# Latest

**URL:** https://discourse.haskell.org/latest.md?page=2

[Latest](https://discourse.haskell.org/latest.md) · [Categories](https://discourse.haskell.org/categories.md) · [Tags](https://discourse.haskell.org/tags.md)

**Page:** 3

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## [Lamda Calculus by Alonzo Church](https://discourse.haskell.org/t/lamda-calculus-by-alonzo-church/14665)

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**Author:** [@barisbaris2005](https://discourse.haskell.org/u/barisbaris2005)\
**Replies:** 2\
**Last updated:** [September 11, 2026, 10:55am UTC](https://discourse.haskell.org/t/lamda-calculus-by-alonzo-church/14665 "2026-09-11T10:55:47Z")

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Original Lambda Calculus paper written by A. Church is below those want to read.

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## [Nullary operations on GADT with constraints](https://discourse.haskell.org/t/nullary-operations-on-gadt-with-constraints/14676)

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**Author:** [@olf](https://discourse.haskell.org/u/olf)\
**Replies:** 5\
**Last updated:** [September 11, 2026, 10:31am UTC](https://discourse.haskell.org/t/nullary-operations-on-gadt-with-constraints/14676 "2026-09-11T10:31:12Z")

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I am trying to define something similar to Data.Monoid.Ap but as GADT with constraints on the constructors: import Data.Monoid (Ap(..)) -- instance (Monoid a, Applicative f) =\> Monoid (Ap f a) data Lifted f a where …

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## [Ld failure (tapi error) after upgrading to macOS 27 Xcode SDK](https://discourse.haskell.org/t/ld-failure-tapi-error-after-upgrading-to-macos-27-xcode-sdk/14675)

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**Author:** [@andreasabel](https://discourse.haskell.org/u/andreasabel)\
**Replies:** 1\
**Last updated:** [September 11, 2026, 8:36am UTC](https://discourse.haskell.org/t/ld-failure-tapi-error-after-upgrading-to-macos-27-xcode-sdk/14675 "2026-09-11T08:36:53Z")

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I upgraded my Xcode command line tools yesterday and now \`cabal build\` fails with errors such as: ld: multiple errors: tapi error: malformed file /Library/Developer/CommandLineTools/SDKs/MacOSX27.0.sdk/usr/lib/libiconv…

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## [Get-tested v0.1.10.0 release](https://discourse.haskell.org/t/get-tested-v0-1-10-0-release/14674)

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**Author:** [@Kleidukos](https://discourse.haskell.org/u/Kleidukos)\
**Replies:** 0\
**Last updated:** [September 10, 2026, 6:12pm UTC](https://discourse.haskell.org/t/get-tested-v0-1-10-0-release/14674 "2026-09-10T18:12:16Z")

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get-tested v0.1.10.0 has been released! get-tested is a CLI tool that retrieves the tested-with stanza of a cabal file and formats it in such a way that GitHub Actions can use it. You can also use it as an action in you…

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## [Issue 541 :: Haskell Weekly newsletter](https://discourse.haskell.org/t/issue-541-haskell-weekly-newsletter/14673)

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**Author:** [@taylorfausak](https://discourse.haskell.org/u/taylorfausak)\
**Replies:** 0\
**Last updated:** [September 10, 2026, 1:50pm UTC](https://discourse.haskell.org/t/issue-541-haskell-weekly-newsletter/14673 "2026-09-10T13:50:40Z")

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## [The Swedish Defence Research Institute (FOI) is hiring research engineers in Linköping, Sweden](https://discourse.haskell.org/t/the-swedish-defence-research-institute-foi-is-hiring-research-engineers-in-linkoping-sweden/14672)

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**Author:** [@tmplt](https://discourse.haskell.org/u/tmplt)\
**Replies:** 0\
**Last updated:** [September 10, 2026, 12:11pm UTC](https://discourse.haskell.org/t/the-swedish-defence-research-institute-foi-is-hiring-research-engineers-in-linkoping-sweden/14672 "2026-09-10T12:11:58Z")

