We show that the Whittaker functor on a regular block of the BGG-category
O of a semisimple complex Lie algebra can be obtained by composing
a translation to the wall functor with Soergel and Mili\v{c}i\'{c}'s
equivalence between the category of Whittaker modules and a singular block of
O. We show that the Whittaker functor is a quotient functor that
commutes with all projective functors and endomorphisms between them.Comment: 14 page