# Latest **URL:** https://discourse.haskell.org/latest.md [Latest](https://discourse.haskell.org/latest.md) · [Categories](https://discourse.haskell.org/categories.md) · [Tags](https://discourse.haskell.org/tags.md) --- ## [Welcome to the Haskell Discourse!](https://discourse.haskell.org/t/welcome-to-the-haskell-discourse/7)
**Author:** [@system](https://discourse.haskell.org/u/system)\ **Replies:** 0\ **Last updated:** [February 16, 2019, 11:18am UTC](https://discourse.haskell.org/t/welcome-to-the-haskell-discourse/7 "2019-02-16T11:18:56Z")
About this forum Haskell is a statically typed, pure, functional programming language. Any discussion about Haskell is welcome on this forum. In particular the following topics are encouraged: Announcements about new … --- ## [Why add extra functions to type classes instead of using rewrite rules?](https://discourse.haskell.org/t/why-add-extra-functions-to-type-classes-instead-of-using-rewrite-rules/14820)
**Author:** [@jvanbruegge](https://discourse.haskell.org/u/jvanbruegge)\ **Replies:** 1\ **Last updated:** [October 8, 2026, 4:52pm UTC](https://discourse.haskell.org/t/why-add-extra-functions-to-type-classes-instead-of-using-rewrite-rules/14820 "2026-10-08T16:52:58Z")
If we look e.g. at the definition of Foldable, aside from foldMap/foldr, it also contains a bunch of other methods like minimum that have a default implementation in terms of foldMap. AFAIK this is done to allow to over… --- ## [Haskell on Codeberg](https://discourse.haskell.org/t/haskell-on-codeberg/14650)
**Author:** [@TeofilC](https://discourse.haskell.org/u/TeofilC)\ **Replies:** 14\ **Last updated:** [October 8, 2026, 3:22pm UTC](https://discourse.haskell.org/t/haskell-on-codeberg/14650 "2026-10-08T15:22:52Z")
I have created a haskell organisation on Codeberg. If you’d like to join please create an issue here and then you should be able to migrate a project over. You can also, of course, host Haskell projects in your personal … --- ## [Designing Haskell libraries for qualified import](https://discourse.haskell.org/t/designing-haskell-libraries-for-qualified-import/14809)
**Author:** [@MrcJkb](https://discourse.haskell.org/u/MrcJkb)\ **Replies:** 9\ **Last updated:** [October 8, 2026, 2:46pm UTC](https://discourse.haskell.org/t/designing-haskell-libraries-for-qualified-import/14809 "2026-10-08T14:46:59Z")
--- ## [Issue 545 :: Haskell Weekly newsletter](https://discourse.haskell.org/t/issue-545-haskell-weekly-newsletter/14819)
**Author:** [@taylorfausak](https://discourse.haskell.org/u/taylorfausak)\ **Replies:** 0\ **Last updated:** [October 8, 2026, 1:30pm UTC](https://discourse.haskell.org/t/issue-545-haskell-weekly-newsletter/14819 "2026-10-08T13:30:50Z")
--- ## [First official release of hs-bindgen](https://discourse.haskell.org/t/first-official-release-of-hs-bindgen/14818)
**Author:** [@edsko](https://discourse.haskell.org/u/edsko)\ **Replies:** 0\ **Last updated:** [October 8, 2026, 11:52am UTC](https://discourse.haskell.org/t/first-official-release-of-hs-bindgen/14818 "2026-10-08T11:52:45Z")
We’re delighted to announce the first official release of hs-bindgen. A lot of things have been improved since the two alpha releases, in part due to issues and PRs opened by external contributors; it’s been great to see… --- ## [Most respondents using Haskell are newer users](https://discourse.haskell.org/t/most-respondents-using-haskell-are-newer-users/14816)
**Author:** [@mchav](https://discourse.haskell.org/u/mchav)\ **Replies:** 1\ **Last updated:** [October 8, 2026, 9:44am UTC](https://discourse.haskell.org/t/most-respondents-using-haskell-are-newer-users/14816 "2026-10-08T09:44:36Z")
--- ## [\[SCAM ALERT\] Recursion 2026 conference (conf.funcp.org)](https://discourse.haskell.org/t/scam-alert-recursion-2026-conference-conf-funcp-org/14817)
**Author:** [@frasertweedale](https://discourse.haskell.org/u/frasertweedale)\ **Replies:** 0\ **Last updated:** [October 8, 2026, 9:17am UTC](https://discourse.haskell.org/t/scam-alert-recursion-2026-conference-conf-funcp-org/14817 "2026-10-08T09:17:24Z")
Haskell Security Response Team has been alerted to an apparent scam website pretending to be the “Recursion 2026” conference (29-30 October, NYC). The registration facility appears (to me) to be closed at the moment, bu… --- ## [Tetration types: Making IO and RealWorld without Magic](https://discourse.haskell.org/t/tetration-types-making-io-and-realworld-without-magic/14802)
