effects: Computational Effects

[ bsd3, control, library, monads ] [ Propose Tags ]

Control.Effects is a library for programming with effects, like in the the Eff language by Andrej Bauer and Matija Pretnar. Effects can be used instead of monad transformers.

See the home page for some example code.

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Versions [faq]	0, 0.1, 0.2, 0.2.1, 0.2.2, 0.2.3
Dependencies	base (>=3 && <5), containers (==0.4.), newtype (==0.2.), void [details]
License	BSD-3-Clause
Author	Sjoerd Visscher
Maintainer	sjoerd@w3future.com
Category	Control, Monads
Home page	http://github.com/sjoerdvisscher/effects
Bug tracker	http://github.com/sjoerdvisscher/effects/issues
Source repo	head: git clone git://github.com/sjoerdvisscher/effects.git
Uploaded	by SjoerdVisscher at Sat Dec 3 15:49:26 UTC 2011
Distributions	NixOS:0.2.3
Downloads	2665 total (129 in the last 30 days)
Rating	(no votes yet) [estimated by rule of succession]
Your Rating	λ λ λ
Status	Docs not available [build log] All reported builds failed as of 2016-12-26 [all 7 reports]

Modules

Control
- Control.Effects
  - Control.Effects.Cont
  - Control.Effects.Either
  - Control.Effects.Error
  - Control.Effects.NonDet
  - Control.Effects.State
  - Control.Effects.Writer

Downloads

effects-0.2.1.tar.gz [browse] (Cabal source package)
Package description (as included in the package)

Maintainer's Corner

For package maintainers and hackage trustees

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Readme for effects-0.2.1

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Control.Effects

Control.Effects is a Haskell library for programming with effects, like in the the Eff language by Andrej Bauer and Matija Pretnar. Effects can be used instead of monad transformers, they are designed to be easier to use and to define.

Installation

cabal install effects

Using effects

Here's an example how to use the state effect from Control.Effects.State.

example :: (Int, Int)
example = run $ do
  with (ref 5) $ \x -> do
    with (ref 10) $ \y -> do
      x =: (+) <$> get x <*> get y
      y =: (+) <$> get x <*> get y
      (,) <$> get x <*> get y

Every instance of an effect is given a name (x and y in this example), which makes is possible to easily mix several instances of the same effect.

For more examples see examples.hs.