module GHC.Cmm.Monad (
PD(..)
, liftP
, failMsgPD
) where
import GHC.Prelude
import Control.Monad
import GHC.Driver.Session
import GHC.Parser.Lexer
newtype PD a = PD { unPD :: DynFlags -> PState -> ParseResult a }
instance Functor PD where
fmap = liftM
instance Applicative PD where
pure = returnPD
(<*>) = ap
instance Monad PD where
(>>=) = thenPD
liftP :: P a -> PD a
liftP (P f) = PD $ \_ s -> f s
failMsgPD :: String -> PD a
failMsgPD = liftP . failMsgP
returnPD :: a -> PD a
returnPD = liftP . return
thenPD :: PD a -> (a -> PD b) -> PD b
(PD m) `thenPD` k = PD $ \d s ->
case m d s of
POk s1 a -> unPD (k a) d s1
PFailed s1 -> PFailed s1
instance HasDynFlags PD where
getDynFlags = PD $ \d s -> POk s d