You can generalize this: A: type level functions from types to (associated) types (i.e. normal generics) B: type level functions from types to type level func

You can generalize this: A: type level functions from types to (associated) types (i.e. normal generics) B: type level functions from types to type level functions (either As or Bs) (GAT). with generic parameters (i.e. higher kinded types, or template template parameters in C++) you could have type level functions that map type functions to (types or type functions), but once you have GATs you can fake them by passing to first order functions a type that has an associated type.