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This is a cross-post from the Nix discourse. Haskell is not explicitly mentioned in the posting, but it is also a wanted expertise (with a focus on R&D). The post is copied verbatim below. Hello. The Swedish Defence Re…

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## [Packages which are difficult for the cabal solver?](https://discourse.haskell.org/t/packages-which-are-difficult-for-the-cabal-solver/14659)

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**Author:** [@sclv](https://discourse.haskell.org/u/sclv)\
**Replies:** 5\
**Last updated:** [September 9, 2026, 8:23am UTC](https://discourse.haskell.org/t/packages-which-are-difficult-for-the-cabal-solver/14659 "2026-09-09T08:23:10Z")

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For a research project I would like examples of packages which give the cabal solver some difficulty — ie for which solving dependencies (or failing to solve) takes a noticeable amount of time, say at least 30 seconds. I…

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## [Effectful is better at running unspecialized mtl-style code than transformers](https://discourse.haskell.org/t/effectful-is-better-at-running-unspecialized-mtl-style-code-than-transformers/14648)

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**Author:** [@arybczak](https://discourse.haskell.org/u/arybczak)\
**Replies:** 3\
**Last updated:** [September 9, 2026, 7:15am UTC](https://discourse.haskell.org/t/effectful-is-better-at-running-unspecialized-mtl-style-code-than-transformers/14648 "2026-09-09T07:15:38Z")

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This is something I’ve discovered a year ago and wanted to include in a refined version of benchmarks, but since I didn’t manage to do that in such a long time, let me just share this particular bit. A reminder: count…

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## [Best way to create a typeclass dependency graph?](https://discourse.haskell.org/t/best-way-to-create-a-typeclass-dependency-graph/14666)

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**Author:** [@B-rando](https://discourse.haskell.org/u/B-rando)\
**Replies:** 3\
**Last updated:** [September 9, 2026, 12:31am UTC](https://discourse.haskell.org/t/best-way-to-create-a-typeclass-dependency-graph/14666 "2026-09-09T00:31:56Z")

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I was doing some refactors for a project I’m working on, and I found myself in a situation where it would be really handy if I could get a graph of the project’s typeclass dependencies. Including cross-module dependencie…

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## [What’s needed to bootstrap GHC with hugs?](https://discourse.haskell.org/t/what-s-needed-to-bootstrap-ghc-with-hugs/6205)

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**Author:** [@nomeata](https://discourse.haskell.org/u/nomeata)\
**Replies:** 81\
**Last updated:** [September 8, 2026, 5:04am UTC](https://discourse.haskell.org/t/what-s-needed-to-bootstrap-ghc-with-hugs/6205 "2026-09-08T05:04:36Z")

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I was recently reminded that we still don’t have a bootstrappable GHC build (in the sense of https://bootstrappable.org/), and that it would would be nice to have. Somehow this caused me to try to combine all of GHC’s s…

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## [\[ANN\] Rivulet & Wayland on Haskell](https://discourse.haskell.org/t/ann-rivulet-wayland-on-haskell/13921)

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**Author:** [@jackiedorland](https://discourse.haskell.org/u/jackiedorland)\
**Replies:** 37\
**Last updated:** [September 7, 2026, 2:43pm UTC](https://discourse.haskell.org/t/ann-rivulet-wayland-on-haskell/13921 "2026-09-07T14:43:55Z")

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Recently, I switched to Asahi Linux on my Mac. I’ve been a Linux user on my desktop PC for years, and for the most part I’ve always used Fedora. So I thought it would be neat to experiment with the Fedora Asahi Remix! Ho…

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## [Haskell Foundation DevOps Monthly Log and Refresher, August 2026](https://discourse.haskell.org/t/haskell-foundation-devops-monthly-log-and-refresher-august-2026/14660)

