> Out of curiosity, how? (If pointers or other mechanisms for memory indirection are allowed then it's pretty easy, so let's agree to ban those.) Here's one po

> Out of curiosity, how? (If pointers or other mechanisms for memory indirection are allowed then it's pretty easy, so let's agree to ban those.) Here's one popular way to do it in C++: https://en.cppreference.com/w/cpp/language/pimpl https://en.cppreference.com/w/cpp/language/pimpl I guess my tongue in cheek response to your parenthetical would be to ban the use of hidden internal data structures ;-)