genprimopcode: Applicative instance for ParserM

Signed-off-by: Austin Seipp <austin@well-typed.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/utils/genprimopcode/ParserM.hs b/utils/genprimopcode/ParserM.hs
index aaaf6ac66f..0a69db6b8f 100644
--- a/utils/genprimopcode/ParserM.hs
+++ b/utils/genprimopcode/ParserM.hs
@@ -16,13 +16,21 @@ module ParserM (
     -- Other
     happyError
  ) where
-
+import Control.Applicative
+import Control.Monad (ap, liftM)
 import Data.Word (Word8)
 import Data.Char (ord)
 
 -- Parser Monad
 newtype ParserM a = ParserM (AlexInput -> St -> Either String (AlexInput, St, a))
 
+instance Functor ParserM where
+  fmap = liftM
+
+instance Applicative ParserM where
+  pure  = return
+  (<*>) = ap
+
 instance Monad ParserM where
     ParserM m >>= k = ParserM $ \i s -> case m i s of
                                             Right (i', s', x) ->