data Either (a b) where
    Left  : a -> Either (a b)
    Right : b -> Either (a b)

unwrapLeft : Either (a b) -> a
unwrapLeft x = case x of
    Left y => y

unwrapRight : Either (a b) -> b
unwrapRight x = case x of
    Right y => y

wow : Either (Int Char)
wow = Left 5

main = unwrapLeft wow