#include <iostream>
class Fill{};
//====================================================================
class Node
{
public:
Node(){}
Node(Fill*) { }
virtual ~Node() {}
virtual Node * clone() const = 0;
virtual void id() { std::cout << "Node\n"; }
};
//====================================================================
template <typename Base, typename Derived>
class NodeWrap : public Base
{
public:
NodeWrap() { }
NodeWrap(Fill * arg1) : Base(arg1) { }
virtual Node *clone() const
{
return new Derived(static_cast<Derived const &>(*this));
}
};
//====================================================================
template <typename Base, typename Derived>
class NodeWrapVirtual : public virtual Base
{
public:
NodeWrapVirtual() { }
NodeWrapVirtual(Fill * arg1) : Base(arg1) { }
virtual Node *clone() const
{
return new Derived(static_cast<Derived const &>(*this));
}
};
//====================================================================
class NodeA : public NodeWrap<Node, NodeA>
{
public:
typedef NodeWrap<Node, NodeA> BaseClass;
NodeA() { }
NodeA(Fill * f) : BaseClass(f) { }
virtual void id() { std::cout << "NodeA\n"; }
};
//====================================================================
class NodeB : public NodeWrapVirtual<Node, NodeB>
{
public:
typedef NodeWrapVirtual<Node, NodeB> BaseClass;
NodeB() { }
NodeB(Fill * f) : BaseClass(f) { }
virtual void id() { std::cout << "NodeB\n"; }
};
//====================================================================
class NodeC : public NodeWrapVirtual<Node, NodeC>
{
public:
typedef NodeWrapVirtual<Node, NodeC> BaseClass;
using BaseClass::clone;
NodeC() { }
NodeC(Fill * f) : BaseClass(f) { }
virtual void id() { std::cout << "NodeC\n"; }
};
//====================================================================
class NodeD : public NodeWrap<NodeB, NodeD>,
public NodeWrap<NodeC, NodeD>
{
public:
typedef NodeWrap<NodeB, NodeD> BaseClassB;
typedef NodeWrap<NodeC, NodeD> BaseClassC;
NodeD() { }
NodeD(Fill * f) : BaseClassB(f), BaseClassC(f) { }
//using BaseClassB::clone; // (1)
virtual NodeD *clone() const { return new NodeD(*this); } // (2)
virtual void id() { std::cout << "NodeD\n"; }
};
int main()
{
Node * a = new NodeA;
Node * b = new NodeB;
Node * c = new NodeC;
Node * d = new NodeD;
a->id();
b->id();
c->id();
d->id();
Node * clone = a->clone();
clone->id();
clone = b->clone();
clone->id();
clone = c->clone();
clone->id();
clone = d->clone();
clone->id();
}