From 67eee0be14c2966e9dcf6f4127e75da16b9942b7 Mon Sep 17 00:00:00 2001
From: Martin Perner <martin@perner.cc>
Date: Thu, 3 Nov 2011 15:36:17 +0100
Subject: fix for ghc6

added applicative instance for ReaderT which was added in GHC7
---
 src/Plugins/Monitors/CoreCommon.hs | 13 +++++++++++--
 xmobar.cabal                       |  4 ++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/Plugins/Monitors/CoreCommon.hs b/src/Plugins/Monitors/CoreCommon.hs
index e508f7d..eb3e17f 100644
--- a/src/Plugins/Monitors/CoreCommon.hs
+++ b/src/Plugins/Monitors/CoreCommon.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE PatternGuards #-}
+{-# LANGUAGE PatternGuards, CPP #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -25,6 +25,15 @@ import Data.Maybe
 import Plugins.Monitors.Common
 import System.Directory
 
+#ifdef GHC6
+import Control.Monad.Reader
+
+instance (Monad f, Applicative f) => Applicative (ReaderT r f) where
+    pure a = ReaderT $ const (pure a)
+    f <*> a = ReaderT $ \r -> 
+              ((runReaderT f r) <*> (runReaderT a r))
+#endif
+
 checkedDataRetrieval :: (Ord a, Num a)
                      => String -> [String] -> Maybe (String, String -> Int)
                      -> (Double -> a) -> (a -> String) -> Monitor String
@@ -131,4 +140,4 @@ readFiles (fval, flbl) = (,) <$> either return (\(f, ex) -> liftM ex
 
 -- | Function that captures if-then-else
 ifthen :: a -> a -> Bool -> a
-ifthen thn els cnd = if cnd then thn else els
\ No newline at end of file
+ifthen thn els cnd = if cnd then thn else els
diff --git a/xmobar.cabal b/xmobar.cabal
index 56cbce3..029dce8 100644
--- a/xmobar.cabal
+++ b/xmobar.cabal
@@ -91,6 +91,10 @@ executable xmobar
     if impl (ghc >= 6.12.1)
        ghc-options: -fno-warn-unused-do-bind
 
+    --  for instance declaration in src/Plugins/Monitors/CoreCommon.hs
+    if impl (ghc < 7)
+       cpp-options: -DGHC6
+
     build-depends: X11>=1.3.0, mtl, unix, parsec, filepath, stm, time
 
     if flag(small_base)
-- 
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