You're right, effect segregation is not a paradigm per se. The fact still stands that it's closely aligned with the functional programming paradigm, and not OO

You're right, effect segregation is not a paradigm per se. The fact still stands that it's closely aligned with the functional programming paradigm, and not OOP. Programing paradigms and language features are closely related: certain features make certain paradigms easier, and paradigms spur the development of particular features.