zio (empty) → 0.1.0.0
raw patch · 7 files changed
+611/−0 lines, 7 filesdep +basedep +mtldep +transformerssetup-changed
Dependencies added: base, mtl, transformers, unexceptionalio, unexceptionalio-trans, zio
Files
- ChangeLog.md +3/−0
- LICENSE +373/−0
- README.md +75/−0
- Setup.hs +2/−0
- src/ZIO/Trans.hs +97/−0
- test/Spec.hs +2/−0
- zio.cabal +59/−0
+ ChangeLog.md view
@@ -0,0 +1,3 @@+# Changelog for haskell-zio++## Unreleased changes
+ LICENSE view
@@ -0,0 +1,373 @@+Mozilla Public License Version 2.0+==================================++1. Definitions+--------------++1.1. "Contributor"+ means each individual or legal entity that creates, contributes to+ the creation of, or owns Covered Software.++1.2. "Contributor Version"+ means the combination of the Contributions of others (if any) used+ by a Contributor and that particular Contributor's Contribution.++1.3. "Contribution"+ means Covered Software of a particular Contributor.++1.4. "Covered Software"+ means Source Code Form to which the initial Contributor has attached+ the notice in Exhibit A, the Executable Form of such Source Code+ Form, and Modifications of such Source Code Form, in each case+ including portions thereof.++1.5. "Incompatible With Secondary Licenses"+ means++ (a) that the initial Contributor has attached the notice described+ in Exhibit B to the Covered Software; or++ (b) that the Covered Software was made available under the terms of+ version 1.1 or earlier of the License, but not also under the+ terms of a Secondary License.++1.6. "Executable Form"+ means any form of the work other than Source Code Form.++1.7. "Larger Work"+ means a work that combines Covered Software with other material, in+ a separate file or files, that is not Covered Software.++1.8. "License"+ means this document.++1.9. "Licensable"+ means having the right to grant, to the maximum extent possible,+ whether at the time of the initial grant or subsequently, any and+ all of the rights conveyed by this License.++1.10. "Modifications"+ means any of the following:++ (a) any file in Source Code Form that results from an addition to,+ deletion from, or modification of the contents of Covered+ Software; or++ (b) any new file in Source Code Form that contains any Covered+ Software.++1.11. "Patent Claims" of a Contributor+ means any patent claim(s), including without limitation, method,+ process, and apparatus claims, in any patent Licensable by such+ Contributor that would be infringed, but for the grant of the+ License, by the making, using, selling, offering for sale, having+ made, import, or transfer of either its Contributions or its+ Contributor Version.++1.12. "Secondary License"+ means either the GNU General Public License, Version 2.0, the GNU+ Lesser General Public License, Version 2.1, the GNU Affero General+ Public License, Version 3.0, or any later versions of those+ licenses.++1.13. "Source Code Form"+ means the form of the work preferred for making modifications.++1.14. "You" (or "Your")+ means an individual or a legal entity exercising rights under this+ License. For legal entities, "You" includes any entity that+ controls, is controlled by, or is under common control with You. For+ purposes of this definition, "control" means (a) the power, direct+ or indirect, to cause the direction or management of such entity,+ whether by contract or otherwise, or (b) ownership of more than+ fifty percent (50%) of the outstanding shares or beneficial+ ownership of such entity.++2. License Grants and Conditions+--------------------------------++2.1. Grants++Each Contributor hereby grants You a world-wide, royalty-free,+non-exclusive license:++(a) under intellectual property rights (other than patent or trademark)+ Licensable by such Contributor to use, reproduce, make available,+ modify, display, perform, distribute, and otherwise exploit its+ Contributions, either on an unmodified basis, with Modifications, or+ as part of a Larger Work; and++(b) under Patent Claims of such Contributor to make, use, sell, offer+ for sale, have made, import, and otherwise transfer either its+ Contributions or its Contributor Version.