Class Template Member Class Template Definition

member_template.cpp

#include<boost/hana.hpp>
#include<iostream>

namespace hana = boost::hana;

template<typename T>
class A
{
  static constexpr const char* t = hana::to<const char*>(T{});

  template<typename>
  class B;

  public:

  template<typename U>
  void print()
  {
    B<U>().print();
  }
};

template<typename T>
template<typename U>
class A<T>::B
{
  static constexpr const char* u = hana::to<const char*>(U{});

  public:

  void print()
  {
    std::cout << t << " " << u;
    std::cout << "\n";
  }
};

int main()
{
  constexpr auto hello = hana::string_c<'h', 'e', 'l', 'l', 'o'>;
  constexpr auto world = hana::string_c<'w', 'o', 'r', 'l', 'd'>;
  A<decltype(hello)>().print<decltype(world)>();
}

I guess I could have done .print(world)