Pass the chunk renderer into unified

app/Main.hs

@@ -23,6 +23,7 @@ import qualified System.IO as IO
 import qualified Data.Text.ICU.Detect as Detect
 import qualified Data.Text.ICU.Convert as Convert
 import Data.Bifunctor.Join
+import Rainbow
 
 -- | The available types of diff rendering.
 data Format = Unified | Split | Patch
@@ -59,7 +60,9 @@ diff = interpret comparable
 -- | Return a renderer from the command-line arguments that will print the diff.
 printDiff :: Arguments -> Renderer T.Text (IO ())
 printDiff arguments diff sources = case format arguments of
-  Unified -> B1.putStr =<< unified diff sources
+  Unified ->  B1.putStr =<< render <$> byteStringMakerFromEnvironment
+    where
+      render renderer = unified renderer diff sources
   Split -> put (output arguments) =<< split diff sources
     where
       put Nothing rendered = TextIO.putStr rendered

src/Unified.hs

@@ -14,10 +14,9 @@ import Data.List hiding (foldl)
 import qualified Data.OrderedMap as Map
 import Rainbow
 
-unified :: Renderer a (IO ByteString)
-unified diff (before, after) = do
-  renderer <- byteStringMakerFromEnvironment
-  return . mconcat . chunksToByteStrings renderer . fst $ iter g mapped where
+unified :: (Chunk String -> [ByteString] -> [ByteString]) -> Renderer a ByteString
+unified renderer diff (before, after) =
+  mconcat . chunksToByteStrings renderer . fst $ iter g mapped where
     mapped = fmap (unifiedPatch &&& range) diff
     g (Annotated (_, info) syntax) = annotationAndSyntaxToChunks after info syntax
     annotationAndSyntaxToChunks source (Info range _) (Leaf _) = (pure . chunk . toList $ slice range source, Just range)