deniok

import Control.Applicative
data B a = B Bool Bool a deriving Show
instance Functor B where fmap h u = pure h <*> u
instance Applicative B where
    pure = B True True
    B b1 k1 f <*> B b2 k2 a = B (if k1 || k2 then b2 else b1) k2 (f a)
{-
pure id <*> B b k a
= B True True <*> B b k a = B b k a

pure f <*> pure a
= B True True f <*> B True True a
= B True True (f a)
= pure (f a)

B True False id <*> pure 0
= B True False id <*> B True True 0
= B True True 0

pure ($ 0) <*> B True False id
= B True True ($ 0) <*> B True False id
= B True False 0

pure (.) <*> B True False id <*> B False True id <*> B False False 0
= ((B True True (.) <*> B True False id) <*> B False True id) <*> B False False 0
= (B True False (id .) <*> B False True id) <*> B False False 0
= B False True id <*> B False False 0
= B False False 0

B True False id <*> (B False True id <*> B False False 0)
= B True False id <*> B False False 0
= B False False 0
-}