- Haskell-Cafe - Haskell.org

[ANN] dunai-0.10.1 and bearriver-0.14.1
by Ivan Perez 07 Mar '23

07 Mar '23

Dear all, I'm happy to announce the release of Dunai 0.10.1 and Bearriver 0.14.1! Dunai is a reactive programming library structured around a notion of Monadic Stream Functions. Dunai can be used to implement other reactive and FRP frameworks on top, including Classic FRP and Arrowized FRP variants. Dunai comes with: - bearriver: API-compatible implementation of Yampa. (The Bear River is a tributary to the Yampa river.) - dunai-test: QuickCheck-based temporal testing library that can be connected with the testing system haskell-titan. See https://github.com/ivanperez-keera/dunai#features for details on Dunai's features. This new release introduces a breaking change in Monadic Stream Functions' instance of VectorSpaces. Most code using that instance should work without changes but, in some cases, the use of 'constantly' is now necessary. (This case is described in the discussion thread of issue #298.) * Summary of Version 0.10.1: - Implement dot in MSF's instance of VectorSpace (#298). - Enable FlexibleContexts in VectorSpace instance module (#344). As always, dunai, dunai-test and bearriver are released in sync. For details, see: - https://github.com/ivanperez-keera/dunai/releases/tag/v0.10.1 * Releases You can explore the current versions at: - https://hackage.haskell.org/package/dunai - https://hackage.haskell.org/package/dunai-test - https://hackage.haskell.org/package/bearriver * Code The github repo is located at: https://github.com/ivanperez-keera/dunai * What's coming This release comes exactly 2 months after the last release. The next release is planned for Apr 21, 2023. There are several issues open that you can contribute to: https://github.com/ivanperez-keera/dunai/issues Following our roadmap, the pending changes remain as follows: - Full conformance to style guide. - Benchmarks: Facilitate making sound, evidence-based decisions about suggested improvements to the implementation, by completing a series of benchmarks. * Donations Our project is now seeking donations to help continue developing dunai, create new open source libraries, new material, and give talks. Special thanks go to @johannes-riecken for sponsoring my work on the dunai project with a regular contribution. Github will match the first 5K donated, so if you donate $1/month, github will donate the same amount. No donation is too small. Any contribution will absolutely help. See https://github.com/sponsors/ivanperez-keera for details. If you can help, please come forward. All the best, Ivan

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Take-over request for: snappy
by Andrey Prokopenko 06 Mar '23

06 Mar '23

Hello, - Few months ago Andrew Martin opened PR in `snappy`: https://github.com/bos/snappy/pull/10 <https://github.com/bos/snappy/pull/10> - The package is either direct or transient dependency for `tensorflow`, `kafka-client` and few more packages. - While forks maintenance is a well-known practice it creates burden on maintainers. - Moreover, I cannot easily fix cabal build for tensorflow for different GHC versions. Note for Bryan: I haven’t forked `snappy` so there will be no name clashes during the transfer. I would like to become a maintainer for `snappy` package and keep it up-to-date at least for a next few years. I have already followed that procedure a few years ago for `blaze-textual` package. (Recently I discovered a flaw in my maintenance setup and fixed it.) So my intent is to resolve recent PRs and to keep supporting for newer compiler versions and build tools. Please consider this message as a step 2 in take-over procedure: https://wiki.haskell.org/Taking_over_a_package <https://wiki.haskell.org/Taking_over_a_package> Kind Regards, Andrey Prokopenko

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[ANNOUNCE] GHC 9.6.1-rc1 is now available
by Ben Gamari 03 Mar '23

03 Mar '23

The GHC team is very pleased to announce the availability of the first (and likely final) release candidate of GHC 9.6.1. As usual, binaries and source distributions are available at [downloads.haskell.org](https://downloads.haskell.org/ghc/9.6.1-rc1/). Beginning with GHC 9.6.1, GHC can be built as a cross-compiler to WebAssembly and JavaScript. This is an important step towards robust support for compiling Haskell to the Web, but there are a few caveats to be aware of in the 9.6 series: - Both the Javascript and WebAssembly backends are still at an early stage of development and are present in this release as a technology preview - Using GHC as a cross-compiler is not as easy as we would like it to be; in particular, there are challenges related to Template Haskell - GHC is not yet run-time retargetable; a given GHC binary targets exactly one platform, and both WebAssembly and JavaScript are considered platforms for this purpose. Cross-compilers must be built from source by their users We hope to lift all of these limitations in future releases. Additionally, 9.6.1 will include: - Significant latency improvements in the non-moving garbage collector - Efficient runtime support for delimited continuations - Improvements in compiler error messages - Numerous improvements in the compiler's memory usage See the [release notes][] for a comprehensive accounting of changes in this release. As always, one can find a migration guide to aid in transitioning from older releases on the [GHC Wiki][migration-guide]. We have also recently started extending our release process to cover a wider set of Linux distributions. In particular, we now offer Rocky 8 and Ubuntu 20.04 binary distributions which cover RedHat-derivative and distributions using older `glibc` releases (namely 2.27), respectively. Please do give this release a try and open a [ticket][] if you see anything amiss. If all goes well we expect the final release should be available by late next week. Happy Haskelling, ~ Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/ [migration-guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6 [release notes]: https://downloads.haskell.org/ghc/9.6.1-rc1/docs/users_guide/9.6.1-notes.ht…

