Add fourmolu plugin

Author: georgefst

exe/Main.hs

@@ -94,6 +94,7 @@ import Ide.Plugin.Example2                as Example2
 import Ide.Plugin.GhcIde                  as GhcIde
 import Ide.Plugin.Floskell                as Floskell
 import Ide.Plugin.Ormolu                  as Ormolu
+import Ide.Plugin.Fourmolu                as Fourmolu
 import Ide.Plugin.StylishHaskell          as StylishHaskell
 #if AGPL
 import Ide.Plugin.Brittany                as Brittany
@@ -129,6 +130,7 @@ idePlugins includeExamples = pluginDescToIdePlugins allPlugins
       , Floskell.descriptor "floskell"
       -- , genericDescriptor     "generic"
       -- , ghcmodDescriptor      "ghcmod"
+      , Fourmolu.descriptor "fourmolu"
       , Ormolu.descriptor   "ormolu"
       , StylishHaskell.descriptor "stylish-haskell"
 #if AGPL

haskell-language-server.cabal

@@ -44,6 +44,7 @@ library
       Ide.Plugin.Config
       Ide.Plugin.Example
       Ide.Plugin.Example2
+      Ide.Plugin.Fourmolu
       Ide.Plugin.GhcIde
       Ide.Plugin.Ormolu
       Ide.Plugin.Pragmas
@@ -72,6 +73,7 @@ library
     , extra
     , filepath
     , floskell == 0.10.*
+    , fourmolu ^>= 0.0.6.0
     , ghc
     , ghcide >= 0.1
     , gitrev

src/Ide/Plugin/Fourmolu.hs

@@ -0,0 +1,78 @@
+{-# LANGUAGE PackageImports #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE ViewPatterns #-}
+
+module Ide.Plugin.Fourmolu
+  (
+    descriptor
+  , provider
+  )
+where
+
+import           Control.Exception
+import qualified Data.Text as T
+import           Development.IDE.Core.Rules
+import           Development.IDE.Types.Diagnostics as D
+import           Development.IDE.Types.Location
+import qualified DynFlags as D
+import qualified EnumSet  as S
+import           GHC
+import           Ide.Types
+import           Ide.PluginUtils
+import           Ide.Plugin.Formatter
+import           Language.Haskell.LSP.Types
+import "fourmolu" Ormolu
+import           Text.Regex.TDFA.Text()
+
+-- ---------------------------------------------------------------------
+
+descriptor :: PluginId -> PluginDescriptor
+descriptor plId = (defaultPluginDescriptor plId)
+  { pluginFormattingProvider = Just provider
+  }
+
+-- ---------------------------------------------------------------------
+
+provider :: FormattingProvider IO
+provider _lf ideState typ contents fp _ = do
+  let
+    fromDyn :: ParsedModule -> IO [DynOption]
+    fromDyn pmod =
+      let
+        df = ms_hspp_opts $ pm_mod_summary pmod
+        pp =
+          let p = D.sPgm_F $ D.settings df
+          in  if null p then [] else ["-pgmF=" <> p]
+        pm = map (("-fplugin=" <>) . moduleNameString) $ D.pluginModNames df
+        ex = map (("-X" <>) . show) $ S.toList $ D.extensionFlags df
+      in
+        return $ map DynOption $ pp <> pm <> ex
+
+  m_parsed <- runAction "Fourmolu" ideState $ getParsedModule fp
+  fileOpts <- case m_parsed of
+          Nothing -> return []
+          Just pm -> fromDyn pm
+
+  let
+    fullRegion = RegionIndices Nothing Nothing
+    rangeRegion s e = RegionIndices (Just s) (Just e)
+    mkConf o region = defaultConfig { cfgDynOptions = o,  cfgRegion = region }
+    fmt :: T.Text -> Config RegionIndices -> IO (Either OrmoluException T.Text)
+    fmt cont conf =
+      try @OrmoluException (ormolu conf (fromNormalizedFilePath fp) $ T.unpack cont)
+
+  case typ of
+    FormatText -> ret <$> fmt contents (mkConf fileOpts fullRegion)
+    FormatRange r ->
+      let
+        Range (Position sl _) (Position el _) = normalize r
+      in
+        ret <$> fmt contents (mkConf fileOpts (rangeRegion sl el))
+ where
+  ret :: Either OrmoluException T.Text -> Either ResponseError (List TextEdit)
+  ret (Left err) = Left
+    (responseError (T.pack $ "fourmoluCmd: " ++ show err) )
+  ret (Right new) = Right (makeDiffTextEdit contents new)

src/Ide/Plugin/Ormolu.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE PackageImports #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -23,7 +24,7 @@ import           Ide.Types
 import           Ide.PluginUtils
 import           Ide.Plugin.Formatter
 import           Language.Haskell.LSP.Types
-import           Ormolu
+import "ormolu"  Ormolu
 import           Text.Regex.TDFA.Text()
 
 -- ---------------------------------------------------------------------