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           Data.Eq (Eq)
   9 import           Data.Monoid (Monoid(..))
  10 import           Text.Show (Show)
  11 import           Prelude (seq)
  12
  13 -- * Type 'Clusive'
  14
  15 -- A data type to calculate an 'inclusive' value
  16 -- (through some propagation mecanism,
  17 -- eg. incorporating the values of the children of a tree node),
  18 -- while keeping the original 'exclusive' value
  19 -- (eg. the original value of a tree node).
  20 data Clusive a
  21  =   Clusive
  22  { exclusive :: !a
  23  , inclusive :: !a
  24  } deriving (Data, Eq, Show, Typeable)
  25 instance -- Monoid
  26  Monoid a
  27  => Monoid (Clusive a) where
  28         mempty = Clusive mempty mempty
  29         mappend (Clusive e0 i0) (Clusive e1 i1) =
  30                 Clusive (e0`mappend`e1) (i0`mappend`i1)
  31 instance -- NFData
  32  NFData a =>
  33  NFData (Clusive a) where
  34         rnf (Clusive e i)  = rnf e `seq` rnf i