Merge pull request #339 from github/output-directory

Output directory

app/Main.hs

@@ -14,18 +14,21 @@ import Control.Comonad.Cofree
 import qualified Data.ByteString.Char8 as B1
 import qualified Data.ByteString.Lazy as B2
 import Options.Applicative
+import System.Directory
 import System.FilePath
+import qualified System.IO as IO
 
-data Output = Unified | Split
+data Renderer = Unified | Split
 
-data Argument = Argument { output :: Output, sourceA :: FilePath, sourceB :: FilePath }
+data Argument = Argument { renderer :: Renderer, output :: Maybe FilePath, sourceA :: FilePath, sourceB :: FilePath }
 
 arguments :: Parser Argument
 arguments = Argument
   <$> (flag Split Unified (long "unified" <> help "output a unified diff")
   <|> flag' Split (long "split" <> help "output a split diff"))
-  <*> argument str (metavar "FILE a")
-  <*> argument str (metavar "FILE b")
+  <*> (optional $ strOption (long "output" <> short 'o' <> help "output directory for split diffs, defaulting to stdout if unspecified"))
+  <*> strArgument (metavar "FILE a")
+  <*> strArgument (metavar "FILE b")
 
 main :: IO ()
 main = do
@@ -38,16 +41,21 @@ main = do
     bTerm <- parse bContents
     return (replaceLeavesWithWordBranches aContents aTerm, replaceLeavesWithWordBranches bContents bTerm)
   let diff = interpret comparable aTerm bTerm in
-    case output arguments of
+    case renderer arguments of
       Unified -> do
-        output <- unified diff aContents bContents
-        B1.putStr output
+        rendered <- unified diff aContents bContents
+        B1.putStr rendered
       Split -> do
-        output <- split diff aContents bContents
-        B2.putStr output
+        rendered <- split diff aContents bContents
+        case output arguments of
+          Just path -> do
+            isDir <- doesDirectoryExist path
+            IO.withFile (if isDir then path </> (takeFileName sourceBPath -<.> ".html") else path) IO.WriteMode (write rendered)
+          Nothing -> B2.putStr rendered
     where
     opts = info (helper <*> arguments)
       (fullDesc <> progDesc "Diff some things" <> header "semantic-diff - diff semantically")
+    write rendered h = B2.hPut h rendered
 
 parserForType :: String -> P.Parser
 parserForType mediaType = maybe P.lineByLineParser parseTreeSitterFile $ case mediaType of

semantic-diff.cabal

@@ -50,6 +50,7 @@ executable semantic-diff-exe
                      , bytestring
                      , optparse-applicative
                      , filepath
+                     , directory
   default-language:    Haskell2010
   extra-libraries:     bridge
   extra-lib-dirs:      .
@@ -69,6 +70,7 @@ executable semantic-diff-profile
                      , bytestring
                      , optparse-applicative
                      , filepath
+                     , directory
   default-language:    Haskell2010
   extra-libraries:     bridge
   extra-lib-dirs:      .