Haskell Weekly


Issue 310 2022-04-07

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.


  • The effect semantics zoo by Alexis King

    Not all effect systems implement the same semantics, particularly when so-called “scoping operators” are involved. This document collects examples that serve as useful “acid tests” for distinguishing a given effect system’s semantics.

  • From Partitions to Wordle - Type Safety with Phantom Types

    Oops! It looks like we put things in the wrong order. The fix is simple, of course, just swap the order in the tuple. But it’d be nice if we could prevent these sorts of mix-ups from happening in the first place.

  • Haskell Adventures: Functors by Dmitry Tsepelev

    In the object-oriented world we have classes with methods that can be polymorphic. How can we do it in the Haskell where we do not have classes in the traditional sense?

  • Haskell in Production: Freckle by Gints Dreimanis

    In this edition of our Haskell in Production series, I interview Pat Brisbin. Pat is a Principal Engineer at Freckle, a company that helps teachers reach students at their level.

  • large-anon: Practical scalable anonymous records for Haskell by Edsko de Vries

    The library offers a small but very expressive API, and it scales to large records (with 100 fields and beyond), with excellent compilation time performance and good runtime performance.

  • Performance improvements for HLS by Well-Typed

    Upcoming HLS releases will be substantially faster and more responsive for large codebases using Template Haskell, thanks to work by Well-Typed on behalf of Mercury.

  • The State of PureScript Survey 2022 - The Results Are In! by Mike Solomon

    As it’s unlikely everyone has time to read 47 pages of survey results, we’re also writing up this short, somewhat-opinionated post with what we believe to be relevant learnings from the survey.

  • Teaching optics through conspiracy theories by Bartosz Milewski

    This post is based on the talk I gave at Functional Conf 2022. There is a video recording of this talk.

  • Variadic functions in Hindley Milner by Philip Hazelden

    I previously mentioned an interest in adding variadic functions to Haskenthetical, the “Haskell with a Lisp syntax” I’m vaguely working on. It sounds difficult. This is an attempt to figure out just how difficult, partly by looking at the state of the art.


  • Haskell Developer at MLabs (ad)

    We are one of the leading Haskell consultancies in the fintech, blockchain and AI space, with a passion for Haskell and open source software. We are looking for a remote Haskeller to join our team. If you are excited about Haskell and are up for a new challenge, please apply here or visit our website! For any questions please email jobs@mlabs.city.

  • Senior Software Engineer - Cloud at Sonatype (ad)

    At Sonatype, we empower developers and security professionals with intelligent tools to innovate more securely at scale. We are looking for Haskell engineers to join our growing SaaS application team. You will contribute to our Lift product, a Continuous Assurance Platform for software teams.

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

In brief

Show & tell

  • VSCode-Haskell version 2.0.0 pre-release

    We are happy to announce a Pre-Release for the new major version release for the VSCode Haskell Extension! Many developers have contributed new features, and this announcement tells you about the latest and greatest changes!

Call for participation