Add back transformers 0.1.* support

Yesod.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE PackageImports #-}
 module Yesod
     (
       module Yesod.Request
@@ -35,4 +36,8 @@ import Yesod.Handler hiding (runHandler)
 import Network.Wai (Application, Method (..))
 import Yesod.Hamlet
 import Data.Convertible.Text (cs)
-import Control.Monad.IO.Class (liftIO)
+#if TRANSFORMERS_02
+import "transformers" Control.Monad.IO.Class (liftIO)
+#else
+import "transformers" Control.Monad.Trans (liftIO)
+#endif

Yesod/Form.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE PackageImports #-}
+{-# LANGUAGE CPP #-}
 -- | Parse forms (and query strings).
 module Yesod.Form
     ( Form (..)
@@ -26,7 +27,11 @@ import Data.Time (Day)
 import Data.Convertible.Text
 import Control.Monad.Attempt
 import Data.Maybe (fromMaybe)
-import "transformers" Control.Monad.IO.Class (MonadIO)
+#if TRANSFORMERS_02
+import "transformers" Control.Monad.IO.Class
+#else
+import "transformers" Control.Monad.Trans
+#endif
 import Yesod.Internal
 
 noParamNameError :: String

Yesod/Handler.hs

@@ -6,6 +6,7 @@
 {-# LANGUAGE PackageImports #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE Rank2Types #-}
+{-# LANGUAGE CPP #-}
 ---------------------------------------------------------
 --
 -- Module        : Yesod.Handler
@@ -56,7 +57,11 @@ import Web.Mime
 import Control.Exception hiding (Handler)
 import Control.Applicative
 
+#if TRANSFORMERS_02
 import "transformers" Control.Monad.IO.Class
+#else
+import "transformers" Control.Monad.Trans
+#endif
 import Control.Monad.Attempt
 import Control.Monad (liftM, ap)
 

Yesod/Request.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE PackageImports #-}
+{-# LANGUAGE CPP #-}
 ---------------------------------------------------------
 --
 -- Module        : Yesod.Request
@@ -37,7 +38,11 @@ import qualified Network.Wai as W
 import Yesod.Definitions
 import Web.Encodings
 import qualified Data.ByteString.Lazy as BL
+#if TRANSFORMERS_02
 import "transformers" Control.Monad.IO.Class
+#else
+import "transformers" Control.Monad.Trans
+#endif
 import Control.Monad (liftM)
 
 type ParamName = String

yesod.cabal

@@ -19,6 +19,8 @@ extra-source-files: CLI/skel/App.hs,
                     CLI/skel/templates/layout.st,
                     CLI/skel/templates/homepage.st
 
+flag transformers_02
+    description: transformers = 0.2.*
 flag buildtests
   description: Build the executable to run unit tests
   default: False
@@ -38,14 +40,13 @@ library
         Buildable: True
     build-depends:   base >= 4 && < 5,
                      time >= 1.1.3 && < 1.2,
-                     wai >= 0.2.0 && < 0.3,
-                     wai-extra >= 0.0.0 && < 0.3,
+                     wai >= 0.0.0 && < 0.3,
+                     wai-extra >= 0.0.0 && < 0.1,
                      authenticate >= 0.6 && < 0.7,
                      bytestring >= 0.9.1.4 && < 0.10,
-                     web-encodings >= 0.2.4 && < 0.5,
+                     web-encodings >= 0.2.4 && < 0.3,
                      data-object >= 0.2.0 && < 0.3,
                      directory >= 1 && < 1.1,
-                     transformers >= 0.2.0 && < 0.3,
                      control-monad-attempt >= 0.2.0 && < 0.3,
                      text >= 0.5 && < 0.8,
                      convertible-text >= 0.2.0 && < 0.3,
@@ -53,6 +54,11 @@ library
                      web-routes >= 0.22 && < 0.23,
                      web-routes-quasi >= 0.0 && < 0.1,
                      hamlet >= 0.0 && < 0.1
+    if flag(transformers_02)
+      build-depends: transformers >= 0.2 && < 0.3
+      CPP-OPTIONS: -DTRANSFORMERS_02
+    else
+      build-depends: transformers >= 0.1 && < 0.2
     exposed-modules: Yesod
                      Yesod.Content
                      Yesod.Definitions