**Author:** [@ApothecaLabs](https://discourse.haskell.org/u/ApothecaLabs)\ **Replies:** 7\ **Last updated:** [October 8, 2026, 1:59am UTC](https://discourse.haskell.org/t/tetration-types-making-io-and-realworld-without-magic/14802 "2026-10-08T01:59:30Z")
Something @jaror said in another thread got me thinking while working on an update (soon! I swear!) to the compiler, that I felt was worth posting about I would like to expand on this, as it is relevant to my current w… --- ## [TemplateHaskell & associated type families](https://discourse.haskell.org/t/templatehaskell-associated-type-families/14815)
**Author:** [@mixphix](https://discourse.haskell.org/u/mixphix)\ **Replies:** 2\ **Last updated:** [October 7, 2026, 7:02pm UTC](https://discourse.haskell.org/t/templatehaskell-associated-type-families/14815 "2026-10-07T19:02:35Z")
I have the following declaration: class Indices xs where type Index xs :: Type type Value xs :: Type {- ... -} I want to write TemplateHaskell to generate the following pattern: instance Indices (x, x) where t… --- ## [Ghc now runs in your browser](https://discourse.haskell.org/t/ghc-now-runs-in-your-browser/13169)
**Author:** [@TerrorJack](https://discourse.haskell.org/u/TerrorJack)\ **Replies:** 34\ **Last updated:** [October 7, 2026, 6:55pm UTC](https://discourse.haskell.org/t/ghc-now-runs-in-your-browser/13169 "2026-10-07T18:55:28Z")
ghc itself can now run purely client-side in the browser, here’s a haskell playground demo. terms and conditions apply, and i’ll write up more detailed explanation some time later, but i thought this is a cool thing to… --- ## [Making Monofunctor and Monofoldable superclasses of Functor and Foldable](https://discourse.haskell.org/t/making-monofunctor-and-monofoldable-superclasses-of-functor-and-foldable/14807)
**Author:** [@ApothecaLabs](https://discourse.haskell.org/u/ApothecaLabs)\ **Replies:** 10\ **Last updated:** [October 7, 2026, 5:15pm UTC](https://discourse.haskell.org/t/making-monofunctor-and-monofoldable-superclasses-of-functor-and-foldable/14807 "2026-10-07T17:15:18Z")
I think that mono-traversable doesn’t get enough love; it is in roughly the same position that Semigroup was in, before the Monoid hierarchy was corrected, or more recently, Functor and Bifunctor themselves. I am sugges… --- ## [\[ANN\] Project Fluent for Haskell](https://discourse.haskell.org/t/ann-project-fluent-for-haskell/14778)
**Author:** [@ners](https://discourse.haskell.org/u/ners)\ **Replies:** 8\ **Last updated:** [October 7, 2026, 4:56pm UTC](https://discourse.haskell.org/t/ann-project-fluent-for-haskell/14778 "2026-10-07T16:56:35Z")
We are happy to announce that Project Fluent has finally come to Haskell! :tada: Fluent is a localisation system for natural-sounding translations. It keeps simple messages simple and lets translators express plurals, g… --- ## [Online edition of Haskell: the Craft of Functional Programming](https://discourse.haskell.org/t/online-edition-of-haskell-the-craft-of-functional-programming/14814)
**Author:** [@SimonThompson](https://discourse.haskell.org/u/SimonThompson)\ **Replies:** 1\ **Last updated:** [October 7, 2026, 4:34pm UTC](https://discourse.haskell.org/t/online-edition-of-haskell-the-craft-of-functional-programming/14814 "2026-10-07T16:34:56Z")
I am pleased to announce that a fully revised edition of my Haskell book is available online and as a PDF, together with a supporting set of video lectures (links in reply below). The source code is in this github repo u… --- ## [Lask — a task runner with its own typed language, written in Haskell](https://discourse.haskell.org/t/lask-a-task-runner-with-its-own-typed-language-written-in-haskell/14713)
**Author:** [@torudev](https://discourse.haskell.org/u/torudev)\ **Replies:** 2\ **Last updated:** [October 7, 2026, 2:16pm UTC](https://discourse.haskell.org/t/lask-a-task-runner-with-its-own-typed-language-written-in-haskell/14713 "2026-10-07T14:16:33Z")
This is my first post here, and I’m afraid it’s about my own project — I hope that’s an acceptable way to introduce myself. What I made Lask is a task runner. It replaces Makefiles and CI YAML with a small typed languag… --- ## [Buck2 build system for Cabal projects](https://discourse.haskell.org/t/buck2-build-system-for-cabal-projects/14770)
