streaming: A free monad transformer optimized for streaming applications.

[ bsd3, data, library, pipes, streaming ] [ Propose Tags ]

Stream can be used wherever FreeT is used. The compiler's standard range of optimizations work better for operations written in terms of Stream. See the examples in Streaming.Prelude for a sense of how simple the library is to use and think about.

Streaming.Prelude closely follows Pipes.Prelude, but cleverly omits the pipes. It is focused on employment with base functors which generate effectful sequences. These appear elsewhere under titles like

pipes:      Producer a m r, Producer a m (Producer a m r), FreeT (Producer a m) m r
io-streams: InputStream a, Generator a r
conduit:    Source m a, ConduitM () o m r

and the like.

Interoperation with pipes is accomplished with this isomorphism:

Pipes.unfoldr        :: Stream (Of a) m r   -> Producer a m r
Streaming.unfoldr        :: Producer a m r      -> Stream (Of a) m r

(If you don't have pipes-HEAD, inline the definition of unfoldr.)

Interoperation with io-streams is thus:

Streaming.reread     :: InputStream a       -> Stream (Of a) IO ()
IOStreams.unfoldM Streaming.uncons  :: Stream (Of a) IO () -> IO (InputStream a)

The separate Generator a r type in io-streams is intended to permit construction of an InputStream with more possibilities (such as the yield statement). This purpose can as well be met with Stream (Of a) m r, which may be friendlier to the compiler.

A simple exit to conduit would be, e.g.:

Conduit.unfoldM Streaming.uncons    :: Stream (Of a) m ()  -> Source m a

These conversions should never be more expensive than a single >-> or =$=.

Dependencies base (>=4.7 && <4.9), mmorph (>=1.0 && <1.2), mtl (>=2.1 && <2.3), transformers (>=0.3 && <0.5) [details]
License BSD-3-Clause
Author michaelt
Category Data, Pipes
Home page
Bug tracker
Source repo head: git clone
Uploaded by MichaelThompson at Sat Aug 22 16:13:59 UTC 2015
Distributions LTSHaskell:, NixOS:, Stackage:
Downloads 9906 total (496 in the last 30 days)
Rating 2.5 (votes: 6) [estimated by rule of succession]
Your Rating
  • λ
  • λ
  • λ
Status Docs uploaded by user
Build status unknown [no reports yet]
Hackage Matrix CI




Maintainer's Corner

For package maintainers and hackage trustees