Paulette Koronkevich, William J. Bowman
One Weird Trick to Untie Landin's Knot
https://arxiv.org/abs/2507.21317

GHC will start maintaining an LTS release – blog.haskell.org/ghc-lts-rele... by @andreaspk.bsky.social

#Haskell

Haskell is a great language if you follow all the same software engineering practices as in any other language. If you believe that Haskell is fundamental different from other languages, you ignore all the past decades' lessons learned about design and you write unmaintainable shit.

Incredibly grateful to @sigplan.bsky.social and @sigplan-pldi.bsky.social for awarding #LeanLang the Programming Languages Software Award 2025 at #PLDI2025!

#LeanProver #FormalMethods #ProgrammingLanguages #Mathematics #SoftwareVerification

shel silverstein on the LLM, 1981

This is a really cool new #LeanLang project with some substantial pedagogical value! @teorth.bsky.social has put out a call looking for volunteers to "playtest" the WIP!

terrytao.wordpress.com/2025/05/31/a...

📣 TWO EXCITING NEW LEAN LECTURES!

Just released: Two Strachey Lectures from @compscioxford.bsky.social featuring Leo de Moura (Chief Architect, Lean FRO) and Kevin Buzzard (Professor, Imperial College). A thread on these must-see talks 🧵👇

#LeanLang #LeanProver

A record increase in atmospheric CO2 according to data released by NOAA gml.noaa.gov/ccgg/trends/..., much higher than projected in the Global Carbon Budget essd.copernicus.org/articles/17/....

This occurred in the presence of an El Niño (red bars, data also from NOAA!).

What does this mean?

1/

This is quite fun.

“America would be better off if more people worked in manufacturing.”

• 80% of Americans agree
• 20% disagree

“I would be better off if I worked in a factory.”

• 25% of Americans agree
• 73% disagree
• 2% currently work in a factory

t.co/ycnHVZ1gT1

Check out these great UX improvements in Lean 4.18!

✅ New gutter decorations for errors/warnings
🔧 "Unsolved goals" markers to guide your proof
🐙 "Goals accomplished!" celebrations

▶️ Try these now in the Lean4 VSCode extension: marketplace.visualstudio.com/items?itemNa...

#LeanLang #LeanProver

👩‍💻Lean users: Lean 4.17 adds inlay hints for automatically-inserted implicit parameters: With autoImplicit enabled you’ll see in-editor visual feedback for parameters that Lean has automatically inferred, improving readability and making code less error-prone!

#LeanLang #LeanProver #DeveloperTools

Litao Zhou, Yaoda Zhou, Qianyong Wan and Bruno C.D.S. Oliveira present a new core calculus that extends F_≤ (a well known polymorphic calculus with bounded quantification) with isorecursive types, tackling the tricky combination of subtyping, recursive types, and bounded quantification.

Mathlib is a community-built library of mathematics in Lean with nearly 1.8MM lines of code and 190K mathematical theorems! Over 500 contributors have helped drive Mathlib forward at an incredible pace! Learn more at: leanprover-community.github.io/index.html

#leanlang #leanprover #community

We're excited to join Bluesky! The Lean FRO develops Lean, an interactive theorem prover and functional programming language advancing mathematics, formal verification, and AI. Follow us for updates on our roadmap and community. #leanlang #leanprover #mathematics #formalverification #ai