Merge pull request #27 from slamdata/transformer-instances

Add MonadAff instances for transformers

Author: jdegoes

docs/Control.Monad.Aff.Class.md

@@ -10,6 +10,15 @@ class MonadAff e m where
 ##### Instances
 ``` purescript
 instance monadAffAff :: MonadAff e (Aff e)
+instance monadAffContT :: (Monad m, MonadAff eff m) => MonadAff eff (ContT r m)
+instance monadAffError :: (Monad m, MonadAff eff m) => MonadAff eff (ErrorT e m)
+instance monadAffExceptT :: (Monad m, MonadAff eff m) => MonadAff eff (ExceptT e m)
+instance monadAffListT :: (Monad m, MonadAff eff m) => MonadAff eff (ListT m)
+instance monadAffMaybe :: (Monad m, MonadAff eff m) => MonadAff eff (MaybeT m)
+instance monadAffReader :: (Monad m, MonadAff eff m) => MonadAff eff (ReaderT r m)
+instance monadAffRWS :: (Monad m, Monoid w, MonadAff eff m) => MonadAff eff (RWST r w s m)
+instance monadAffState :: (Monad m, MonadAff eff m) => MonadAff eff (StateT s m)
+instance monadAffWriter :: (Monad m, Monoid w, MonadAff eff m) => MonadAff eff (WriterT w m)
 ```
 
 

src/Control/Monad/Aff/Class.purs

@@ -1,9 +1,50 @@
 module Control.Monad.Aff.Class where
-  import Prelude (id)
+
+  import Prelude
+
   import Control.Monad.Aff
+  import Control.Monad.Cont.Trans (ContT())
+  import Control.Monad.Error.Trans (ErrorT())
+  import Control.Monad.Except.Trans (ExceptT())
+  import Control.Monad.List.Trans (ListT())
+  import Control.Monad.Maybe.Trans (MaybeT())
+  import Control.Monad.Reader.Trans (ReaderT())
+  import Control.Monad.RWS.Trans (RWST())
+  import Control.Monad.State.Trans (StateT())
+  import Control.Monad.Trans (lift)
+  import Control.Monad.Writer.Trans (WriterT())
+
+  import Data.Monoid (Monoid)
 
   class MonadAff e m where
     liftAff :: forall a. Aff e a -> m a
 
   instance monadAffAff :: MonadAff e (Aff e) where
     liftAff = id
+
+  instance monadAffContT :: (Monad m, MonadAff eff m) => MonadAff eff (ContT r m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffError :: (Monad m, MonadAff eff m) => MonadAff eff (ErrorT e m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffExceptT :: (Monad m, MonadAff eff m) => MonadAff eff (ExceptT e m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffListT :: (Monad m, MonadAff eff m) => MonadAff eff (ListT m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffMaybe :: (Monad m, MonadAff eff m) => MonadAff eff (MaybeT m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffReader :: (Monad m, MonadAff eff m) => MonadAff eff (ReaderT r m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffRWS :: (Monad m, Monoid w, MonadAff eff m) => MonadAff eff (RWST r w s m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffState :: (Monad m, MonadAff eff m) => MonadAff eff (StateT s m) where
+    liftAff = lift <<< liftAff
+
+  instance monadAffWriter :: (Monad m, Monoid w, MonadAff eff m) => MonadAff eff (WriterT w m) where
+    liftAff = lift <<< liftAff