Add SIMonadTrans.

Control/SemiIso/Trans.hs

@@ -0,0 +1,23 @@
+{- |
+Module      :  Control.SemiIso.Trans
+Description :  SemiIsoMonad transformers.
+Copyright   :  (c) Paweł Nowak
+License     :  MIT
+
+Maintainer  :  Paweł Nowak <pawel834@gmail.com>
+Stability   :  experimental
+
+Monad transformers for the SemiIso hierarchy.
+-}
+module Control.SemiIso.Trans where
+
+import Data.SemiIsoFunctor
+
+-- | Monad transformer. Should satisfy laws:
+--
+-- prop> silift . sipure = sipure
+--
+-- prop> silift (m //= f) = silift m //= (silift . f)
+class SIMonadTrans t where
+    -- | Lifts a computation from the base monad.
+    silift :: SemiIsoMonad m => m a -> t m a

semi-iso.cabal

@@ -22,6 +22,7 @@ source-repository head
 library
   exposed-modules:     Control.Lens.SemiIso
                        Control.Lens.Internal.SemiIso
+                       Control.SemiIso.Trans
                        Data.SemiIsoFunctor
                        Data.Profunctor.Exposed
   build-depends:       base >= 4 && < 5, profunctors, transformers, lens, tuple-morph