text: //  Copyright John Maddock 2018.
  //  Use, modification and distribution are subject to the
  //  Boost Software License, Version 1.0. (See accompanying file
  //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  
  //
  // Tools for operator on complex as well as scalar types.
  //
  
  #ifndef BOOST_MATH_TOOLS_COMPLEX_HPP
  #define BOOST_MATH_TOOLS_COMPLEX_HPP
  
  #include <utility>
  #include <boost/math/tools/is_detected.hpp>
  
  namespace boost {
     namespace math {
        namespace tools {
  
           namespace detail {
           template <typename T, typename = void>
           struct is_complex_type_impl
           {
              static constexpr bool value = false;
           };
  
           template <typename T>
           struct is_complex_type_impl<T, void_t<decltype(std::declval<T>().real()), 
                                                 decltype(std::declval<T>().imag())>>
           {
              static constexpr bool value = true;
           };
           } // Namespace detail
  
           template <typename T>
           struct is_complex_type : public detail::is_complex_type_impl<T> {};
           
           //
           // Use this trait to typecast integer literals to something
           // that will interoperate with T:
           //
           template <class T, bool = is_complex_type<T>::value>
           struct integer_scalar_type
           {
              typedef int type;
           };
           template <class T>
           struct integer_scalar_type<T, true>
           {
              typedef typename T::value_type type;
           };
           template <class T, bool = is_complex_type<T>::value>
           struct unsigned_scalar_type
           {
              typedef unsigned type;
           };
           template <class T>
           struct unsigned_scalar_type<T, true>
           {
              typedef typename T::value_type type;
           };
           template <class T, bool = is_complex_type<T>::value>
           struct scalar_type
           {
              typedef T type;
           };
           template <class T>
           struct scalar_type<T, true>
           {
              typedef typename T::value_type type;
           };
  
  
  } } }
  
  #endif // BOOST_MATH_TOOLS_COMPLEX_HPP
  