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+--------------------------------------------------------------------------------
+-- | There are a number of steps that sort items: 'Imports' and 'ModuleHeader',
+-- and maybe more in the future. This module provides consistent sorting
+-- utilities.
+{-# LANGUAGE LambdaCase #-}
+module Language.Haskell.Stylish.Ordering
+ ( compareLIE
+ , compareWrappedName
+ , unwrapName
+ ) where
+
+
+--------------------------------------------------------------------------------
+import Data.Char (isUpper)
+import Data.Ord (comparing)
+import GHC.Hs
+import RdrName (RdrName)
+import SrcLoc (unLoc)
+
+
+--------------------------------------------------------------------------------
+import Language.Haskell.Stylish.GHC (showOutputable)
+import Outputable (Outputable)
+
+
+--------------------------------------------------------------------------------
+-- | NOTE: Can we get rid off this by adding a properly sorting newtype around
+-- 'RdrName'?
+compareLIE :: LIE GhcPs -> LIE GhcPs -> Ordering
+compareLIE = comparing $ ieKey . unLoc
+ where
+ -- | The implementation is a bit hacky to get proper sorting for input specs:
+ -- constructors first, followed by functions, and then operators.
+ ieKey :: IE GhcPs -> (Int, String)
+ ieKey = \case
+ IEVar _ n -> nameKey n
+ IEThingAbs _ n -> nameKey n
+ IEThingAll _ n -> nameKey n
+ IEThingWith _ n _ _ _ -> nameKey n
+ IEModuleContents _ n -> nameKey n
+ _ -> (2, "")
+
+
+--------------------------------------------------------------------------------
+compareWrappedName :: IEWrappedName RdrName -> IEWrappedName RdrName -> Ordering
+compareWrappedName = comparing nameKey
+
+
+--------------------------------------------------------------------------------
+unwrapName :: IEWrappedName n -> n
+unwrapName (IEName n) = unLoc n
+unwrapName (IEPattern n) = unLoc n
+unwrapName (IEType n) = unLoc n
+
+
+--------------------------------------------------------------------------------
+nameKey :: Outputable name => name -> (Int, String)
+nameKey n = case showOutputable n of
+ o@('(' : _) -> (2, o)
+ o@(o0 : _) | isUpper o0 -> (0, o)
+ o -> (1, o)