++2.2. Effective Date++The licenses granted in Section 2.1 with respect to any Contribution+become effective for each Contribution on the date the Contributor first+distributes such Contribution.++2.3. Limitations on Grant Scope++The licenses granted in this Section 2 are the only rights granted under+this License. No additional rights or licenses will be implied from the+distribution or licensing of Covered Software under this License.+Notwithstanding Section 2.1(b) above, no patent license is granted by a+Contributor:++(a) for any code that a Contributor has removed from Covered Software;+ or++(b) for infringements caused by: (i) Your and any other third party's+ modifications of Covered Software, or (ii) the combination of its+ Contributions with other software (except as part of its Contributor+ Version); or++(c) under Patent Claims infringed by Covered Software in the absence of+ its Contributions.++This License does not grant any rights in the trademarks, service marks,+or logos of any Contributor (except as may be necessary to comply with+the notice requirements in Section 3.4).++2.4. Subsequent Licenses++No Contributor makes additional grants as a result of Your choice to+distribute the Covered Software under a subsequent version of this+License (see Section 10.2) or under the terms of a Secondary License (if+permitted under the terms of Section 3.3).++2.5. Representation++Each Contributor represents that the Contributor believes its+Contributions are its original creation(s) or it has sufficient rights+to grant the rights to its Contributions conveyed by this License.++2.6. Fair Use++This License is not intended to limit any rights You have under+applicable copyright doctrines of fair use, fair dealing, or other+equivalents.++2.7. Conditions++Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted+in Section 2.1.++3. Responsibilities+-------------------++3.1. Distribution of Source Form++All distribution of Covered Software in Source Code Form, including any+Modifications that You create or to which You contribute, must be under+the terms of this License. You must inform recipients that the Source+Code Form of the Covered Software is governed by the terms of this+License, and how they can obtain a copy of this License. You may not+attempt to alter or restrict the recipients' rights in the Source Code+Form.++3.2. Distribution of Executable Form++If You distribute Covered Software in Executable Form then:++(a) such Covered Software must also be made available in Source Code+ Form, as described in Section 3.1, and You must inform recipients of+ the Executable Form how they can obtain a copy of such Source Code+ Form by reasonable means in a timely manner, at a charge no more+ than the cost of distribution to the recipient; and++(b) You may distribute such Executable Form under the terms of this+ License, or sublicense it under different terms, provided that the+ license for the Executable Form does not attempt to limit or alter+ the recipients' rights in the Source Code Form under this License.++3.3. Distribution of a Larger Work++You may create and distribute a Larger Work under terms of Your choice,+provided that You also comply with the requirements of this License for+the Covered Software. If the Larger Work is a combination of Covered+Software with a work governed by one or more Secondary Licenses, and the+Covered Software is not Incompatible With Secondary Licenses, this+License permits You to additionally distribute such Covered Software+under the terms of such Secondary License(s), so that the recipient of+the Larger Work may, at their option, further distribute the Covered+Software under the terms of either this License or such Secondary+License(s).++3.4. Notices++You may not remove or alter the substance of any license notices+(including copyright notices, patent notices, disclaimers of warranty,+or limitations of liability) contained within the Source Code Form of+the Covered Software, except that You may alter any license notices to+the extent required to remedy known factual inaccuracies.