checked-0.1.0.0: checked.h

#define TYPEABLE_INSTANCE(Type,Cons) instance Typeable Type where {\
    typeOf (Cons x) = typeOf x; }

#define SHOW_INSTANCE(Type,Cons) instance Show Type where {\
    showsPrec p (Cons x) = showsPrec p x; \
    show (Cons x) = show x; }



#define MAX(typ) (fromIntegral (maxBound :: (typ)))
#define MIN(typ) (fromIntegral (minBound :: (typ)))

#define ASSERT(x,typ) (if not (x) then error "Datatype \"typ\" out of bounds." else id)

#define ASSERT_BOUNDS(var,typ) (ASSERT((var) <= MAX(typ) && (var) >= MIN(typ),typ))
#define MAP_ASSERT(typ,f) (map (\a -> ASSERT_BOUNDS(a,typ) ((f) a)))




#define READ_INSTANCE(Type) instance Read Type where {\
    readsPrec n str \
        = map (\(n, str) -> (ASSERT_BOUNDS(n,Type) $ fromInteger n, str)) (readsPrec n str) ;}




#define INTEGER_BINOP(x,y,op) ((op) (toInteger (x)) (toInteger (y)))
#define SAFE_BINOP(op,Type,Cons) \
  (op) (Cons x) (Cons y) = let z = INTEGER_BINOP(x,y,op) in ASSERT_BOUNDS(z,Type) (Cons ((op) (x) (y)))

#define INTEGER_UNOP(x,op) ((op) (toInteger (x)))
#define SAFE_UNOP(op,Type,Cons) \
  (op) (Cons x) = let z = INTEGER_UNOP(x,op) in ASSERT_BOUNDS(z,Type) (Cons ((op) (x)))

#define NUM_INSTANCE(Type,Cons) instance Num Type where { \
    SAFE_BINOP((+),Type,Cons) ; \
    SAFE_BINOP((-),Type,Cons) ; \
    SAFE_BINOP((*),Type,Cons) ; \
    SAFE_UNOP(negate,Type,Cons) ; \
    SAFE_UNOP(abs,Type,Cons) ; \
    SAFE_UNOP(signum,Type,Cons) ; \
    fromInteger i = ASSERT_BOUNDS(i,Type) $ Cons $ fromInteger i; }



#define ENUM_INSTANCE(Type,Cons) instance Enum Type where { \
    succ (Cons y) = ASSERT(y < maxBound,Type) Cons $ succ y;    \
    pred (Cons y) = ASSERT(y > minBound,Type) Cons $ pred y;	\
    toEnum n = ASSERT_BOUNDS(n,Type) $ Cons $ toEnum n; \
    fromEnum (Cons y) = fromEnum y; \
    enumFrom (Cons y) = MAP_ASSERT(Type,Cons) $ enumFrom y; \
    enumFromThen (Cons x) (Cons y) = MAP_ASSERT(Type,Cons) $ enumFromThen x y; \
    enumFromTo (Cons x) (Cons y) = MAP_ASSERT(Type,Cons) $ enumFromTo x y; \
    enumFromThenTo (Cons x) (Cons y) (Cons z) = map Cons $ enumFromThenTo x y z; }



#define STANDARD_DERIVING deriving (Bits, Bounded, Eq, Integral, Ix, Ord, PrintfArg, Real, Storable)

#define CHECKED_WRAPPER(Type,Cons,BaseType) newtype Type = Cons BaseType STANDARD_DERIVING; \
  TYPEABLE_INSTANCE(Type,Cons); \
  SHOW_INSTANCE(Type,Cons); \
  READ_INSTANCE(Type); \
  NUM_INSTANCE(Type,Cons); \
  ENUM_INSTANCE(Type,Cons);