Set and check identifier groups

src/Hakyll/Core/Identifier.hs

@@ -25,6 +25,8 @@ module Hakyll.Core.Identifier
     ( Identifier (..)
     , parseIdentifier
     , toFilePath
+    , setGroup
+    , hasGroup
     ) where
 
 import Control.Arrow (second)
@@ -73,3 +75,13 @@ parseIdentifier = Identifier Nothing
 --
 toFilePath :: Identifier -> FilePath
 toFilePath = identifierPath
+
+-- | Set the identifier group for some identifier
+--
+setGroup :: String -> Identifier -> Identifier
+setGroup g (Identifier _ p) = Identifier (Just g) p
+
+-- | Check if an identifier belongs to a certain group
+--
+hasGroup :: String -> Identifier -> Bool
+hasGroup g (Identifier g' _) = Just g == g'