module OrdList (
OrdList,
nilOL, isNilOL, unitOL, appOL, consOL, snocOL, concatOL,
- fromOL, toOL, foldOL
+ fromOL, toOL, foldrOL, foldlOL
) where
infixl 5 `appOL`
appOL as None = as
appOL as bs = Two as bs
-foldOL :: (a->b->b) -> b -> OrdList a -> b
-foldOL k z None = z
-foldOL k z (One x) = k x z
-foldOL k z (Two b1 b2) = foldOL k (foldOL k z b2) b1
-foldOL k z (Many xs) = foldr k z xs
+foldrOL :: (a->b->b) -> b -> OrdList a -> b
+foldrOL k z None = z
+foldrOL k z (One x) = k x z
+foldrOL k z (Two b1 b2) = foldrOL k (foldrOL k z b2) b1
+foldrOL k z (Many xs) = foldr k z xs
+
+foldlOL :: (b->a->b) -> b -> OrdList a -> b
+foldlOL k z None = z
+foldlOL k z (One x) = k z x
+foldlOL k z (Two b1 b2) = foldlOL k (foldlOL k z b1) b2
+foldlOL k z (Many xs) = foldl k z xs
fromOL :: OrdList a -> [a]
fromOL ol