@@ -38,8 +38,11 @@ import qualified Data.Text.Lazy as Lazy ( Text )
38import Data.Time.Clock ( DiffTime, NominalDiffTime )
38import Data.Time.Clock ( DiffTime, NominalDiffTime )
41+-- | The class of 'DBType's that form a semigroup. This class is purely a Rel8
42+-- concept, and exists to mirror the 'Monoid' class.
41type DBMonoid :: Type -> Constraint
43type DBMonoid :: Type -> Constraint
42class DBSemigroup a => DBMonoid a where
44class DBSemigroup a => DBMonoid a where
45+ -- The identity for '<>.'
43 memptyExpr :: Expr a
46 memptyExpr :: Expr a