effin: A Typeable-free implementation of extensible effects

[ bsd3, control, effect, library ] [ Propose Tags ] [ Report a vulnerability ]

This package implements extensible effects, an alternative to monad transformers. The original paper can be found at http://okmij.org/ftp/Haskell/extensible/exteff.pdf. The main differences between this library and the one described in the paper are that this library does not use the Typeable type class, does not require that effects implement the Functor type class, and has a simpler API for handling effects.

For example, the following code implements a handler for exceptions:

newtype Exception e = Throw e

runException :: Effect (Exception e :+ es) a -> Effect es (Either e a)
runException = eliminate
    (\x -> return (Right x))
    (\(Throw e) k -> return (Left e))

Compare this to the corresponding code in extensible-effects (http://hackage.haskell.org/package/extensible-effects):

runExc :: Typeable e => Eff (Exc e :> r) a -> Eff r (Either e a)
runExc = loop . admin
  where
    loop (Val x) = return (Right x)
    loop (E u)   = handleRelay u loop (\(Exc e) -> return (Left e))

In particular, effect implementors are not required to do any recursion, thereby making effect handlers more composeable.

Flags

Manual Flags

NameDescriptionDefault
mtl

Enable MTL support

Enabled

Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info

Downloads

Maintainer's Corner

Package maintainers

For package maintainers and hackage trustees

Candidates

  • No Candidates
Versions [RSS] 0.1.0.0, 0.1.0.1, 0.1.1.0, 0.2.0.0, 0.2.1.0, 0.2.1.1, 0.2.1.2, 0.2.1.3, 0.3.0.1, 0.3.0.2, 0.3.0.3
Dependencies base (>=4.7 && <4.11), mtl (>=2.1 && <3) [details]
License BSD-3-Clause
Copyright (c) 2014 Anthony Vandikas
Author Anthony Vandikas
Maintainer yellpika@gmail.com
Category Control, Effect
Home page https://github.com/YellPika/effin
Source repo head: git clone git://github.com/YellPika/effin.git
Uploaded by AnthonyVandikas at 2017-08-03T04:03:13Z
Distributions
Reverse Dependencies 3 direct, 0 indirect [details]
Downloads 8746 total (15 in the last 30 days)
Rating (no votes yet) [estimated by Bayesian average]
Your Rating
  • λ
  • λ
  • λ
Status Docs available [build log]
Last success reported on 2017-08-03 [all 1 reports]