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dynamic web form generation for algebraic data types
by Olaf Klinke 03 Mar '23

03 Mar '23

Dear Cafe, has anyone ever attempted (and maybe succeeded) in building dynamic forms using one of the Haskell web frameworks (Yesod,Servant,...)? By "dynamic" form I mean a form that changes the number of fields based on selections the user makes in other fields of the form. For example, say one has an algebraic data type data T = Number Int | Check Bool T A form for such a type would initially consist of radio buttons or a drop-down list with options "Number" and "Check" that lets the user select the constructor. When "Number" is selected, an <input type="number"> field is shown. When "Check" is selected, an <input type="checkbox"> is displayed next to another form of this kind. In the end, one would use the GHC.Generics machinery to generate forms for a wide range of algebraic data types. I've seen this in the Clean language's iTask library [1] and it's very convenient. Of course this would involve a lot of JavaScript like document.createElement() as well as book-keeping how to re-asseble the fields into a T value upon submission. At least the latter is already handled by libraries such as yesod-form. Olaf [1] https://cloogle.org/src/#itasks/iTasks/UI/Editor/Generic [2] https://github.com/haskell-servant/servant-swagger/issues/80

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Re: [Haskell-cafe] dynamic web form generation for algebraic data types
by Gustavo Bicalho 03 Mar '23

03 Mar '23

>From briefly reading the wiki page https://wiki.haskell.org/Tangible_Value, it looks like it relies on Applicative functors for combining values. So maybe the missing piece for sum-types was Selective functors https://hackage.haskell.org/package/selective? Gustavo Bicalho > ---------- Forwarded message ---------- > From: Olaf Klinke <olf(a)aatal-apotheke.de> > To: Ivan Perez <ivanperezdominguez(a)gmail.com> > Cc: "Haskell Café" <haskell-cafe(a)haskell.org> > Bcc: > Date: Thu, 02 Mar 2023 17:40:18 +0100 > Subject: Re: [Haskell-cafe] dynamic web form generation for algebraic data types > On Thu, 2023-03-02 at 07:34 -0800, Ivan Perez wrote: > > All of this reminds me of Conal Elliott's Tangible Values. > > > > http://conal.net/papers/Eros/ > > > > (Not for web but the idea still applies.) > > > > Ivan > > Yes, the concept has been re-invented multiple times, as is the case > with most good ideas. TVs are general enough to bolt a web interface on > top, I guess. > > Seems that Conal, too, has not solved the sum type problem. > The tangible value GADT > https://hackage.haskell.org/package/TV-0.5.0/docs/Interface-TV-Input.html > has a Pair constructor but not for Sum. I wonder whether there is a > deeper categorical reason for this. > > So I should re-phrase my question: > Has anyone extended tangible values to Generic types and given them a > modern html interface? > > Olaf

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Re: [Haskell-cafe] Status of ghcup?
by Anthony Clayden 03 Mar '23

03 Mar '23

> Sigh. As a college educator who is trying to use Haskell in as many classes as possible, ... > you better fire up Notepad.exe. ... some decent syntax highlighting, Hi Todd, and Mig, I too feel your pain. And Windows seems to have always been a neglected child in distros -- even when SPJ was actually sponsored by MSoft. If you're only trying to give a flavour of Haskell for (say) a few weeks intro, I don't see that you even need all the drama of ghcup. Perhaps just ignore what it says on the GHC download pages, and grab the compiler plus minimal libraries. Then you can either defer a 'proper' install until students are motivated enough to go through the pain; or don't bother/they've gone on to other subjects. I agree syntax highlighting is very helpful for newbies: I use NotePad++ for editing and not even VSCode for compiling, but GHCi. I suspect these fully integrated dev environments are quite confusing for newbies. (Unless they've already experienced them with other languages.) Hard for me to be sure: they simply weren't a thing when I learned Haskell. These days I have installed VSCode; I seldom use it (just way too much clutter around the screen). AntC

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[ANN] landlock 0.2.1.0
by Nicolas Trangez 27 Feb '23

