Add MonadMetadata and instances

7 files changed, 68 insertions, 20 deletions

diff --git a/src/Hakyll/Core/Compiler.hs b/src/Hakyll/Core/Compiler.hs
index 7193e4f..c542ce7 100644
--- a/src/Hakyll/Core/Compiler.hs
+++ b/src/Hakyll/Core/Compiler.hs
@@ -6,7 +6,6 @@ module Hakyll.Core.Compiler
     , getUnderlying
     , makeItem
     , getRoute
-    , getMetadata
     , getResourceBody
     , getResourceString
     , getResourceLBS
@@ -32,11 +31,9 @@ import           System.Environment            (getProgName)
 --------------------------------------------------------------------------------
 import           Hakyll.Core.Compiler.Internal
 import           Hakyll.Core.Compiler.Require
-import           Hakyll.Core.Dependencies
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Item
 import           Hakyll.Core.Logger            as Logger
-import           Hakyll.Core.Metadata
 import           Hakyll.Core.Provider
 import           Hakyll.Core.Routes
 import qualified Hakyll.Core.Store             as Store
@@ -63,15 +60,6 @@ getRoute identifier = do
     return $ runRoutes routes identifier
 
 
-
---------------------------------------------------------------------------------
-getMetadata :: Identifier -> Compiler Metadata
-getMetadata identifier = do
-    provider <- compilerProvider <$> compilerAsk
-    compilerTellDependencies [IdentifierDependency identifier]
-    compilerUnsafeIO $ resourceMetadata provider identifier
-
-
 --------------------------------------------------------------------------------
 -- | Get the body of the underlying resource
 getResourceBody :: Compiler (Item String)
diff --git a/src/Hakyll/Core/Compiler/Internal.hs b/src/Hakyll/Core/Compiler/Internal.hs
index 89227ef..981ddda 100644
--- a/src/Hakyll/Core/Compiler/Internal.hs
+++ b/src/Hakyll/Core/Compiler/Internal.hs
@@ -25,16 +25,18 @@ module Hakyll.Core.Compiler.Internal
 
 
 --------------------------------------------------------------------------------
-import           Control.Applicative          (Alternative (..),
-                                               Applicative (..))
-import           Control.Exception            (SomeException, handle)
-import           Data.Monoid                  (Monoid (..))
+import           Control.Applicative            (Alternative (..),
+                                                 Applicative (..), (<$>))
+import           Control.Exception              (SomeException, handle)
+import           Data.Monoid                    (Monoid (..))
 
 
 --------------------------------------------------------------------------------
 import           Hakyll.Core.Dependencies
 import           Hakyll.Core.Identifier
+import           Hakyll.Core.Identifier.Pattern
 import           Hakyll.Core.Logger
+import           Hakyll.Core.Metadata
 import           Hakyll.Core.Provider
 import           Hakyll.Core.Routes
 import           Hakyll.Core.Store
@@ -128,6 +130,12 @@ instance Applicative Compiler where
 
 
 --------------------------------------------------------------------------------
+instance MonadMetadata Compiler where
+    getMetadata = compilerGetMetadata
+    getMatches  = compilerGetMatches
+
+
+--------------------------------------------------------------------------------
 runCompiler :: Compiler a -> CompilerRead -> IO (CompilerResult a)
 runCompiler compiler read' = handle handler $ unCompiler compiler read'
   where
@@ -195,3 +203,20 @@ compilerTellDependencies ds = compilerTell mempty {compilerDependencies = ds}
 compilerTellCacheHits :: Int -> Compiler ()
 compilerTellCacheHits ch = compilerTell mempty {compilerCacheHits = ch}
 {-# INLINE compilerTellCacheHits #-}
+
+
+--------------------------------------------------------------------------------
+compilerGetMetadata :: Identifier -> Compiler Metadata
+compilerGetMetadata identifier = do
+    provider <- compilerProvider <$> compilerAsk
+    compilerTellDependencies [IdentifierDependency identifier]
+    compilerUnsafeIO $ resourceMetadata provider identifier
+
+
+--------------------------------------------------------------------------------
+compilerGetMatches :: Pattern -> Compiler [Identifier]
+compilerGetMatches pattern = do
+    universe <- compilerUniverse <$> compilerAsk
+    let matching = filterMatches pattern universe
+    compilerTellDependencies [PatternDependency pattern matching]
+    return matching
diff --git a/src/Hakyll/Core/Compiler/Require.hs b/src/Hakyll/Core/Compiler/Require.hs
index a7c47ce..b9e0cc7 100644
--- a/src/Hakyll/Core/Compiler/Require.hs
+++ b/src/Hakyll/Core/Compiler/Require.hs
@@ -19,6 +19,7 @@ import           Hakyll.Core.Dependencies
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Identifier.Pattern
 import           Hakyll.Core.Item
+import           Hakyll.Core.Metadata
 import           Hakyll.Core.Store              (Store)
 import qualified Hakyll.Core.Store              as Store
 
