Haskell styles

This includes cosmetic changes to improve styles

app/App.hs

@@ -11,6 +11,7 @@ import qualified Data.Bifunctor as B
 import Control.Monad.Reader
 import Control.Monad.Except
 import Data.Maybe (isJust)
+import Data.Bool (bool)
 import Unused.Grouping (CurrentGrouping(..), groupedResponses)
 import Unused.Types (TermMatchSet, RemovalLikelihood(..))
 import Unused.TermSearch (SearchResults(..), fromResults)
@@ -48,7 +49,8 @@ data Options = Options
 
 runProgram :: Options -> IO ()
 runProgram options = withRuntime $
-    runExceptT (runReaderT (runApp run) options) >>= either renderError return
+    either renderError return
+        =<< runExceptT (runReaderT (runApp run) options)
 
 run :: App ()
 run = do
@@ -72,36 +74,33 @@ renderError (InvalidConfigError e) = V.invalidConfigError e
 renderError (CacheError e) = V.fingerprintError e
 
 retrieveGitContext :: TermMatchSet -> App TermMatchSet
-retrieveGitContext tms = do
-    commitCount <- numberOfCommits
-    case commitCount of
-        Just c -> liftIO $ loadGitContext c tms
-        Nothing -> return tms
+retrieveGitContext tms =
+    maybe (return tms) (liftIO . flip loadGitContext tms)
+        =<< numberOfCommits
 
 printResults :: TermMatchSet -> App ()
-printResults ts = do
-    filters <- optionFilters ts
+printResults tms = do
+    filters <- optionFilters tms
     grouping <- groupingOptions
     formatter <- resultFormatter
     liftIO $ V.searchResults formatter $ groupedResponses grouping filters
 
 loadAllConfigs :: App [LanguageConfiguration]
-loadAllConfigs = do
-    configs <- liftIO (B.first InvalidConfigError <$> loadAllConfigurations)
-    either throwError return configs
+loadAllConfigs =
+    either throwError return
+        =<< B.first InvalidConfigError <$> liftIO loadAllConfigurations
 
 calculateTagInput :: App [String]
-calculateTagInput = do
-    tags <- liftIO . fmap (B.first TagError) . loadTags =<< readFromStdIn
-    either throwError return tags
-  where
-    loadTags b = if b then loadTagsFromPipe else loadTagsFromFile
+calculateTagInput =
+    either throwError return
+        =<< liftIO .
+            fmap (B.first TagError) .
+            bool loadTagsFromFile loadTagsFromPipe =<< readFromStdIn
 
 withCache :: IO SearchResults -> App SearchResults
 withCache f =
-    operateCache =<< runWithCache
+    bool (liftIO f) (withCache' f) =<< runWithCache
   where
-    operateCache b = if b then withCache' f else liftIO f
     withCache' :: IO SearchResults -> App SearchResults
     withCache' r =
         either (throwError . CacheError) (return . SearchResults) =<<
@@ -118,11 +117,8 @@ optionFilters tms = foldl (>>=) (pure tms) matchSetFilters
         ]
 
 singleOccurrenceFilter :: AppConfig m => TermMatchSet -> m TermMatchSet
-singleOccurrenceFilter tms = do
-    allowsSingleOccurrence <- asks oSingleOccurrenceMatches
-    return $ if allowsSingleOccurrence
-        then withOneOccurrence tms
-        else tms
+singleOccurrenceFilter tms =
+    bool tms (withOneOccurrence tms) <$> asks oSingleOccurrenceMatches
 
 likelihoodsFilter :: AppConfig m => TermMatchSet -> m TermMatchSet
 likelihoodsFilter tms =
@@ -152,8 +148,4 @@ numberOfCommits :: AppConfig m => m (Maybe Int)
 numberOfCommits = asks oCommitCount
 
 resultFormatter :: AppConfig m => m V.ResultsFormat
-resultFormatter = do
-    c <- numberOfCommits
-    return $ if isJust c
-        then V.List
-        else V.Column
+resultFormatter = bool V.Column V.List . isJust <$> numberOfCommits