Oops. Sorry for stupid question. Michael Ackerman Levent Erkok wrote:

On Friday 29 June 2001 07:42 am, you wrote:

...

Hello,

I tried this:

data Nat = Zero | Succ Nat

instance Enum Nat where fromEnum Zero = 0 fromEnum (Succ n) = 1 + fromEnum n toEnum 0 = Zero toEnum n = if n > 0 then 1 + toEnum n else error "bah"

Don't you actually mean:

if n > 0 then Succ (toEnum n) else error "bah"

in the last line?

-Levent.