++3.5. Application of Additional Terms++You may choose to offer, and to charge a fee for, warranty, support,+indemnity or liability obligations to one or more recipients of Covered+Software. However, You may do so only on Your own behalf, and not on+behalf of any Contributor. You must make it absolutely clear that any+such warranty, support, indemnity, or liability obligation is offered by+You alone, and You hereby agree to indemnify every Contributor for any+liability incurred by such Contributor as a result of warranty, support,+indemnity or liability terms You offer. You may include additional+disclaimers of warranty and limitations of liability specific to any+jurisdiction.++4. Inability to Comply Due to Statute or Regulation+---------------------------------------------------++If it is impossible for You to comply with any of the terms of this+License with respect to some or all of the Covered Software due to+statute, judicial order, or regulation then You must: (a) comply with+the terms of this License to the maximum extent possible; and (b)+describe the limitations and the code they affect. Such description must+be placed in a text file included with all distributions of the Covered+Software under this License. Except to the extent prohibited by statute+or regulation, such description must be sufficiently detailed for a+recipient of ordinary skill to be able to understand it.++5. Termination+--------------++5.1. The rights granted under this License will terminate automatically+if You fail to comply with any of its terms. However, if You become+compliant, then the rights granted under this License from a particular+Contributor are reinstated (a) provisionally, unless and until such+Contributor explicitly and finally terminates Your grants, and (b) on an+ongoing basis, if such Contributor fails to notify You of the+non-compliance by some reasonable means prior to 60 days after You have+come back into compliance. Moreover, Your grants from a particular+Contributor are reinstated on an ongoing basis if such Contributor+notifies You of the non-compliance by some reasonable means, this is the+first time You have received notice of non-compliance with this License+from such Contributor, and You become compliant prior to 30 days after+Your receipt of the notice.++5.2. If You initiate litigation against any entity by asserting a patent+infringement claim (excluding declaratory judgment actions,+counter-claims, and cross-claims) alleging that a Contributor Version+directly or indirectly infringes any patent, then the rights granted to+You by any and all Contributors for the Covered Software under Section+2.1 of this License shall terminate.++5.3. In the event of termination under Sections 5.1 or 5.2 above, all+end user license agreements (excluding distributors and resellers) which+have been validly granted by You or Your distributors under this License+prior to termination shall survive termination.++************************************************************************+* *+* 6. Disclaimer of Warranty *+* ------------------------- *+* *+* Covered Software is provided under this License on an "as is" *+* basis, without warranty of any kind, either expressed, implied, or *+* statutory, including, without limitation, warranties that the *+* Covered Software is free of defects, merchantable, fit for a *+* particular purpose or non-infringing. The entire risk as to the *+* quality and performance of the Covered Software is with You. *+* Should any Covered Software prove defective in any respect, You *+* (not any Contributor) assume the cost of any necessary servicing, *+* repair, or correction. This disclaimer of warranty constitutes an *+* essential part of this License. No use of any Covered Software is *+* authorized under this License except under this disclaimer. *+* *+************************************************************************++************************************************************************+* *+* 7. Limitation of Liability *+* -------------------------- *+* *+* Under no circumstances and under no legal theory, whether tort *+* (including negligence), contract, or otherwise, shall any *+* Contributor, or anyone who