diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,20 @@ +Copyright (c) 2014 Oleg Kiselyov, Amr Sabry, Cameron Swords, Ben Foppa + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be included +in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, +TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE +SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,25 @@ +extensible-effects is based on the work +[Extensible Effects: An Alternative to Monad Transformers](http://okmij.org/ftp/Haskell/extensible/). +Please read the [paper](http://okmij.org/ftp/Haskell/extensible/exteff.pdf) for details. + +## Advantages + + * Effects can be added, removed, and interwoven without changes to code not + dealing with those effects. + +## Disadvantages + + * Common functions can't be grouped using typeclasses, e.g. + the `ask` and `getState` functions can't be grouped with some + + class Get t a where + ask :: Member (t a) r => Eff r a + + `ask` is inherently ambiguous, since the type signature only provides + a constraint on `t`, and nothing more. To specify fully, a parameter + involving the type `t` would need to be added, which would defeat the point + of having the grouping in the first place. + + * Requires a `Typeable` instance on the return type. + * Neither `Eff` nor `(:>)` has a `Typeable` instance, and can thus often not + be used as a return type (e.g. `State` type) for other `Eff`s. diff --git a/extensible-effects.cabal b/extensible-effects.cabal --- a/extensible-effects.cabal +++ b/extensible-effects.cabal @@ -1,28 +1,64 @@ -Name: extensible-effects -Version: 1.7.1.1 -Synopsis: An Alternative to Monad Transformers -Description: This package introduces datatypes for typeclass-constrained effects, +name: extensible-effects + +-- The package version. See the Haskell package versioning policy (PVP) +-- for standards guiding when and how versions should be incremented. +-- http://www.haskell.org/haskellwiki/Package_versioning_policy +-- PVP summary: +-+------- breaking API changes +-- | | +----- non-breaking API additions +-- | | | +--- code changes with no API change +version: 1.7.1.2 + +-- A short (one-line) description of the package. +synopsis: An Alternative to Monad Transformers + +-- A longer description of the package. +description: This package introduces datatypes for typeclass-constrained effects, as an alternative to monad-transformer based (datatype-constrained) approach of multi-layered effects. For more information, see the original paper at . Any help is appreciated! -Category: Control, Effect -Author: Oleg Kiselyov, Amr Sabry, Cameron Swords, Ben Foppa -Stability: Experimental -Homepage: https://github.com/RobotGymnast/extensible-effects -Maintainer: suhailshergill@gmail.com -License: MIT -Tested-With: GHC==7.8.2 -Build-Type: Simple -Cabal-Version: >= 1.9.2 +stability: Experimental + +-- URL for the project homepage or repository. +homepage: https://github.com/RobotGymnast/extensible-effects + +-- The license under which the package is released. +license: MIT + +-- The file containing the license text. +license-file: LICENSE + +-- The package author(s). +author: Oleg Kiselyov, Amr Sabry, Cameron Swords, Ben Foppa + +-- An email address to which users can send suggestions, bug reports, and +-- patches. +maintainer: suhailshergill@gmail.com + +-- A copyright notice. +-- copyright: + +category: Control, Effect + +tested-with: GHC==7.8.2 + +build-type: Simple + +-- Extra files to be distributed with the package, such as examples or a +-- README. +extra-source-files: README.md + +-- Constraint on the version of Cabal needed to build this package. +cabal-version: >=1.10 + + library - hs-source-dirs: src/ - ghc-options: -Wall - extensions: Trustworthy - exposed-modules: Control.Eff + ghc-options: -Wall + -- Modules exported by the library. + exposed-modules: Control.Eff Control.Eff.Choose Control.Eff.Coroutine Control.Eff.Cut @@ -38,12 +74,45 @@ Control.Eff.Trace Data.OpenUnion1 - build-depends: - base >= 4.6 && < 5 - -- For MonadIO instance - , transformers >= 0.3 && < 0.5 - -- For MonadBase instance - , transformers-base == 0.4.* + -- Modules included in this library but not exported. + -- other-modules: + + default-extensions: Trustworthy + -- LANGUAGE extensions used by modules in this package. + other-extensions: BangPatterns + , CPP + , DeriveDataTypeable + , DeriveFunctor + , EmptyDataDecls + , ExistentialQuantification + , FlexibleContexts + , FlexibleInstances + , FunctionalDependencies + , GeneralizedNewtypeDeriving + , KindSignatures + , MultiParamTypeClasses + , NoMonomorphismRestriction + , OverlappingInstances + , PatternGuards + , PolyKinds + , RankNTypes + , ScopedTypeVariables + , TupleSections + , TypeOperators + , UndecidableInstances + + -- Other library packages from which modules are imported. + build-depends: base >= 4.6 && < 5 + -- For MonadIO instance + , transformers >= 0.3 && < 0.5 + -- For MonadBase instance + , transformers-base == 0.4.* + + -- Directories containing source files. + hs-source-dirs: src + + -- Base language which the package is written in. + default-language: Haskell2010 test-suite extensible-effects-tests type: exitcode-stdio-1.0