semigroup and monoid instance for bottom and top (#246)

hgeometry-combinatorial/src/HGeometry/Unbounded.hs

@@ -37,6 +37,7 @@ import qualified Data.Traversable     as T
 -- >>> data Top a = ValT a | Top
 newtype Top a = GTop (Maybe a)
                 deriving (Eq,Functor,F.Foldable,T.Traversable,Applicative,Monad,Eq1)
+                deriving newtype (Semigroup,Monoid)
 
 -- | @Top a@ values are isomorphing to @Maybe a@ values.
 topToMaybe :: Top a -> Maybe a
@@ -51,6 +52,8 @@ pattern Top    = GTop Nothing
 {-# COMPLETE ValT, Top #-}
 
 
+
+
 instance Ord1 Top where
   liftCompare _   Top       Top     = EQ
   liftCompare _   _         Top     = LT
@@ -102,6 +105,7 @@ _TopMaybe = iso topToMaybe GTop
 -- >>> data Bottom a = Bottom | ValB a
 newtype Bottom a = GBottom (Maybe a)
                  deriving (Eq,Ord,Functor,F.Foldable,T.Traversable,Applicative,Monad,Eq1,Ord1)
+                 deriving newtype (Semigroup,Monoid)
 
 -- | `Bottom a` values are isomorphing to `Maybe a` values.
 bottomToMaybe :: Bottom a -> Maybe a