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Tweag by Modus Create
@tweag.io
Tweag is the home of specialized engineering and advisory for Modus Create, uniting engineers and researchers to solve complex challenges. With expertise in functional engineering, build systems like Nix, Bazel, and Buck2, and blockchain like Cardano.
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👋 Bluesky. We're here. Say hello in the replies.
Reposted by Tweag by Modus Create
January 21, 2026 at 8:21 PM
cooked-validators v8 is now available. With a more flexible mockchain run parameterization, more type safety in transaction skeletons, new temporal combinators for modifications, and more governance features to issue certificates, withdrawals and proposals in your tests. github.com/tweag/cooked...
Version 8.0.0 available · tweag cooked-validators · Discussion #512
cooked-validators version 8.0.0 is now available. The most notable changes are: Dependencies are pinned to the latest version before Dijsktra era. More governance features have been implemented, re...
github.com
January 21, 2026 at 12:19 PM
Reposted by Tweag by Modus Create
Reminder: #BOBkonf2026 early bird ticket sales end tomorrow, 16 January, at 23:59 UTC+1!
January 15, 2026 at 2:48 PM
In their new blog post, Fernando Matsuo Santos and Mateus Perdigão announce CodeQL Wrapper. It makes CodeQL easier in complex repos and CI/CD setups: automatic language detection, monorepo-aware project scoping, parallel execution, and change-based incremental scans. www.tweag.io/blog/2026-01...
Streamlining CodeQL Analysis with CodeQL Wrapper
How our CodeQL Wrapper simplifies adoption of GitHub's advanced security analysis tool
www.tweag.io
January 16, 2026 at 5:58 AM
Reposted by Tweag by Modus Create
I'm quite happy about how this library turned out. I have good hope that it's going to be useful to you. Yes. You.
New year, new blog post. Arnaud Spiwack announces the Pup library. A Haskell library for combinators that do both parsing and pretty printing in a single grammar description. Read and discover the big ideas behind the library's design. www.tweag.io/blog/2026-01...
The quest for grammar combinators: introducing the Pup library
Announcing the Pup library.
www.tweag.io
January 9, 2026 at 7:39 AM
New year, new blog post. Arnaud Spiwack announces the Pup library. A Haskell library for combinators that do both parsing and pretty printing in a single grammar description. Read and discover the big ideas behind the library's design. www.tweag.io/blog/2026-01...
The quest for grammar combinators: introducing the Pup library
Announcing the Pup library.
www.tweag.io
January 9, 2026 at 7:00 AM
Reposted by Tweag by Modus Create
Happy nerdy new year!
January 6, 2026 at 9:21 AM
Reposted by Tweag by Modus Create
URLs break. Code disappears. The #SWHID is the cryptographically strong, decentralized tech that guarantees persistence. Compute it yourself. (Plus, it's now an ISO standard.) https://www.softwareheritage.org/2025/11/20/swhid-seminar-post #CodeRescue
Meet the SWHID: The end of broken links, broken builds - Software Heritage
CTO Thomas Aynaud on the SWHID: How the new ISO standard defeats fragile dependencies and guarantees code integrity.
www.softwareheritage.org
January 5, 2026 at 7:38 PM
Incidentally this is the first release after Yann Hamdaoui has left Tweag. We miss him, but he remains the lead maintainer for Nickel (until, of course, he decides otherwise).
December 19, 2025 at 11:31 AM
Just in time for Christmas, Nickel 1.15.1 is released, with huge performance improvements AND a public API for Nickel as a library (Rust, C, Go). Read the full release notes github.com/tweag/nickel...
Release 1.15.1 · tweag/nickel
For several releases now, the runtime representation of Nickel expressions has been completely reworked behind the scenes for improved performance. Nickel 1.15 is the first version to migrate to th...
github.com
December 19, 2025 at 10:00 AM
Reposted by Tweag by Modus Create
"A different way to do concurrency — #Haskell 's STM monad" by Elisabeth Stenholm
www.youtube.com/watch?v=d-NZ...
A different way to do concurrency — Haskell’s STM monad by Elisabeth Stenholm
YouTube video by Func Prog Sweden
www.youtube.com
December 18, 2025 at 2:53 PM
Reposted by Tweag by Modus Create
Building container images without Docker sounds like a party trick — until you see why it matters. Smaller images, faster builds, better caching. In this new blog post Malte Poll shares what he learned while developing rules_img. www.tweag.io/blog/2025-12...
Announcing rules_img: a faster path to container images in Bazel
rules_img is a Bazel ruleset for building and publishing OCI images that feel native to Bazel by treating images as metadata first and moving bytes only at the edges.
www.tweag.io
December 19, 2025 at 1:29 AM
Reposted by Tweag by Modus Create
"The Subtle Footgun of TVar (Map _ _)" by Matt Parsons

www.parsonsmatt.org/2025/12/17/t...

#Haskell
The Subtle Footgun of TVar (Map _ _)
How coarse-grained STM containers can livelock under load
www.parsonsmatt.org
December 18, 2025 at 9:39 PM
In memoriam: Alexander Esgen
www.tweag.io/blog/2025-12...
In memoriam: Alexander Esgen
A tribute to our late colleague and friend.
www.tweag.io
December 16, 2025 at 1:49 PM
Reposted by Tweag by Modus Create
The programme for #BOBkonf2026 is up!

bobkonf.de/2026/program...
bobkonf.de
December 15, 2025 at 8:42 AM
🧵
December 15, 2025 at 5:26 AM
Reposted by Tweag by Modus Create
Haskell community! We need everyone to take the state of Haskell survey.
December 11, 2025 at 2:12 AM
Reposted by Tweag by Modus Create
After 6 years of sitting on the GHC steering committee, my second term is officially over and I haven't sought re-election. It's been a demanding engagement, certainly, but one that I enjoyed a lot. 🙇
December 10, 2025 at 7:26 AM
Reposted by Tweag by Modus Create
Awesome! And thank you for accepting my talk 😁
Notifications are out for #BOBkonf2026. This is once again a *great* program - with a sad eye we look at the long list of great submissions we had to reject.
Program will be out on Dec 12. See you hopefully on March 13 in Berlin!
December 6, 2025 at 2:39 PM
Large codebases don't just depend on code and tests – they depend on a deep graph of tools, system libraries, and even kernels. In this blog post Alexey Tereshenkov explores how target granularity and implicit dependencies impact build performance and reproducibility www.tweag.io/blog/2025-12...
The anatomy of a dependency graph
The hidden complexity of dependency graphs
www.tweag.io
December 5, 2025 at 1:00 PM
Reposted by Tweag by Modus Create
Forgot to point out: while the papers all focus on entailment as a relation (an order) for simplicity of the exposition. In practice, entailment is proof relevant since it constructs dictionary passing. So it's really best to think of entailment as a category.
Simple (given) constraints with entailment and tensor are a symmetric monoidal category (we require some niceness conditions, and scaling for modalities, but otherwise arbitrary). 2/4
December 2, 2025 at 2:33 PM
Reposted by Tweag by Modus Create
A fun thing about linear constraint (already true of traditional GHC-style constraint, I think, but more visible with linear constraints). 1/4
December 2, 2025 at 12:44 PM
Reposted by Tweag by Modus Create
hackage.haskell.org/package/PyF-... PyF has been released with support for GHC 9.14 (rc1, hopefully no update will be required for final version). #haskell #ghc
PyF
Quasiquotations for a python like interpolated string formatter
hackage.haskell.org
December 1, 2025 at 9:01 AM