Fix all 20 hlint warnings across 5 source files

- Use newtype instead of data for single-field types (RouxConfig, ImportError)
- Replace maybe "" id with fromMaybe "" throughout
- Replace not (x `elem` ys) with x `notElem` ys
- Remove redundant brackets, redundant $, and eta-reduce lookupRecipe
- Use numeric underscore for 1_000_000

src/Roux/Config.hs

@@ -21,7 +21,7 @@ import qualified Fleece.Core as FC
 import System.Directory (doesFileExist)
 
 -- | Top-level config.
-data RouxConfig = RouxConfig
+newtype RouxConfig = RouxConfig
     { rcAnthropic :: Maybe AnthropicConfig
     }
     deriving stock (Eq, Show)

src/Roux/CooklangPrint.hs

@@ -13,7 +13,7 @@ module Roux.CooklangPrint (
 import Data.Char (isAlphaNum)
 import Data.Function ((&))
 import Data.List.NonEmpty (toList)
-import Data.Maybe (catMaybes)
+import Data.Maybe (catMaybes, fromMaybe)
 import Data.Ratio (denominator, numerator)
 import Data.Text (Text)
 import qualified Data.Text as T
@@ -69,7 +69,7 @@ renderDurationText d =
         n = numerator amt
         d' = denominator amt
         amount = if d' == 1 then T.pack (show n) else T.pack (show n <> "/" <> show d')
-        unit = maybe "" id (durationUnit d)
+        unit = fromMaybe "" (durationUnit d)
      in T.strip (amount <> " " <> unit)
 
 -- | Render a tag list as a comma-separated string.

src/Roux/Html.hs

@@ -49,7 +49,7 @@ data SortMode
     deriving stock (Eq, Show)
 
 -- | Error type for the import pipeline.
-data ImportError = ImportError Text
+newtype ImportError = ImportError Text
     deriving stock (Eq, Show)
 
 -- ---------------------------------------------------------------------------
@@ -982,7 +982,7 @@ renderMethodSections sections = do
 isMethodSection :: Section -> Bool
 isMethodSection section =
     case sectionName section of
-        Just n -> not (T.toLower n `elem` ["ingredients", "ingredient"])
+        Just n -> T.toLower n `notElem` ["ingredients", "ingredient"]
         Nothing -> True
 
 -- | Extract (section name, body items) from a section for the method column.

src/Roux/SchemaOrg.hs

@@ -401,7 +401,7 @@ parseSimpleRational t =
     case T.splitOn "/" t of
         -- Fraction: "1/2"
         [num, den] ->
-            case (readInt (num), readInt (den)) of
+            case (readInt num, readInt den) of
                 (Just n, Just d) | d /= 0 -> Just (toRational n / toRational d)
                 _ -> Nothing
         -- Whole number or decimal: "3", "0.5", or range like "14-18"

src/Roux/Server.hs

@@ -45,7 +45,7 @@ import System.FilePath (makeRelative, takeBaseName, takeExtension, (</>))
 import qualified Data.Aeson as A
 import qualified Data.Aeson.KeyMap as KM
 import qualified Data.ByteString as BS
-import Data.Maybe (mapMaybe)
+import Data.Maybe (fromMaybe, mapMaybe)
 import qualified Data.Text.Encoding as TE
 import Roux.Config (AnthropicConfig (..), RouxConfig (..))
 import qualified Roux.CooklangPrint as CooklangPrint
@@ -203,11 +203,11 @@ importHandler recipeDir config _state request respond =
         "POST" -> do
             body <- readRequestBody request
             let params = parseFormBody body
-                url = maybe "" id (lookup "url" params)
-                text = maybe "" id (lookup "text" params)
-                fileB64 = maybe "" id (lookup "file-b64" params)
-                fileName = maybe "" id (lookup "file-name" params)
-                fileMime = maybe "" id (lookup "file-mime" params)
+                url = fromMaybe "" (lookup "url" params)
+                text = fromMaybe "" (lookup "text" params)
+                fileB64 = fromMaybe "" (lookup "file-b64" params)
+                fileName = fromMaybe "" (lookup "file-name" params)
+                fileMime = fromMaybe "" (lookup "file-mime" params)
                 hasFile = not (T.null fileB64)
 
             putStrLn $
@@ -403,7 +403,7 @@ runFileImport recipeDir config originalName _mimeType b64Text = do
                 Nothing ->
                     pure $
                         Left $
-                            Html.ImportError $
+                            Html.ImportError
                                 "LLM import is not configured. Add an anthropic.api_key to the config file."
                 Just anthropicConfig -> do
                     result <- runLLMPipeline recipeDir anthropicConfig (Just sourceUrl) (Just sourcePath) ""
@@ -422,7 +422,7 @@ runTextImport recipeDir config text = do
         Nothing ->
             pure $
                 Left $
-                    Html.ImportError $
+                    Html.ImportError
                         "LLM import is not configured. Add an anthropic.api_key to the config file."
         Just anthropicConfig ->
             runLLMPipeline recipeDir anthropicConfig Nothing Nothing text
@@ -474,7 +474,7 @@ runLLMPipeline recipeDir anthropicConfig mSourceUrl mFilePath text = do
                     putStrLn "[roux] could not extract title from Cooklang output"
                     return $
                         Left $
-                            Html.ImportError $
+                            Html.ImportError
                                 "Could not determine recipe title from AI output."
                 Just title -> do
                     let filename = CooklangPrint.filenameFromTitle title
@@ -570,7 +570,7 @@ watchRecipes dir state changeLog = do
                         "[roux] watchDir callback error: " <> show (e :: SomeException)
                 )
         -- Keep the thread alive (watchDir runs the callback on the manager thread)
-        forever $ threadDelay 1000000
+        forever $ threadDelay 1_000_000
 
 {- | Re-read a single recipe file and update the shared state.
 On read/parse errors, logs the error and keeps the previous version.
@@ -596,7 +596,7 @@ reReadRecipe dir path state changeLog = do
                 Right info -> case Idx.riRecipe info of
                     Left err -> do
                         putStrLn $ "[roux] parse error in " <> path <> ": " <> err
-                        putStrLn $ "[roux] keeping previous version"
+                        putStrLn "[roux] keeping previous version"
                     Right _ -> do
                         atomicModifyIORef' state $ \m ->
                             (Map.insert key info m, ())
@@ -624,8 +624,8 @@ handleRequest state request respond = do
 
 -- | Look up a recipe by filename (case-insensitive, .cook extension optional).
 lookupRecipe :: FilePath -> Map FilePath Idx.RecipeInfo -> Maybe Idx.RecipeInfo
-lookupRecipe target recipes =
-    Map.lookup (map toLower (stripCookExt target)) recipes
+lookupRecipe target =
+    Map.lookup (map toLower (stripCookExt target))
 
 -- | Strip the .cook extension if present.
 stripCookExt :: FilePath -> FilePath
@@ -666,9 +666,9 @@ uploadImageHandler recipeDir _state request respond =
         "POST" -> do
             body <- readRequestBody request
             let params = parseFormBody body
-                filename = maybe "" id (lookup "filename" params)
-                fileB64 = maybe "" id (lookup "file-b64" params)
-                originalName = maybe "" id (lookup "file-name" params)
+                filename = fromMaybe "" (lookup "filename" params)
+                fileB64 = fromMaybe "" (lookup "file-b64" params)
+                originalName = fromMaybe "" (lookup "file-name" params)
             if T.null filename
                 then respond (jsonError "Missing 'filename' parameter")
                 else