Copyright	(C) Frank Staals
License	see the LICENSE file
Maintainer	Frank Staals
Safe Haskell	None
Language	Haskell2010

Data.List.Zipper

Description

Synopsis

data Zipper a = Zipper [a] [a]
fromList :: [a] -> Zipper a
goNext :: Zipper a -> Maybe (Zipper a)
goPrev :: Zipper a -> Maybe (Zipper a)
allNexts :: Zipper a -> [Zipper a]
extractNext :: Zipper a -> Maybe (a, Zipper a)
dropNext :: Zipper a -> Maybe (Zipper a)
allNonEmptyNexts :: Zipper a -> [Zipper a]

Documentation

data Zipper a Source #

Simple Zipper for Lists.

Constructors

Zipper [a] [a]

Instances

Instances details

Functor Zipper Source #
Instance details Defined in Data.List.Zipper Methods fmap :: (a -> b) -> Zipper a -> Zipper b # (<$) :: a -> Zipper b -> Zipper a #
Foldable Zipper Source #
Instance details Defined in Data.List.Zipper Methods fold :: Monoid m => Zipper m -> m # foldMap :: Monoid m => (a -> m) -> Zipper a -> m # foldMap' :: Monoid m => (a -> m) -> Zipper a -> m # foldr :: (a -> b -> b) -> b -> Zipper a -> b # foldr' :: (a -> b -> b) -> b -> Zipper a -> b # foldl :: (b -> a -> b) -> b -> Zipper a -> b # foldl' :: (b -> a -> b) -> b -> Zipper a -> b # foldr1 :: (a -> a -> a) -> Zipper a -> a # foldl1 :: (a -> a -> a) -> Zipper a -> a # toList :: Zipper a -> [a] # null :: Zipper a -> Bool # length :: Zipper a -> Int # elem :: Eq a => a -> Zipper a -> Bool # maximum :: Ord a => Zipper a -> a # minimum :: Ord a => Zipper a -> a # sum :: Num a => Zipper a -> a # product :: Num a => Zipper a -> a #
Eq a => Eq (Zipper a) Source #
Instance details Defined in Data.List.Zipper Methods (==) :: Zipper a -> Zipper a -> Bool # (/=) :: Zipper a -> Zipper a -> Bool #
Show a => Show (Zipper a) Source #
Instance details Defined in Data.List.Zipper Methods showsPrec :: Int -> Zipper a -> ShowS # show :: Zipper a -> String # showList :: [Zipper a] -> ShowS #

fromList :: [a] -> Zipper a Source #

Construct a Zipper from a list

running time: $O(1)$

goNext :: Zipper a -> Maybe (Zipper a) Source #

Go to the Next Element

running time: $O(1)$

goPrev :: Zipper a -> Maybe (Zipper a) Source #

Go to the previous Element

running time: $O(1)$

allNexts :: Zipper a -> [Zipper a] Source #

Computes all nexts, even one that has no elements initially or at the end.

>>> mapM_ print $ allNexts $ fromList [1..5]
Zipper [] [1,2,3,4,5]
Zipper [1] [2,3,4,5]
Zipper [2,1] [3,4,5]
Zipper [3,2,1] [4,5]
Zipper [4,3,2,1] [5]
Zipper [5,4,3,2,1] []

extractNext :: Zipper a -> Maybe (a, Zipper a) Source #

Returns the next element, and the zipper without it

dropNext :: Zipper a -> Maybe (Zipper a) Source #

Drops the next element in the zipper.

running time: $O(1)$

allNonEmptyNexts :: Zipper a -> [Zipper a] Source #

Computes all list that still have next elements.

>>> mapM_ print $ allNonEmptyNexts $ fromList [1..5]
Zipper [] [1,2,3,4,5]
Zipper [1] [2,3,4,5]
Zipper [2,1] [3,4,5]
Zipper [3,2,1] [4,5]
Zipper [4,3,2,1] [5]