(=@|) :: (Foldable t, Eq a) => a -> t a -> Bool
(=@|) = elem
(=@) :: (Foldable t, Eq a) => a -> t a -> Bool
(=@) = elem
(|@=) :: (Foldable t, Eq a) => t a -> a -> Bool
(|@=) x y = y `elem` x

(@=@) :: (Foldable t1, Foldable t2, Eq a) => t1 a -> t2 a -> Bool
(@=@) x y = foldr (\a b -> elem a y || b) False x