Add support for post qualified import formatting.

Adds an option to use post qualified module imports.

Related to haskell#284
Resolves haskell#334

Author: jhmcstanton

data/stylish-haskell.yaml

@@ -261,21 +261,25 @@ steps:
       # Default: false
       space_surround: false
 
-      # Enabling this argument will use the new GHC lib parse to format imports.
+      # Post qualify option moves any qualifies found in import declarations
+      # to the end of the declaration. This also adjust padding for any
+      # unqualified import declarations.
       #
-      # This currently assumes a few things, it will assume that you want post
-      # qualified imports. It is also not as feature complete as the old
-      # imports formatting.
+      # - true: Qualified as <module name> is moved to the end of the
+      #   declaration.
       #
-      # It does not remove redundant lines or merge lines. As such, the full
-      # feature scope is still pending.
+      #   > import Data.Bar
+      #   > import Data.Foo qualified as F
       #
-      # It _is_ however, a fine alternative if you are using features that are
-      # not parseable by haskell src extensions and you're comfortable with the
-      # presets.
+      # - false: Qualified remains in the default location and unqualified
+      #   imports are padded to align with qualified imports.
+      #
+      #   > import           Data.Bar
+      #   > import qualified Data.Foo as F
       #
       # Default: false
-      ghc_lib_parser: false
+      post_qualify: false
+
 
   # Language pragmas
   - language_pragmas:

lib/Language/Haskell/Stylish/Config.hs

@@ -274,6 +274,7 @@ parseImports config o = fmap (Imports.step columns) $ Imports.Options
       <*> (o A..:? "list_padding" >>= maybe (pure $ def Imports.listPadding) parseListPadding)
       <*> o A..:? "separate_lists" A..!= def Imports.separateLists
       <*> o A..:? "space_surround" A..!= def Imports.spaceSurround
+      <*> o A..:? "post_qualify" A..!= def Imports.postQualified
   where
     def f = f Imports.defaultOptions
 

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

@@ -61,6 +61,7 @@ data Options = Options
     , listPadding     :: ListPadding
     , separateLists   :: Bool
     , spaceSurround   :: Bool
+    , postQualified   :: Bool
     } deriving (Eq, Show)
 
 defaultOptions :: Options
@@ -73,6 +74,7 @@ defaultOptions = Options
     , listPadding     = LPConstant 4
     , separateLists   = True
     , spaceSurround   = False
+    , postQualified   = False
     }
 
 data ListPadding
@@ -143,8 +145,8 @@ formatImports
     -> NonEmpty (Located Import) -> Lines
 formatImports maxCols options m moduleStats rawGroup =
   runPrinter_ (PrinterConfig maxCols) [] m do
-  let 
-     
+  let
+
     group
       = NonEmpty.sortWith unLocated rawGroup
       & mergeImports
@@ -177,10 +179,10 @@ printQualified Options{..} padNames stats (L _ decl) = do
 
   when (isSafe decl) (putText "safe" >> space)
 
-  case (isQualified decl, isAnyQualified stats) of
-    (True, _) -> putText "qualified" >> space
-    (_, True) -> putText "         " >> space
-    _         -> pure ()
+  case (postQualified, isQualified decl, isAnyQualified stats) of
+    (False, True, _) -> putText "qualified" >> space
+    (False, _, True) -> putText "         " >> space
+    _                -> pure ()
 
   moduleNamePosition <- length <$> getCurrentLine
   forM_ (ideclPkgQual decl') $ \pkg -> putText (stringLiteral pkg) >> space
@@ -194,8 +196,11 @@ printQualified Options{..} padNames stats (L _ decl) = do
         replicate (isLongestImport stats - importModuleNameLength decl) ' '
 
   beforeAliasPosition <- length <$> getCurrentLine
-  forM_ (ideclAs decl') \(L _ name) ->
-    space >> putText "as" >> space >> putText (moduleNameString name)
+  if not postQualified then
+    forM_ (ideclAs decl') \(L _ name) ->
+      space >> putText "as" >> space >> putText (moduleNameString name)
+  else
+    pure ()
   afterAliasPosition <- length <$> getCurrentLine
 
   when (isHiding decl) (space >> putText "hiding")
@@ -301,6 +306,13 @@ printQualified Options{..} padNames stats (L _ decl) = do
               modifyCurrentLine trimRight
               newline >> putOffset >> printAsSingleLine)
             printAsMultiLine)
+  if postQualified && isQualified decl
+  then do
+    space
+    putText "qualified"
+    forM_ (ideclAs decl') \(L _ name) ->
+      space >> putText "as" >> space >> putText (moduleNameString name)
+  else pure ()
   where
     -- We cannot wrap/repeat 'hiding' imports since then we would get multiple
     -- imports hiding different things.

