src/Streamly/Strict.hs · streamly

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streamly/src/Streamly/Strict.hs

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1-- |

2-- Module : Streamly.Strict

5-- License : BSD3

6-- Maintainer : harendra.kumar@gmail.com

7-- Stability : experimental

8-- Portability : GHC

9--

10-- | Strict data types to be used as accumulator for strict left folds and

11-- scans. For more comprehensive strict data types see

12-- https://hackage.haskell.org/package/strict-base-types . The names have been

13-- suffixed by a prime so that programmers can easily distinguish the strict

14-- versions from the lazy ones.

15--

16-- One major advantage of strict data structures as accumulators in folds and

17-- scans is that it helps the compiler optimize the code much better by

18-- unboxing. In a big tight loop the difference could be huge.

19--

20module Streamly.Strict

21 (

22 Tuple' (..)

23 , Tuple3' (..)

24 , Maybe' (..)

25 , fromStrictMaybe

26 , Either' (..)

27 )

28where

30-------------------------------------------------------------------------------

31-- Tuples

32-------------------------------------------------------------------------------

33--

34data Tuple' a b = Tuple' !a !b

35data Tuple3' a b c = Tuple3' !a !b !c

37-------------------------------------------------------------------------------

38-- Maybe

39-------------------------------------------------------------------------------

40--

41-- | A strict 'Maybe'

42data Maybe' a = Just' !a | Nothing'

44-- XXX perhaps we can use a type class having fromStrict/toStrict operations.

45--

46-- | Convert strict Maybe' to lazy Maybe

47{-# INLINABLE fromStrictMaybe #-}

48fromStrictMaybe :: Monad m => Maybe' a -> m (Maybe a)

49fromStrictMaybe Nothing' = return $ Nothing

50fromStrictMaybe (Just' a) = return $ Just a

52-------------------------------------------------------------------------------

53-- Either

54-------------------------------------------------------------------------------

55--

56-- | A strict 'Either'

57data Either' a b = Left' !a | Right' !b