-\begin{code}
-flattenOrdList :: OrdList a -> [a]
-
-flattenOrdList ol
- = flat ol []
- where
- flat NoObj rest = rest
- flat (OrdObj x) rest = x:rest
- flat (ParList a b) rest = flat a (flat b rest)
- flat (SeqList a b) rest = flat a (flat b rest)
-
-{- DEBUGGING ONLY:
-instance Text (OrdList a) where
- showsPrec _ NoObj = showString "_N_"
- showsPrec _ (OrdObj _) = showString "_O_"
- showsPrec _ (ParList a b) = showString "(PAR " . shows a . showChar ')'
- showsPrec _ (SeqList a b) = showString "(SEQ " . shows a . showChar ')'
--}
+appOL None bs = bs
+appOL as None = as
+appOL as bs = Two as bs
+
+mapOL :: (a -> b) -> OrdList a -> OrdList b
+mapOL f None = None
+mapOL f (One x) = One (f x)
+mapOL f (Two x y) = Two (mapOL f x) (mapOL f y)
+mapOL f (Many xs) = Many (map f xs)
+
+instance Functor OrdList where
+ fmap = mapOL
+
+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
+ = flat ol []
+ where
+ flat None rest = rest
+ flat (One x) rest = x:rest
+ flat (Two a b) rest = flat a (flat b rest)
+ flat (Many xs) rest = xs ++ rest
+
+toOL :: [a] -> OrdList a
+toOL xs = Many xs