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module ComposingTypesScratch where
import Data.Function ((&))
import Data.Bifunctor
import qualified Data.Foldable as F
--------------------------------------------------------------------------------
newtype Identity a =
Identity { getIdentity :: a }
deriving (Eq, Show)
newtype Compose f g a =
Compose { getCompose :: f (g a) }
deriving (Eq, Show)
--------------------------------------------------------------------------------
instance (Functor f, Functor g) => Functor (Compose f g) where
fmap f (Compose getCompose) = Compose $ (fmap . fmap) f getCompose
instance (Applicative f, Applicative g) => Applicative (Compose f g) where
pure x = x & pure & pure & Compose
fgf <*> fga = undefined
--------------------------------------------------------------------------------
instance (Foldable f, Foldable g) => Foldable (Compose f g) where
foldMap toMonoid x = undefined
instance (Traversable f, Traversable g) => Traversable (Compose f g) where
traverse = undefined
--------------------------------------------------------------------------------
data Deux a b = Deux a b deriving (Show, Eq)
instance Bifunctor Deux where
bimap f g (Deux x y) = Deux (f x) (g y)
data Const a b = Const a deriving (Show, Eq)
instance Bifunctor Const where
bimap f _ (Const x) = Const (f x)
data Drei a b c = Drei a b c deriving (Show, Eq)
instance Bifunctor (Drei a) where
bimap f g (Drei x y z) = Drei x (f y) (g z)
data SuperDrei a b c = SuperDrei a b deriving (Show, Eq)
instance Bifunctor (SuperDrei a) where
bimap f g (SuperDrei x y) = SuperDrei x (f y)
data SemiDrei a b c = SemiDrei a deriving (Show, Eq)
instance Bifunctor (SemiDrei a) where
bimap _ _ (SemiDrei x) = SemiDrei x
data Quadriceps a b c d = Quadzzz a b c d
instance Bifunctor (Quadriceps a b) where
bimap f g (Quadzzz w x y z) = Quadzzz w x (f y) (g z)
-- | Analogue for Either
data LeftRight a b
= Failure a
| Success b
deriving (Show, Eq)
instance Bifunctor LeftRight where
bimap f _ (Failure x) = Failure (f x)
bimap _ g (Success y) = Success (g y)
|
