68b6736 · streamly · git.iko.soy

git.iko.soy/streamly

Merge pull request #35 from hussein-aitlahcen/zipstream-applicative

fix: Zip/AsyncZip applicative instances

commit68b6736794db0d31ab1bd9e0ed7339ae499462c8 authorHarendra Kumar <harendra.kumar@gmail.com> dateFri 23 Mar 2018, 00:05 (9 years ago) parentf5adde8 20b2d97

4 files changed+17−4

compare with master

unifiedsplit

Changelog.md+5 src/Streamly/Core.hs+4 src/Streamly/Streams.hs+2−2 test/Main.hs+6−2

Changelog.md+5

@@ -1,3 +1,8 @@

1+## Unreleased

3+### Bug Fixes

4+* Fix Zip/AsyncZip applicative instances to handle applicative injection of function like `pure f <*> s1 <*> s2`

16## 0.1.1

38### Enhancements

src/Streamly/Core.hs+4

@@ -25,6 +25,7 @@ module Streamly.Core

2525

2626 -- * Construction

2727 , scons

28+ , srepeat

2829 , snil

2930

3031 -- * Composition

@@ -217,6 +218,9 @@ type MonadAsync m = (MonadIO m, MonadBaseControl IO m, MonadThrow m)

217218scons :: a -> Maybe (Stream m a) -> Stream m a

218219scons a r = Stream $ \_ _ yld -> yld a r

219220

221+srepeat :: a -> Stream m a

222+srepeat a = let x = scons a (Just x) in x

223+

220224snil :: Stream m a

221225snil = Stream $ \_ stp _ -> stp

222226

src/Streamly/Streams.hs+2−2

@@ -751,7 +751,7 @@ instance Monad m => Functor (ZipStream m) where

751751 in m Nothing stp yield

752752

753753instance Monad m => Applicative (ZipStream m) where

754− pure a = ZipStream $ scons a Nothing

754+ pure = ZipStream . srepeat

755755 (<*>) = zipWith id

756756

757757instance Streaming ZipStream where

@@ -838,7 +838,7 @@ instance Monad m => Functor (ZipAsync m) where

838838 in m Nothing stp yield

839839

840840instance MonadAsync m => Applicative (ZipAsync m) where

841− pure a = ZipAsync $ scons a Nothing

841+ pure = ZipAsync . srepeat

842842 (<*>) = zipAsyncWith id

843843

844844instance Streaming ZipAsync where

test/Main.hs+6−2

@@ -422,8 +422,12 @@ zipOps z zM app = do

422422 it "Applicative zip" $

423423 let s1 = adapt $ serially $ foldMapWith (<>) return [1..10]

424424 s2 = adapt $ serially $ foldMapWith (<>) return [1..]

425− in (A.toList . app) ((+) <$> s1 <*> s2)

426− `shouldReturn` ([2,4..20] :: [Int])

425+ f = A.toList . app

426+ functorial = f $ (+) <$> s1 <*> s2

427+ applicative = f $ pure (+) <*> s1 <*> s2

428+ expected = ([2,4..20] :: [Int])

429+ in (,) <$> functorial <*> applicative

430+ `shouldReturn` (expected, expected)

427431

428432timed :: Int -> StreamT IO Int

429433timed x = liftIO (threadDelay (x * 100000)) >> return x