{- | Module : Data.Set.Range.List Description : Conversion of range sets to and from lists. Copyright : (c) 2017 Daniel Lovasko License : BSD2 Maintainer : Daniel Lovasko <daniel.lovasko@gmail.com> Stability : stable Portability : portable -} module Data.Set.Range.List ( fromAscList , fromDescList , fromList , toList ) where import Data.Set.Range.General import Data.Set.Range.Modify import Data.Set.Range.Types -- | Create a range set from a list of points. The ordering of the points is -- not important. The list can contain duplicates. fromList :: (Ord a, Enum a) => [a] -- ^ list of points -> RangeSet a -- ^ range set fromList = foldr insertPoint empty -- | Create a range set from a list of ascending points. The list can contain -- duplicates. fromAscList :: (Ord a, Enum a) => [a] -- ^ list of ascending points -> RangeSet a -- ^ range set fromAscList = foldr combine [] where combine p [] = [(p,p)] combine p ((a,b) : xs) | p < a && succ p == a = (p,b) : xs | b < p && succ b == p = (a,p) : xs | a <= p && p <= b = (a,b) : xs | otherwise = (p,p) : (a,b) : xs -- | Create a range set from a list of descending points. The list can contain -- duplicates. fromDescList :: (Ord a, Enum a) => [a] -- ^ list of ascending points -> RangeSet a -- ^ range set fromDescList = reverse . fromAscList -- | Convert the range set into a list of points. toList :: Enum a => RangeSet a -- ^ range set -> [a] -- ^ points toList [] = [] toList ((a,b) : xs) = [a .. b] ++ toList xs