December 2023 - Haskell-Cafe

CGO'24 - Student Research Competition (SRC) and more
by L. Cicolini 08 Dec '23

08 Dec '23

Dear all, The International Symposium on Code Generation and Optimization (CGO) is hosting a Student Research Competition (SRC). Our SRC is a unique opportunity for undergraduate and graduate students to present their original research before a panel of judges and attendees at CGO'24. The winner will be invited to the Grand 2024 ACM SRC competition. If you are an undergraduate or postgraduate student doing research in compiler-related topics, consider applying. We look forward to meeting you! CGO'24 is a compiler conference happening in Edinburgh, March 2nd to 6th 2024. This conference is a great opportunity for anyone interested in compilers to connect with great researchers and professionals and will host four existing workshops: LLVM [1], the BuildIt Framework [2], LATHC [3], and C4ML [4]. Find more information on https://conf.researchr.org/home/cgo-2024 and share this message with anyone who might be interested! Best, Luisa Cicolini [1] LLVM Performance Workshop: https://llvm.org/devmtg/2024-03/ [2] BuildIt: Building DSLs made easy with the BuildIt Framework: https://buildit.so/tutorial/ [3] LATHC: Languages, Architectures, and Tools for Heterogeneous Computing Workshop: https://jnamaral.github.io/LATHC24/ [4] C4ML - Compilers For Machine Learning: https://www.c4ml.org/c4ml-2024

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Haskell.org Call for Nominations (for the terms 2024-2027)
by Ida Bzo 05 Dec '23

05 Dec '23

Dear Haskellers, We are pleased to announce that nominations are now open for the Haskell.org committee. You can nominate yourself or a friend for a three-year term (2024-2027) by sending an email to [committee at haskell.org] by January 10, 2024. Self-nominations and re-nominations are also welcome. Please include any relevant information about yourself or your nominee that you think will help us make our decision. Committee members do not have to be technical experts in Haskell. We are looking for people who are enthusiastic about improving the Haskell community and come from a variety of backgrounds, such as academia, industry, open-source development, and community building. Our goal is to represent the various facets of the Haskell world, including gender, race, location, and industry or research. The committee's responsibilities include setting policies, providing guidance for Haskell.org infrastructure, planning for the long term, and being fiscally responsible with Haskell.org funds and donations. Being a committee member does not require a significant amount of time, but members should be responsive during discussions and should be able to attend monthly calls and participate in the Haskell.org Slack and mailing lists. Candidates for the committee should possess strong leadership, communication, and judgment skills. They must be able to set aside personal or business-related biases and make decisions with the good of the open-source Haskell community in mind. For more information about the committee's roles and responsibilities, please visit https://www.haskell.org/haskell-org-committee/ If you have any questions about the nomination process, please feel free to email us at [committee at haskell.org] or contact one of us individually. λCheers, Ida Bzo

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Download stats not updated on Hackage
by Harendra Kumar 05 Dec '23

05 Dec '23

Hi, It seems the download count for packages on Hackage is stuck for quite some time now. Is this issue known to the Hackage maintainers? -harendra

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by Ihab Mohsen 05 Dec '23

05 Dec '23

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by Ihab Mohsen 05 Dec '23

05 Dec '23

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garn: a Nix/Cabal/Stack alternative
by Julian Arni 03 Dec '23

03 Dec '23

Dear list, garn is a new take on Nix - configured in Typescript rather than the Nix language, and with a nicer and simpler CLI (thanks optparse-applicative!). The repository is https://github.com/garnix-io/garn, and the website is https://garn.io/. I'm mentioning it here because we just added better Haskell support, which makes it now a plausible alternative to managing your Haskell projects with Nix, Stack or Cabal. An example Haskell project: import * as garn from "https://garn.io/ts/v0.0.18/mod.ts"; import * as pkgs from "https://garn.io/ts/v0.0.18/nixpkgs.ts"; export const project = garn.haskell.mkHaskellProject({ description: "My project", src: ".", executables: ["server", "openapi-generation"] overrideDependencies: { "servant": "0.19.1" }, ghcVersion: "ghc94" }).addExecutable("format")`${pkgs.ormolu}/bin/ormolu --mode inplace $(find . -name '*.hs')` Which allows for `garn build project` to build the project, and `garn enter project` to be in a devshell with cabal, ghc94 and all the dependencies installed, and `garn run project.format` for formatting all files with ormolu. (`garn init` is capable of generating most of that file for you.) # Comparisons First, compared to all of the options below, garn is much less mature - there'll be rougher edges or features not yet supported. It's also still changing very quickly, and backwards compatibility is not, for now, a priority. - Cabal: Like Cabal, garn still uses a cabal file, and in fact expects you to develop with cabal. garn brings in the dependencies itself and makes them known to ghc/cabal, and they're snapshot-based rather than resolver-based. In addition, garn makes it easy to include system (non-Haskell) dependencies, it sandboxes builds and tests for better reproduciblity (making CI in particular quite easy); it allows for shared caches; it supports scripts for project janitoring and management; and it supports devshells. - Stack: Like Stack, garn uses a snapshot-based approach to dependencies. In fact, it's based on the stackage releases. It also supports overriding versions from Hackage, but not yet from git. Unlike Stack, it allows specifying system dependencies (non-Haskell dependencies); it sandboxes builds and tests for better reproduciblity (making CI in particular quite easy); it allows for shared caches; it supports scripts for project janitoring and management; and it supports devshells. - Nix: the focus of garn has been a simplified and more productive user experience when compared to Nix. A typed language means you can get autocompletion, documentation, and type errors in your editor, for example. And, even if Typescript is by no means perfect, it's much easier to program in than Nix, so it becomes more fun to abstract away functionality (e.g.: an addGhcidToProject function). garn "transpiles" to Nix, and Nix can be embedded in garn, so the choice is not binary. # Feedback If you try it out, please let us know what you think, or if you run into any roadblocks. You can email me at this address, or open issues on GitHub, or join the Discord channel at https://discord.com/invite/XtDrPsqpVx. It also happens to be partly written in Haskell; hopefully that makes it more easy and fun to get involved! Cheers, Julian

