From 68eee5e258571a7c953916272841c3defa1b0ac4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Nowak?= <pawel834@gmail.com>
Date: Tue, 25 Nov 2014 22:39:16 +0100
Subject: [PATCH] Add SIMonadTrans.

---
 Control/SemiIso/Trans.hs | 23 +++++++++++++++++++++++
 semi-iso.cabal           |  1 +
 2 files changed, 24 insertions(+)
 create mode 100644 Control/SemiIso/Trans.hs

diff --git a/Control/SemiIso/Trans.hs b/Control/SemiIso/Trans.hs
new file mode 100644
index 0000000..1961179
--- /dev/null
+++ b/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
diff --git a/semi-iso.cabal b/semi-iso.cabal
index 08da64c..278be65 100644
--- a/semi-iso.cabal
+++ b/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