Add convertor from int to Nat

peano.hs

@@ -3,3 +3,6 @@ data Nat = Zero | Succ Nat
 intValOf thisNat = case thisNat of
 	Zero -> 0
 	Succ nextNat -> 1 + intValOf nextNat
+
+natValOf thisInt = if thisInt == 0 then Zero else Succ (natValOf (thisInt - 1))
+