Added pure renderAndConcat function.

src/Text/Hakyll/Render.hs

@@ -10,7 +10,7 @@ module Text.Hakyll.Render
     , css
     ) where
 
-import Control.Monad (unless, mapM, foldM)
+import Control.Monad (unless, mapM)
 
 import System.Directory (copyFile)
 import System.IO
@@ -64,14 +64,10 @@ renderAndConcatWith :: Renderable a
                     -> FilePath
                     -> [a]
                     -> IO String
-renderAndConcatWith manipulation templatePath renderables =
-    foldM concatRender' [] renderables
-  where
-    concatRender' :: Renderable a => String -> a -> IO String
-    concatRender' chunk renderable = do
-        rendered <- renderWith manipulation templatePath renderable
-        let body = getBody rendered
-        return $ chunk ++ body
+renderAndConcatWith manipulation templatePath renderables = do
+    template <- readFile templatePath
+    contexts <- mapM toContext renderables
+    return $ pureRenderAndConcatWith manipulation template contexts
 
 -- | Chain a render action for a page with a number of templates. This will
 --   also write the result to the site destination. This is the preferred way

src/Text/Hakyll/Render/Internal.hs

@@ -4,6 +4,7 @@ module Text.Hakyll.Render.Internal
     , regularSubstitute
     , finalSubstitute
     , pureRenderWith
+    , pureRenderAndConcatWith
     , pureRenderChainWith
     , writePage
     ) where
@@ -55,6 +56,18 @@ pureRenderWith manipulation template context =
     -- Force the body to be rendered.
     in ($|) id rnf (M.insert "body" body context)
 
+-- | A pure renderAndConcat function.
+pureRenderAndConcatWith :: ContextManipulation
+                        -> String -- ^ Template to use.
+                        -> [Context] -- ^ Different renderables.
+                        -> String
+pureRenderAndConcatWith manipulation template contexts =
+    foldl' renderAndConcat [] contexts
+  where
+    renderAndConcat chunk context =
+        let rendered = pureRenderWith manipulation template context
+        in chunk ++ fromMaybe "" (M.lookup "body" rendered)
+
 -- | A pure renderChain function.
 pureRenderChainWith :: ContextManipulation
                     -> [String]