src/OptionalConfiguration.hs: make OptionalConfiguration.hs a Semigroup.

[mailbox-count.git] / src / OptionalConfiguration.hs

diff --git a/src/OptionalConfiguration.hs b/src/OptionalConfiguration.hs
index 2d74d27965e1281f0e816ae45500af9221f67440..16a61bf802630250feb0dad9029d4e12cf1615e5 100644 (file)
--- a/src/OptionalConfiguration.hs
+++ b/src/OptionalConfiguration.hs
@@ -21,6 +21,7 @@ import qualified Data.Configurator as DC (
 import Data.Data ( Data )
 import Data.Typeable ( Typeable )
 import Data.Monoid ( Monoid(..) )
+import Data.Semigroup ( Semigroup( (<>) ) )
 import Paths_mailbox_count ( getSysconfDir )
 import System.Directory ( getHomeDirectory )
 import System.FilePath ( (</>) )
@@ -75,8 +76,9 @@ instance Monoid OptionalConfiguration where
              Nothing
              Nothing
 
+instance Semigroup OptionalConfiguration where
   -- | Combine @cfg1@ and @cfg2@, giving precedence to @cfg2@.
-  cfg1 `mappend` cfg2 =
+  cfg1 <> cfg2 =
     OptionalConfiguration
       (merge_maybes (database cfg1) (database cfg2))
       (merge_maybes (detail cfg1) (detail cfg2))