Utilities/std/cm/type_traits

// -*-c++-*-
// vim: set ft=cpp:

/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   file Copyright.txt or https://cmake.org/licensing for details.  */
#ifndef cm_type_traits
#define cm_type_traits

#include <type_traits> // IWYU pragma: export

namespace cm {

#if __cplusplus >= 201402L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201402L)

// Miscellaneous transformations
template <bool B, typename T = void>
using enable_if_t = std::enable_if_t<B, T>;

#else

// Miscellaneous transformations
template <bool B, typename T = void>
using enable_if_t = typename std::enable_if<B, T>::type;

#endif

#if __cplusplus >= 201703L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703)

// Helper classes
using std::bool_constant;

// Miscellaneous transformations
using std::invoke_result;
using std::invoke_result_t;

using std::void_t;

#else

// Helper classes
template <bool B>
using bool_constant = std::integral_constant<bool, B>;

// Miscellaneous transformations
template <typename F, typename... ArgTypes>
using invoke_result = std::result_of<F(ArgTypes...)>;

template <class F, typename... ArgTypes>
using invoke_result_t = typename invoke_result<F, ArgTypes...>::type;

template <typename... ArgTypes>
struct make_void
{
  typedef void type;
};
template <typename... ArgTypes>
using void_t = typename make_void<ArgTypes...>::type;

#endif

} // namespace cm

#endif