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**Author:** [@chreekat](https://discourse.haskell.org/u/chreekat)\
**Replies:** 0\
**Last updated:** [September 7, 2026, 9:48am UTC](https://discourse.haskell.org/t/haskell-foundation-devops-monthly-log-and-refresher-august-2026/14660 "2026-09-07T09:48:06Z")

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Yes, it’s another monthly log. But it’s also time for a refresher on the DevOps role. DevOps role refresher The HF DevOps role was born in 2022 as a full-time position. It became an 80% contract after the first year or…

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## [Quic-simple: Quick-start wrappers for QUIC](https://discourse.haskell.org/t/quic-simple-quick-start-wrappers-for-quic/13341)

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**Author:** [@wiz](https://discourse.haskell.org/u/wiz)\
**Replies:** 4\
**Last updated:** [September 6, 2026, 6:22pm UTC](https://discourse.haskell.org/t/quic-simple-quick-start-wrappers-for-quic/13341 "2026-09-06T18:22:07Z")

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If you want, for some reason, to interleave rapid-fire RPC with file transfer while hopping between the networks (or just dislike websockets), and/but can’t be bothered with setting up a proper TLS PKI… Here’s a quic-an…

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## [Miso-1.13 release](https://discourse.haskell.org/t/miso-1-13-release/14629)

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**Author:** [@dmjio](https://discourse.haskell.org/u/dmjio)\
**Replies:** 6\
**Last updated:** [September 6, 2026, 5:32pm UTC](https://discourse.haskell.org/t/miso-1-13-release/14629 "2026-09-06T17:32:16Z")

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New website here too http://haskell-miso.org

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## [The Inaugural North America Haskell Hackathon](https://discourse.haskell.org/t/the-inaugural-north-america-haskell-hackathon/12964)

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**Author:** [@jmct](https://discourse.haskell.org/u/jmct)\
**Replies:** 34\
**Last updated:** [September 6, 2026, 10:59am UTC](https://discourse.haskell.org/t/the-inaugural-north-america-haskell-hackathon/12964 "2026-09-06T10:59:22Z")

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North American Hackathon The Haskell Foundation is proud to announce the inaugural AmeriHac, a two day haskell hackathon, with this iteration being in New York City! Jane Street has kindly offered to host the Haskell Fou…

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## [Haskell Language Server 2.15.0.0 is now available](https://discourse.haskell.org/t/haskell-language-server-2-15-0-0-is-now-available/14638)

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**Author:** [@fendor](https://discourse.haskell.org/u/fendor)\
**Replies:** 11\
**Last updated:** [September 6, 2026, 4:08am UTC](https://discourse.haskell.org/t/haskell-language-server-2-15-0-0-is-now-available/14638 "2026-09-06T04:08:57Z")

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The HLS team is excited to announce the release 2.15.0.0 of the Haskell Language Server. Binaries for this release are available at Index of /~hls/haskell-language-server-2.15.0.0/. These binaries can be installed usi…

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## [Operating systems written in Haskell](https://discourse.haskell.org/t/operating-systems-written-in-haskell/14607)

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**Author:** [@swell\_miguell](https://discourse.haskell.org/u/swell_miguell)\
**Replies:** 11\
**Last updated:** [September 5, 2026, 10:37pm UTC](https://discourse.haskell.org/t/operating-systems-written-in-haskell/14607 "2026-09-05T22:37:58Z")

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Greetings. I have found many sites discussing various projects to build a full operating system in haskell. All of them seem to be a good decade old. This indicates that there was definite interest in this at one time…

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## [Hundreds of newtypes versus worse API](https://discourse.haskell.org/t/hundreds-of-newtypes-versus-worse-api/14644)

