90f0a97 · streamly · git.iko.soy

git.iko.soy/streamly

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Add nilM to create an empty stream with side effect

90f0a97Harendra Kumar7 years ago

src/Streamly/Internal/Prelude.hs+1

compare with master

unifiedsplit

@@ -23,6 +23,7 @@ module Streamly.Internal.Prelude

23 -- * Construction

24 -- ** Primitives

25 K.nil

26+ , K.nilM

26 , K.cons

27 , K.cons

27 , (K..:)

28 , (K..:)

src/Streamly/Streams/StreamD.hs+6

@@ -50,6 +50,7 @@ module Streamly.Streams.StreamD

51 -- * Construction

52 , nil

53+ , nilM

53 , cons

54 , cons

55 -- * Deconstruction

56 -- * Deconstruction

@@ -326,6 +327,11 @@ import Foreign.ForeignPtr (ForeignPtr, touchForeignPtr)

326nil :: Monad m => Stream m a

327nil :: Monad m => Stream m a

327nil = Stream (\_ _ -> return Stop) ()

328nil = Stream (\_ _ -> return Stop) ()

328

329

330+-- | An empty 'Stream' with a side effect.

331+{-# INLINE_NORMAL nilM #-}

332+nilM :: Monad m => m b -> Stream m a

333+nilM m = Stream (\_ _ -> m >> return Stop) ()

334+

329{-# INLINE_NORMAL consM #-}

335{-# INLINE_NORMAL consM #-}

330consM :: Monad m => m a -> Stream m a -> Stream m a

336consM :: Monad m => m a -> Stream m a -> Stream m a

331consM m (Stream step state) = Stream step1 Nothing

337consM m (Stream step state) = Stream step1 Nothing

src/Streamly/Streams/StreamK.hs+1

@@ -40,6 +40,7 @@ module Streamly.Streams.StreamK

40 -- * Construction Primitives

41 , mkStream

42 , nil

43+ , nilM

43 , cons

44 , cons

44 , (.:)

45 , (.:)

src/Streamly/Streams/StreamK/Type.hs+14

@@ -67,6 +67,7 @@ module Streamly.Streams.StreamK.Type

67 , yield

69 , nil

70+ , nilM

70 , conjoin

71 , conjoin

71 , serial

72 , serial

72 , map

73 , map

@@ -324,6 +325,19 @@ infixr 5 .:

324nil :: IsStream t => t m a

325nil :: IsStream t => t m a

325nil = mkStream $ \_ _ _ stp -> stp

326nil = mkStream $ \_ _ _ stp -> stp

326

327

328+-- | An empty stream producing a side effect.

329+--

330+-- @

331+-- > toList (nilM (print "nil"))

332+-- "nil"

333+-- []

334+-- @

335+--

336+-- /Internal/

337+{-# INLINE_NORMAL nilM #-}

338+nilM :: (IsStream t, Monad m) => m b -> t m a

339+nilM m = mkStream $ \_ _ _ stp -> m >> stp

340+

327{-# INLINE_NORMAL yield #-}

341{-# INLINE_NORMAL yield #-}

328yield :: IsStream t => a -> t m a

342yield :: IsStream t => a -> t m a

329yield a = mkStream $ \_ _ single _ -> single a

343yield a = mkStream $ \_ _ single _ -> single a