Make 'nix flake check' work

src/HCat.hs

@@ -1,6 +1,6 @@
 module HCat (
-    runHCat,
-    defaultMain,
+  runHCat,
+  defaultMain,
 ) where
 
 import System.Environment qualified as Env
@@ -15,16 +15,16 @@ import HCat.Internal (parseArgs)
 
 runHCat :: IO ()
 runHCat = do
-    fileNameOrError <- parseArgs <$> Env.getArgs
-    fileName <- eitherToError fileNameOrError
-    TextIO.readFile fileName >>= TextIO.putStr
+  fileNameOrError <- parseArgs <$> Env.getArgs
+  fileName <- eitherToError fileNameOrError
+  TextIO.readFile fileName >>= TextIO.putStr
 
 eitherToError :: Show a => Either a b -> IO b
 eitherToError = either (Exception.throwIO . IOError.userError . show) return
 
 handleError :: IOError -> IO ()
 handleError e = do
-    hPutStrLn stderr $ "I ran into an issue: " <> show e
+  hPutStrLn stderr $ "I ran into an issue: " <> show e
 
 defaultMain :: IO ()
 defaultMain = Exception.catch runHCat handleError

src/HCat/Internal.hs

@@ -7,9 +7,9 @@ module HCat.Internal where
 -- Right "foo"
 parseArgs :: [String] -> Either String FilePath
 parseArgs args = case args of
-    [] -> Left "No filename given!"
-    [arg] -> Right arg
-    _ -> Left "Only a single file is supported"
+  [] -> Left "No filename given!"
+  [arg] -> Right arg
+  _ -> Left "Only a single file is supported"
 
 -- | @chunksOf n@ splits a list into chunks of at most @n@ items.
 --
@@ -24,7 +24,7 @@ parseArgs args = case args of
 chunksOf :: Int -> [a] -> [[a]]
 chunksOf _ [] = []
 chunksOf n xs@(_ : _)
-    | n <= 0 = []
-    | otherwise =
-        let (chunk, rest) = splitAt n xs
-         in chunk : chunksOf n rest
+  | n <= 0 = []
+  | otherwise =
+      let (chunk, rest) = splitAt n xs
+       in chunk : chunksOf n rest