ed85ad8 · streamly · git.iko.soy

git.iko.soy/streamly

on master help sign in

Add a foldStream signature

ed85ad8Harendra Kumar4 years ago

core/src/Streamly/Internal/Data/Fold/Type.hs+12

compare with master

unifiedsplit

@@ -411,6 +411,7 @@ module Streamly.Internal.Data.Fold.Type

411 , snoc

412 , duplicate

413 , finish

414+ , isDone

414 )

415 )

415where

416where

416

417

@@ -1429,6 +1430,17 @@ finish (Fold _ initial extract) = do

1429 Partial fs -> extract fs

1430 Partial fs -> extract fs

1430 Done b -> return b

1431 Done b -> return b

1431

1432

1433+-- | Check if the fold is done and can take no more input.

1434+--

1435+-- /Pre-release/

1436+{-# INLINE isDone #-}

1437+isDone :: Monad m => Fold m a b -> m (Maybe b)

1438+isDone (Fold _ initial _) = do

1439+ res <- initial

1440+ return $ case res of

1441+ Partial _ -> Nothing

1442+ Done b -> Just b

1443+

1432------------------------------------------------------------------------------

1444------------------------------------------------------------------------------

1433-- Parsing

1445-- Parsing

1434------------------------------------------------------------------------------

1446------------------------------------------------------------------------------

core/src/Streamly/Internal/Data/Stream/StreamD/Type.hs+14

@@ -44,6 +44,7 @@ module Streamly.Internal.Data.Stream.StreamD.Type

44 , fold

45 , foldBreak

46 , foldContinue

47+ , foldStream

48 -- * Right Folds

49 -- * Right Folds

49 , foldrT

50 , foldrT

@@ -305,6 +306,9 @@ foldBreak (Fold fstep begin done) (UnStream step state) = do

305 b <- done fs

306 b <- done fs

306 return $! (b, Stream (\ _ _ -> return Stop) ())

307 return $! (b, Stream (\ _ _ -> return Stop) ())

307

308

309+-- | If the fold finishes before the stream, we can detect that the fold is

310+-- done by checking if the initial action returns Done. But the remaining

311+-- stream is discarded.

308{-# INLINE_NORMAL foldContinue #-}

312{-# INLINE_NORMAL foldContinue #-}

309foldContinue :: Monad m => Fold m a b -> Stream m a -> Fold m a b

313foldContinue :: Monad m => Fold m a b -> Stream m a -> Fold m a b

310foldContinue (Fold fstep finitial fextract) (Stream sstep state) =

314foldContinue (Fold fstep finitial fextract) (Stream sstep state) =

@@ -330,6 +334,16 @@ foldContinue (Fold fstep finitial fextract) (Stream sstep state) =

330 Skip s -> go SPEC fs s

334 Skip s -> go SPEC fs s

331 Stop -> return $ FL.Partial fs

335 Stop -> return $ FL.Partial fs

332

336

337+-- | Returns when either the fold or the stream finishes. If the Fold finishes

338+-- first we can check that using Fold.done. If the fold is not done then stream

339+-- would be nil.

340+--

341+-- /Unimplemented/

342+{-# INLINE_NORMAL foldStream #-}

343+foldStream :: -- Monad m =>

344+ Fold m a b -> Stream m a -> m (Fold m a b, Stream m a)

345+foldStream = undefined

346+

333------------------------------------------------------------------------------

347------------------------------------------------------------------------------

334-- Right Folds

348-- Right Folds

335------------------------------------------------------------------------------

349------------------------------------------------------------------------------