| // Copyright 2020 The Tint Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef SRC_AST_TRAITS_H_ |
| #define SRC_AST_TRAITS_H_ |
| |
| #include <type_traits> |
| |
| namespace tint { |
| namespace ast { |
| namespace traits { |
| |
| /// FirstParamType is a traits helper that infers the type of the first |
| /// parameter of the function, method, static method, lambda, or function-like |
| /// object `F`. |
| template <typename F> |
| struct FirstParamType { |
| /// The type of the first parameter of the function-like object `F` |
| using type = typename FirstParamType<decltype(&F::operator())>::type; |
| }; |
| |
| /// FirstParamType specialization for a regular function or static method. |
| template <typename R, typename Arg> |
| struct FirstParamType<R (*)(Arg)> { |
| /// The type of the first parameter of the function |
| using type = typename std::decay<Arg>::type; |
| }; |
| |
| /// FirstParamType specialization for a non-static method. |
| template <typename R, typename C, typename Arg> |
| struct FirstParamType<R (C::*)(Arg)> { |
| /// The type of the first parameter of the function |
| using type = typename std::decay<Arg>::type; |
| }; |
| |
| /// FirstParamType specialization for a non-static, const method. |
| template <typename R, typename C, typename Arg> |
| struct FirstParamType<R (C::*)(Arg) const> { |
| /// The type of the first parameter of the function |
| using type = typename std::decay<Arg>::type; |
| }; |
| |
| /// FirstParamTypeT is an alias to `typename FirstParamType<F>::type`. |
| template <typename F> |
| using FirstParamTypeT = typename FirstParamType<F>::type; |
| |
| } // namespace traits |
| } // namespace ast |
| } // namespace tint |
| |
| #endif // SRC_AST_TRAITS_H_ |