{-# htermination (enumFromMyInt :: MyInt  ->  (List MyInt)) #-} 
import qualified Prelude 
data MyBool = MyTrue | MyFalse 
data List a = Cons a (List a) | Nil 
data MyInt = Pos Nat  | Neg Nat ;

data Nat = Succ Nat  | Zero ;

data WHNF a = WHNF a ;

enforceWHNF :: WHNF a  ->  b  ->  b;
enforceWHNF (WHNF x) y = y;

seq :: a  ->  b  ->  b;
seq x y = enforceWHNF (WHNF x) y;

dsEm :: (a  ->  b)  ->  a  ->  b;
dsEm f x = seq x (f x);

fromIntMyInt :: MyInt  ->  MyInt
fromIntMyInt x = x;

primMinusNat :: Nat  ->  Nat  ->  MyInt;
primMinusNat Zero Zero = Pos Zero;
primMinusNat Zero (Succ y) = Neg (Succ y);
primMinusNat (Succ x) Zero = Pos (Succ x);
primMinusNat (Succ x) (Succ y) = primMinusNat x y;

primPlusNat :: Nat  ->  Nat  ->  Nat;
primPlusNat Zero Zero = Zero;
primPlusNat Zero (Succ y) = Succ y;
primPlusNat (Succ x) Zero = Succ x;
primPlusNat (Succ x) (Succ y) = Succ (Succ (primPlusNat x y));

primPlusInt :: MyInt  ->  MyInt  ->  MyInt;
primPlusInt (Pos x) (Neg y) = primMinusNat x y;
primPlusInt (Neg x) (Pos y) = primMinusNat y x;
primPlusInt (Neg x) (Neg y) = Neg (primPlusNat x y);
primPlusInt (Pos x) (Pos y) = Pos (primPlusNat x y);

psMyInt :: MyInt  ->  MyInt  ->  MyInt
psMyInt = primPlusInt;

numericEnumFrom n = Cons n (dsEm numericEnumFrom (psMyInt n (fromIntMyInt (Pos (Succ Zero)))));

enumFromMyInt :: MyInt  ->  (List MyInt)
enumFromMyInt = numericEnumFrom;