> Even if you look at well-designed non-OO code like, say the Linux kernel but the linux kernel is definitely OO, except vtables are filled by hand instead tha

> Even if you look at well-designed non-OO code like, say the Linux kernel but the linux kernel is definitely OO, except vtables are filled by hand instead than with the help of a compiler. https://www.kernel.org/doc/html/v4.10/driver-api/infrastructure.html https://www.kernel.org/doc/html/v4.10/driver-api/infrastruct... structs with data + function pointers are literally OOP objects. see e.g. https://lwn.net/Articles/444910/ https://lwn.net/Articles/444910/ > you'll see that there are object oriented concepts like information hiding and polymorphism all over the place; they just don't formalize them with the "class" or "private" keywords. yes, that's still OO. python doesn't have a private keyword either and that does not make its classes not OO.