John Velman
data Relation a i b = Rel {name::RN, arity::Int, members::(Set [EN])}
Why do you parametrize the data type when you don't use the parameters? Either do data Relation = Rel {name::RN, arity::Int, members::Set [EN]} or data Relation a i b = {name::a, arity::i, members::Set b} (or whatever you intended).
instance (Show a, Show i, Show b) => Show (Relation a i b) where show (Rel a i b) = a ++ "/" ++ (show i) ++ " " ++ (show b)
It doesn't matter whether a,i,b are in Show, as you don't use them (they are completely unrelated to the a,i,b in (Rel a i b), the former are types, the latter are variables) -kzm PS: Please don't quote the entire thread in each message. Although I haven't seen Andreas' message on the list (yet). -- If I haven't seen further, it is by standing in the footprints of giants