compile-time constant factory with templated parameter set

/** requires gcc5.0+ and C++14
 * g++ -std=c++14 -o test test.cpp
 */
#include <iostream>

/**
 * Struct with compiler-constant parameters
 */
struct FFT_Inplace {
  static constexpr bool IsInplace = true;
  //..
};

/**
 * ... same, but different values ...
 */
struct FFT_Outplace {
  static constexpr bool IsInplace = false;
};

/**
 * Our implementation for an FFT Plan+Execution.
 */
template<typename TFFT>
struct PlanImpl {
  static constexpr bool IsInplace = TFFT::IsInplace;
  void operator()() {
    std::cout << "IsInplace = " << IsInplace << std::endl;
  }
};

/**
 * Compiler-constant factory
 * TFFT is struct with compiler-constant parameters
 */
template<
  typename TFFT,
  template<typename> typename TPlan
  >
constexpr
auto makePlan() {
  return TPlan<TFFT>();
}

/**
 * Let's play
 */
int main(void)
{
  auto inplace = makePlan<FFT_Inplace,PlanImpl>();
  inplace();
  auto outplace = makePlan<FFT_Outplace,PlanImpl>();
  outplace();
  return 0;
}