{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveDataTypeable #-}
#if __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE DeriveGeneric #-}
#endif
#if __GLASGOW_HASKELL__ >= 704
{-# LANGUAGE Safe #-}
#elif __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE Trustworthy #-}
#endif
#if __GLASGOW_HASKELL__ >= 706
{-# LANGUAGE PolyKinds #-}
#endif
#include "bifunctors-common.h"
module Data.Bifunctor.Flip
( Flip(..)
) where
#if __GLASGOW_HASKELL__ < 710
import Control.Applicative
#endif
import Data.Biapplicative
import Data.Bifoldable
import Data.Bifunctor.Functor
import Data.Bitraversable
#if __GLASGOW_HASKELL__ < 710
import Data.Foldable
import Data.Monoid
import Data.Traversable
#endif
#if __GLASGOW_HASKELL__ >= 708
import Data.Typeable
#endif
#if __GLASGOW_HASKELL__ >= 702
import GHC.Generics
#endif
#if LIFTED_FUNCTOR_CLASSES
import Data.Functor.Classes
#endif
newtype Flip p a b = Flip { runFlip :: p b a }
deriving ( Eq, Ord, Show, Read
#if __GLASGOW_HASKELL__ >= 702
, Generic
#endif
#if __GLASGOW_HASKELL__ >= 708
, Typeable
#endif
)
#if LIFTED_FUNCTOR_CLASSES
instance (Eq2 p, Eq a) => Eq1 (Flip p a) where
liftEq = liftEq2 (==)
instance Eq2 p => Eq2 (Flip p) where
liftEq2 f g (Flip x) (Flip y) = liftEq2 g f x y
instance (Ord2 p, Ord a) => Ord1 (Flip p a) where
liftCompare = liftCompare2 compare
instance Ord2 p => Ord2 (Flip p) where
liftCompare2 f g (Flip x) (Flip y) = liftCompare2 g f x y
instance (Read2 p, Read a) => Read1 (Flip p a) where
liftReadsPrec = liftReadsPrec2 readsPrec readList
instance Read2 p => Read2 (Flip p) where
liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do
("Flip", s1) <- lex s0
("{", s2) <- lex s1
("runFlip", s3) <- lex s2
(x, s4) <- liftReadsPrec2 rp2 rl2 rp1 rl1 0 s3
("}", s5) <- lex s4
return (Flip x, s5)
instance (Show2 p, Show a) => Show1 (Flip p a) where
liftShowsPrec = liftShowsPrec2 showsPrec showList
instance Show2 p => Show2 (Flip p) where
liftShowsPrec2 sp1 sl1 sp2 sl2 p (Flip x) = showParen (p > 10) $
showString "Flip {runFlip = "
. liftShowsPrec2 sp2 sl2 sp1 sl1 0 x
. showChar '}'
#endif
instance Bifunctor p => Bifunctor (Flip p) where
first f = Flip . second f . runFlip
{-# INLINE first #-}
second f = Flip . first f . runFlip
{-# INLINE second #-}
bimap f g = Flip . bimap g f . runFlip
{-# INLINE bimap #-}
instance Bifunctor p => Functor (Flip p a) where
fmap f = Flip . first f . runFlip
{-# INLINE fmap #-}
instance Biapplicative p => Biapplicative (Flip p) where
bipure a b = Flip (bipure b a)
{-# INLINE bipure #-}
Flip fg <<*>> Flip xy = Flip (fg <<*>> xy)
{-# INLINE (<<*>>) #-}
instance Bifoldable p => Bifoldable (Flip p) where
bifoldMap f g = bifoldMap g f . runFlip
{-# INLINE bifoldMap #-}
instance Bifoldable p => Foldable (Flip p a) where
foldMap f = bifoldMap f (const mempty) . runFlip
{-# INLINE foldMap #-}
instance Bitraversable p => Bitraversable (Flip p) where
bitraverse f g = fmap Flip . bitraverse g f . runFlip
{-# INLINE bitraverse #-}
instance Bitraversable p => Traversable (Flip p a) where
traverse f = fmap Flip . bitraverse f pure . runFlip
{-# INLINE traverse #-}
instance BifunctorFunctor Flip where
bifmap f (Flip p) = Flip (f p)