC, Виталий Фадеев 
wrote:
Reason:
    Reuse component,
    bind custom callback without creating new class.
Concept example:
    class SaveFilePopup
    {
        void onSuccess() { /* default operations */ }
    }

    auto saveFile = new SaveFilePopup();
    saveFile.onSuccess = { /* New operations */ }

Delegate:
    may be... but, for speed reason, is possible to set the 
default code at compile-time ?

    class X
    {
       void delegate() onSuccess = { /* default code */ };
    }

Context:
    GUI, components, callbacks

Possible to change the vtbl record at runtime ?
Has functional for update vtbl records ?

It is possible to change to context of a delegate:

class A {
    int x = 10;
    void foo() {
        writeln(x);
    }
}

class B {
    int x = 20;
}

void main() {
    auto a = new A;
    auto b = new B;

    auto fn = &a.foo;
    fn();

    fn.ptr = &b.__vptr;
    fn();
}

But this is maybe not the best practice. If you just do not want 
to repeat yourself for identical code each class, use a mixin 
template for it.