Haskell Weekly


Issue 292 2021-12-02

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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.


  • Assessing Haskell by Nyeogmi

    I considered trying to assess Haskell without mentioning my own opinions at all. I don’t think that’s fair or possible, nor do I think that would lead people to an accurate assessment of Haskell.

  • Fallback of actions by Magnus Therning

    In a tool I’m writing I want to load a file that may reside on the local disk, but if it isn’t there I want to fetch it from the web. Basically it’s very similar to having a cache and dealing with a miss, except in my case I don’t populate the cache.

  • Flora.pm — An alternative package index for Haskell by Théophile Choutri

    For a little less than a month now, I have been working on a fantastic project: An alternative package index for the Haskell ecosystem: Flora.

  • Jet - A Structural JSON editor by Chris Penner

    I.e. an editor which is aware of the structure of JSON and allows you to manipulate it directly. The document is always in a valid state.

  • Learn Haskell by building a blog generator by Gil Mizrahi

    In this book we will implement a simple static blog generator in Haskell, converting documents written in our own custom markup language to HTML.

  • RankNTypes via Lambda Calculus by Matt Parsons

    The most basic explanation is that it allows the implementer of a function to pick a type, rather than the caller of the function.

  • See and Believe: Visualizing with Gloss by Monday Morning Haskell

    Writing abstract algorithms isn’t as interesting as seeing them in action. So this week I’ll re-introduce Gloss, a really neat framework I’ve used to make some simple games in Haskell.

  • The varieties of the Haskelling experience by Noon van der Silk

    Recently, a group of Haskellers within Tweag had a knowledge-sharing event where we shared our varied Haskell setups with each other, and learned some nice tricks and tips for every-day life.

  • What’s That Typeclass: Foldable by Alyona Antonova

    These two functions are core methods of the Foldable type class, about which we are going to learn in this article.


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In brief

  • Announcing genvalidity- by Tom Sydney Kerckhove

    This post announces the latest release of genvalidity and all its companion packages. It re-introduces validity-based testing and elaborates on the choices that went into the new release.

  • Call for Haskell.org Committee Nominations by Jasper Van der Jeugt

    It is time to put out a call for new nominations (as usual, self-nominations and re-nominations are also welcome) for the Haskell.org committee.

  • Episode 6: Graham Hutton by The Haskell Interlude

    Graham Hutton is interviewed by Wouter Swierstra and Andres Löh. Graham is known for his work on Haskell both in research and teaching Haskell, and in particular his Haskell book.

  • Monthly Hask Anything (December 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!

  • The !-modality Is a Comonad by Vanessa McHale

    In particular, it is a functor; we can lift any function/procedure to work on perennial types with map.

Show & tell

  • Amazonka version 2.0.0-rc1 by Brendan Hay

    The Amazonka team is happy to announce the availability of the first release candidate for the upcoming 2.0.0 release. This release collects the past few years’ worth of bug fixes and AWS service updates, and also includes some fairly major changes to repository organisation and conventions.

  • Brittany version by Taylor Fausak

    Added support for GHC 9.0. Dropped support for all other versions of GHC.

  • Haskell Language Server version 1.5.1 by Javier Neira

    This is a bug fix release for two regressions found after releasing 1.5.0.

Call for participation