Different import alignment styles

4 files changed, 74 insertions, 19 deletions

diff --git a/.stylish-haskell.yaml b/.stylish-haskell.yaml
index e86b2bf..1dd89bf 100644
--- a/.stylish-haskell.yaml
+++ b/.stylish-haskell.yaml
@@ -4,14 +4,25 @@ steps:
 
   # Import cleanup
   - imports:
-      # Align import names and import lists. Default: true.
-      align: true
+      # There are different ways we can align names and lists.
+      #
+      # - global: Align the import names and import list throughout the entire
+      #   file.
+      #
+      # - group: Only align the imports per group (a group is formed by adjacent
+      #   import lines).
+      #
+      # - none: Do not perform any alignment.
+      #
+      # Default: global.
+      align: global
 
   # Language pragmas
   - language_pragmas:
       # We can generate different styles of language pragma lists.
       #
       # - vertical: Vertical-spaced language pragmas, one per line.
+      #
       # - compact: A more compact style.
       #
       # Default: vertical.
diff --git a/src/StylishHaskell/Config.hs b/src/StylishHaskell/Config.hs
index a4da1aa..9b533c6 100644
--- a/src/StylishHaskell/Config.hs
+++ b/src/StylishHaskell/Config.hs
@@ -46,7 +46,7 @@ instance FromJSON Config where
 --------------------------------------------------------------------------------
 defaultConfig :: Config
 defaultConfig = Config $
-    [ Imports.step True
+    [ Imports.step Imports.Global
     , LanguagePragmas.step LanguagePragmas.Vertical True
     , TrailingWhitespace.step
     ]
@@ -132,7 +132,13 @@ parseEnum strs _   (Just k) = case lookup k strs of
 --------------------------------------------------------------------------------
 parseImports :: A.Object -> A.Parser Step
 parseImports o = Imports.step
-    <$> o A..:? "align" A..!= True
+    <$> (o A..:? "align" >>= parseEnum aligns Imports.Global)
+  where
+    aligns =
+        [ ("global", Imports.Global)
+        , ("group",  Imports.Group)
+        , ("none",   Imports.None)
+        ]
 
 
 --------------------------------------------------------------------------------
diff --git a/src/StylishHaskell/Step/Imports.hs b/src/StylishHaskell/Step/Imports.hs
index 6312aae..fc77c55 100644
--- a/src/StylishHaskell/Step/Imports.hs
+++ b/src/StylishHaskell/Step/Imports.hs
@@ -1,6 +1,7 @@
 --------------------------------------------------------------------------------
 module StylishHaskell.Step.Imports
-    ( step
+    ( Align (..)
+    , step
     ) where
 
 
@@ -21,6 +22,14 @@ import           StylishHaskell.Util
 
 
 --------------------------------------------------------------------------------
+data Align
+    = Global
+    | Group
+    | None
+    deriving (Eq, Show)
+
+
+--------------------------------------------------------------------------------
 imports :: H.Module l -> [H.ImportDecl l]
 imports (H.Module _ _ _ is _) = is
 imports _                     = []
@@ -82,11 +91,11 @@ sortImportSpecs imp = imp {H.importSpecs = fmap sort $ H.importSpecs imp}
 
 
 --------------------------------------------------------------------------------
-prettyImport :: Bool -> Int -> H.ImportDecl l -> String
-prettyImport align longest imp = unwords $ concat
+prettyImport :: Bool -> Bool -> Int -> H.ImportDecl l -> String
+prettyImport padQualified padName longest imp = unwords $ concat
     [ ["import"]
     , qualified
-    , [(if hasExtras && align then padRight longest else id) (importName imp)]
+    , [(if hasExtras && padName then padRight longest else id) (importName imp)]
     , ["as " ++ as | H.ModuleName _ as <- maybeToList $ H.importAs imp]
     , [H.prettyPrint specs | specs <- maybeToList $ H.importSpecs imp]
     ]
@@ -95,23 +104,34 @@ prettyImport align longest imp = unwords $ concat
 
     qualified
         | H.importQualified imp = ["qualified"]
-        | align                 = ["         "]
+        | padQualified          = ["         "]
         | otherwise             = []
 
 
 --------------------------------------------------------------------------------
-prettyImportGroup :: Bool -> Int -> [H.ImportDecl LineBlock] -> Lines
-prettyImportGroup align longest =
-    map (prettyImport align longest) . sortBy compareImports
+prettyImportGroup :: Align -> Int -> [H.ImportDecl LineBlock] -> Lines
+prettyImportGroup align longest imps =
+    map (prettyImport padQual padName longest') $ sortBy compareImports imps
+  where
+    longest' = case align of
+        Group -> longestImport imps
+        _     -> longest
+
+    padName = align /= None
+
+    padQual = case align of
+        Global -> True
+        Group  -> any H.importQualified imps
+        None   -> False
 
 
 --------------------------------------------------------------------------------
-step :: Bool -> Step
+step :: Align -> Step
 step = makeStep "Imports" . step'
 
 
 --------------------------------------------------------------------------------
-step' :: Bool -> Lines -> Module -> Lines
+step' :: Align -> Lines -> Module -> Lines
 step' align ls (module', _) = flip applyChanges ls
     [ change block (prettyImportGroup align longest importGroup)
     | (block, importGroup) <- groups
diff --git a/tests/StylishHaskell/Step/Imports/Tests.hs b/tests/StylishHaskell/Step/Imports/Tests.hs
index e86282f..45a821d 100644
--- a/tests/StylishHaskell/Step/Imports/Tests.hs
+++ b/tests/StylishHaskell/Step/Imports/Tests.hs
@@ -20,6 +20,7 @@ tests :: Test
 tests = testGroup "StylishHaskell.Step.Imports.Tests"
     [ case01
     , case02
+    , case03
     ]
 
 
@@ -32,7 +33,7 @@ input = unlines
     , "import Control.Monad"
     , "import       Data.Map     (lookup, (!), insert, Map)"
     , ""
-    , "import Herp.Derp.Internals"
+    , "import Herp.Derp.Internals hiding (foo)"
     , ""
     , "herp = putStrLn \"import Hello world\""
     ]
@@ -40,7 +41,7 @@ input = unlines
 
 --------------------------------------------------------------------------------
 case01 :: Test
-case01 = testCase "case 01" $ expected @=? testStep (step True) input
+case01 = testCase "case 01" $ expected @=? testStep (step Global) input
   where
     expected = unlines
         [ "module Herp where"
@@ -49,7 +50,7 @@ case01 = testCase "case 01" $ expected @=? testStep (step True) input
         , "import           Data.Map            (Map, insert, lookup, (!))"
         , "import qualified Data.Map            as M"
         , ""
-        , "import           Herp.Derp.Internals"
+        , "import           Herp.Derp.Internals hiding (foo)"
         , ""
         , "herp = putStrLn \"import Hello world\""
         ]
@@ -57,7 +58,24 @@ case01 = testCase "case 01" $ expected @=? testStep (step True) input
 
 --------------------------------------------------------------------------------
 case02 :: Test
-case02 = testCase "case 02" $ expected @=? testStep (step False) input
+case02 = testCase "case 02" $ expected @=? testStep (step Groups) input
+  where
+    expected = unlines
+        [ "module Herp where"
+        , ""
+        , "import           Control.Monad"
+        , "import           Data.Map      (Map, insert, lookup, (!))"
+        , "import qualified Data.Map      as M"
+        , ""
+        , "import Herp.Derp.Internals hiding (foo)"
+        , ""
+        , "herp = putStrLn \"import Hello world\""
+        ]
+
+
+--------------------------------------------------------------------------------
+case03 :: Test
+case03 = testCase "case 03" $ expected @=? testStep (step None) input
   where
     expected = unlines
         [ "module Herp where"
@@ -66,7 +84,7 @@ case02 = testCase "case 02" $ expected @=? testStep (step False) input
         , "import Data.Map (Map, insert, lookup, (!))"
         , "import qualified Data.Map as M"
         , ""
-        , "import Herp.Derp.Internals"
+        , "import Herp.Derp.Internals hiding (foo)"
         , ""
         , "herp = putStrLn \"import Hello world\""
         ]