Add MonadLogic instence for ReaderT

src/Control/Monad/Logic/Class.purs

@@ -3,8 +3,8 @@ module Control.Monad.Logic.Class (class MonadLogic, msplit, interleave, fbind, r
 import Prelude
 
 import Control.MonadPlus (class MonadPlus, (<|>), empty)
-import Control.Monad.State (runStateT)
-import Control.Monad.State.Trans (StateT(..))
+import Control.Monad.State.Trans (StateT(..), runStateT)
+import Control.Monad.Reader.Trans (ReaderT(..), runReaderT)
 import Data.Tuple.Nested (type (/\), (/\))
 import Data.Maybe (Maybe(..))
 
@@ -32,3 +32,10 @@ instance MonadLogic m => MonadLogic (StateT s m) where
             Nothing -> pure (Nothing /\ s)
             Just ((a /\ s') /\ m) -> pure (Just (a /\ (StateT $ const m)) /\ s')
     interleave m1 m2 = StateT $ \s -> runStateT m1 s <|> runStateT m2 s
+
+instance MonadLogic m => MonadLogic (ReaderT r m) where
+    msplit sm = ReaderT $ \r -> do
+        msplit (runReaderT sm r) >>= case _ of
+            Nothing -> pure Nothing
+            Just (a /\ m) -> pure $ Just $ a /\ (ReaderT $ const m)
+    interleave m1 m2 = ReaderT $ \r -> runReaderT m1 r <|> runReaderT m2 r