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ANN: hledger 1.32
by Simon Michael 02 Dec '23

02 Dec '23

G'day all, I'm very pleased to announce hledger 1.32, including work from contributors Jonathan Dowland, S. Zeid, Charlie Ambrose, Jacob Weisz, Peter Sagerson, Philipp Klocke, Stephen Morgan, and bobobo1618. Highlights: More precision control, beancount output, TSV output, --summary-only, strict/idempotent import, CSV rule enhancements, timedot letters, fixes - there's a lot in this one, set aside some time to read the notes. - https://github.com/simonmichael/hledger/releases/1.32 - https://hledger.org/release-notes.html#2023-12-01-hledger-132 - https://hledger.org/install hledger is free, fast, reliable, multicurrency, double-entry, plain text accounting software for unix, mac, windows, and the web; built around human-readable, version-controllable plain text files; inspired by and largely compatible with Ledger CLI; convertible to and from Beancount; written in Haskell for reliability and longevity. For help getting started or more info, see https://hledger.org and join our Matrix/IRC chat or mail list: https://hledger.org/support . Newcomers, experts, contributors, sponsors, feedback are welcome! For more about plain text accounting, see https://plaintextaccounting.org . May you be free from danger; may you have happy, peaceful, prosperous holidays. -Simon

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Request to take over floating-bits package
by Julia Longtin 01 Dec '23

01 Dec '23

This is an attempt to follow the process at wiki.haskell.org/Taking_over_a_package I have set up a git repository at github.com/julialongtin/floating-bits/ , and fixed compatibility issues with ghc-9.4. I would like to be made maintainer of this package in hackage. Julia Longtin

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Does the constraints library give (a :- b) -> Dict (a |- b)?
by Tom Ellis 01 Dec '23

01 Dec '23

The constraints library [1] has implied :: forall a b. (a => b) => a :- b from which I can obtain implied' :: Dict (a |- b) -> a :- b implied' Dict = implied but can I get the converse of this, that is coimplied :: (a :- b) -> Dict (a |- b) coimplied = error "Can it be done?" I don't see how. The library itself only mentions "|-" in its definition. Would this combinator violate some guarantee that's essential for the safe use of type classes? I'm a bit confused why the same library allows abstraction over type variables with forall_[2] forall_ :: (forall a. Dict (p a)) -> Dict (Forall p) but not abstraction over "term" variables (i.e. of kind Constraint), as in coimplied. Alternatively, can someone help me achieve my goal another way? That is, I need to be able to dischange the quantified constraint forall i. T0 i => T2 i given that I can already discharge the constraint forall i. T1 i => T2 i and I have available the value forall i. T0 i => Dict (T1 i) >From the latter I can easily get forall i. T0 i :- T1 i But without coimplied I don't know how to proceed. Thanks, Tom [1] https://hackage.haskell.org/package/constraints-0.14/docs/Data-Constraint-F… [2] https://hackage.haskell.org/package/constraints-0.14/docs/Data-Constraint-F…

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[Haskell] [ANNOUNCE] Haskell Language Server 2.5.0.0 released
by Zubin Duggal 01 Dec '23

01 Dec '23

Binaries for this release are available at https://downloads.haskell.org/~hls/haskell-language-server-2.5.0.0/. These binaries can be installed using [GHCup](https://www.haskell.org/ghcup/), using the vanilla metadata channel: ghcup --url-source=https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-vanilla-0.0.8.yaml install hls 2.5.0.0 All of these tarballs have associated GPG signatures. The signature should be from `Zubin Duggal <zubin(a)well-typed.com>` (key ID [588764FBE22D19C4](https://keys.openpgp.org/search?q=588764FBE22D19C4)) The prebuilt binaries in this release support the following GHC versions: - 9.2.8 - 9.4.8 - 9.6.3 - 9.8.1 # Changelog - Bindists for GHC 9.4.8 - Drop support for GHC 9.0 - Re-add stan plugin - Load default operator fixities in Fourmolu plugin Happy editing! - Zubin

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