{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE CPP, TemplateHaskell #-}
module GHC.Check.Util (MyVersion(..), liftTyped) where
import Data.Maybe
import Data.Version
import GHC.Exts (IsList (fromList), toList)
import qualified GHC.Paths
import Language.Haskell.TH
import Language.Haskell.TH.Syntax as TH
import System.Environment (lookupEnv)
newtype MyVersion = MyVersion Version
deriving (Eq, IsList, Show)
instance Lift MyVersion where
#if MIN_VERSION_template_haskell(2,16,0)
liftTyped = liftMyVersion
#endif
lift = unTypeQ . liftMyVersion
liftMyVersion :: MyVersion -> TExpQ MyVersion
liftMyVersion ver = do
verLifted <- TH.lift (toList ver)
[|| fromList $$(pure $ TExp verLifted) ||]
#if !MIN_VERSION_template_haskell(2,16,0)
liftTyped :: Lift a => a -> TExpQ a
liftTyped = unsafeTExpCoerce . lift
#endif