Data.List.Zipper

Documentation

data Zipper a

Constructors

Zip ![a] ![a]

empty :: Zipper a

fromList :: [a] -> Zipper a

fromListEnd :: [a] -> Zipper a

toList :: Zipper a -> [a]

endp :: Zipper a -> Bool

emptyp :: Zipper a -> Bool

beginp :: Zipper a -> Bool

cursor :: Zipper a -> a

cursor z returns the targeted element in z.

This function is not total, but the invariant is that endp z == False means that you can safely call cursor z.

right :: Zipper a -> Zipper a

left :: Zipper a -> Zipper a

push :: a -> Zipper a -> Zipper a

insert :: a -> Zipper a -> Zipper a

pop :: Zipper a -> Zipper a

delete :: Zipper a -> Zipper a

replace :: a -> Zipper a -> Zipper a

replace a z changes the current element in the zipper to the passed in value. If there is no current element, the zipper is unchanged. If you want to add the element in that case instead, use insert a (delete z).