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

@@ -62,6 +62,9 @@ tests = testGroup "Language.Haskell.Stylish.Step.Imports.Tests"
     , testCase "case 28" case28
     , testCase "case 29" case29
     , testCase "case 30" case30
+    , testCase "case 31" case31
+    , testCase "case 32" case32
+    , testCase "case 33" case33
     ]
 
 
@@ -190,7 +193,7 @@ case07 = assertSnippet (step (Just 80) $ fromImportAlign File)
 case08 :: Assertion
 case08 =
   let
-    options = Options Global WithAlias True Inline Inherit (LPConstant 4) True False
+    options = Options Global WithAlias True Inline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options) input
     [ "module Herp where"
@@ -214,7 +217,7 @@ case08 =
 case08b :: Assertion
 case08b =
   let
-    options = Options Global WithModuleName True Inline Inherit (LPConstant 4) True False
+    options = Options Global WithModuleName True Inline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options) input
     ["module Herp where"
@@ -237,7 +240,7 @@ case08b =
 case09 :: Assertion
 case09 =
   let
-    options = Options Global WithAlias True Multiline Inherit (LPConstant 4) True False
+    options = Options Global WithAlias True Multiline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options) input
     [ "module Herp where"
@@ -272,7 +275,7 @@ case09 =
 case10 :: Assertion
 case10 =
   let
-    options = Options Group WithAlias True Multiline Inherit (LPConstant 4) True False
+    options = Options Group WithAlias True Multiline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 40) options) input
     [ "module Herp where"
@@ -313,7 +316,7 @@ case10 =
 case11 :: Assertion
 case11 =
   let
-    options = Options Group NewLine True Inline Inherit (LPConstant 4) True False
+    options = Options Group NewLine True Inline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options) input
     [ "module Herp where"
@@ -340,7 +343,7 @@ case11 =
 case11b :: Assertion
 case11b =
   let
-    options = Options Group WithModuleName True Inline Inherit (LPConstant 4) True False
+    options = Options Group WithModuleName True Inline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options) input
     [ "module Herp where"
@@ -363,7 +366,7 @@ case11b =
 case12 :: Assertion
 case12 =
   let
-    options = Options Group NewLine True Inline Inherit (LPConstant 2) True False
+    options = Options Group NewLine True Inline Inherit (LPConstant 2) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import Data.List (map)"
@@ -377,7 +380,7 @@ case12 =
 case12b :: Assertion
 case12b =
   let
-    options = Options Group WithModuleName True Inline Inherit (LPConstant 2) True False
+    options = Options Group WithModuleName True Inline Inherit (LPConstant 2) True False False
   in
     assertSnippet (step (Just 80) options)
     ["import Data.List (map)"]
@@ -388,7 +391,7 @@ case12b =
 case13 :: Assertion
 case13 =
   let
-    options = Options None WithAlias True InlineWithBreak Inherit (LPConstant 4) True False
+    options = Options None WithAlias True InlineWithBreak Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import qualified Data.List as List (concat, foldl, foldr, head, init,"
@@ -402,7 +405,7 @@ case13 =
 case13b :: Assertion
 case13b =
   let
-    options = Options None WithModuleName True InlineWithBreak Inherit (LPConstant 4) True False
+    options = Options None WithModuleName True InlineWithBreak Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import qualified Data.List as List (concat, foldl, foldr, head, init,"
@@ -418,7 +421,7 @@ case13b =
 case14 :: Assertion
 case14 =
   let
-    options = Options None WithAlias True InlineWithBreak Inherit (LPConstant 10) True False
+    options = Options None WithAlias True InlineWithBreak Inherit (LPConstant 10) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import qualified Data.List as List (concat, map, null, reverse, tail, (++))"
@@ -431,7 +434,7 @@ case14 =
 case15 :: Assertion
 case15 =
   let
-    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) True False
+    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import Data.Acid (AcidState)"
@@ -456,7 +459,7 @@ case15 =
 case16 :: Assertion
 case16 =
   let
-    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) False False
+    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) False False False
   in
     assertSnippet (step (Just 80) options)
     [ "import Data.Acid (AcidState)"
@@ -479,7 +482,7 @@ case16 =
 case17 :: Assertion
 case17 =
   let
-    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) True False
+    options = Options None AfterAlias True Multiline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 80) options)
     [ "import Control.Applicative (Applicative ((<*>),pure))"
@@ -496,7 +499,7 @@ case17 =
 case18 :: Assertion
 case18 =
   let
-    options = Options None AfterAlias True InlineToMultiline Inherit (LPConstant 4) True False
+    options = Options None AfterAlias True InlineToMultiline Inherit (LPConstant 4) True False False
   in
     assertSnippet (step (Just 40) options)
     [ "import Data.Foo as Foo (Bar, Baz, Foo)"
@@ -523,7 +526,7 @@ case18 =
