Line data    Source code

       1            0 : // Distributed under the MIT License.
       2              : // See LICENSE.txt for details.
       3              : 
       4              : #pragma once
       5              : 
       6              : #include <type_traits>
       7              : 
       8              : namespace tt {
       9              : namespace detail {
      10              : template <template <typename...> class U, typename T>
      11              : struct is_a : std::false_type {};
      12              : 
      13              : template <template <typename...> class U, typename... Args>
      14              : struct is_a<U, U<Args...>> : std::true_type {};
      15              : 
      16              : template <template <typename...> class U>
      17              : struct is_a_wrapper;
      18              : 
      19              : template <typename U, typename T>
      20              : struct wrapped_is_a;
      21              : 
      22              : template <template <typename...> class U, typename T>
      23              : struct wrapped_is_a<is_a_wrapper<U>, T> : detail::is_a<U, T> {};
      24              : }  // namespace detail
      25              : 
      26              : /// @{
      27              : /// \ingroup TypeTraitsGroup
      28              : /// \brief Check if type `T` is a template specialization of `U`
      29              : ///
      30              : /// \requires `U` is a class template
      31              : /// \effects If `T` is a template specialization of `U`, then inherits from
      32              : /// std::true_type, otherwise inherits from std::false_type
      33              : ///
      34              : /// \usage
      35              : /// For any type `T` and class template `U`
      36              : /// \code
      37              : /// using result = tt::is_a<U, T>;
      38              : /// \endcode
      39              : /// \metareturns
      40              : /// std::bool_constant
      41              : ///
      42              : /// \semantics
      43              : /// If the type `T` is a template specialization of the type `U`, then
      44              : /// \code
      45              : /// typename result::type = std::true_type;
      46              : /// \endcode
      47              : /// otherwise
      48              : /// \code
      49              : /// typename result::type = std::false_type;
      50              : /// \endcode
      51              : ///
      52              : /// \example
      53              : /// \snippet Test_IsA.cpp is_a_example
      54              : /// \see is_std_array
      55              : /// \tparam T type to check
      56              : /// \tparam U the type that T might be a template specialization of
      57              : template <template <typename...> class U, typename T>
      58            1 : using is_a = detail::wrapped_is_a<detail::is_a_wrapper<U>, T>;
      59              : 
      60              : /// \see is_a
      61              : template <template <typename...> class U, typename T>
      62            1 : constexpr bool is_a_v = is_a<U, T>::value;
      63              : 
      64              : /// \see is_a
      65              : template <template <typename...> class U, typename T>
      66            1 : using is_a_t = typename is_a<U, T>::type;
      67              : /// @}
      68              : }  // namespace tt