27 Feb '23

I’m happy to announce the latest version of `landlock`, a Haskell library to access the Linux Landlock LSM API. This version updates the library to expose all Landlock features up to Linux 6.2 (Landlock ABI 3). It also introduces `landlocked`[1], a utility to spawn some process in a landlocked environment, and serves as a demo of how to use the API (next to the library documentation[2] and README.md[3]). It’s available on Hackage[4] and GitHub[5]. The Linux kernel Landlock API provides unprivileged access control. The goal of Landlock is to enable to restrict ambient rights (e.g. global filesystem access) for a set of processes. Because Landlock is a stackable LSM, it makes possible to create safe security sandboxes as new security layers in addition to the existing system-wide access- controls. This kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves. For more information, see the Landlock homepage[6] and its kernel documentation[7]. [1] https://github.com/NicolasT/landlock-hs/blob/27d2d95478f8c85cfbf4025bb41d57… [2] https://hackage.haskell.org/package/landlock-0.2.1.0/docs/System-Landlock.h… [3] https://github.com/NicolasT/landlock-hs/tree/main/landlock#readme [4] https://hackage.haskell.org/package/landlock-0.2.1.0 [5] https://github.com/NicolasT/landlock-hs [6] https://landlock.io/ [7] https://docs.kernel.org/userspace-api/landlock.html

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[Haskell] [ANNOUNCE] GHC 9.2.7 released
by Zubin Duggal 27 Feb '23

27 Feb '23

The GHC developers are happy to announce the availability of GHC 9.2.7. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org](https://downloads.haskell.org/ghc/9.2.7). Download Page: https://www.haskell.org/ghc/download_ghc_9_2_7.html Blog Post: https://www.haskell.org/ghc/blog/20230227-ghc-9.2.7-released.html This release is primarily a bugfix release addressing a few issues found in 9.2.6. These include: * A fix for a bug with the RTS linker being unable to resolve the `setKeepCafs` symbol which started being used by the GHC library in 9.2.6, resulting in code depending on this symbol failing to load in GHCi or via a compile time splice when using a statically linked GHC, such as on Windows (#22961). * A fix a bug with the alignment of RTS data structures that could result in segfaults when compiled with high optimisation settings on certain platforms (#22975 , #22965). * A fix for a bug in the simplifier related to placeholder values (rubbish literals) emitted by the worker/wrapper optimisation leading to -dcore-lint errors and compiler panics in certain cases (#19882, #22914, #23000). * Easier installation of binary distribution on MacOS platforms by changing the installation Makefile to remove the quarantine attribute when installing. * ... and a few more. See the [release notes] for a full accounting. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, Haskell Foundation, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do give this release a try and open a [ticket][] if you see anything amiss. Happy compiling, - Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.2.7/docs/html/users_guide/9.2.7-notes.…

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Munich Haskell Meeting, 2023-02-28 @ 19:30
by Leah Neukirchen 27 Feb '23

27 Feb '23

Dear all, Next week, our monthly Munich Haskell Meeting will take place again on Tuesday, February 28 at Cafe Puck at 19h30. For details see here: http://muenchen.haskell.bayern/dates.html If you plan to join, please add yourself to this nuudel so we can reserve enough seats! It is OK to add yourself to the dudle anonymously or pseudonymously. https://nuudel.digitalcourage.de/1HlsYFhVtoBdDSSM Everybody is welcome! cu, -- Leah Neukirchen <leah(a)vuxu.org> https://leahneukirchen.org/

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[ANN] NASA's Ogma 1.0.7
by Ivan Perez 25 Feb '23

25 Feb '23

Hi everyone! I'm really excited to announce the release of Ogma 1.0.7! Ogma is a NASA tool that facilitates integrating runtime monitors or runtime verification applications into other systems. Ogma extends Copilot [1], a high-level runtime verification framework that generates hard real-time code. In spite of the small increase in the version number, the feature included in this version is big: we now generate monitors for Robot Operating System (ROS 2) applications. Use cases supported by Ogma also include generating monitors directly from requirements specified using a structure natural language framework, and producing NASA Core Flight System (cFS) monitoring applications. For more details, including videos of monitors being generated and flown in simulators, see: https://github.com/nasa/ogma * Releases Ogma is released as a collection of packages in Hackage. The entry point is https://hackage.haskell.org/package/ogma-cli. * Code The github repo is located at: https://github.com/nasa/ogma. * What's coming The next release is planned for March 21st, 2023. Ogma is currently undergoing the qualification process necessary for NASA Class D Software. Apart from the changes required by that process, we also have the following in our roadmap: - Extend ROS 2 monitors with further information about sources of violations. - Add tests to generated code. - Simplify NASA cFS monitor generation process. Happy Haskelling! Ivan [1] https://github.com/Copilot-Language/copilot/

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