b625332 · streamly · git.iko.soy

git.iko.soy/streamly

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Add foldIterateM

b625332Adithya Kumar6 years ago

src/Streamly/Internal/Data/Stream/IsStream/Nesting.hs+7−12

compare with master

unifiedsplit

@@ -130,7 +130,7 @@ module Streamly.Internal.Data.Stream.IsStream.Nesting

130 , foldMany

131 , foldManyPost

132 , foldSequence

133− , foldIterate

133+ , foldIterateM

134

135 -- ** Parsing

136 -- | Apply parsers on a stream.

@@ -1009,9 +1009,9 @@ foldSequence _f _m = undefined

1009--

1010-- @

1011-- > import Data.Monoid (Sum(..))

1012−-- > f x = Fold.take 2 (Fold.sconcat x)

1012+-- > f x = return (Fold.take 2 (Fold.sconcat x))

1013-- > s = Stream.map Sum $ Stream.fromList [1..10]

1014−-- > Stream.toList $ Stream.map getSum $ Stream.foldIterate f 0 s

1014+-- > Stream.toList $ Stream.map getSum $ Stream.foldIterateM f 0 s

1015-- [3,10,21,36,55,55]

1016--

1017-- @

@@ -1021,15 +1021,10 @@ foldSequence _f _m = undefined

1021--

1022-- /Pre-release/

1023--

1024−{-# INLINE foldIterate #-}

1024+{-# INLINE foldIterateM #-}

1025−foldIterate

1025+foldIterateM ::

1026− :: -- (IsStream t, Monad m) =>

1026+ (IsStream t, Monad m) => (b -> m (Fold m a b)) -> b -> t m a -> t m b

1027− (b -> Fold m a b)

1028− -> b

1029− -> t m a

1030− -> t m b

1031−foldIterate _f _i _m = undefined

1032−-- D.fromStreamD $ D.foldIterate f i (D.toStreamD m)

1027+foldIterateM f i m = D.fromStreamD $ D.foldIterateM f i (D.toStreamD m)

1033

1028

1034------------------------------------------------------------------------------

1029------------------------------------------------------------------------------

1035-- Parsing

1030-- Parsing

src/Streamly/Internal/Data/Stream/StreamD/Nesting.hs+45

@@ -112,6 +112,7 @@ module Streamly.Internal.Data.Stream.StreamD.Nesting

112 -- ** Folding

113 -- | Apply folds on a stream.

114 , foldMany

115+ , foldIterateM

115

116

116 -- ** Parsing

117 -- ** Parsing

117 -- | Parsing is opposite to flattening. 'parseMany' is dual to concatMap or

118 -- | Parsing is opposite to flattening. 'parseMany' is dual to concatMap or

@@ -957,6 +958,50 @@ gintercalate

957 return $ Yield x (ICALFirstInner s1 s2 i1 i2)

958 return $ Yield x (ICALFirstInner s1 s2 i1 i2)

958 -}

959 -}

959

960

961+------------------------------------------------------------------------------

962+-- Folding

963+------------------------------------------------------------------------------

964+

965+{-# ANN type FIterState Fuse #-}

966+data FIterState s f m a b

967+ = FIterInit s f

968+ | forall fs. FIterStream s (fs -> a -> m (FL.Step fs b)) fs (fs -> m b)

969+ | FIterYield b (FIterState s f m a b)

970+ | FIterStop

971+

972+{-# INLINE_NORMAL foldIterateM #-}

973+foldIterateM ::

974+ Monad m => (b -> m (FL.Fold m a b)) -> b -> Stream m a -> Stream m b

975+foldIterateM func seed0 (Stream step state) =

976+ Stream stepOuter (FIterInit state seed0)

977+

978+ where

979+

980+ {-# INLINE iterStep #-}

981+ iterStep from st fstep extract = do

982+ res <- from

983+ return

984+ $ Skip

985+ $ case res of

986+ FL.Partial fs -> FIterStream st fstep fs extract

987+ FL.Done fb -> FIterYield fb $ FIterInit st fb

988+

989+ {-# INLINE_LATE stepOuter #-}

990+ stepOuter _ (FIterInit st seed) = do

991+ (FL.Fold fstep initial extract) <- func seed

992+ iterStep initial st fstep extract

993+ stepOuter gst (FIterStream st fstep fs extract) = do

994+ r <- step (adaptState gst) st

995+ case r of

996+ Yield x s -> do

997+ iterStep (fstep fs x) s fstep extract

998+ Skip s -> return $ Skip $ FIterStream s fstep fs extract

999+ Stop -> do

1000+ b <- extract fs

1001+ return $ Skip $ FIterYield b FIterStop

1002+ stepOuter _ (FIterYield a next) = return $ Yield a next

1003+ stepOuter _ FIterStop = return Stop

1004+

960------------------------------------------------------------------------------

1005------------------------------------------------------------------------------

961-- Parsing

1006-- Parsing

962------------------------------------------------------------------------------

1007------------------------------------------------------------------------------