#pragma once namespace crepe { /** * \brief Optional reference utility * * This class doesn't need to know the full definition of \c T to be used. * * \tparam T Value type */ template <typename T> class OptionalRef { public: //! Initialize empty (nonexistant) reference OptionalRef() = default; //! Initialize reference with value OptionalRef(T & ref); /** * \brief Assign new reference * * \param ref Reference to assign * * \return Reference to this (required for operator) */ OptionalRef<T> & operator=(T & ref); /** * \brief Retrieve this reference * * \returns Internal reference if it is set * * \throws std::runtime_error if this function is called while the reference it not set */ operator T &() const; /** * \brief Check if this reference is not empty * * \returns `true` if reference is set, or `false` if it is not */ explicit operator bool() const noexcept; /** * \brief Make this reference empty */ void clear() noexcept; private: /** * \brief Reference to the value of type \c T * * \note This raw pointer is *not* managed, and only used as a reference! */ T * ref = nullptr; }; } // namespace crepe #include "OptionalRef.hpp"