module Data.Empty where

import qualified Data.NonEmpty.Class as C

import qualified Data.Traversable as Trav
import qualified Data.Foldable as Fold
import Control.Applicative (pure, )
import Control.DeepSeq (NFData, rnf, )

import qualified Test.QuickCheck as QC

data T a = Cons
   deriving (Eq, Ord)

instance Show (T a) where
   show Cons = "Empty.Cons"

instance C.Show T where
   showsPrec _p Cons = showString "Empty.Cons"

instance Functor T where
   fmap _ Cons = Cons

instance Fold.Foldable T where
   foldr _ y Cons = y

instance Trav.Traversable T where
   sequenceA Cons = pure Cons

instance C.ViewL T where
   viewL _ = Nothing

instance C.ViewR T where
   viewR _ = Nothing

instance C.View T where

instance QC.Arbitrary (T a) where
   arbitrary = return Cons
   shrink _ = []

instance C.Arbitrary T where
   arbitrary = return Cons
   shrink _ = []

instance C.Gen T where
   genOf _gen = return Cons

instance C.Empty T where
   empty = Cons

instance C.Zip T where
   zipWith _f Cons Cons = Cons

instance C.Reverse T where reverse = id

instance C.Sort T where
   sort Cons = Cons

instance C.SortBy T where
   sortBy _ Cons = Cons

This instance allows us to use @transposeClip@ on fixed sized containers.
instance C.Repeat T where
   repeat _ = Cons

This instance allows us to iterate on fixed length lists.
instance C.Iterate T where
   iterate _ _ = Cons

instance C.NFData T where
   rnf Cons = ()

instance NFData (T a) where
   rnf Cons = ()