Move EventM from Brick.Types to Brick.Types.EventM, stop exporting internals of EventM

brick.cabal

@@ -108,6 +108,7 @@ library
   other-modules:
     Brick.Types.Common
     Brick.Types.TH
+    Brick.Types.EventM
     Brick.Types.Internal
     Brick.Widgets.Internal
 

src/Brick/Main.hs

@@ -79,7 +79,7 @@ import Graphics.Vty
 import Graphics.Vty.Attributes (defAttr)
 
 import Brick.BChan (BChan, newBChan, readBChan, readBChan2, writeBChan)
-import Brick.Types (EventM(..))
+import Brick.Types.EventM
 import Brick.Types.Internal
 import Brick.Widgets.Internal
 import Brick.AttrMap

src/Brick/Types.hs

@@ -1,9 +1,6 @@
 -- | Basic types used by this library.
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE RankNTypes #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 module Brick.Types
   ( -- * The Widget type
@@ -30,7 +27,7 @@ module Brick.Types
   , ClickableScrollbarElement(..)
 
   -- * Event-handling types
-  , EventM(..)
+  , EventM
   , BrickEvent(..)
   , withLens
   , nestEventM
@@ -104,7 +101,6 @@ where
 import Lens.Micro (_1, _2, to, (^.), Lens')
 import Lens.Micro.Type (Getting)
 import Lens.Micro.Mtl ((.=), use)
-import Control.Monad.Catch (MonadThrow, MonadCatch, MonadMask)
 #if !MIN_VERSION_base(4,13,0)
 import Control.Monad.Fail (MonadFail)
 #endif
@@ -114,6 +110,7 @@ import Graphics.Vty (Attr)
 
 import Brick.Types.TH
 import Brick.Types.Internal
+import Brick.Types.EventM
 import Brick.AttrMap (AttrName, attrMapLookup)
 
 -- | The type of padding.
@@ -169,20 +166,6 @@ withLens target act = do
     target .= val'
     return result
 
--- | The monad in which event handlers run. Although it may be tempting
--- to dig into the reader value yourself, just use
--- 'Brick.Main.lookupViewport'.
-newtype EventM n s a =
-    EventM { runEventM :: ReaderT (EventRO n) (StateT (EventState n s) IO) a
-           }
-           deriving ( Functor, Applicative, Monad, MonadIO
-                    , MonadThrow, MonadCatch, MonadMask, MonadFail
-                    )
-
-instance MonadState s (EventM n s) where
-    get = EventM $ lift $ gets applicationState
-    put s = EventM $ lift $ modify $ \es -> es { applicationState = s }
-
 -- | The rendering context's current drawing attribute.
 attrL :: forall r n. Getting r (Context n) Attr
 attrL = to (\c -> attrMapLookup (c^.ctxAttrNameL) (c^.ctxAttrMapL))

src/Brick/Types/EventM.hs

@@ -0,0 +1,28 @@
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE FlexibleInstances #-}
+module Brick.Types.EventM
+  ( EventM(..)
+  )
+where
+
+import Control.Monad.Catch (MonadThrow, MonadCatch, MonadMask)
+import Control.Monad.Reader
+import Control.Monad.State.Strict
+
+import Brick.Types.Internal
+
+-- | The monad in which event handlers run. Although it may be tempting
+-- to dig into the reader value yourself, just use
+-- 'Brick.Main.lookupViewport'.
+newtype EventM n s a =
+    EventM { runEventM :: ReaderT (EventRO n) (StateT (EventState n s) IO) a
+           }
+           deriving ( Functor, Applicative, Monad, MonadIO
+                    , MonadThrow, MonadCatch, MonadMask, MonadFail
+                    )
+
+instance MonadState s (EventM n s) where
+    get = EventM $ lift $ gets applicationState
+    put s = EventM $ lift $ modify $ \es -> es { applicationState = s }
+