f68cec3 · streamly · git.iko.soy

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Fix performance of streamEqBy

f68cec3Harendra Kumar4 years ago

core/src/Streamly/Internal/Data/Parser/ParserD.hs+13−9

compare with master

unifiedsplit

@@ -2159,7 +2159,7 @@ groupByRollingEither

2159--

2160{-# INLINE listEqBy #-}

2161listEqBy :: Monad m => (a -> a -> Bool) -> [a] -> Parser a m [a]

2162−listEqBy cmp xs = streamEqBy cmp (D.fromList xs) *> fromPure xs

2162+listEqBy cmp xs = streamEqByInternal cmp (D.fromList xs) *> fromPure xs

2163{-

2164listEqBy cmp str = Parser step initial extract

2165

@@ -2189,14 +2189,9 @@ listEqBy cmp str = Parser step initial extract

2189 ++ show (length xs) ++ " elements"

2190-}

2191

2192−-- | Like 'listEqBy' but uses a stream instead of a list and does not return

2192+{-# INLINE streamEqByInternal #-}

2193−-- the stream.

2194−--

2195−-- See also: "Streamly.Data.Stream.streamEqBy"

2196−--

2197−{-# INLINE streamEqBy #-}

2198−streamEqBy :: Monad m => (a -> a -> Bool) -> D.Stream m a -> Parser a m ()

2193+streamEqByInternal :: Monad m => (a -> a -> Bool) -> D.Stream m a -> Parser a m ()

2199−streamEqBy cmp (D.Stream sstep state) = Parser step initial extract

2194+streamEqByInternal cmp (D.Stream sstep state) = Parser step initial extract

2200

2195

2201 where

2196 where

2202

2197

@@ -2231,6 +2226,15 @@ streamEqBy cmp (D.Stream sstep state) = Parser step initial extract

2231

2226

2232 extract _ = return $ Error "streamEqBy: end of input"

2227 extract _ = return $ Error "streamEqBy: end of input"

2233

2228

2229+-- | Like 'listEqBy' but uses a stream instead of a list and does not return

2230+-- the stream.

2231+--

2232+{-# INLINE streamEqBy #-}

2233+streamEqBy :: Monad m => (a -> a -> Bool) -> D.Stream m a -> Parser a m ()

2234+-- XXX Somehow composing this with "*>" is much faster on the microbenchmark.

2235+-- Need to investigate why.

2236+streamEqBy cmp stream = streamEqByInternal cmp stream *> fromPure ()

2237+

2234-- Rename to "list".

2238-- Rename to "list".

2235-- | Match the input sequence with the supplied list and return it if

2239-- | Match the input sequence with the supplied list and return it if

2236-- successful.

2240-- successful.