distributes Covered Software as *+* permitted above, be liable to You for any direct, indirect, *+* special, incidental, or consequential damages of any character *+* including, without limitation, damages for lost profits, loss of *+* goodwill, work stoppage, computer failure or malfunction, or any *+* and all other commercial damages or losses, even if such party *+* shall have been informed of the possibility of such damages. This *+* limitation of liability shall not apply to liability for death or *+* personal injury resulting from such party's negligence to the *+* extent applicable law prohibits such limitation. Some *+* jurisdictions do not allow the exclusion or limitation of *+* incidental or consequential damages, so this exclusion and *+* limitation may not apply to You. *+* *+************************************************************************++8. Litigation+-------------++Any litigation relating to this License may be brought only in the+courts of a jurisdiction where the defendant maintains its principal+place of business and such litigation shall be governed by laws of that+jurisdiction, without reference to its conflict-of-law provisions.+Nothing in this Section shall prevent a party's ability to bring+cross-claims or counter-claims.++9. Miscellaneous+----------------++This License represents the complete agreement concerning the subject+matter hereof. If any provision of this License is held to be+unenforceable, such provision shall be reformed only to the extent+necessary to make it enforceable. Any law or regulation which provides+that the language of a contract shall be construed against the drafter+shall not be used to construe this License against a Contributor.++10. Versions of the License+---------------------------++10.1. New Versions++Mozilla Foundation is the license steward. Except as provided in Section+10.3, no one other than the license steward has the right to modify or+publish new versions of this License. Each version will be given a+distinguishing version number.++10.2. Effect of New Versions++You may distribute the Covered Software under the terms of the version+of the License under which You originally received the Covered Software,+or under the terms of any subsequent version published by the license+steward.++10.3. Modified Versions++If you create software not governed by this License, and you want to+create a new license for such software, you may create and use a+modified version of this License if you rename the license and remove+any references to the name of the license steward (except to note that+such modified license differs from this License).++10.4. Distributing Source Code Form that is Incompatible With Secondary+Licenses++If You choose to distribute Source Code Form that is Incompatible With+Secondary Licenses under the terms of this version of the License, the+notice described in Exhibit B of this License must be attached.++Exhibit A - Source Code Form License Notice+-------------------------------------------++ This Source Code Form is subject to the terms of the Mozilla Public+ License, v. 2.0. If a copy of the MPL was not distributed with this+ file, You can obtain one at http://mozilla.org/MPL/2.0/.++If it is not possible or desirable to put the notice in a particular+file, then You may include the notice in a location (such as a LICENSE+file in a relevant directory) where a recipient would be likely to look+for such a notice.++You may add additional accurate notices of copyright ownership.++Exhibit B - "Incompatible With Secondary Licenses" Notice+---------------------------------------------------------++ This Source Code Form is "Incompatible With Secondary Licenses", as+ defined by the Mozilla Public License, v. 2.0.
+ README.md view
