1 /* 2 * Copyright 2014 Google Inc. All rights reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef FRUIT_META_MAP_H 18 #define FRUIT_META_MAP_H 19 20 #include <fruit/impl/meta/set.h> 21 22 namespace fruit { 23 namespace impl { 24 namespace meta { 25 26 // A Map is a Set whose elements have the form Pair<Key, Value> 27 28 struct GetMapKeys { 29 template <typename M> 30 struct apply; 31 32 template <typename... Pairs> 33 struct apply<Vector<Pairs...>> { 34 using type = Vector<typename Pairs::First...>; 35 }; 36 }; 37 38 // TODO: Consider implementing this by finding the position. 39 struct MapContainsKey { 40 template <typename TToFind> 41 struct Helper { 42 template <typename CurrentResult, typename T> 43 struct apply { 44 using type = CurrentResult; 45 }; 46 template <typename CurrentResult, typename Value> 47 struct apply<CurrentResult, Pair<TToFind, Value>> { 48 using type = Bool<true>; 49 }; 50 }; 51 52 template <typename M, typename TToFind> 53 struct apply { 54 using type = FoldVector(M, Helper<TToFind>, Bool<false>); 55 }; 56 }; 57 58 // TODO: Consider implementing this by finding the position first, then calling VectorRemoveFirstN 59 // and getting the first element. 60 struct FindInMap { 61 template <typename TToFind> 62 struct Helper { 63 template <typename CurrentResult, typename T> 64 struct apply { 65 using type = CurrentResult; 66 }; 67 template <typename CurrentResult, typename Value> 68 struct apply<CurrentResult, Pair<TToFind, Value>> { 69 using type = Value; 70 }; 71 }; 72 73 template <typename M, typename TToFind> 74 struct apply { 75 using type = FoldVector(M, Helper<TToFind>, None); 76 }; 77 }; 78 79 // TODO: Consider implementing this by finding the position first, then calling VectorRemoveFirstN 80 // and getting the first element. 81 struct FindValueInMap { 82 template <typename TToFind> 83 struct Helper { 84 template <typename CurrentResult, typename T> 85 struct apply { 86 using type = CurrentResult; 87 }; 88 template <typename CurrentResult, typename Value> 89 struct apply<CurrentResult, Pair<Value, TToFind>> { 90 using type = Value; 91 }; 92 }; 93 94 template <typename M, typename TToFind> 95 struct apply { 96 using type = FoldVector(M, Helper<TToFind>, None); 97 }; 98 }; 99 100 } // namespace meta 101 } // namespace impl 102 } // namespace fruit 103 104 #endif // FRUIT_META_MAP_H 105
