I'd like to add two instances to Data.Monoid, alongside of All/Any, Sum/Product, and First/Last. Here's a current instance (as a style example): -- | Boolean monoid under conjunction. newtype All = All { getAll :: Bool } deriving (Eq, Ord, Read, Show, Bounded) instance Monoid All where mempty = All True All x `mappend` All y = All (x && y) My proposed addition: -- | Ordered monoid under 'max'. newtype Max a = Max { getMax :: a } deriving (Eq, Ord, Read, Show, Bounded) instance (Ord a, Bounded a) => Monoid (Max a) where mempty = Max minBound Max a `mappend` Max b = Max (a `max` b) -- | Ordered monoid under 'min'. newtype Min a = Min { getMin :: a } deriving (Eq, Ord, Read, Show, Bounded) instance (Ord a, Bounded a) => Monoid (Min a) where mempty = Min minBound Min a `mappend` Min b = Min (a `min` b) I have a niggling uncertainty about the Ord & Bounded instances for Min a? Is there a reason flip the a ordering instead of preserving it? Suggested review period: two weeks (ending December 16). Comments? - Conal