RollingList

Module description

Functions

fromList : List a -> RollingList a

Create a rolling list from a normal list

>>> toList (fromList [1,2,3])
[1,2,3]

roll : RollingList a -> RollingList a

Return a New RollingList, with the current element set to the next element

>>> toList (roll (fromList [1,2,3]))
[2,3,1]


>>> current (roll (fromList [1,2,3]))
Just 2

rollBack : RollingList a -> RollingList a

Return a New RollingList, with the current element set to the previous element

>>> toList (roll (fromList [1,2,3]))
[3,1,2]


>>> current (roll (fromList [1,2,3]))
Just 3

current : RollingList a -> Maybe a

Returns the currently selected element in the list

>>> current (fromList [1,2,3])
Just 1

toList : RollingList a -> List a

Create a normal list from a rolling list

>>> toList (fromList [1,2])
[1,2]

type alias RollingList a =

{ previous : List a

, next : List a

}

The rolling list type.