Hello Everyone! I am relatively new to Haskell (actually it's my second day) and I have the following problem: If I define a new datatype, for example a Binary tree, how can i use the show function to put an instance of my datatype into a String representation. I have seen in different Tutorials that there is a way for overloading the show function for my own type, and I tried out, what was presented in the tutorials, but it didn't work. Does somebody know, how to manage this? Here my attempts: data Entry a = EmptyEntry | MakeEntry a a showEntry :: (Show a) => Entry a -> String showEntry EmptyEntry = "Empty" showEntry MakeEntry a b = show a ++ ": " ++ show b what am I doing wrong? I have seen this way on some tutorials. btw: I am working with Hugs98 thank you in advance for your help Stephan