-- | Indicate that something is `Existing`.
module NewtypeZoo.Existing
  ( Existing(Existing)
  , _theExisting
  , theExisting
  ) where

import           Control.DeepSeq (NFData)
import           Control.Monad.Fix (MonadFix)
import           Control.Monad.Zip (MonadZip)
import           Data.Bits       (Bits,FiniteBits)
import           Data.Copointed  (Copointed)
import           Data.Default    (Default)
import           Data.Functor.Classes (Eq1, Ord1, Read1, Show1)
import           Data.Functor.Identity
import           Data.Ix         (Ix)
import           Data.Profunctor (Profunctor, dimap)
import           Data.Pointed    (Pointed)
import           Data.String     (IsString)
import           Data.Typeable   (Typeable)
import           Foreign.Storable (Storable)
import           GHC.Generics    (Generic, Generic1)
import           System.Random   (Random)
import           Test.QuickCheck (Arbitrary)

newtype Existing a = Existing a
  deriving ( Eq
           , Ord
           , Read
           , Show
           , NFData
           , Foldable
           , Traversable
           , Functor
           , Default
           , Monoid
           , Semigroup
           , Typeable
           , Generic
           , Generic1
           , Random
           , Arbitrary
           , Bounded
           , Enum
           , Floating
           , Fractional
           , Integral
           , Num
           , Real
           , RealFloat
           , RealFrac
           , Ix
           , IsString
           , Bits
           , FiniteBits
           )
  deriving ( Eq1
           , Ord1
           , Read1
           , Show1
           , Pointed
           , Copointed
           , Applicative
           , MonadFix
           , Monad
           , MonadZip

           )
           via Identity

_theExisting :: Existing x -> x
_theExisting (Existing !x) = x
{-# INLINE _theExisting #-}

theExisting :: forall a b p f. (Profunctor p, Functor f) => p a (f b) -> p (Existing a) (f (Existing b))
theExisting = dimap _theExisting (fmap Existing)
{-# INLINE theExisting #-}