[isotropy]

OOPs = "object-oriented programming", BUT it's a more restrained and thoughtful complaint than just "objects suck" or "inheritance sucks". He cabins it pretty clearly at 11:00 minutes in: "compile-time hierarchy of encapsulation that matches the domain model was a mistake"

[ocrow]

To unpack that a little, he looks to the writings of the early developers of object oriented programming and identifies the ways this assumption became established. People like Bjarne Stroustrup (developer of C++) took on and promulgated the view that the inheritance hierarchy of classes in an object oriented system can be or should be a literal instantiation of the types of objects from the domain model (e.g. different types of shapes in a drawing program).

This is a mistake is because it puts the broad-scale modularization boundaries of a system in the wrong places and makes the system brittle and inflexible. A better approach is one where large scale system boundaries fall along computational capability lines, as exemplified by modern Entity Component Systems. Class hierarchies that rigidly encode domain categorizations don't make for flexible systems.

Some of the earliest writers on object encapsulation, e.g. Tony Hoare, Doug Ross, understood this, but later language creators and promoters missed some of the subtleties of their writings and left us with a poor version of object-oriented programming as the accepted default.

[igouy]

> This is a mistake is because

https://news.ycombinator.com/item?id=44638183

[mariodiana]

Is Objective-C discussed at all?

[lisbbb]

Inheritance sucks if you wish to write good unit tests easily. It just totally freaking sucks due to encapsulation. When you step back, you realize that composition is a far better approach to writing testable code.