diff --git a/app/Main.hs b/app/Main.hs
index 6ee12f63c..5bb051545 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -24,10 +24,10 @@ import qualified Data.Text.ICU.Convert as Convert
 import Data.Bifunctor.Join
 
 -- | The available types of diff rendering.
-data Renderer = Unified | Split | Patch
+data Format = Unified | Split | Patch
 
 -- | The command line arguments to the application.
-data Arguments = Arguments { renderer :: Renderer, output :: Maybe FilePath, sourceA :: FilePath, sourceB :: FilePath }
+data Arguments = Arguments { format :: Format, output :: Maybe FilePath, sourceA :: FilePath, sourceB :: FilePath }
 
 -- | A parser for the application's command-line arguments.
 arguments :: Parser Arguments
@@ -53,7 +53,7 @@ main = do
 
 -- | Print a diff, given the command-line arguments, source files, and terms.
 printDiff :: Arguments -> (Source Char, Source Char) -> (Term T.Text Info, Term T.Text Info) -> IO ()
-printDiff arguments (aSource, bSource) (aTerm, bTerm) = case renderer arguments of
+printDiff arguments (aSource, bSource) (aTerm, bTerm) = case format arguments of
   Unified -> do
     rendered <- unified diff aSource bSource
     B1.putStr rendered
diff --git a/semantic-diff.cabal b/semantic-diff.cabal
index 06bfd4784..6b5803861 100644
--- a/semantic-diff.cabal
+++ b/semantic-diff.cabal
@@ -30,6 +30,7 @@ library
                      , Split
                      , Unified
                      , Parser
+                     , Renderer
                      , TreeSitter
                      , Source
   build-depends:       base >= 4.8 && < 5
diff --git a/src/PatchOutput.hs b/src/PatchOutput.hs
index b7e56eb33..4d8a2235a 100644
--- a/src/PatchOutput.hs
+++ b/src/PatchOutput.hs
@@ -6,6 +6,7 @@ module PatchOutput (
 import Diff
 import Line
 import Range
+import Renderer
 import Row
 import Source hiding ((++), break)
 import Split
@@ -15,7 +16,7 @@ import Control.Monad.Free
 import Data.Maybe
 import Data.Monoid
 
-patch :: Diff a Info -> Source Char -> Source Char -> String
+patch :: Renderer a String
 patch diff sourceA sourceB = mconcat $ showHunk (sourceA, sourceB) <$> hunks diff (sourceA, sourceB)
 
 data Hunk a = Hunk { offset :: (Sum Int, Sum Int), changes :: [Change a], trailingContext :: [Row a] }
diff --git a/src/Renderer.hs b/src/Renderer.hs
new file mode 100644
index 000000000..5414c1920
--- /dev/null
+++ b/src/Renderer.hs
@@ -0,0 +1,7 @@
+module Renderer where
+
+import Diff
+import Source
+
+-- | A function that will render a diff, given the two source files.
+type Renderer a b = Diff a Info -> Source Char -> Source Char -> b
diff --git a/src/Split.hs b/src/Split.hs
index a815ab318..b1ea4aa41 100644
--- a/src/Split.hs
+++ b/src/Split.hs
@@ -6,6 +6,7 @@ import Diff
 import Line
 import Row
 import Patch
+import Renderer
 import Term
 import Syntax
 import Control.Comonad.Cofree
@@ -30,7 +31,7 @@ type ClassName = T.Text
 classifyMarkup :: Foldable f => f String -> Markup -> Markup
 classifyMarkup categories element = maybe element ((element !) . A.class_ . stringValue . ("category-" ++)) $ maybeFirst categories
 
-split :: Diff leaf Info -> Source Char -> Source Char -> IO TL.Text
+split :: Renderer leaf (IO TL.Text)
 split diff before after = return . renderHtml
   . docTypeHtml
     . ((head $ link ! A.rel "stylesheet" ! A.href "style.css") <>)
diff --git a/src/Unified.hs b/src/Unified.hs
index 9505af74b..56b25fea4 100644
--- a/src/Unified.hs
+++ b/src/Unified.hs
@@ -5,6 +5,7 @@ import Patch
 import Syntax
 import Term
 import Range
+import Renderer
 import Source hiding ((++))
 import Control.Arrow
 import Control.Monad.Free
@@ -13,7 +14,7 @@ import Data.List hiding (foldl)
 import qualified Data.OrderedMap as Map
 import Rainbow
 
-unified :: Diff a Info -> Source Char -> Source Char -> IO ByteString
+unified :: Renderer a (IO ByteString)
 unified diff before after = do
   renderer <- byteStringMakerFromEnvironment
   return . mconcat . chunksToByteStrings renderer . fst $ iter g mapped where