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**Author:** [@AliceRixte](https://discourse.haskell.org/u/AliceRixte)\
**Replies:** 28\
**Last updated:** [September 5, 2026, 8:30pm UTC](https://discourse.haskell.org/t/hundreds-of-newtypes-versus-worse-api/14644 "2026-09-05T20:30:40Z")

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Hi there ! TL;DR Which is best and why ? Practice 1 : Lots of newtypes, but nice API newtype Second a = Second a deriving ( Show, Eq, Ord, Num, Fractional, Floating, Real, RealFrac, RealFloat) newtype Minute a = M…

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## [Haskue: exploring CUE evaluation in Haskell](https://discourse.haskell.org/t/haskue-exploring-cue-evaluation-in-haskell/14643)

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**Author:** [@jzhonx](https://discourse.haskell.org/u/jzhonx)\
**Replies:** 4\
**Last updated:** [September 5, 2026, 12:35pm UTC](https://discourse.haskell.org/t/haskue-exploring-cue-evaluation-in-haskell/14643 "2026-09-05T12:35:42Z")

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Hi everyone, I would like to share a project I have been working on for a while: Haskue, an experimental Haskell implementation of part of the CUE configuration language. Try it online — it runs as WebAssembly, so no …

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## [Bluefin is a capability system](https://discourse.haskell.org/t/bluefin-is-a-capability-system/14632)

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**Author:** [@tomjaguarpaw](https://discourse.haskell.org/u/tomjaguarpaw)\
**Replies:** 14\
**Last updated:** [September 5, 2026, 12:11pm UTC](https://discourse.haskell.org/t/bluefin-is-a-capability-system/14632 "2026-09-05T12:11:22Z")

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I decided I am going to start describing Bluefin as a “capability system”. This article explains why: Bluefin is a capability system

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## [Haskell on Codeberg](https://discourse.haskell.org/t/haskell-on-codeberg/14650)

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**Author:** [@TeofilC](https://discourse.haskell.org/u/TeofilC)\
**Replies:** 12\
**Last updated:** [September 5, 2026, 8:37am UTC](https://discourse.haskell.org/t/haskell-on-codeberg/14650 "2026-09-05T08:37:12Z")

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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 …

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## [\[Well-Typed Blog\] Whole project loading for Haskell IDE tooling](https://discourse.haskell.org/t/well-typed-blog-whole-project-loading-for-haskell-ide-tooling/14649)

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**Author:** [@adamgundry](https://discourse.haskell.org/u/adamgundry)\
**Replies:** 0\
**Last updated:** [September 4, 2026, 12:10pm UTC](https://discourse.haskell.org/t/well-typed-blog-whole-project-loading-for-haskell-ide-tooling/14649 "2026-09-04T12:10:49Z")

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## [Welcome again the Case Split plugin for HLS](https://discourse.haskell.org/t/welcome-again-the-case-split-plugin-for-hls/14469)

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**Author:** [@enlico](https://discourse.haskell.org/u/enlico)\
**Replies:** 9\
**Last updated:** [September 4, 2026, 8:38am UTC](https://discourse.haskell.org/t/welcome-again-the-case-split-plugin-for-hls/14469 "2026-09-04T08:38:09Z")

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Welcome again the Case Split plugin for HLS Hello everybody! This summer I am a contributor to GSoC, and I’m pouring my energies and keystrokes into the HLS ecosystem, specifically into #5013, by bringing back to life a…

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## [Experiments with Template Haskell, SQL, and Records](https://discourse.haskell.org/t/experiments-with-template-haskell-sql-and-records/14636)

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**Author:** [@stevechy](https://discourse.haskell.org/u/stevechy)\
**Replies:** 9\
**Last updated:** [September 3, 2026, 2:04pm UTC](https://discourse.haskell.org/t/experiments-with-template-haskell-sql-and-records/14636 "2026-09-03T14:04:50Z")

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Hello, I’ve been playing around with Template Haskell and Hasql and have posted the results on github. The idea is to generate code to make lining up db columns and record field names easier. It’s been a while since I…