**Author:** [@simonmar](https://discourse.haskell.org/u/simonmar)\ **Replies:** 33\ **Last updated:** [October 7, 2026, 1:22pm UTC](https://discourse.haskell.org/t/buck2-build-system-for-cabal-projects/14770 "2026-10-07T13:22:57Z")
This started as a little experiment and got a bit out of hand, but anyway: I’ve built an extension to Cabal to let you use Buck2 as the build system for a Cabal project. Why, might you ask? Well, it’s faster for one thin… --- ## [Lambda Nantes Workshop #5](https://discourse.haskell.org/t/lambda-nantes-workshop-5/14808)
**Author:** [@abailly](https://discourse.haskell.org/u/abailly)\ **Replies:** 0\ **Last updated:** [October 7, 2026, 5:47am UTC](https://discourse.haskell.org/t/lambda-nantes-workshop-5/14808 "2026-10-07T05:47:24Z")
I know it’s a bit provocative to advertise an OCaml workshop on a Haskell forum, but our communities and ecosystems are not so large and growing we can afford to ignore what’s going on in our cousins’ house. So if you a… --- ## [Making a GTK application in Haskell, part 1 and 2](https://discourse.haskell.org/t/making-a-gtk-application-in-haskell-part-1-and-2/14801)
**Author:** [@rumaan](https://discourse.haskell.org/u/rumaan)\ **Replies:** 3\ **Last updated:** [October 6, 2026, 2:45pm UTC](https://discourse.haskell.org/t/making-a-gtk-application-in-haskell-part-1-and-2/14801 "2026-10-06T14:45:48Z")
Hi everyone, I wrote the first two articles of a series to teach how to make desktop applications using Haskell and GTK 4 / Libadwaita, using the Elm architecture. It’s not a complete guide, and it’s not focused on a d… --- ## [CLC proposals RFC](https://discourse.haskell.org/t/clc-proposals-rfc/14334)
**Author:** [@TeofilC](https://discourse.haskell.org/u/TeofilC)\ **Replies:** 22\ **Last updated:** [October 6, 2026, 12:38pm UTC](https://discourse.haskell.org/t/clc-proposals-rfc/14334 "2026-10-06T12:38:06Z")
CLC proposals are the process for changing the interface of base. They have a broad impact and often benefit from the perspectives of members of the community, although the decision on whether to accept or reject them li… --- ## [\[RFC\] yamlet: a YAML 1.2 library](https://discourse.haskell.org/t/rfc-yamlet-a-yaml-1-2-library/14795)
**Author:** [@arybczak](https://discourse.haskell.org/u/arybczak)\ **Replies:** 5\ **Last updated:** [October 5, 2026, 9:26pm UTC](https://discourse.haskell.org/t/rfc-yamlet-a-yaml-1-2-library/14795 "2026-10-05T21:26:15Z")
I’ve been stress-testing Claude Opus 5.5 and thought a YAML library with a good API would fill a hole in the ecosystem. The result: Repo: GitHub - arybczak/yamlet · GitHub Package candidate: yamlet: A pure, fast and co… --- ## [You don't need an effect system](https://discourse.haskell.org/t/you-dont-need-an-effect-system/14792)
**Author:** [@BurningWitness](https://discourse.haskell.org/u/BurningWitness)\ **Replies:** 26\ **Last updated:** [October 5, 2026, 9:09pm UTC](https://discourse.haskell.org/t/you-dont-need-an-effect-system/14792 "2026-10-05T21:09:35Z")
--- ## [Status of servant-multipart / Call for co-maintainers (blocking downstream Stackage packages)](https://discourse.haskell.org/t/status-of-servant-multipart-call-for-co-maintainers-blocking-downstream-stackage-packages/14698)
**Author:** [@tusharad](https://discourse.haskell.org/u/tusharad)\ **Replies:** 5\ **Last updated:** [October 5, 2026, 12:30am UTC](https://discourse.haskell.org/t/status-of-servant-multipart-call-for-co-maintainers-blocking-downstream-stackage-packages/14698 "2026-10-05T00:30:56Z")
Hi everyone, I’m writing to check on the current maintenance status of haskell-servant/servant-multipart and see if we can help get maintenance moving again, or find co-maintainers who can help with triage and releases. … --- ## [Monad of No Return: The Great Patchening](https://discourse.haskell.org/t/monad-of-no-return-the-great-patchening/14207)