@@ -0,0 +1,75 @@+# haskell-zio++A [small](src/ZIO/Trans.hs) monad-transformer analogue to the+Scala [ZIO](https://github.com/zio/zio)+library (basically, [UIO](http://hackage.haskell.org/package/unexceptionalio) ++[Reader](hackage.haskell.org/package/transformers/docs/Control-Monad-Trans-Reader.html) ++[Either/ExceptT](hackage.haskell.org/package/mtl/docs/Control-Monad-Except.html)).++I like to call `ZIO` a *best-practices monad for applications*. It+wraps in a `Reader` monad for carrying around configuration and+environment data, and slightly more controversially, makes+error-handling more explicit by making all recoverable\+[exceptions and errors](https://wiki.haskell.org/Error_vs._Exception)+part of the return-type of functions.++Note that this is meant to provide the same basic functionality of the `ZIO` monad.+While I'm not immediately looking into other features of ZIO-the-library, such as+concurrency, I welcome suggestions via issues or pull requests.++## Comparison to other Haskell libraries++- [UIO](http://hackage.haskell.org/package/unexceptionalio) This ZIO library+builds upon UIO (Unexceptional-IO) as a dependency, and it is the+inner-most monad in the transformer stack. We use UIO, in conjunction+with `ExceptT`, to model possible error states (or the lack thereof)+more explicitly. In other words, we are trying to make all errors or+exceptions.+[checked exceptions](https://en.wikibooks.org/wiki/Java_Programming/Checked_Exceptions), where possible. See the [blog post](https://singpolyma.net/2018/05/error-handling-in-haskell/) (or [backup](docs/UIO.md)) for more details.+- [RIO](https://hackage.haskell.org/package/rio)+[integrates](hackage.haskell.org/package/rio/docs/src/RIO.Prelude.RIO.html#RIO) `ReaderT` with `IO`, but somewhat like Scala ZIO, provides+much additional functionality, and providing much of that functionality\+will be a goal of haskell-zio as well.+- [Trio](https://github.com/snoyberg/trio) has essentially the same goals+as ZIO (and I believe it is isomorphic to ZIO), but is a self-described+experiment at the moment. The major experimental aspect I'm aware of is+that it is avoiding usage of `ExceptT` to improve performance, which+I have not investigated. We are currently aiming for stability here,+but ideally any code written for haskell-ZIO could easily be transferred+to using `Trio`, or vice versa. If you see a difference, **please raise an+issue** so we can document it or fix it.++## The Scala-Haskell ZIO dictionary++### Type Aliases+The Scala ZIO type parameters and+[aliases](https://zio.dev/docs/overview/overview_index#type-aliases) are+largely reproduced in Haskell, though in some cases we can't exactly+reproduce them. For instance, `IO` is already taken in Haskell at+a very fundamental level. As well, `UIO` has the same meaning as in+the Scala implementation, but it isn't an alias, since it is an inner+monad of the `ZIO` type.++An apparent downsize of having `UIO`, `EIO`, and `ZIO` as distinct+(non-aliased) types is that one might feel inclined to provide APIs+for one or more of these when warranted. For this reason `UEIO e`,+`UZIO a`, and other aliases along with associated lift and unlift+functions are provided. These aliases have `Void` in the expanded type,+and in some cases, it is more appropriate to use a universal quantifier,+e.g., when lifting into a type, we usually have some Error type in mind+other than `Void` (that's one big reason why we're using this library!),+so we'd prefer to have e.g. `uelift :: ∀ e a. UIO a -> EIO e a`,+not `uelift :: UIO a -> UEIO a`.++[//]: # (Table generated from docs/type_aliases.csv using https://www.tablesgenerator.com/markdown_tables)++| Haskell Type | Alias for | Scala Type | Notes |+|-------------- |------------------------------------- |-------------- |------------------------------------------------------------------------------------------------------- |+| `ZIO r e a` | | `ZIO[R,E,A]` | |+| `UIO a` | | `UIO[A]` | This is a type alias in Scala but a concrete type in Haskell due to UIO being an inner monadic type. |+| `EIO e a` | | `IO[E, A]` | This is a type alias in Scala but a concrete type in Haskell due to EIO being an inner monadic type. |+| `RIO r a` | `ZIO r SomeNonPseudoException a` | `RIO[R, A]` | Same idea as in Scala. Not to be confused with the RIO library's `RIO` monad, but they are isomorphic. |+| `Task a` | `ZIO Void SomeNonPseudoException a` | `Task[A]` | |+| `UEIO a` | `EIO Void a` | `UIO[A]` | |+| `URIO r a` | `ZIO r Void a` | `URIO[R, A]` | Same idea as in Scala; a ZIO value isomorphic to a RIO value (can be projected to the RIO value). |+| `UZIO a` | `ZIO Void Void a` | `UIO[A]` | |
