Right, you'd need a CPS version of map. Luckily map isn't really a "primitive", it's just a library function, so using a different version of map is not a big d

Right, you'd need a CPS version of map. Luckily map isn't really a "primitive", it's just a library function, so using a different version of map is not a big deal. One way to think about it is that languages with callCC built in are just transformed to CPS by the compiler before being run, which includes transforming the definition of map. (In fact, this is a reasonable strategy for compiling Scheme, I believe.) It's pretty easy in Haskell which wraps CPS into a monad (Cont) because you use mapM from the Control.Monad library instead of having to write a specifically CPSed version of the function.