-import EXCEPTION ( throwDyn )
-import DATA_IOREF
-import UNSAFE_IO ( unsafePerformIO )
-import Monad ( when )
-import Char ( isDigit )
-import List ( sort, intersperse )
+import Control.Exception ( throwDyn )
+import Data.IORef
+import System.IO.Unsafe ( unsafePerformIO )
+import Control.Monad ( when )
+import Data.Char ( isDigit )
+import Data.List ( sort, intersperse, nub )