diff --git a/changelog.md b/changelog.md new file mode 100644 --- /dev/null +++ b/changelog.md @@ -0,0 +1,11 @@ +### 1.0.0.2 (2023-01-10) + +Support GHC 9.4 + +### 1.0.0.1 (2022-02-25) + +Support GHC 9.2 + +### 1.0.0.0 (2021-07-27) + +Initial release diff --git a/changelog.txt b/changelog.txt deleted file mode 100644 --- a/changelog.txt +++ /dev/null @@ -1,2 +0,0 @@ -v1.0.0.0 - Initial release -v1.0.0.1 - Support GHC 9.2 diff --git a/lazy-async.cabal b/lazy-async.cabal --- a/lazy-async.cabal +++ b/lazy-async.cabal @@ -1,118 +1,102 @@ cabal-version: 3.0 name: lazy-async -version: 1.0.0.1 +version: 1.0.0.2 synopsis: Asynchronous actions that don't start right away +category: Concurrency -description: +description: Sometimes we have a bunch of I/O actions that might not end up + being needed, and we don't want to simply run all the actions upfront. + We also don't want to simply run an action right before its result is + needed, because it might be needed in more than one place, which opens + the possibility of unnecessarily running the same action more than once. + In situations like these, we use LazyAsync. - Sometimes we have a bunch of 'IO' actions that do things like - read files, make HTTP requests, or query a database. Some of the - information that these actions produce might not end up being - needed, depending on the breaks. In the interest of avoiding - unnecessary effort, we don't want to simply run all the actions - and collect their results upfront. We also don't want to simply - run an action right before its result is needed, because it might - be needed in more than one place, which opens the possibility of - unnecessarily running the same action more than once. In - situations like these, we use "LazyAsync". +homepage: https://github.com/typeclasses/lazy-async +bug-reports: https://github.com/typeclasses/lazy-async/issues - Under the hood, an 'IO' action is turned into a @LazyAsync@ by - constructing two things: An @Async@ (from the @async@ package), - and a @TVar Bool@ (from the @stm@ package). The TVar, initialized - to @False@, indicates whether the action is wanted yet. The async - thread waits until the TVar turns @True@ and then runs the action. +author: Chris Martin +maintainer: Chris Martin, Julie Moronuki -homepage: https://github.com/typeclasses/lazy-async -bug-reports: https://github.com/typeclasses/lazy-async/issues -author: Chris Martin -maintainer: Chris Martin, Julie Moronuki -copyright: 2021 Mission Valley Software LLC -license: MIT -license-file: license.txt -category: Concurrency -build-type: Simple +copyright: 2021 Mission Valley Software LLC +license: MIT +license-file: license.txt -extra-source-files: changelog.txt +extra-source-files: *.md source-repository head - type: git - location: https://github.com/typeclasses/lazy-async + type: git + location: https://github.com/typeclasses/lazy-async common language - default-language: Haskell2010 - ghc-options: -Wall - default-extensions: DeriveFoldable - default-extensions: DeriveFunctor - default-extensions: DeriveTraversable - default-extensions: ExistentialQuantification - default-extensions: FlexibleContexts - default-extensions: NoImplicitPrelude - default-extensions: StandaloneDeriving + default-language: Haskell2010 + ghc-options: -Wall + default-extensions: + DeriveFoldable + DeriveFunctor + DeriveTraversable + ExistentialQuantification + FlexibleContexts + NoImplicitPrelude + StandaloneDeriving common dependencies - build-depends: base ^>= 4.14 || ^>= 4.15 - || ^>= 4.16 - build-depends: exceptions ^>= 0.10.4 - build-depends: lifted-async ^>= 0.10.0.6 - build-depends: monad-control ^>= 1.0.2.3 - build-depends: rank2classes ^>= 1.4.0.1 - build-depends: stm ^>= 2.5 - build-depends: transformers ^>= 0.5.6.2 - build-depends: transformers-base ^>= 0.4.5.1 - -common test-language - import: language - default-extensions: BlockArguments - default-extensions: OverloadedStrings - default-extensions: TemplateHaskell - -common test-dependencies - import: dependencies - build-depends: hedgehog ^>= 1.0.4 - build-depends: lazy-async - build-depends: optics-core ^>= 0.3 || ^>= 0.4 - build-depends: optics-th ^>= 0.3 || ^>= 0.4 - -common test-modules - other-modules: Test.Counter - other-modules: Test.Exceptions - other-modules: Test.General - other-modules: Test.Optics - other-modules: Test.Person - -common test - import: test-language, test-dependencies, test-modules + build-depends: + , base ^>= 4.14 || ^>= 4.15 || ^>= 4.16 || ^>= 4.17 + , exceptions ^>= 0.10.4 + , lifted-async ^>= 0.10.2 + , monad-control ^>= 1.0.3 + , rank2classes ^>= 1.4.4 + , stm ^>= 2.5 + , transformers ^>= 0.5.6 + , transformers-base ^>= 0.4.6 library - import: language, dependencies - hs-source-dirs: src - exposed-modules: LazyAsync - other-modules: LazyAsync.Actions - other-modules: LazyAsync.Actions.Empty - other-modules: LazyAsync.Actions.Memoize - other-modules: LazyAsync.Actions.Merge - other-modules: LazyAsync.Actions.Poll - other-modules: LazyAsync.Actions.Pure - other-modules: LazyAsync.Actions.Spawn - other-modules: LazyAsync.Actions.Start - other-modules: LazyAsync.Actions.StartWait - other-modules: LazyAsync.Actions.Wait - other-modules: LazyAsync.Libraries.Async - other-modules: LazyAsync.Libraries.Rank2 - other-modules: LazyAsync.Orphans - other-modules: LazyAsync.Prelude - other-modules: LazyAsync.Types - other-modules: LazyAsync.Types.Complex - other-modules: LazyAsync.Types.LazyAsync - other-modules: LazyAsync.Types.NoAlternative - other-modules: LazyAsync.Types.Outcome - other-modules: LazyAsync.Types.Resource - other-modules: LazyAsync.Types.StartPoll - other-modules: LazyAsync.Types.Status + import: language, dependencies + hs-source-dirs: src + exposed-modules: + LazyAsync + other-modules: + LazyAsync.Actions + LazyAsync.Actions.Empty + LazyAsync.Actions.Memoize + LazyAsync.Actions.Merge + LazyAsync.Actions.Poll + LazyAsync.Actions.Pure + LazyAsync.Actions.Spawn + LazyAsync.Actions.Start + LazyAsync.Actions.StartWait + LazyAsync.Actions.Wait + LazyAsync.Libraries.Async + LazyAsync.Libraries.Rank2 + LazyAsync.Orphans + LazyAsync.Prelude + LazyAsync.Types + LazyAsync.Types.Complex + LazyAsync.Types.LazyAsync + LazyAsync.Types.NoAlternative + LazyAsync.Types.Outcome + LazyAsync.Types.Resource + LazyAsync.Types.StartPoll + LazyAsync.Types.Status test-suite test - import: test - hs-source-dirs: test - type: exitcode-stdio-1.0 - main-is: test.hs + import: language, dependencies + hs-source-dirs: test + type: exitcode-stdio-1.0 + main-is: test.hs + default-extensions: + BlockArguments + OverloadedStrings + TemplateHaskell + build-depends: + , hedgehog ^>= 1.0.5 || ^>= 1.1 || ^>= 1.2 + , lazy-async + , optics-core ^>= 0.4.1 + , optics-th ^>= 0.4.1 + other-modules: + Test.Counter + Test.Exceptions + Test.General + Test.Optics + Test.Person diff --git a/readme.md b/readme.md new file mode 100644 --- /dev/null +++ b/readme.md @@ -0,0 +1,18 @@ +Sometimes we have a bunch of `IO` actions that do things like read files, make +HTTP requests, or query a database. Some of the information that these actions +produce might not end up being needed, depending on the breaks. In the interest +of avoiding unnecessary effort, we don't want to simply run all the actions and +collect their results upfront. We also don't want to simply run an action right +before its result is needed, because it might be needed in more than one place, +which opens the possibility of unnecessarily running the same action more than +once. In situations like these, we use `LazyAsync`. + +Under the hood, an `IO` action is turned into a `LazyAsync` by constructing two +things: An `Async` (from the [async] package), and a `TVar Bool` (from the [stm] +package). The `TVar`, initialized to `False`, indicates whether the action is +wanted yet. The asynchronous thread waits until the `TVar` turns @True@ and then +runs the action. + + [async]: https://hackage.haskell.org/package/async + + [stm]: https://hackage.haskell.org/package/stm