Hi!
I'm trying to work out the best way to generate (ideally derive) instances for
the Fix type. Here's a cut down example:
data Greet x = AlloAllo x x | AuRevoir deriving Show
newtype Fix f = In { out :: f (Fix f) } -- deriving Show -- DOESN'T COMPILE
-- workaround
instance Show (Fix Greet) where show (In i) = "In " ++ show i
In other words, given a number of parametised types that I can derive, say,
Ord, Eq and Show for, how should I go about getting the instances for the Fix-d
version of them as well? I've tried a few things, but no luck so far.
Any clues?
Cheers,
Sam
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