pipes

Compositional pipelines

Version on this page:4.3.4
LTS Haskell 24.18:4.3.16@rev:6
Stackage Nightly 2025-11-04:4.3.16@rev:6
Latest on Hackage:4.3.16@rev:6

See all snapshots pipes appears in

BSD-3-Clause licensed by Gabriel Gonzalez
Maintained by [email protected]
This version can be pinned in stack with:pipes-4.3.4@sha256:b751135c7982df63e61f9fb2e0f0f46f6672c470cd7a6390625eaf0710c4f0eb,3589

Module documentation for 4.3.4

pipes is a clean and powerful stream processing library that lets you build and connect reusable streaming components

Advantages over traditional streaming libraries:

  • Concise API: Use simple commands like for, (>->), await, and yield

  • Blazing fast: Implementation tuned for speed, including shortcut fusion

  • Lightweight Dependency: pipes is small and compiles very rapidly, including dependencies

  • Elegant semantics: Use practical category theory

  • ListT: Correct implementation of ListT that interconverts with pipes

  • Bidirectionality: Implement duplex channels

  • Extensive Documentation: Second to none!

Import Pipes to use the library.

Read Pipes.Tutorial for an extensive tutorial.

Changes

4.3.4

  • Increase upper bound on mmorph

4.3.3

  • Make X a synonym for Data.Void.Void

4.3.2

  • BUG FIX: Fix MMonad instance for ListT
    • The old instance was an infinite loop

4.3.1

  • Support building against ghc-7.4

4.3.0

  • BREAKING CHANGE: Remove Alternative/MonadPlus instances for Proxy
    • See commit 08e7302f43dbf2a40bd367c5ee73ee3367e17768 which explains why
  • Add Traversable instance for ListT
  • New MonadThrow/MonadCatch/MMonad/Semigroup/MonadZip instances for ListT
  • New MonadThrow/MonadCatch instances for Proxy
  • Fix lower bound on mtl
  • Increase upper bound on optparse-applicative

4.2.0

  • BREAKING CHANGE: Switch from ErrorT to ExceptT
  • Add Foldable instance for ListT
  • Fix all warnings
  • Enable foldr/build fusion for toList

4.1.9

  • Increase lower bound on criterion
  • Increase upper bound on transformers for tests/benchmarks
  • Optimize code by delaying INLINABLE annotations

4.1.8

  • Increase upper bound on transformers
  • Prepare for MRP (Monad of no Return Proposal)

4.1.7

  • Increase lower bound on deepseq
  • Add unfoldr
  • Add loop
  • Add toListM'
  • Improve efficiency of drop
  • License tutorial under Creative Commons license

4.1.6

  • Increase lower bound on base
  • Add diagrams to Pipes.Core documentation
  • Add mapM_
  • Add takeWhile'
  • Add seq
  • Improve efficiency of toListM

4.1.5

  • Increase upper bound on criterion

4.1.4

  • Increase upper bound on criterion
  • Add Monoid instance for Proxy

4.1.3

  • Increase lower bound on mtl
  • Re-export void
  • Add fold'
  • Add foldM'

4.1.2

  • Increase upper bounds on transformers and mtl

4.1.1

  • Add runListT
  • Add MMonad instance for Proxy
  • Add repeatM
  • Add laws to documentation of Pipes.Prelude utilities

4.1.0

  • Remove Haskell98 support
  • Use internal X type instead of Data.Void
  • Document Pipes.Lift module:w
  • Add drain
  • Add sequence

4.0.2

  • Improve performance of each
  • Add tutorial appendix explaining how to work around quadratic time complexity

4.0.1

  • Remove WriterT and RWST benchmarks
  • Add Enumerable instance for ErrorT
  • Add cabal flag for Haskell98 compilation
  • Add several rewrite rules
  • Add mtl instances for ListT
  • Fix implementation of pass, which did not satisfy Writer laws
  • Implement fail for ListT
  • Add type synonym table to tutorial appendix
  • Add QuickCheck tests for pipes laws
  • Add mapFoldable
  • Add Monoid instance for ListT
  • Add manual proofs of pipes laws in laws.md

4.0.0

Major upgrade of pipes to no longer use Proxy type class