I am trying to make all polynomial functors (in the categorical sense) an instance of the class Functor. Consider a datatype (corresponsing to a constant functor): data ConstInt a = Const Int ConstInt is clearly a functor in the categorical sense, but is 'ConstInt' also a functor in Haskell?? Any ideas how to make 'ConstInt' an instance of class Functor? -Tobi -- GMX - Die Kommunikationsplattform im Internet. http://www.gmx.net