C++, template 초보질문 드립니다. 조언 좀 부탁드려요...

#include <iostream>
#include <typeinfo>
#include <boost/utility.hpp>
#include <boost/type_traits.hpp>
#include <vector>
 
class Nil {
};
 
template <typename Current, typename Next>
class Tuple {
};
 
class my_visitor {
	public:
	template <typename T>
	void operator()(T & v) {
		std::cout << v << std::endl;
	}
};
 
template <typename Types>
class MyData;
 
template <>
class MyData<Nil> {
	public:
	template <typename Visitor>
	void forall(Visitor &) {
	}
};
 
template <typename Current, typename Next>
class MyData<Tuple<Current, Next> > : public MyData<Next> {
	typedef MyData<Next> p_t;
	std::vector<Current> items;
 
	public:
	template <typename T>
	void push(T a, typename boost::enable_if<boost::is_same<T, Current> >::type * = 0) {
		items.push_back(a);
	}
	template <typename T>
	void push(T a, typename boost::disable_if<boost::is_same<T, Current> >::type * = 0) {
		p_t::push(a);
	}
	template <typename Visitor>
	void forall(Visitor & v) {
		for (size_t i = 0; i < items.size(); ++i) v(items[i]);
		p_t::forall(v);
	}
};
 
int main() {
	MyData<Tuple<int, Tuple<char , Nil> > > a;
	a.push(42);
	a.push('a');
	my_visitor v;
	a.forall(v);
	return 0;
}