 case19 :: Assertion
 case19 =
   let
-    options = Options Global NewLine True InlineWithBreak RightAfter (LPConstant 17) True False
+    options = Options Global NewLine True InlineWithBreak RightAfter (LPConstant 17) True False False
   in
     assertSnippet (step (Just 40) options) case19input
        ----------------------------------------
@@ -539,7 +542,7 @@ case19 =
 case19b :: Assertion
 case19b =
   let
-    options = Options File NewLine True InlineWithBreak RightAfter (LPConstant 17) True False
+    options = Options File NewLine True InlineWithBreak RightAfter (LPConstant 17) True False False
   in
     assertSnippet (step (Just 40) options) case19input
        ----------------------------------------
@@ -554,7 +557,7 @@ case19b =
 case19c :: Assertion
 case19c =
   let
-    options = Options File NewLine True InlineWithBreak RightAfter LPModuleName True False
+    options = Options File NewLine True InlineWithBreak RightAfter LPModuleName True False False
   in
     assertSnippet (step (Just 40) options) case19input
        ----------------------------------------
@@ -569,7 +572,7 @@ case19c =
 case19d :: Assertion
 case19d =
   let
-    options = Options Global NewLine True InlineWithBreak RightAfter LPModuleName True False
+    options = Options Global NewLine True InlineWithBreak RightAfter LPModuleName True False False
   in
     assertSnippet (step (Just 40) options) case19input
        ----------------------------------------
@@ -665,7 +668,7 @@ case22 = assertSnippet (step (Just 80) defaultOptions)
 case23 :: Assertion
 case23 =
   let
-    options = Options None AfterAlias False Inline Inherit (LPConstant 4) True True
+    options = Options None AfterAlias False Inline Inherit (LPConstant 4) True True False
   in
     assertSnippet (step (Just 40) options)
     [ "import Data.Acid (AcidState)"
@@ -690,7 +693,7 @@ case23 =
 case23b :: Assertion
 case23b =
   let
-    options = Options None WithModuleName False Inline Inherit (LPConstant 4) True True
+    options = Options None WithModuleName False Inline Inherit (LPConstant 4) True True False
   in
     assertSnippet (step (Just 40) options)
     [ "import Data.Acid (AcidState)"
@@ -716,7 +719,7 @@ case23b =
 case24 :: Assertion
 case24 =
   let
-    options = Options None AfterAlias False InlineWithBreak Inherit (LPConstant 4) True True
+    options = Options None AfterAlias False InlineWithBreak Inherit (LPConstant 4) True True False
   in
     assertSnippet (step (Just 40) options)
     [ "import Data.Acid (AcidState)"
@@ -740,7 +743,7 @@ case24 =
 case25 :: Assertion
 case25 =
   let
-    options = Options Group AfterAlias False Multiline Inherit (LPConstant 4) False False
+    options = Options Group AfterAlias False Multiline Inherit (LPConstant 4) False False False
   in
     assertSnippet (step (Just 80) options)
     [ "import Data.Acid (AcidState)"
@@ -807,7 +810,7 @@ case28 = assertSnippet (step (Just 80) $ fromImportAlign Global)
     , "import Data.Set (empty, nub)"
     ]
     [ "import           Control.Monad"
-    ,  "import qualified Data.Aeson         as JSON"
+    , "import qualified Data.Aeson         as JSON"
     , "import           Data.Default.Class (Default (def))"
     , ""
     , "import           Data.Maybe         (Maybe (Just, Nothing))"
@@ -842,3 +845,43 @@ case30 :: Assertion
 case30 = assertSnippet (step Nothing defaultOptions {separateLists = False})
     ["import           Data.Monoid (Monoid (..))"]
     ["import           Data.Monoid (Monoid(..))"]
+
+--------------------------------------------------------------------------------
+case31 :: Assertion
+case31 = assertSnippet (step Nothing defaultOptions {postQualified = True})
+    ["import           Data.Monoid (Monoid (..))"]
+    ["import Data.Monoid (Monoid (..))"]
+
+--------------------------------------------------------------------------------
+case32 :: Assertion
+case32 = assertSnippet (step Nothing defaultOptions {postQualified = True})
+    ["import qualified Data.Monoid as M"]
+    ["import Data.Monoid qualified as M"]
+
+--------------------------------------------------------------------------------
+case33 :: Assertion
+case33 = assertSnippet (step Nothing defaultOptions {postQualified = True})
+    [ "import Data.Default.Class (Default(def))"
+    , "import qualified Data.Aeson as JSON"
+    , "import qualified Data.Aeson as JSON"
+    , "import Control.Monad"
+    , "import Control.Monad"
+    , ""
+    , "import Data.Maybe (Maybe   (Just, Nothing))"
+    , "import qualified Data.Maybe.Extra (Maybe(Just, Nothing))"
+    , ""
+    , "import Data.Foo (Foo (Foo,Bar), Goo(Goo))"
+    , "import Data.Foo (Foo (Foo,Bar))"
+    , "import Data.Set (empty, intersect)"
+    , "import Data.Set (empty, nub)"
+    ]
+    [ "import Control.Monad"
+    , "import Data.Aeson         qualified as JSON"
+    , "import Data.Default.Class (Default (def))"
+    , ""
+    , "import Data.Maybe         (Maybe (Just, Nothing))"
+    , "import Data.Maybe.Extra   (Maybe (Just, Nothing)) qualified"
+    , ""
+    , "import Data.Foo           (Foo (Bar, Foo), Goo (Goo))"
+    , "import Data.Set           (empty, intersect, nub)"
+    ]