[Haskell-beginners] Using derived Show most of the time

I have a data type for which I want to generate my own show string in a few cases, e.g., *data *T = T1 ... | T2 ... | T3 ... ... I'd like to do something like this, *instance *Show T *where* show T5 ... = <something special> show t = showTheDerived t Is there a way to do something like that simply? * -- Russ *