applicative/h1.hs


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import Control.Applicative

data MyMaybe a = MyNothing | MyJust a
    deriving (Show)

instance Functor MyMaybe where
    fmap _ MyNothing = MyNothing
    fmap f (MyJust x) = MyJust (f x) 

instance Applicative MyMaybe where
    pure x = MyJust x
    MyNothing <*> _ = MyNothing
    _ <*> MyNothing = MyNothing
    (MyJust f) <*> (MyJust g) = MyJust (f g)