Haskell Weekly

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.

Featured

• Decode and encode JSON in Haskell like an Elm developer by Dwayne Crooks

  If you’re an Elm developer writing Haskell and you like elm/json, you might like dwayne/hs-json-codec. hs-json-codec provides JSON decoders and encoders for Haskell in the style of elm/json. It’s built on dwayne/hs-json-parser, a general-purpose JSON parser and printer that I also wrote.

• Haskell Foundation DevOps Monthly Log and Refresher, August 2026 by Bryan Richter

  Yes, it’s another monthly log. But it’s also time for a refresher on the DevOps role.

• Haskell Language Server 2.15.0.0 is now available by Fendor

  The HLS team is excited to announce the release 2.15.0.0 of the Haskell Language Server.

• Whole project loading for Haskell IDE tooling by Andrea Vezzosi

  From Haskell Language Server 2.15.0.0 onwards, users can opt-in to loading all components of their current project up front, rather than as needed. Doing so ensures information about every module is fully available from the start, and avoids pauses to re-initialize the session when opening a file from a new component.

• Why Function Arguments Are Not Function Colors by Jeremy Bowers

  In several debates online about function colors over the years, people have argued the apparently reasonable position that function arguments can constitute colors as well. But understanding the situation deeply from one example is difficult. Here is my attempt to turn it into a criterion rather than a single example.

In brief

• Haskell on Codeberg by Teo Camarasu

  I have created a haskell organisation on Codeberg. If you’d like to join please create an issue here and then you should be able to migrate a project over. You can also, of course, host Haskell projects in your personal namespace on Codeberg.

Show & tell

• Effectful is better at running unspecialized mtl-style code than transformers by Andrzej Rybczak

  This is something I’ve discovered a year ago and wanted to include in a refined version of benchmarks, but since I didn’t manage to do that in such a long time, let me just share this particular bit.

• Haskue: exploring CUE evaluation in Haskell by jzhonx

  I would like to share a project I have been working on for a while: Haskue, an experimental Haskell implementation of part of the CUE configuration language.

• Hsue: A Modern UI Engine in Haskell & SDL3 GPU — Progress, Redesign, and Future Plans by Qerfcxz

  Following up on my previous posts about building a declarative/functional UI engine in Haskell, I have major updates to share. I have completely redesigned and rewritten the engine from the ground up, transitioning from the old SDL2 pipeline to SDL3 and its modern SDL3 GPU API.

Call for participation

• gren-lang/compiler: Output to STDOUT blocks reporting to STDERR