that's just poor wording -- the first example wasn't supposed to be linked to the second example; A better sentence is probably A monad is a datatype (e.g. Ei

that's just poor wording -- the first example wasn't supposed to be linked to the second example; A better sentence is probably A monad is a datatype (e.g. Either<T,U>) that encapsulates some control flow (e.g. if T != null return T else U) if I understand it correctly