Define Foldable and Traversable instances for Located

1 files changed, 23 insertions, 8 deletions

diff --git a/src/Haddock/GHC/Utils.hs b/src/Haddock/GHC/Utils.hs
index c0e73425..7cbcf07f 100644
--- a/src/Haddock/GHC/Utils.hs
+++ b/src/Haddock/GHC/Utils.hs
@@ -17,6 +17,8 @@ import Data.Char
 import Data.Version
 import qualified Data.Map as Map
 import Control.Arrow
+import Data.Foldable hiding (concatMap)
+import Data.Traversable
 
 import HsSyn
 import SrcLoc
@@ -26,14 +28,6 @@ import Packages
 import Module
 
 
-unL :: Located a -> a
-unL (L _ x) = x
-
-
-reL :: a -> Located a
-reL = L undefined
-
-
 moduleString :: Module -> String
 moduleString = moduleNameString . moduleName 
 
@@ -118,6 +112,27 @@ trace_ppr x y = trace (pretty x) y
 
 
 -------------------------------------------------------------------------------
+-- Located
+-------------------------------------------------------------------------------
+
+
+unL :: Located a -> a
+unL (L _ x) = x
+
+
+reL :: a -> Located a
+reL = L undefined
+
+
+instance Foldable Located where
+  foldMap f (L _ x) = f x
+
+
+instance Traversable Located where
+  mapM f (L l x) = (return . L l) =<< f x  
+
+
+-------------------------------------------------------------------------------
 -- NamedThing instances
 -------------------------------------------------------------------------------