lib/Hcompta/Lib/Strict.hs

   1 {-# LANGUAGE DeriveDataTypeable #-}
   2 {-# LANGUAGE StandaloneDeriving #-}
   3 {-# OPTIONS_GHC -fno-warn-orphans #-}
   4 module Hcompta.Lib.Strict where
   5
   6 import           Control.DeepSeq (NFData(..))
   7 import           Data.Data
   8 import qualified Data.Strict.Maybe as Strict
   9
  10 deriving instance Data x => Data (Strict.Maybe x)
  11 instance Monoid x => Monoid (Strict.Maybe x) where
  12         mempty = Strict.Nothing
  13         mappend (Strict.Just x) (Strict.Just y) = Strict.Just (x `mappend` y)
  14         mappend x Strict.Nothing = x
  15         mappend Strict.Nothing y = y
  16 instance NFData x => NFData (Strict.Maybe x) where
  17         rnf Strict.Nothing = ()
  18         rnf (Strict.Just x) = rnf x