Haskell Weekly


Issue 285 2021-10-14

Subscribe now! We'll never send you spam. You can also follow us on Twitter or with 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.


  • GHC activities report: August – September 2021 by Well-Typed

    This is the eighth edition of our GHC activities report where we describe the work on GHC and related projects that we are doing at Well-Typed. The current edition covers roughly the months of August and September 2021.

  • How to protect aeson code from hash flooding by Fraser Tweedale

    A new aeson release addresses the hash flooding issue, but you need more than a version bump to ensure your programs are protected. This post outlines how aeson addressed the vulnerability and what action you need to take.

  • Pattern-matching-based AST Evaluation as Prisms by ubikium

    This blog post will introduce a way to use prism-like functions to express such complex pattern-matching-based evaluation rules.

  • Testing Polysemy With polysemy-check by Sandy Maguire

    By forcing yourself to think about effects, you are forced to pull concerns apart, and use the type-system to document what’s going on. But more importantly for today, it gives us a layer of indirection inside of which we can insert testing machinery.


  • Software Engineer at ACI Learning

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

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

In brief

  • Book of Monads by Alejandro Serrano Mena

    This book provides a journey from the very first concepts, to the myriad of monads available to programmers, down to the categorical foundations.

  • How and why Haskell is better (than your favorite $LANGUAGE) by vados

    Rah-Rah Haskell posts in 2021? You betcha.

  • Why Haskell? by Monday Morning Haskell

    When I tell other programmers I do a lot of programming in Haskell, a common question is “Why”?

Show & tell

  • aeson version by Oleg Grenrus

    Make map type used by Object abstract so the underlying implementation can be modified, thanks to Callan McGill.

  • Cabal version by Emily Pillmore

    The Cabal team is excited to announce the release of Cabal-, and cabal-install-

  • linear-generics by David Feuer

    This package offers a version of GHC.Generics with two important improvements: The to, from, to1, and from1 methods have multiplicity-polymorphic types, allowing them to be used with either traditional Haskell code or linearly typed code; and the representations used for Generic1 are modified slightly.

Call for participation