is_specialization_of.hpp

//
// libsemigroups - C++ library for semigroups and monoids
// Copyright (C) 2025 James D. Mitchell
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
 
// This file contains the struct is_specialization_of and the alias
// is_specialization_of_v.
 
#ifndef LIBSEMIGROUPS_IS_SPECIALIZATION_OF_HPP_
#define LIBSEMIGROUPS_IS_SPECIALIZATION_OF_HPP_
 
#include <type_traits>  // for true_type
 
namespace libsemigroups {
  // From https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2098r0.pdf
  template <typename Thing, template <typename...> typename Primary>
  struct is_specialization_of : std::false_type {};

  template <template <typename...> typename Primary, typename... Args>
  struct is_specialization_of<Primary<Args...>, Primary> : std::true_type {};

  template <typename Thing, template <typename...> typename Primary>
  inline constexpr bool is_specialization_of_v
      = is_specialization_of<Thing, Primary>::value;
}  // namespace libsemigroups
 
#endif  // LIBSEMIGROUPS_IS_SPECIALIZATION_OF_HPP_