any.h

#ifndef any_h
#define any_h

namespace utility {

class any {
    struct impl_base {
        virtual impl_base* clone() const = 0;
        virtual ~impl_base() = default;
    };

    template<typename T> struct impl : impl_base {
        template<typename U> impl(U&& value) : value{forward<U>(value)} {}
        virtual impl* clone() const override { return new impl{value}; }
        T value;
    };

    impl_base* pimpl = nullptr;

public:
    any() = default;
    ~any() { delete pimpl; }

    template<typename T> any(T&& t) : pimpl{new impl<T>{forward<T>(t)}} {}
    any(const any& other) : pimpl{other.pimpl->clone()} {}
    any(any&& other) noexcept : pimpl{other.pimpl} { other.pimpl = nullptr; }

    any& operator=(const any& other) { delete pimpl; pimpl = other.pimpl->clone(); return *this; }
    any& operator=(any&& other) noexcept { std::swap(pimpl, other.pimpl); return *this; }

    template<typename T> T& get() noexcept { return static_cast<impl<T>*>(pimpl)->value; }
    // template<typename T> bool is() { return dynamic_cast<impl<T>*>(pimpl); }
};

} /* namespace any */

#endif /* any_h */