I am writing graphics code, and there is a pattern that I am repeating. I imagine that there could be some way to automate the code that I am creating. I have a collection of type classes like the ones below (minus fundeps, and other elements to make it compile). class Vertex a ... class (Coordinate b, Vertex a) => Positionable a b where getPosition :: a -> b class (Vertex a) => Colorable a where getColor :: a -> Color class (Vertex a) => Textureable a where getUVs :: a -> (Double, Double) etc... Basically I have a bunch of type classes with one method getSomeType. The following would be an instance of all of the type classes: data ColorVertex = ColorVertex Cart3Coordinate Color (Double, Double) Additionally I have collection type classes as follows: class (Coordinate b) => PositionCollection a b where getPositionList :: a -> [b] class ColorList a where getColorList :: a -> [Color] class UVList a where getUVList :: a -> [(Double, Double)] So, for every getSomeType class, there is a getSomeTypeList class. An instance of these types would look like data StreamCollection3 = StreamCollection3 [Cart3Coordinate] [Color] [(Double, Double)] add it would also an instance of the following class, and I would like to figure out how to generate the functions for the class. class (Vertex b) => VertexCollection a b where getElement :: a -> Int -> b getVertexList :: a -> [b] fromVertexList :: [b] -> a The Vertex in this case would be ColorVertex. I was thinking I could reduce the code by making the classes class Gets a b where gets :: a -> b class GetsList a b where getsList :: a -> [b] But I think I could go further. I'm wondering if there is a way to completely automate the construction of these classes, data types and methods, such that all I would provide is definition of the element type such as data PositionVertex = PositionVertex Cart3Coordinate and everything else would get generated. I can see how I would write code to generate this. Is the time to learn Template Haskell, or is there another way to generate my boilerplate? -Jonathan Fischoff