NotTreeExercises.hs

-- A ConcatList is just a fancy way to divide lists using 'Concat' instead of
-- 'Cons'. Where 'Cons' took one element on the left, and a list on the right,
-- 'Concat' takes a list on both sides.
data ConcatList a
  = Nil
  | Single a
  | Concat (ConcatList a) (ConcatList a)
  deriving (Show)

-- The length of a list is the length of its sub-lists
myLength :: ConcatList a -> Int
myLength Nil = undefined
myLength (Single x) = undefined
myLength (Concat xs ys) = undefined

-- The sum of a list is the sum of all of its elements
mySum :: Num a => ConcatList a -> a
mySum Nil = undefined
mySum (Single x) = undefined
mySum (Concat xs ys) = undefined

-- The depth of a list is the most possible steps to reach a 'Nil'.
myDepth :: ConcatList a -> Int
myDepth Nil = undefined
myDepth (Single x) = undefined
myDepth (Concat xs ys) = undefined