a6f041c · streamly · git.iko.soy

git.iko.soy/streamly

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Add scanMany to Fold

a6f041cRanjeet Kumar Ranjan5 years ago

benchmark/Streamly/Benchmark/Data/Fold.hs+4

compare with master

unifiedsplit

@@ -373,6 +373,10 @@ o_1_space_serial_transformation value =

373 value

374 "fold-scan"

375 (S.fold $ FL.scan FL.sum FL.drain)

376+ , benchIOSink

377+ value

378+ "fold-scanMany"

379+ (S.fold $ FL.scanMany (FL.take 2 FL.drain) FL.drain)

376 , benchIOSink

380 , benchIOSink

377 value

381 value

378 "fold-postscan"

382 "fold-postscan"

core/src/Streamly/Internal/Data/Fold.hs+27−10

@@ -126,6 +126,7 @@ module Streamly.Internal.Data.Fold

126 --, lsequence

127 , lmapM

128 , scan

129+ , scanMany

129 , postscan

130 , postscan

130 , indexed

131 , indexed

131

132

@@ -292,10 +293,9 @@ import qualified Data.IntSet as IntSet

292import qualified Data.Map.Strict as Map

293import qualified Data.Map.Strict as Map

293import qualified Data.Set as Set

294import qualified Data.Set as Set

294import qualified Streamly.Internal.Data.IsMap as IsMap

295import qualified Streamly.Internal.Data.IsMap as IsMap

296+import qualified Prelude

295import qualified Streamly.Internal.Data.Pipe.Type as Pipe

297import qualified Streamly.Internal.Data.Pipe.Type as Pipe

296import qualified Streamly.Internal.Data.Stream.StreamD.Type as StreamD

298import qualified Streamly.Internal.Data.Stream.StreamD.Type as StreamD

297−-- import qualified Streamly.Internal.Data.Stream.IsStream.Enumeration as Stream

298−import qualified Prelude

299

300import Prelude hiding

301 ( filter, foldl1, drop, dropWhile, take, takeWhile, zipWith

@@ -417,17 +417,13 @@ transform (Pipe pstep1 pstep2 pinitial) (Fold fstep finitial fextract) =

417

418 extract (Tuple' _ fs) = fextract fs

419

420−-- | Scan the input of a 'Fold' to change it in a stateful manner using another

421−-- 'Fold'.

422−-- /Pre-release/

423−{-# INLINE scan #-}

420+{-# INLINE scanWith #-}

424−scan :: Monad m => Fold m a b -> Fold m b c -> Fold m a c

421+scanWith :: Monad m => Bool -> Fold m a b -> Fold m b c -> Fold m a c

425−scan (Fold stepL initialL extractL) (Fold stepR initialR extractR) =

422+scanWith isMany (Fold stepL initialL extractL) (Fold stepR initialR extractR) =

426 Fold step initial extract

423 Fold step initial extract

427

424

428 where

425 where

429

426

430− -- XXX It can be moved out and used for both scan and postscan

431 {-# INLINE runStep #-}

427 {-# INLINE runStep #-}

432 runStep actionL sR = do

428 runStep actionL sR = do

433 rL <- actionL

429 rL <- actionL

@@ -435,7 +431,10 @@ scan (Fold stepL initialL extractL) (Fold stepR initialR extractR) =

435 Done bL -> do

431 Done bL -> do

436 rR <- stepR sR bL

432 rR <- stepR sR bL

437 case rR of

433 case rR of

434+ Partial sR1 ->

435+ if isMany

436+ then runStep initialL sR1

438− Partial sR1 -> Done <$> extractR sR1

437+ else Done <$> extractR sR1

439 Done bR -> return $ Done bR

438 Done bR -> return $ Done bR

440 Partial sL -> do

439 Partial sL -> do

441 !b <- extractL sL

440 !b <- extractL sL

@@ -455,6 +454,24 @@ scan (Fold stepL initialL extractL) (Fold stepR initialR extractR) =

455

454

456 extract = extractR . snd

455 extract = extractR . snd

457

456

457+-- | Scan the input of a 'Fold' to change it in a stateful manner using another

458+-- 'Fold'. The scan stops as soon as the fold terminates.

459+--

460+-- /Pre-release/

461+{-# INLINE scan #-}

462+scan :: Monad m => Fold m a b -> Fold m b c -> Fold m a c

463+scan = scanWith False

464+

465+-- XXX This does not fuse beacuse of the recursive step. Need to investigate.

466+--

467+-- | Scan the input of a 'Fold' to change it in a stateful manner using another

468+-- 'Fold'. The scan restarts with a fresh state if the fold terminates.

469+--

470+-- /Pre-release/

471+{-# INLINE scanMany #-}

472+scanMany :: Monad m => Fold m a b -> Fold m b c -> Fold m a c

473+scanMany = scanWith True

474+

458-- | Postscan the input of a 'Fold' to change it in a stateful manner using

475-- | Postscan the input of a 'Fold' to change it in a stateful manner using

459-- another 'Fold'.

476-- another 'Fold'.

460-- /Pre-release/

477-- /Pre-release/