5fc469a · streamly · git.iko.soy

git.iko.soy/streamly

Add uniq, indexed, indexedR.

commit5fc469ad7774651deef3fdc9a727d39cca349c67 authorPranay Sashank <pranaysashank@gmail.com> dateWed 21 Nov 2018, 14:03 (8 years ago) parent5bb0a49

3 files changed+75−1

compare with master

unifiedsplit

Changelog.md+5−1 src/Streamly/Prelude.hs+22 src/Streamly/Streams/StreamD.hs+48

Changelog.md+5−1

@@ -2,7 +2,11 @@

33* Add benchmarks to measure composed and iterated operations

44* Performance improvements

5−* Add `(!!)`, `insertBy`, `mergeBy`, `merge`, `splitAt`, `the` to Prelude.

5+* Add `(!!)`, `insertBy`, `mergeBy`, `merge`, `splitAt`, `the`, `maximumBy`,

6+ `minimumBy`, `scanl1`, `scanl1M`, `scanl1'`, `scanl1M'`, `scanl`, `scanlM`,

7+ `deleteBy`, `isPrefixOf`, `isSubsequenceOf`, `stripPrefix`,

8+ `replicate`, `generateM`, `generate`, `concatMap`, `concatMapM`,

9+ `findM`, `uniq`, `indexed`, `indexedR` to Prelude.

610

711## 0.5.2

812

src/Streamly/Prelude.hs+22

@@ -204,6 +204,7 @@ module Streamly.Prelude

204204 -- ** Filtering

205205 , filter

206206 , filterM

207+ , uniq

207208 , take

208209 , takeWhile

209210 , takeWhileM

@@ -235,6 +236,8 @@ module Streamly.Prelude

235236 , elemIndices

236237

237238 -- * Zipping

239+ , indexed

240+ , indexedR

238241 , zipWith

239242 , zipWithM

240243 , Z.zipAsyncWith

@@ -993,6 +996,12 @@ filter = K.filter

993996filterM :: (IsStream t, Monad m) => (a -> m Bool) -> t m a -> t m a

994997filterM p m = fromStreamD $ D.filterM p $ toStreamD m

995998

999+-- | Drop repeated elements that are adjacent to each other.

1000+--

1001+{-# INLINE uniq #-}

1002+uniq :: (Eq a, IsStream t, Monad m) => t m a -> t m a

1003+uniq = fromStreamD . D.uniq . toStreamD

1004+

9961005-- | Take first 'n' elements from the stream and discard the rest.

9971006--

9981007-- @since 0.1.0

@@ -1170,6 +1179,19 @@ deleteBy cmp x m = fromStreamS $ S.deleteBy cmp x (toStreamS m)

11701179-- Zipping

11711180------------------------------------------------------------------------------

11721181

1182+-- | Pair each element in a stream with its index.

1183+--

1184+{-# INLINE indexed #-}

1185+indexed :: (IsStream t, Monad m) => t m a -> t m (Int, a)

1186+indexed = fromStreamD . D.indexed . toStreamD

1187+

1188+-- | Pair each element in a stream with its index, starting from the

1189+-- given index @n@ and counting down.

1190+--

1191+{-# INLINE indexedR #-}

1192+indexedR :: (IsStream t, Monad m) => Int -> t m a -> t m (Int, a)

1193+indexedR n = fromStreamD . D.indexedR n . toStreamD

1194+

11731195-- | Zip two streams serially using a monadic zipping function.

11741196--

11751197-- @since 0.4.0

src/Streamly/Streams/StreamD.hs+48

@@ -123,6 +123,7 @@ module Streamly.Streams.StreamD

123123 -- * Filtering

124124 , filter

125125 , filterM

126+ , uniq

126127 , take

127128 , takeWhile

128129 , takeWhileM

@@ -146,6 +147,8 @@ module Streamly.Streams.StreamD

146147 , mapMaybeM

147148

148149 -- * Zipping

150+ , indexed

151+ , indexedR

149152 , zipWith

150153 , zipWithM

151154

@@ -954,6 +957,25 @@ filterM f (Stream step state) = Stream step' state

954957filter :: Monad m => (a -> Bool) -> Stream m a -> Stream m a

955958filter f = filterM (return . f)

956959

960+{-# INLINE_NORMAL uniq #-}

961+uniq :: (Eq a, Monad m) => Stream m a -> Stream m a

962+uniq (Stream step state) = Stream step' (Nothing, state)

963+ where

964+ {-# INLINE_LATE step' #-}

965+ step' gst (Nothing, st) = do

966+ r <- step (rstState gst) st

967+ case r of

968+ Yield x s -> return $ Yield x (Just x, s)

969+ Skip s -> return $ Skip (Nothing, s)

970+ Stop -> return Stop

971+ step' gst (Just x, st) = do

972+ r <- step (rstState gst) st

973+ case r of

974+ Yield y s | x == y -> return $ Skip (Just x, s)

975+ | otherwise -> return $ Yield x (Just y, s)

976+ Skip s -> return $ Skip (Just x, s)

977+ Stop -> return Stop

978+

957979------------------------------------------------------------------------------

958980-- Transformation by Mapping

959981------------------------------------------------------------------------------

@@ -1055,6 +1077,32 @@ mapMaybeM f = fmap fromJust . filter isJust . mapM f

10551077-- Zipping

10561078------------------------------------------------------------------------------

10571079

1080+{-# INLINE_NORMAL indexed #-}

1081+indexed :: Monad m => Stream m a -> Stream m (Int, a)

1082+indexed (Stream step state) = Stream step' (state, 0)

1083+ where

1084+ {-# INLINE_LATE step' #-}

1085+ step' gst (st, i) = i `seq` do

1086+ r <- step (rstState gst) st

1087+ case r of

1088+ Yield x s -> return $ Yield (i, x) (s, i+1)

1089+ Skip s -> return $ Skip (s, i)

1090+ Stop -> return Stop

1091+

1092+{-# INLINE_NORMAL indexedR #-}

1093+indexedR :: Monad m => Int -> Stream m a -> Stream m (Int, a)

1094+indexedR m (Stream step state) = Stream step' (state, m)

1095+ where

1096+ {-# INLINE_LATE step' #-}

1097+ step' gst (st, i) = i `seq` do

1098+ r <- step (rstState gst) st

1099+ case r of

1100+ Yield x s -> let i' = i - 1

1101+ in

1102+ return $ Yield (i', x) (s, i')

1103+ Skip s -> return $ Skip (s, i)

1104+ Stop -> return Stop

1105+

10581106{-# INLINE_NORMAL zipWithM #-}

10591107zipWithM :: Monad m

10601108 => (a -> b -> m c) -> Stream m a -> Stream m b -> Stream m c