scanl -text +base

scanl :: (a -> b -> a) -> a -> [b] -> [a]
base Prelude, base Data.List
scanl is similar to foldl, but returns a list of successive reduced values from the left: > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...] Note that > last (scanl f z xs) == foldl f z xs.
scanl1 :: (a -> a -> a) -> [a] -> [a]
base Prelude, base Data.List
scanl1 is a variant of scanl that has no starting value argument: > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]