d68e0e6 · streamly · git.iko.soy

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Simplify fold and foldBreak implementation

d68e0e6Harendra Kumar4 years ago

src/Streamly/Internal/Data/Stream/IsStream/Common.hs+9−7

@@ -75,7 +75,7 @@ import Streamly.Internal.Data.Fold.Type (Fold (..))

75import Streamly.Internal.Data.Stream.IsStream.Combinators (maxYields)

76import Streamly.Internal.Data.Stream.IsStream.Type

77 (IsStream(..), fromStreamD, toStreamD, fromStreamS, toStreamS)

78−import Streamly.Internal.Data.Stream.Serial (SerialT)

78+import Streamly.Internal.Data.Stream.Serial (SerialT(..))

79import Streamly.Internal.Data.Time.Units (AbsTime, RelTime64, addToAbsTime64)

81import qualified Streamly.Internal.Data.Array.Foreign.Type as A

@@ -307,15 +307,17 @@ foldContinue f s = D.foldContinue f $ IsStream.toStreamD s

307-- @since 0.7.0

308{-# INLINE fold #-}

309fold :: Monad m => Fold m a b -> SerialT m a -> m b

310−fold fl strm = do

310+fold fl (SerialT strm) = D.fold fl $ D.fromStreamK strm

311− (b, _) <- foldBreak fl strm

312− return $! b

313

311

312+-- XXX This shows quadratic performance when used recursively perhaps because

313+-- of StreamK to StreamD conversions not getting eliminated sue to recursion.

314{-# INLINE foldBreak #-}

315foldBreak :: Monad m => Fold m a b -> SerialT m a -> m (b, SerialT m a)

316−foldBreak fl strm = do

316+foldBreak fl (SerialT strm) = fmap f $ D.foldBreak fl $ D.fromStreamK strm

317− (b, str) <- D.foldBreak fl $ IsStream.toStreamD strm

317+

318− return $! (b, IsStream.fromStreamD str)

318+ where

319+

320+ f (b, str) = (b, SerialT (D.toStreamK str))

319

321

320------------------------------------------------------------------------------

322------------------------------------------------------------------------------

321-- Transformation

323-- Transformation