{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveFunctor #-}
module GHC.Data.Pair
( Pair(..)
, unPair
, toPair
, swap
, pLiftFst
, pLiftSnd
)
where
#include "HsVersions.h"
import GHC.Prelude
import GHC.Utils.Outputable
import qualified Data.Semigroup as Semi
data Pair a = Pair { forall a. Pair a -> a
pFst :: a, forall a. Pair a -> a
pSnd :: a }
deriving (forall a b. a -> Pair b -> Pair a
forall a b. (a -> b) -> Pair a -> Pair b
forall (f :: * -> *).
(forall a b. (a -> b) -> f a -> f b)
-> (forall a b. a -> f b -> f a) -> Functor f
<$ :: forall a b. a -> Pair b -> Pair a
$c<$ :: forall a b. a -> Pair b -> Pair a
fmap :: forall a b. (a -> b) -> Pair a -> Pair b
$cfmap :: forall a b. (a -> b) -> Pair a -> Pair b
Functor)
instance Applicative Pair where
pure :: forall a. a -> Pair a
pure a
x = forall a. a -> a -> Pair a
Pair a
x a
x
(Pair a -> b
f a -> b
g) <*> :: forall a b. Pair (a -> b) -> Pair a -> Pair b
<*> (Pair a
x a
y) = forall a. a -> a -> Pair a
Pair (a -> b
f a
x) (a -> b
g a
y)
instance Foldable Pair where
foldMap :: forall m a. Monoid m => (a -> m) -> Pair a -> m
foldMap a -> m
f (Pair a
x a
y) = a -> m
f a
x forall a. Monoid a => a -> a -> a
`mappend` a -> m
f a
y
instance Traversable Pair where
traverse :: forall (f :: * -> *) a b.
Applicative f =>
(a -> f b) -> Pair a -> f (Pair b)
traverse a -> f b
f (Pair a
x a
y) = forall a. a -> a -> Pair a
Pair forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> a -> f b
f a
x forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> a -> f b
f a
y
instance Semi.Semigroup a => Semi.Semigroup (Pair a) where
Pair a
a1 a
b1 <> :: Pair a -> Pair a -> Pair a
<> Pair a
a2 a
b2 = forall a. a -> a -> Pair a
Pair (a
a1 forall a. Semigroup a => a -> a -> a
Semi.<> a
a2) (a
b1 forall a. Semigroup a => a -> a -> a
Semi.<> a
b2)
instance (Semi.Semigroup a, Monoid a) => Monoid (Pair a) where
mempty :: Pair a
mempty = forall a. a -> a -> Pair a
Pair forall a. Monoid a => a
mempty forall a. Monoid a => a
mempty
mappend :: Pair a -> Pair a -> Pair a
mappend = forall a. Semigroup a => a -> a -> a
(Semi.<>)
instance Outputable a => Outputable (Pair a) where
ppr :: Pair a -> SDoc
ppr (Pair a
a a
b) = forall a. Outputable a => a -> SDoc
ppr a
a SDoc -> SDoc -> SDoc
<+> Char -> SDoc
char Char
'~' SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr a
b
unPair :: Pair a -> (a,a)
unPair :: forall a. Pair a -> (a, a)
unPair (Pair a
x a
y) = (a
x,a
y)
toPair :: (a,a) -> Pair a
toPair :: forall a. (a, a) -> Pair a
toPair (a
x,a
y) = forall a. a -> a -> Pair a
Pair a
x a
y
swap :: Pair a -> Pair a
swap :: forall a. Pair a -> Pair a
swap (Pair a
x a
y) = forall a. a -> a -> Pair a
Pair a
y a
x
pLiftFst :: (a -> a) -> Pair a -> Pair a
pLiftFst :: forall a. (a -> a) -> Pair a -> Pair a
pLiftFst a -> a
f (Pair a
a a
b) = forall a. a -> a -> Pair a
Pair (a -> a
f a
a) a
b
pLiftSnd :: (a -> a) -> Pair a -> Pair a
pLiftSnd :: forall a. (a -> a) -> Pair a -> Pair a
pLiftSnd a -> a
f (Pair a
a a
b) = forall a. a -> a -> Pair a
Pair a
a (a -> a
f a
b)