module Or where

import Data.Semigroup
import Test.QuickCheck

data Or a b =
    Fst a
  | Snd b
  deriving (Eq, Show)

instance Semigroup (Or a b) where
    (Snd x) <> _ = Snd x
    _ <> x = x

instance (Arbitrary a, Arbitrary b) => Arbitrary (Or a b) where
    arbitrary = do
        x <- arbitrary
        y <- arbitrary
        frequency [ (1, return $ Fst x), (1, return $ Snd y) ]