a3ee4a8 · streamly · git.iko.soy

git.iko.soy/streamly

expose lcatMaybes via the Streamly.Internal module

commita3ee4a852d11a6afb9a76ae8e6fba8962fdcb531 authorHarendra Kumar <harendra.kumar@gmail.com> dateWed 7 Aug 2019, 01:32 (7 years ago) parent27d7ea8

3 files changed+12−8

compare with master

unifiedsplit

src/Streamly/Fold/Types.hs+8 src/Streamly/Internal.hs+3−1 src/Streamly/Prelude.hs+1−7

src/Streamly/Fold/Types.hs+8

@@ -17,6 +17,7 @@ module Streamly.Fold.Types

1717 , lmapM

1818 , lfilter

1919 , lfilterM

20+ , lcatMaybes

2021 , ltake

2122 , ltakeWhile

2223 , lsessionsOf

@@ -33,6 +34,7 @@ import Control.Monad (void)

3334import Control.Monad.Catch (throwM)

3435import Control.Monad.IO.Class (MonadIO(..))

3536import Control.Monad.Trans.Control (control)

37+import Data.Maybe (isJust, fromJust)

3638import Data.Semigroup (Semigroup(..))

3739import Streamly.Strict (Tuple'(..), Tuple3'(..), Either'(..))

3840import Streamly.SVar (MonadAsync)

@@ -241,6 +243,12 @@ lfilterM f (Fold step begin done) = Fold step' begin done

241243 use <- f a

242244 if use then step x a else return x

243245

246+-- | Transform a fold from a pure input to a 'Maybe' input, consuming only

247+-- 'Just' values.

248+{-# INLINE lcatMaybes #-}

249+lcatMaybes :: Monad m => Fold m a b -> Fold m (Maybe a) b

250+lcatMaybes = lfilter isJust . lmap fromJust

251+

244252-- | Take first 'n' elements from the stream and discard the rest.

245253--

246254-- @since 0.7.0

src/Streamly/Internal.hs+3−1

@@ -28,6 +28,7 @@ module Streamly.Internal

2828 , lmapM

2929 , lfilter

3030 , lfilterM

31+ , lcatMaybes

3132 , ltake

3233 , ltakeWhile

3334 , lsessionsOf

@@ -36,6 +37,7 @@ module Streamly.Internal

3637 )

3738where

3839

39−import Streamly.Fold.Types

4040import Streamly.Streams.Combinators (inspectMode)

4141import Streamly.Streams.Parallel (tapAsync)

42+

43+import Streamly.Fold.Types

src/Streamly/Prelude.hs+1−7

@@ -2674,12 +2674,6 @@ chunksOf

26742674 => Int -> Fold m a b -> t m a -> t m b

26752675chunksOf n f m = D.fromStreamD $ D.groupsOf n f (D.toStreamD m)

26762676

2677−-- | Transform a fold from a pure input to a 'Maybe' input, consuming only

2678−-- 'Just' values.

2679−{-# INLINE lcatMaybes #-}

2680−lcatMaybes :: Monad m => Fold m a b -> Fold m (Maybe a) b

2681−lcatMaybes = FL.lfilter isJust . FL.lmap fromJust

2682−

26832677-- XXX we can implement this by repeatedly applying the 'lrunFor' fold.

26842678-- XXX add this example after fixing the serial stream rate control

26852679-- >>> S.toList $ S.take 5 $ sessionsOf 1 FL.sum $ constRate 2 $ S.enumerateFrom 1

@@ -2694,7 +2688,7 @@ sessionsOf

26942688 :: (IsStream t, MonadAsync m)

26952689 => Double -> Fold m a b -> t m a -> t m b

26962690sessionsOf n f xs =

2697− splitBySuffix isNothing (lcatMaybes f)

2691+ splitBySuffix isNothing (FL.lcatMaybes f)

26982692 (intersperseByTime n (return Nothing) (Serial.map Just xs))

26992693

27002694------------------------------------------------------------------------------