| Copyright | (c) 2021 Composewell Technologies |
|---|---|
| License | BSD-3-Clause |
| Maintainer | streamly@composewell.com |
| Stability | experimental |
| Portability | GHC |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Streamly.Internal.Data.Array.Stream.Fold.Foreign
Description
Fold a stream of foreign arrays. Fold m a b in this module works
on a stream of "Array a" and produces an output of type b.
Though Fold m a b in this module works on a stream of Array a it is
different from Data.Fold m (Array a) b. While the latter works on arrays
as a whole treating them as atomic elements, the folds in this module can
work on the stream of arrays as if it is an element stream with all the
arrays coalesced together. This module allows adapting the element stream
folds in Data.Fold to correctly work on an array stream as if it is an
element stream. For example:
>>>import qualified Streamly.Data.Fold as Fold>>>import qualified Streamly.Internal.Data.Array.Stream.Foreign as ArrayStream>>>import qualified Streamly.Internal.Data.Array.Stream.Fold.Foreign as ArrayFold>>>import qualified Streamly.Internal.Data.Stream.IsStream as Stream (arraysOf)>>>import qualified Streamly.Prelude as Stream
>>>ArrayStream.foldArr (ArrayFold.fromFold (Fold.take 7 Fold.toList)) $ Stream.arraysOf 5 $ Stream.fromList "hello world""hello w"
Synopsis
- newtype Fold m a b = Fold (Parser m (Array a) b)
- fromFold :: forall m a b. (MonadIO m, Storable a) => Fold m a b -> Fold m a b
- fromParser :: forall m a b. (MonadThrow m, MonadIO m, Storable a) => Parser m a b -> Fold m a b
- fromParserD :: forall m a b. (MonadIO m, Storable a) => Parser m a b -> Fold m a b
- fromArrayFold :: forall m a b. MonadIO m => Fold m (Array a) b -> Fold m a b
- rmapM :: Monad m => (b -> m c) -> Fold m a b -> Fold m a c
- fromPure :: Monad m => b -> Fold m a b
- fromEffect :: Monad m => m b -> Fold m a b
- serialWith :: MonadThrow m => (a -> b -> c) -> Fold m x a -> Fold m x b -> Fold m x c
- concatMap :: MonadThrow m => (b -> Fold m a c) -> Fold m a b -> Fold m a c
- take :: forall m a b. (Monad m, Storable a) => Int -> Fold m a b -> Fold m a b
Documentation
Array stream fold.
An array stream fold is basically an array stream Parser that does not
fail. In case of array stream folds the count in Partial, Continue and
Done is a count of elements that includes the leftover element count in
the array that is currently being processed by the parser. If none of the
elements is consumed by the parser the count is at least the whole array
length. If the whole array is consumed by the parser then the count will be
0.
Pre-release
Instances
| MonadThrow m => Applicative (Fold m a) Source # |
|
| Functor m => Functor (Fold m a) Source # | Maps a function over the result of fold. Pre-release |
| MonadThrow m => Monad (Fold m a) Source # | Monad instance applies folds sequentially. Next fold can depend on the
output of the previous fold. See (>>=) = flip concatMap |
Construction
fromFold :: forall m a b. (MonadIO m, Storable a) => Fold m a b -> Fold m a b Source #
Convert an element Fold into an array stream fold.
Pre-release
fromParser :: forall m a b. (MonadThrow m, MonadIO m, Storable a) => Parser m a b -> Fold m a b Source #
Convert an element Parser into an array stream fold. If the parser
fails the fold would throw an exception.
Pre-release
fromParserD :: forall m a b. (MonadIO m, Storable a) => Parser m a b -> Fold m a b Source #
Convert an element Parser into an array stream fold. If the
parser fails the fold would throw an exception.
Pre-release
fromArrayFold :: forall m a b. MonadIO m => Fold m (Array a) b -> Fold m a b Source #
Adapt an array stream fold.
Pre-release
Mapping
rmapM :: Monad m => (b -> m c) -> Fold m a b -> Fold m a c Source #
Map a monadic function on the output of a fold.
Pre-release
Applicative
fromPure :: Monad m => b -> Fold m a b Source #
A fold that always yields a pure value without consuming any input.
Pre-release
fromEffect :: Monad m => m b -> Fold m a b Source #
A fold that always yields the result of an effectful action without consuming any input.
Pre-release
serialWith :: MonadThrow m => (a -> b -> c) -> Fold m x a -> Fold m x b -> Fold m x c Source #
Applies two folds sequentially on the input stream and combines their results using the supplied function.
Pre-release
Monad
concatMap :: MonadThrow m => (b -> Fold m a c) -> Fold m a b -> Fold m a c Source #
Applies a fold on the input stream, generates the next fold from the output of the previously applied fold and then applies that fold.
Pre-release