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## [Haskell Paris Meetup announcements](https://discourse.haskell.org/t/haskell-paris-meetup-announcements/14040)

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**Author:** [@Kleidukos](https://discourse.haskell.org/u/Kleidukos)\
**Replies:** 1\
**Last updated:** [September 3, 2026, 1:21pm UTC](https://discourse.haskell.org/t/haskell-paris-meetup-announcements/14040 "2026-09-03T13:21:16Z")

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The Paris Haskell meetup is back for Spring, in partnership with HackENS, ENS Ulm’s hackerspace. This will be the occasion to see each other, talk about the new things happening in the ecosystem, and spend time quality …

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## [Issue 540 :: Haskell Weekly newsletter](https://discourse.haskell.org/t/issue-540-haskell-weekly-newsletter/14639)

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**Author:** [@taylorfausak](https://discourse.haskell.org/u/taylorfausak)\
**Replies:** 0\
**Last updated:** [September 3, 2026, 12:32pm UTC](https://discourse.haskell.org/t/issue-540-haskell-weekly-newsletter/14639 "2026-09-03T12:32:43Z")

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## [Call for Contributions: BOB 2027 (Berlin, Feb 26 - Deadline Nov 2)](https://discourse.haskell.org/t/call-for-contributions-bob-2027-berlin-feb-26-deadline-nov-2/14637)

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**Author:** [@sperber](https://discourse.haskell.org/u/sperber)\
**Replies:** 0\
**Last updated:** [September 3, 2026, 8:44am UTC](https://discourse.haskell.org/t/call-for-contributions-bob-2027-berlin-feb-26-deadline-nov-2/14637 "2026-09-03T08:44:08Z")

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Haskell is always hot at BOB! BOB Conference 2027 - Call for Contributions “What happens when we use what’s best for a change?” https://bobkonf.de/2027/cfc.html Berlin, Feb 26 Deadline: November 2, 2026 Looking for Sp…

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## [Which extensions should be part of the next GHC20xx?](https://discourse.haskell.org/t/which-extensions-should-be-part-of-the-next-ghc20xx/14579)

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**Author:** [@adamgundry](https://discourse.haskell.org/u/adamgundry)\
**Replies:** 56\
**Last updated:** [September 2, 2026, 7:06pm UTC](https://discourse.haskell.org/t/which-extensions-should-be-part-of-the-next-ghc20xx/14579 "2026-09-02T19:06:31Z")

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The GHC20xx language editions seek to collect commonly-used and generally accepted extensions under a single flag. (Unlike Haskell2010, there’s no full standardization process, just the GHC user’s guide documentation.) G…

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## [Is anyone using MicroHs?](https://discourse.haskell.org/t/is-anyone-using-microhs/11437)

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**Author:** [@augustss](https://discourse.haskell.org/u/augustss)\
**Replies:** 46\
**Last updated:** [September 2, 2026, 12:46am UTC](https://discourse.haskell.org/t/is-anyone-using-microhs/11437 "2026-09-02T00:46:27Z")

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Some of you might have heard the MicroHs; a small Haskell compiler. I’m not getting much feedback on MicroHs, so I’m simply curious to hear if any of you have been using it, and if so, for what? – Lennart

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## [Bluefin naming: "handle" or "capability"?](https://discourse.haskell.org/t/bluefin-naming-handle-or-capability/13903)

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**Author:** [@tomjaguarpaw](https://discourse.haskell.org/u/tomjaguarpaw)\
**Replies:** 6\
**Last updated:** [September 1, 2026, 7:30am UTC](https://discourse.haskell.org/t/bluefin-naming-handle-or-capability/13903 "2026-09-01T07:30:12Z")

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Bluefin represents effects at the value level. Should I call these value level parameters “handles” (their current name) or “capabilities” (a name for a similar concept used elsewhere in programming laguage design)? My…

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