Any.h

// =====================================================================================================================
// Copyright 2024 Medusa Slockbower
// 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 ANY_H
#define ANY_H
 
#include <Utility/TemplateUtils.h>
 
template<typename...Ts> class Any;
 
template<typename T, typename...Rest>
class Any<T, Rest...> : public Any<Rest...>
{
    // Ensure each element is unique
    static_assert(IsUnique<Rest...>);
    using ThisType = T;
    using BaseType = Any<Rest...>;
 
public:
    Any()                                             : BaseType()        , Value() { }
    Any(const ThisType& value, const Rest&...other)   : BaseType(other...), Value(value) { }
    Any(ThisType&& value, Rest&&...other)             : BaseType(other...), Value(value) { }
    Any(const Any& other)                             = default;
    Any(Any&& other)                                  = default;
    ~Any()                                            = default;
 
    Any& operator=(const Any&) = default;
    Any& operator=(Any&&)      = default;
 
    operator       ThisType  () const { return  Value; }
    operator       ThisType& ()       { return  Value; }
    operator const ThisType& () const { return  Value; }
    operator       ThisType&&()       { return  Value; }
    operator       ThisType* ()       { return &Value; }
    operator const ThisType* () const { return &Value; }
 
private:
    static constexpr size_t Size = sizeof...(Rest);
    ThisType                Value;
};
 
template<>
class Any<> { };
 
#endif //ANY_H