a4464a8 · streamly · git.iko.soy

git.iko.soy/streamly

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Fix a bug in zipWithM rule that causes effects to run only once.

a4464a8Pranay Sashank7 years ago

src/Streamly/Streams/StreamD.hs+3−1

@@ -11,6 +11,7 @@

11{-# LANGUAGE ViewPatterns #-}

12{-# LANGUAGE RankNTypes #-}

13{-# LANGUAGE MagicHash #-}

14+{-# LANGUAGE TypeApplications #-}

15#include "inline.hs"

16#include "inline.hs"

@@ -255,6 +256,7 @@ import Control.Monad.Catch (MonadCatch)

255import Control.Monad.IO.Class (MonadIO(..))

256import Control.Monad.IO.Class (MonadIO(..))

256import Control.Monad.Trans (MonadTrans(lift))

257import Control.Monad.Trans (MonadTrans(lift))

257import Data.Bits (shiftR, shiftL, (.|.), (.&.))

258import Data.Bits (shiftR, shiftL, (.|.), (.&.))

259+import Data.Functor.Identity (Identity)

258import Data.Maybe (fromJust, isJust)

260import Data.Maybe (fromJust, isJust)

259import Data.Word (Word32)

261import Data.Word (Word32)

260import Foreign.Ptr (Ptr)

262import Foreign.Ptr (Ptr)

@@ -2353,7 +2355,7 @@ zipWithM f (Stream stepa ta) (Stream stepb tb) = Stream step (ta, tb, Nothing)

2353 Stop -> return Stop

2355 Stop -> return Stop

2354

2356

2355{-# RULES "zipWithM xs xs"

2357{-# RULES "zipWithM xs xs"

2356− forall f xs. zipWithM f xs xs = mapM (\x -> f x x) xs #-}

2358+ forall f xs. zipWithM @Identity f xs xs = mapM (\x -> f x x) xs #-}

2357

2359

2358{-# INLINE zipWith #-}

2360{-# INLINE zipWith #-}

2359zipWith :: Monad m => (a -> b -> c) -> Stream m a -> Stream m b -> Stream m c

2361zipWith :: Monad m => (a -> b -> c) -> Stream m a -> Stream m b -> Stream m c