Haskell Weekly


Issue 253 2021-03-04

Subscribe now! We'll never send you spam. You can also follow our feed. Read more issues in the archives.

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.


  • Arrows Zoo by Veronika Romashkina

    Don’t know about you, folks, but I had a hard time remembering all the Haskell arrows that you can bump into in all different situations.

  • Building a Web app with FP - Part I - Servant by Iori Matsuhara

    I believe the world of Functional Programming can sometimes be a bit obscure and frustrating for beginners, so I hope this series will help you into your path towards loving Functional Programming

  • Building REST from GraphQL - a story of engineering in Haskell by Lyndon Maydwell

    Recently our team delivered a new Hasura feature and the experience was one of those moments where you ask yourself - Why can’t it always be like this?

  • Go straight to STM by Chris Martin

    Everybody wants to know. Does Haskell have mutable state? Yes! In fact, several different kinds — IORef, MVar, TVar — that have various tradeoffs depending on… Ugh.

  • Haskell Executable Sizes by Dan Fithian

    This post is an experiment with reducing Haskell executable sizes.

  • nix-script by Brian Hicks

    Well, that works, but I’ve traded speed for flexibility: run time has grown to over 2 seconds! Eep! I don’t think I should have to make this trade, so I wrote nix-script.

  • PureScript 0.14 Released by Thomas Honeyman

    PureScript 0.14 introduces many improvements to the compiler, documentation, and core libraries. It also introduces two new features to the language: polymorphic kinds and safe zero-cost coercions!

  • Watching changes in Yesod by Tom Sydney Kerckhove

    The idea of the feedback loop is to be able answer the question “am I done?” as quickly as possible. The shorter this loop is, the quicker you can iterate.

  • Why you should use IHP instead of express by Jannis Jorre

    If undefined errors, configuration messes, hours of hunting bugs annoy you as much as it annoys us, now’s the perfect time to try out IHP.


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

In brief

  • Using Nix for Haskell development in Emacs with LSP by Jonas Collberg

    This article covers basic setup of development environment for Haskell in Emacs, using lsp-mode.

  • Where Lions Roam: RISC-V on the VELDT by David Cox

    I am excited to announce the release of Lion, a formally verified, 5-stage pipeline RISC-V core. Lion is written using Clash and available on Hackage as a library so that users may create their own System-on-Chip (SoC) around the Lion core.

Show & tell

  • ghcup version 0.1.13 by Julian Ospald

  • HGeometry version 0.12 by David Himmelstrup

    HGeometry is a swiss army knife for computational geometry. Wondering if a point is inside a polygon? HGeometry will tell you.

  • IHP version 0.9.0 by Marc Scholten

    A lot has been done since the last IHP release in january. With v0.9 we’re now getting closer to the first major version of IHP!

  • optics version 0.4 by Andrzej Rybczak

  • text-ascii by Koz Ross

    A total-by-default, tested and documented library for working with ASCII text. Low on dependencies , high on usability.

Call for participation