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Within LTS Haskell 24.34 (ghc-9.10.3)
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mapMStep :: Applicative m => (a -> m b) -> Step s a -> m (Step s b)streamly-core Streamly.Internal.Data.Fold Map a monadic function over the result b in Step s b. Internal
mapMaybe :: forall (m :: Type -> Type) a b r . Monad m => (a -> Maybe b) -> Fold m b r -> Fold m a rstreamly-core Streamly.Internal.Data.Fold mapMaybe f fold maps a Maybe returning function f on the input of the fold, filters out Nothing elements, and return the values extracted from Just.
>>> mapMaybe f = Fold.lmap f . Fold.catMaybes >>> mapMaybe f = Fold.mapMaybeM (return . f)
>>> f x = if even x then Just x else Nothing >>> fld = Fold.mapMaybe f Fold.toList >>> Stream.fold fld (Stream.enumerateFromTo 1 10) [2,4,6,8,10]
mapMaybeM :: Monad m => (a -> m (Maybe b)) -> Fold m b r -> Fold m a rstreamly-core Streamly.Internal.Data.Fold >>> mapMaybeM f = Fold.lmapM f . Fold.catMaybes
mapAlterF :: (IsMap f, Functor g) => (Maybe a -> g (Maybe a)) -> Key f -> f a -> g (f a)streamly-core Streamly.Internal.Data.IsMap No documentation available.
mapDelete :: IsMap f => Key f -> f a -> f astreamly-core Streamly.Internal.Data.IsMap No documentation available.
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streamly-core Streamly.Internal.Data.IsMap No documentation available.
mapInsert :: IsMap f => Key f -> a -> f a -> f astreamly-core Streamly.Internal.Data.IsMap No documentation available.
mapLookup :: IsMap f => Key f -> f a -> Maybe astreamly-core Streamly.Internal.Data.IsMap No documentation available.
mapNull :: IsMap f => f a -> Boolstreamly-core Streamly.Internal.Data.IsMap No documentation available.
mapTraverseWithKey :: (IsMap f, Applicative t) => (Key f -> a -> t b) -> f a -> t (f b)streamly-core Streamly.Internal.Data.IsMap No documentation available.