1 files changed, 37 insertions, 0 deletions
diff --git a/src/Text/Pandoc/Compat/Except.hs b/src/Text/Pandoc/Compat/Except.hs
new file mode 100644
index 000000000..9ce7c0d36
--- /dev/null
+++ b/src/Text/Pandoc/Compat/Except.hs
@@ -0,0 +1,37 @@
+{-# LANGUAGE CPP #-}
+module Text.Pandoc.Compat.Except ( ExceptT
+                                 , Except
+                                 , Error(..)
+                                 , runExceptT
+                                 , runExcept
+                                 , MonadError
+                                 , throwError
+                                 , catchError )
+       where
+
+#if MIN_VERSION_mtl(2,2,1)
+import Control.Monad.Except
+
+class Error a where
+  noMsg  :: a
+  strMsg :: String -> a
+
+  noMsg    = strMsg ""
+  strMsg _ = noMsg
+
+#else
+import Control.Monad.Error
+import Control.Monad.Identity (Identity, runIdentity)
+
+type ExceptT = ErrorT
+
+type Except s a = ErrorT s Identity a
+
+runExceptT ::  ExceptT e m a -> m (Either e a)
+runExceptT = runErrorT
+
+runExcept :: ExceptT e Identity a -> Either e a
+runExcept = runIdentity . runExceptT
+#endif
+
+