#include <yorel/multi_methods.hpp>
using yorel::multi_methods::virtual_;
#include <iostream>
using namespace std;

class Geometry
{
public:
    virtual ~Geometry() {}
};

class Arc : public Geometry
{
public:
    virtual ~Arc() {}
};

class Edge : public Geometry
{
public:
    virtual ~Edge() {}
};


class Painter
{
public:
    void paint(Geometry& g);
private:
    int counter = 0;
    template<class Sig> friend class paintObject_specialization;
};

MULTI_METHOD(paintObject, void, virtual_<Geometry>&, Painter&);

BEGIN_SPECIALIZATION(paintObject, void, Geometry& g, Painter& p) {
    cout << "painting geometry\n";
    p.counter++; //accessible now
} END_SPECIALIZATION;

BEGIN_SPECIALIZATION(paintObject, void, Arc& a, Painter& p) {
    next(a, p); //passing the Painter
    cout << "painting arc\n";
} END_SPECIALIZATION;

BEGIN_SPECIALIZATION(paintObject, void, Edge& e, Painter& p) {
    next(e, p); //passing the Painter
    cout << "painting edge\n";
} END_SPECIALIZATION;

void Painter::paint(Geometry& g)
{
    //passing the Painter
    paintObject(g, *this);
}

//I cannot change the Geometry classes in my case
MM_FOREIGN_CLASS(Geometry);
MM_FOREIGN_CLASS(Arc, Geometry);
MM_FOREIGN_CLASS(Edge, Geometry);

int main(int argc, char *argv[])
{
    yorel::multi_methods::initialize();

    Arc a;
    Edge e;
    Painter p;

    p.paint(a);
    p.paint(e);
}