Recursion schemes test

error.txt

error:
    • Couldn't match type ‘Base (Fix WindowF Bool)’ with ‘WindowF Bool’
      Expected type: Base (Fix WindowF Bool) Bool -> Bool
        Actual type: WindowF Bool Bool -> Bool
    • In the first argument of ‘cata’, namely ‘alg’
      In the expression: cata alg w
      In an equation for ‘allActive’:
          allActive (Window w)
            = cata alg w
            where
                alg (Split _ _ l r) = l && r
                alg (Single _ b) = b

tree.hs

data Dir = Hor
         | Vert
         deriving (Show)

data WindowF r a =
  Split Dir SplitInfo r r
    | Single ViewInfo a
    deriving (Show, Functor)

instance Bifunctor WindowF where
  bimap f _g (Split dir si x y) = Split dir si (f x) (f y)
  bimap _f g (Single vi a) = Single vi (g a)

newtype Window a = Window (Fix WindowF a) deriving Functor

allTree :: Window Bool -> Bool
allTree (Window w) = cata alg w
  where
    alg (Split _ _ x y) = x && y
    alg (Single _ x) = x