Add MonadMetadata and instances

1 files changed, 15 insertions, 1 deletions

diff --git a/src/Hakyll/Core/Rules/Internal.hs b/src/Hakyll/Core/Rules/Internal.hs
index a067b02..249ae3b 100644
--- a/src/Hakyll/Core/Rules/Internal.hs
+++ b/src/Hakyll/Core/Rules/Internal.hs
@@ -12,8 +12,10 @@ module Hakyll.Core.Rules.Internal
 
 
 --------------------------------------------------------------------------------
-import           Control.Applicative            (Applicative)
+import           Control.Applicative            (Applicative, (<$>))
+import           Control.Monad.Reader           (ask)
 import           Control.Monad.RWS              (RWST, runRWST)
+import           Control.Monad.Trans            (liftIO)
 import qualified Data.Map                       as M
 import           Data.Monoid                    (Monoid, mappend, mempty)
 import           Data.Set                       (Set)
@@ -24,6 +26,7 @@ import           Hakyll.Core.Compiler.Internal
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Identifier.Pattern
 import           Hakyll.Core.Item.SomeItem
+import           Hakyll.Core.Metadata
 import           Hakyll.Core.Provider
 import           Hakyll.Core.Routes
 
@@ -71,6 +74,17 @@ newtype Rules a = Rules
 
 
 --------------------------------------------------------------------------------
+instance MonadMetadata Rules where
+    getMetadata identifier = Rules $ do
+        provider <- rulesProvider <$> ask
+        liftIO $ resourceMetadata provider identifier
+
+    getMatches pattern = Rules $ do
+        provider <- rulesProvider <$> ask
+        return $ filterMatches pattern $ resourceList provider
+
+
+--------------------------------------------------------------------------------
 -- | Run a Rules monad, resulting in a 'RuleSet'
 runRules :: Rules a -> Provider -> IO RuleSet
 runRules rules provider = do