import std;

​

​

void main()

{

    Renderer renderer;

​

    auto chip = new Chip();

​

    // Test Draw

    // 1. Init

    chip.Draw( renderer );

    // 2. Hovered

    chip.to!Chip_Hovered();

    chip.Draw( renderer );

​

    // 3. Init

    chip.to!Chip_Init();

    chip.Draw( renderer );

    // 4. Hovered

    chip.to!Chip_Hovered();

    chip.Draw( renderer );

}

​

abstract

class O

{

    void Draw( Renderer renderer ) {};

    void to(CLS)()

    {

        // if (same fields && same interfaces && same instance size)

        this.__vptr =

            cast(immutable(void*)*)typeid(CLS).vtbl.ptr;

    }

}

​

alias Chip_Init = Chip;

class Chip : O

{

    override

    void Draw( Renderer renderer )

    {

        writeln( "Chip.Draw" );

    }

}

​

class Chip_Hovered : Chip

{

    override

    void Draw( Renderer renderer )

    {

        writeln( "Chip_Hovered.Draw" );

    }

}

​

alias Renderer = void*;

​