[c++] Get hold of any class' private members. Lawfully.

access_member.hpp

/* Inspired to the work of hliberacki: https://github.com/hliberacki/cpp-member-accessor
 * But made it much shorter, and works even with C++98.
 *
 * Usage:
 *
 *    class PrivateStuff 
 *    {
 *        int dont_steal;
 *    };
 *
 *    struct privy: access_member<privy, int PrivateStuff::*>{};
 *    template class privy::set<&PrivateStuff::dont_steal>;
 *
 *    int robber(PrivateStuff *p)
 *    {
 *       return p->*privy::get;
 *    }
 */

#ifndef ACCESS_MEMBER_HPP
#define ACCESS_MEMBER_HPP

template <typename Tag, typename MemberType>
struct access_member {
    template <MemberType Member>
    class set {
        struct worker {
            worker() { get = Member; }
        };
        
        static worker worker_;
    };
    
    static MemberType get;    
};

template <typename Tag, typename MemberType>
MemberType access_member<Tag, MemberType>::get;

template <typename Tag, typename MemberType>
template <MemberType Member>
typename access_member<Tag, MemberType>::template set<Member>::worker access_member<Tag, MemberType>::template set<Member>::worker_;

#endif

Working example on godbolt: https://godbolt.org/z/8asGns