+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ src/ZIO/Trans.hs view
@@ -0,0 +1,97 @@+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE RankNTypes #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE UnicodeSyntax #-}+++module ZIO.Trans (+ EIO(..), ZIO(..)+ , UEIO, URIO, UZIO, Task, RIO+ , elift, ezlift, zlift+ , uelift, uzlift+ , euUnlift, zuUnlift+ , mapEError, mapZError+ , runEIO, runZIO+ , withEIO, withZIO+ , module Control.Monad.Except+ , module Control.Monad.Reader+ , module UnexceptionalIO+ , module UnexceptionalIO.Trans++) where++import Control.Monad.Except+import Control.Monad.Reader hiding (lift)+import Data.Void (Void, absurd)+import UnexceptionalIO hiding (fromIO, lift, run)+import UnexceptionalIO.Trans (UIO, fromIO, run)++-- | Corresponds to IO[E, A] in Scala+newtype EIO e a = EIO { _unEIO :: ExceptT e UIO a }+ deriving ( Functor, Applicative, Monad, MonadError e, MonadFix, Unexceptional )++newtype ZIO r e a = ZIO { _unZIO :: ReaderT r (EIO e) a }+ deriving ( Functor, Applicative, Monad, MonadError e, MonadFix, MonadReader r, Unexceptional )++type UEIO a = EIO Void a++type URIO r a = ZIO r Void a++type UZIO a = ZIO Void Void a++type Task a = ZIO Void SomeNonPseudoException a++type RIO r a = ZIO r SomeNonPseudoException a++elift :: IO a -> EIO SomeNonPseudoException a+elift = EIO . fromIO++zlift :: IO a -> ZIO r SomeNonPseudoException a+zlift = ZIO . lift . elift++ezlift :: forall r e a. EIO e a -> ZIO r e a+ezlift = ZIO . lift++uelift :: ∀ e a. UIO a -> EIO e a+uelift = EIO . lift++uzlift :: ∀ r e a. UIO a -> ZIO r e a+uzlift = ezlift . uelift++euUnlift :: UEIO a -> UIO a+euUnlift ueio = (either absurd id) <$> ((runExceptT . _unEIO) ueio)++zuUnlift :: UZIO a -> UIO a+zuUnlift = euUnlift . flip runReaderT undefined . _unZIO++runEIO :: MonadIO m => EIO e a -> (e -> m a) -> m a+runEIO eio handler = do+ resEi :: Either e a <- (run . runExceptT . _unEIO) eio+ either handler pure resEi++withEIO :: (e -> e') -> EIO e a -> EIO e' a+withEIO h = EIO+ . withExceptT h+ . _unEIO++mapEError :: (e -> e') -> EIO e a -> EIO e' a+mapEError = withEIO++runZIO :: MonadIO m => ZIO r e a -> r -> (e -> m a) -> m a+runZIO app env handler = do+ let eio = runReaderT (_unZIO app) env+ runEIO eio handler++withZIO :: r -> (e -> e') -> ZIO r e a -> ZIO r e' a+withZIO r h = ezlift+ . EIO+ . withExceptT h+ . _unEIO+ . flip runReaderT r+ . _unZIO++mapZError :: (e -> e') -> ZIO r e a -> ZIO r e' a+mapZError h m = do+ r <- ask+ withZIO r h m+
+ test/Spec.hs view
@@ -0,0 +1,2 @@+main :: IO ()+main = putStrLn "Test suite not yet implemented"
+ zio.cabal view
@@ -0,0 +1,59 @@+cabal-version: 1.12++-- This file has been generated from package.yaml by hpack version 0.33.0.+--+-- see: https://github.com/sol/hpack+--+-- hash: 6be80043f3a5bef1bd4f8f34b4c51639fdb74962f2377876443eab74c7fd669e++name: zio+version: 0.1.0.0+description: Please see the README on GitHub at <https://github.com/githubuser/haskell-zio#readme>+homepage: https://github.com/githubuser/haskell-zio#readme+bug-reports: https://github.com/githubuser/haskell-zio/issues+author: Brandon Elam Barker+maintainer: brandon.barker@cornell.edu+copyright: 2020 Brandon Elam Barker+license: MPL-2.0+license-file: LICENSE+build-type: Simple+extra-source-files:+ README.md+ ChangeLog.md++source-repository head+ type: git+ location: https://github.com/githubuser/haskell-zio++library+ exposed-modules:+ ZIO.Trans+ other-modules:+ Paths_zio+ hs-source-dirs:+ src+ ghc-options: -Wall -Wtabs -Wincomplete-record-updates+ build-depends:+ base >=4.7 && < 5+ , mtl >= 2.2 && < 2.3+ , transformers >= 0.5.6 && < 0.6+ , unexceptionalio >= 0.5.1 && < 0.6+ , unexceptionalio-trans >= 0.5.1 && < 0.6+ default-language: Haskell2010++test-suite zio-test+ type: exitcode-stdio-1.0+ main-is: Spec.hs+ other-modules:+ Paths_zio+ hs-source-dirs:+ test+ ghc-options: -threaded -rtsopts -with-rtsopts=-N+ build-depends:+ base+ , mtl+ , transformers+ , unexceptionalio+ , unexceptionalio-trans+ , zio+ default-language: Haskell2010