**Author:** [@L0neGamer](https://discourse.haskell.org/u/L0neGamer)\ **Replies:** 7\ **Last updated:** [October 4, 2026, 5:02pm UTC](https://discourse.haskell.org/t/monad-of-no-return-the-great-patchening/14207 "2026-10-04T17:02:10Z")
Hi all! tl;dr: I have 148 packages on stackage to patch for compatibility, and I’d like your help! I’ve got another update on the Monad of No Return/Monoid of No Mappend proposal. Following proposal acceptance just un… --- ## [Containers-0.8.1 released](https://discourse.haskell.org/t/containers-0-8-1-released/14796)
**Author:** [@bmobn00b](https://discourse.haskell.org/u/bmobn00b)\ **Replies:** 0\ **Last updated:** [October 4, 2026, 3:24pm UTC](https://discourse.haskell.org/t/containers-0-8-1-released/14796 "2026-10-04T15:24:40Z")
--- ## [The wasted potential of Haskell: Language & Compiler](https://discourse.haskell.org/t/the-wasted-potential-of-haskell-language-compiler/14743)
**Author:** [@mastarija](https://discourse.haskell.org/u/mastarija)\ **Replies:** 68\ **Last updated:** [October 4, 2026, 9:41am UTC](https://discourse.haskell.org/t/the-wasted-potential-of-haskell-language-compiler/14743 "2026-10-04T09:41:12Z")
This quite resonates with me at the moment, so I’m interested to hear other’s opinions. A common insult hurled at Haskell is that it’s a “committee language”. My take is that this was not the case initial… --- ## [Refine polynomial types](https://discourse.haskell.org/t/refine-polynomial-types/14779)
**Author:** [@olf](https://discourse.haskell.org/u/olf)\ **Replies:** 7\ **Last updated:** [October 3, 2026, 7:35pm UTC](https://discourse.haskell.org/t/refine-polynomial-types/14779 "2026-10-03T19:35:26Z")
In the aftermath to a talk I gave at LeFUNK, I’d like to share the algorithm that computes a refinement type. For the sake of conciseness, This demo is untyped and unsafe, in the sense that type mismatches are incomplete… --- ## [Is there any hope that \`OrPatters\` become more broadly usable?](https://discourse.haskell.org/t/is-there-any-hope-that-orpatters-become-more-broadly-usable/14783)
**Author:** [@enlico](https://discourse.haskell.org/u/enlico)\ **Replies:** 2\ **Last updated:** [October 3, 2026, 8:51am UTC](https://discourse.haskell.org/t/is-there-any-hope-that-orpatters-become-more-broadly-usable/14783 "2026-10-03T08:51:05Z")
Freom the documentation on OrPatterns: \[…\] they may not bind any variables or constraints. This prohibits code like value :: Either a a -\> a value (Left x; Right x) = x -- binds a variable I see that it would be pro… --- ## [Announcing: Little Haskell Compiler v0.1.0 pre-release - Try it online!](https://discourse.haskell.org/t/announcing-little-haskell-compiler-v0-1-0-pre-release-try-it-online/14702)
**Author:** [@ApothecaLabs](https://discourse.haskell.org/u/ApothecaLabs)\ **Replies:** 15\ **Last updated:** [October 3, 2026, 5:39am UTC](https://discourse.haskell.org/t/announcing-little-haskell-compiler-v0-1-0-pre-release-try-it-online/14702 "2026-10-03T05:39:17Z")
I am pleased to announce the (pre) release of v0.1.0 of the Little Haskell Compiler, or LHC for short. The Little Haskell Compiler is a lightweight functional virtual machine based on Peter Landin’s SECD machine, which … --- ## [One Billion Row challenge in Hs](https://discourse.haskell.org/t/one-billion-row-challenge-in-hs/8946)
**Author:** [@ocramz](https://discourse.haskell.org/u/ocramz)\ **Replies:** 239\ **Last updated:** [October 2, 2026, 7:46pm UTC](https://discourse.haskell.org/t/one-billion-row-challenge-in-hs/8946 "2026-10-02T19:46:28Z")
The 1BRC is a fun challenge in data processing that was originally restricted to JVM languages. Essentially, you have to compute averages and extreme values of a set of recordings. The benchmark to beat is 1.53 seconds… --- ## [Haskell Interlude #87: Edward Kmett](https://discourse.haskell.org/t/haskell-interlude-87-edward-kmett/14784)
**Author:** [@sperber](https://discourse.haskell.org/u/sperber)\ **Replies:** 0\ **Last updated:** [October 2, 2026, 1:33pm UTC](https://discourse.haskell.org/t/haskell-interlude-87-edward-kmett/14784 "2026-10-02T13:33:06Z")
For the new Haskell Interlude, we sat down with Edward Kmett. Ed is the Founder and Chief Scientist of Positron AI. More importantly, he’s a legend in the Haskell community for authoring many, many popular Haskell packag… [Next page](https://discourse.haskell.org/latest.md?page=1)