Add a Renderer type for rendering diffs

semantic-diff.cabal

@@ -30,6 +30,7 @@ library
                      , Split
                      , Unified
                      , Parser
+                     , Renderer
                      , TreeSitter
                      , Source
   build-depends:       base >= 4.8 && < 5

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] }

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

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") <>)

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