I think I finally understand why they are called density matrices. Never felt this dense before....

As I never tire of reminding him, @shriram.bsky.social named the Expression Problem. Maybe if the industry had listened harder, we wouldn't be having this conversation...

"Vibe-coding is in. Software Engineering is useless!" Wrong. The Expression Problem is why your AI-generated pattern-driven code is still broken. Its two solutions let AI reason over the structure of your problem — not guess at it. johnazariah.github.io/2026/05/08/the-craft-isnt-dead.html

To make it easier esp. for junior folks (students, postdocs, jr faculty) to talk to me, I'm trying a new thing: open office hours at conferences! Come find me at PLDI 2026, using the public calendar linked to the page below. Please feel free to reshare! cs.brown.edu/people/sk/Co...

A very brief thread about how I came to understand Hungary, starting in the early 1990s.

Every single one of the astronauts who went to the moon and back on Artemis II was educated at a public school. Thinking of the teachers who poured into Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen tonight. You helped send a kid to the moon! 🌕 💛

My department is looking to hire a professor of practice in CS, with a focus on AI. Job posting below. If you have questions I'll do my best to answer them, else find someone who can! We are in Providence, easy commute access from Boston. jobs.chronicle.com/job/37970844...

Mea culpa: Free Monads in F# can support parallelism. We just need a different implementation! New GitBook page comparing Program pattern variations for domain workflows — Free Monad vs Tagless Final, #FSharp & #CSharp. Featuring @azariah.bsky.social work 🙏 👉 rdeneau.gitbook.io/safe-clean-a...

Night sky on Mars

My dad passed away 25 years ago to the day. Still hurts. Still miss him. Still remember everything that happened that last week. Can't believe how fast time has flown...

Ack I need to stay off caffeine for 24h for a blood test, and I'm at hour 20 and I don't think I can make it!

📖 After four months of work, the book “Safe Clean Architecture” is now complete 🎉 🔗 Check it out online. rdeneau.gitbook.io/safe-clean-a... #fsharp #free #e-book

🧵 New blog series: "Your Clean Architecture Has a Dirty Secret" Every architecture pattern — Clean, CQRS, microservices, vertical slices — has the same unspoken coupling: what and how are fused in the same code. None of them even name it. 6 posts. 3 languages. Half a century of math. Let's fix it.

Many years ago, I implemented the paper @runarorama.bsky.social wrote to help with developing Q#. I promised myself and my readers to demystify Trampolines and Free Monads - and other scary #functional #programming stuff! Here is that #blog post! johnazariah.github.io/2026/03/04/t...

I've been travelling a bit for work, so I have had some down time to write, and some interesting conversations to trigger me! