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--------------------------------------------------------------------------------
-- | An item is a combination of some content and its 'Identifier'. This way, we
-- can still use the 'Identifier' to access metadata.
{-# LANGUAGE DeriveDataTypeable #-}
module Hakyll.Core.Item
( Item (..)
, itemSetBody
, itemM
) where
--------------------------------------------------------------------------------
import Control.Applicative ((<$>), (<*>))
import Data.Binary (Binary (..))
import Data.Typeable (Typeable)
--------------------------------------------------------------------------------
import Hakyll.Core.Identifier
--------------------------------------------------------------------------------
data Item a = Item
{ itemIdentifier :: Identifier
, itemBody :: a
} deriving (Show, Typeable)
--------------------------------------------------------------------------------
instance Functor Item where
fmap f (Item i x) = Item i (f x)
--------------------------------------------------------------------------------
instance Binary a => Binary (Item a) where
put (Item i x) = put i >> put x
get = Item <$> get <*> get
--------------------------------------------------------------------------------
itemSetBody :: a -> Item b -> Item a
itemSetBody x (Item i _) = Item i x
--------------------------------------------------------------------------------
itemM :: Monad m => (a -> m b) -> Item a -> m (Item b)
itemM f (Item i b) = f b >>= \b' -> return (Item i b')
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