-- | Indicate that something is `Missing`.
module NewtypeZoo.Missing
  ( Missing(Missing)
  , _theMissing
  , theMissing
  ) 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 Missing a = Missing 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

_theMissing :: Missing x -> x
_theMissing (Missing !x) = x
{-# INLINE _theMissing #-}

theMissing :: forall a b p f. (Profunctor p, Functor f) => p a (f b) -> p (Missing a) (f (Missing b))
theMissing = dimap _theMissing (fmap Missing)
{-# INLINE theMissing #-}