90f0a97 · streamly · git.iko.soy

git.iko.soy/streamly

Add nilM to create an empty stream with side effect

commit90f0a9730088cd3a39dd8a6cf5f4ddf15cb96a62 authorHarendra Kumar <harendra.kumar@gmail.com> dateThu 10 Oct 2019, 18:22 (7 years ago) parent103705f

4 files changed+22

compare with master

unifiedsplit

src/Streamly/Internal/Prelude.hs+1 src/Streamly/Streams/StreamD.hs+6 src/Streamly/Streams/StreamK.hs+1 src/Streamly/Streams/StreamK/Type.hs+14

src/Streamly/Internal/Prelude.hs+1

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

2323 -- * Construction

2424 -- ** Primitives

2525 K.nil

26+ , K.nilM

2627 , K.cons

2728 , (K..:)

2829

src/Streamly/Streams/StreamD.hs+6

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

5050

5151 -- * Construction

5252 , nil

53+ , nilM

5354 , cons

5455

5556 -- * Deconstruction

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

326327nil :: Monad m => Stream m a

327328nil = Stream (\_ _ -> return Stop) ()

328329

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+

329335{-# INLINE_NORMAL consM #-}

330336consM :: Monad m => m a -> Stream m a -> Stream m a

331337consM m (Stream step state) = Stream step1 Nothing

src/Streamly/Streams/StreamK.hs+1

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

4040 -- * Construction Primitives

4141 , mkStream

4242 , nil

43+ , nilM

4344 , cons

4445 , (.:)

4546

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

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

6767 , yield

6868

6969 , nil

70+ , nilM

7071 , conjoin

7172 , serial

7273 , map

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

324325nil :: IsStream t => t m a

325326nil = mkStream $ \_ _ _ stp -> stp

326327

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+

327341{-# INLINE_NORMAL yield #-}

328342yield :: IsStream t => a -> t m a

329343yield a = mkStream $ \_ _ single _ -> single a