Function get_if

sample/customAsPointer.cpp:43–47

template <typename T>
auto get_if(Num const *num)
{
  std::cout << "get_if" << std::endl;
  return static_cast<T const *>(num->kind() == T::k ? num : nullptr);
}

constexpr int32_t staticCastAs(Num const &input)
{