Nicholls, Mark wrote:
*instance* ShapeInterface SquareType *where*area (SquareConstructor sideLength) = sideLength * sideLength
*data* SquareType a = Num a => SquareConstructor a
Now you have changed your type from SquareType to SquareType a, you need to change the instance to:
instance ShapeInterface (SquareType a) where... Jules _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
