Hi,
I can't understand how the arithmatic operators like (+),(-) are defined and fromInteger works in that context.

Type Fun a = Int -> a

fun :: Fun Int
fun = (+1)

instance (Num a) => Num (Fun a) where
.........

(fun + 2) 10 and (2 + fun) 10 works fine. But how does it know it has to use fromInteger?

But If I want these,
(Just 2 + fun) 10 and (fun + Just 2) 10
to work, then is there a way to tell which conversion function to use?

Thanks,
Saswat