Haskell Weekly


Issue 288 2021-11-04

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Welcome to another issue of Haskell Weekly! Haskell is a safe, purely functional programming language with a fast, concurrent runtime. This is a weekly summary of what’s going on in its community.


  • 2021 State of Haskell Survey by Haskell Weekly

    This survey opens on November 1st and closes on the 15th. The goal of this survey is to better understand what people think of the Haskell programming language, together with its ecosystem and community.


  • Haskell eXchange Online Conference (November 15–17, 2021) (ad)

    This year’s conference includes a number of talks exploring Haskell’s use in enterprise from companies like SimSpace, JUSPAY, Chordify, CarbonCloud, Flipstone, Foxhound Systems and more. Join us as we discover why sometimes Haskell is actually the best business decision.

  • GHC 9.2.1 released by Ben Gamari

    The GHC developers are very happy to at long last announce the availability of GHC 9.2.1. GHC 9.2 brings a number of exciting features.

  • Haskell series part 6 by Pierre Guillemot

    This is the sixth article of a series on the functional language Haskell for beginners. In this article we are covering high order functions.

  • Counterexamples of Type Classes, Interactive! by Phil Freeman

    It is also instructive to look at counterexamples, of types which inhabit a superclass, but not a subclass, to understand why these refinements are useful.

  • Hacking on Ormolu: An internship report by Alexander Esgen

    I started using Ormolu for all personal projects, and submitted bug reports and minor pull requests. Therefore, an internship to work on Ormolu full-time came like a call!

  • The Interesting Part of Monadic Effects by Vanessa McHale

    Nevertheless, there remain some practical limitations to Haskell’s IO type.

  • Tuning Haskell RTS for Kubernetes, Part 2 by No Red Ink

    We kept on tweaking our Haskell RTS after we reached “stable enough” in part 1 of this series, trying to address two main things.


  • Software Engineer at ACI Learning

    We are currently accepting applications for full-stack software professionals to join our small, but talented, multidisciplinary team.

  • Channable is looking for a Haskell team lead (ad)

    Channable is always hiring talented Haskell engineers and is now looking for someone to lead one of our Haskell teams. We’re a fast-growing international scale-up and while you can still benefit from the start-up vibe, working at Channable also means being part of a professional company with an outstanding development team.

Trying to hire a Haskell developer? You should advertise with us!

In brief

  • 7 Useful Tools Written in Haskell by Nikolay Rulev

    Though Haskell is already quite widely used in the industry, it’s still sometimes believed to be an “academical” language used exclusively for scientific purposes. In this post, I’d like to tell you about several rather popular Haskell tools which may be of use to you.

  • Competitive programming in Haskell: BFS, part 3 (implementation via HashMap) by Brent Yorgey

    For today, though, I want to finally show one way to implement this API efficiently.

  • Don’t Worry Be Happy by Solomon

    When I was first learning Haskell it was emphasized to me via blog posts, books, and conversations how wonderful Haskell is for language design. One of the major points in favor of this was parser combinators.

  • Episode 4: Jasper Van der Jeugt by The Haskell Interlude

    Jasper plays an important role in the Haskell community, helping with haskell.org, the Google Summer of Code project, ZuriHac and the ICPF programming contest, so there is much to talk about.

  • Haskell Foundation October Update by Andrew Boardman

    The big news is the announcement of our first official strategy! The next step is to work with Haskellers that meet the profile and figure out what would help their productivity the most given the resources we have available.

  • Monthly Hask Anything (November 2021)

    This is your opportunity to ask any questions you feel don’t deserve their own threads, no matter how small or simple they might be!

  • A mostly allocation-free optional type by Joachim Breitner

    In this post, I explain how Motoko represents such optional values (almost) without allocation.

  • Request: Universal Haskell value printer by Chris Done

    I would like to propose either to the Haskell foundation or to the community at large to make a universal way to print any Haskell value in any context, anywhere.

  • Why Haskell by Co-Star

    We currently have exactly two backend engineers. A single Haskell engineer can support a 2:3+:1 data:FE:BE developer ratio and still have free BE time.

Show & tell

  • cgroup-rts-threads by Connor James

    A container/cgroup-aware substitute for the GHC RTS -N flag.

  • data-interval by Masahiro Sakai

    Interval datatype, interval arithmetic and interval-based containers for Haskell.

  • jordan by Anthony Super

    Jordan provides an abstract interface for converting to or from JSON.

  • text-display by Théophile Choutri

    The Display typeclass provides a solution for user-facing output that does not have to abide by the rules of the Show typeclass.

Call for participation