@@ -59,9 +60,7 @@ requireBody = fmap itemBody . require
 --------------------------------------------------------------------------------
 requireAll :: (Binary a, Typeable a) => Pattern -> Compiler [Item a]
 requireAll pattern = do
-    universe <- compilerUniverse <$> compilerAsk
-    let matching = filterMatches pattern universe
-    compilerTellDependencies [PatternDependency pattern matching]
+    matching <- getMatches pattern
     mapM require matching
 
 
diff --git a/src/Hakyll/Core/Metadata.hs b/src/Hakyll/Core/Metadata.hs
index f3e99f5..884acd3 100644
--- a/src/Hakyll/Core/Metadata.hs
+++ b/src/Hakyll/Core/Metadata.hs
@@ -1,12 +1,32 @@
 --------------------------------------------------------------------------------
 module Hakyll.Core.Metadata
     ( Metadata
+    , MonadMetadata (..)
     ) where
 
 
 --------------------------------------------------------------------------------
+import           Control.Monad                  (forM)
 import           Data.Map                       (Map)
 
 
 --------------------------------------------------------------------------------
+import           Hakyll.Core.Identifier
+import           Hakyll.Core.Identifier.Pattern
+
+
+--------------------------------------------------------------------------------
 type Metadata = Map String String
+
+
+--------------------------------------------------------------------------------
+class Monad m => MonadMetadata m where
+    getMetadata    :: Identifier -> m Metadata
+    getMatches     :: Pattern -> m [Identifier]
+
+    getAllMetadata :: Pattern -> m [(Identifier, Metadata)]
+    getAllMetadata pattern = do
+        matches' <- getMatches pattern
+        forM matches' $ \id' -> do
+            metadata <- getMetadata id'
+            return (id', metadata)
diff --git a/src/Hakyll/Core/Rules.hs b/src/Hakyll/Core/Rules.hs
index d9dea01..0d9b7e2 100644
--- a/src/Hakyll/Core/Rules.hs
+++ b/src/Hakyll/Core/Rules.hs
@@ -174,6 +174,7 @@ route route' = Rules $ do
 --------------------------------------------------------------------------------
 -- | Get a list of resources matching the current pattern. This will also set
 -- the correct group to the identifiers.
+-- TODO: Make this private?
 resources :: Rules [Identifier]
 resources = Rules $ do
     pattern  <- rulesPattern  <$> ask
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
diff --git a/src/Hakyll/Web/Template/Context.hs b/src/Hakyll/Web/Template/Context.hs
index acc01bf..11491bf 100644
--- a/src/Hakyll/Web/Template/Context.hs
+++ b/src/Hakyll/Web/Template/Context.hs
@@ -39,6 +39,7 @@ import           Hakyll.Core.Compiler
 import           Hakyll.Core.Compiler.Internal
 import           Hakyll.Core.Identifier
 import           Hakyll.Core.Item
+import           Hakyll.Core.Metadata
 import           Hakyll.Core.Provider
 import           Hakyll.Core.Util.String       (splitAll)
 import           Hakyll.Web.Urls