lib/Hcompta/Lib/Strict.hs

   1 {-# LANGUAGE DeriveDataTypeable #-}
   2 {-# LANGUAGE StandaloneDeriving #-}
   3 {-# OPTIONS_GHC -fno-warn-deprecations #-} -- FIXME: to be removed when dropping GHC-7.6 support
   4 {-# OPTIONS_GHC -fno-warn-orphans #-}
   5 module Hcompta.Lib.Strict where
   6
   7 import           Control.DeepSeq (NFData(..))
   8 import           Data.Data
   9 import           Data.Monoid (Monoid(..))
  10 import qualified Data.Strict.Maybe as Strict
  11
  12 deriving instance Data x => Data (Strict.Maybe x)
  13 deriving instance Typeable1 Strict.Maybe
  14 instance Monoid x => Monoid (Strict.Maybe x) where
  15         mempty = Strict.Nothing
  16         mappend (Strict.Just x) (Strict.Just y) = Strict.Just (x `mappend` y)
  17         mappend x Strict.Nothing = x
  18         mappend Strict.Nothing y = y
  19 instance NFData x => NFData (Strict.Maybe x) where
  20         rnf Strict.Nothing = ()
  21         rnf (Strict.Just x) = rnf x