ModuleHeader: Add separate_lists option

See #320

Author: jaspervdj

data/stylish-haskell.yaml

@@ -27,6 +27,9 @@ steps:
   #     # Should export lists be sorted?  Sorting is only performed within the
   #     # export section, as delineated by Haddock comments.
   #     sort: true
+  #
+  #     # See `separate_lists` for the `imports` step.
+  #     separate_lists: true
 
   # Format record definitions. This is disabled by default.
   #

lib/Language/Haskell/Stylish/Config.hs

@@ -195,8 +195,11 @@ parseEnum strs _   (Just k) = case lookup k strs of
 --------------------------------------------------------------------------------
 parseModuleHeader :: Config -> A.Object -> A.Parser Step
 parseModuleHeader _ o = fmap ModuleHeader.step $ ModuleHeader.Config
-    <$> o A..:? "indent" A..!= (ModuleHeader.indent ModuleHeader.defaultConfig)
-    <*> o A..:? "sort"   A..!= (ModuleHeader.sort ModuleHeader.defaultConfig)
+    <$> o A..:? "indent"         A..!= ModuleHeader.indent        def
+    <*> o A..:? "sort"           A..!= ModuleHeader.sort          def
+    <*> o A..:? "separate_lists" A..!= ModuleHeader.separateLists def
+  where
+    def = ModuleHeader.defaultConfig
 
 --------------------------------------------------------------------------------
 parseSimpleAlign :: Config -> A.Object -> A.Parser Step

lib/Language/Haskell/Stylish/Step/ModuleHeader.hs

@@ -40,16 +40,16 @@ import           Language.Haskell.Stylish.Step
 
 
 data Config = Config
-    -- TODO(jaspervdj): Use the same sorting as in `Imports`?
-    -- TODO: make sorting optional?
-    { indent :: Int
-    , sort   :: Bool
+    { indent        :: Int
+    , sort          :: Bool
+    , separateLists :: Bool
     }
 
 defaultConfig :: Config
 defaultConfig = Config
-    { indent = 4
-    , sort   = True
+    { indent        = 4
+    , sort          = True
+    , separateLists = True
     }
 
 step :: Config -> Step
@@ -218,21 +218,23 @@ printExportList conf (L srcLoc exports) = do
     printExportsGroupTail (x : xs) = printExportsTail [([], x :| xs)]
     printExportsGroupTail []       = pure ()
 
+    -- NOTE(jaspervdj): This code is almost the same as the import printing
+    -- in 'Imports' and should be merged.
     printExport :: GHC.LIE GhcPs -> P ()
     printExport (L _ export) = case export of
       IEVar _ name -> putOutputable name
       IEThingAbs _ name -> putOutputable name
       IEThingAll _ name -> do
         putOutputable name
-        space
+        when (separateLists conf) space
         putText "(..)"
       IEModuleContents _ (L _ m) -> do
         putText "module"
         space
         putText (showOutputable m)
       IEThingWith _ name _wildcard imps _ -> do
         putOutputable name
-        space
+        when (separateLists conf) space
         putText "("
         sep (comma >> space) $
           fmap putOutputable $ L.sortBy (compareWrappedName `on` unLoc) imps

tests/Language/Haskell/Stylish/Step/ModuleHeader/Tests.hs

@@ -34,6 +34,7 @@ tests = testGroup "Language.Haskell.Stylish.Printer.ModuleHeader"
     , testCase "Indents with 2 spaces" ex14
     , testCase "Group doc with 2 spaces" ex15
     , testCase "Does not sort" ex16
+    , testCase "Repects separate_lists" ex17
     ]
 
 --------------------------------------------------------------------------------
@@ -299,3 +300,14 @@ ex16 = assertSnippet (step defaultConfig {sort = False}) input input
       , "    , no"
       , "    ) where"
       ]
+
+ex17 :: Assertion
+ex17 = assertSnippet (step defaultConfig {separateLists = False})
+    [ "module Foo"
+    , "    ( Bar (..)"
+    , "    ) where"
+    ]
+    [ "module Foo"
+    , "    ( Bar(..)"
+    , "    ) where"
+    ]