Haskell Weekly


Issue 312 2022-04-21

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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.


  • Create recursion schemes using comonads by Luc Tielen

    In today’s post, I explain how comonads can be used to create a tailor-made recursion scheme to perform computations based on multiple simultaneous folds over a single recursive datatype.

  • Announcing webauthn by Erin van der Veen & Silvan Mosberger

    Tweag and Mercury are happy to announce a server-side library for the the WebAuthn specification (part of the FIDO2 project), available as webauthn on Hackage!

  • Combining Ideas: mapAccum by Monday Morning Haskell

    In the last couple weeks, we’ve learned about folding and scanning, which are valuable tools for replacing conventional for loops in our Haskell code. Today we’ll go over a lesser known idea that sort of combines folding and scanning (or just folding and mapping).

  • DevOps engineer for the Haskell Foundation by Andrew Lelechenko

    On behalf of the DevOps Hiring Committee I’m thrilled to announce that Bryan Richter will be joining HF as a DevOps engineer from mid May.

  • Introduction to Doctests in Haskell by Nurlan Alkuatov

    Documenting software can be challenging, but it doesn’t always need to be so. In this article, we’ll introduce doctests: a concept that makes the documentation process pleasant and effective.

  • Let’s go find out! by Mark Dominus

    One question that came up in several interviews was “why do you want to learn Haskell?” I had a lot of trouble with this question, and often rambled about the answer to some other question instead.

  • Prospective Haskell.org applicants for Google Summer of Code

    If you’re interested working on some exciting Haskell projects over the summer while earning a stipend for your work and being part of a blossoming community then join our community discord to learn more about us and the programme.


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

Show & tell

  • Hasklee by Wojciech Szalajko

    Hasklee is a library for creating interactive 3D objects / scenes. Its creations are brought to life through external 3D engines.

  • keter version 1.8.3 by Jappie Klooster

    This release for keter includes a security fix for the default response when the host is not found. All keter users are advised to upgrade to the latest version.

Call for participation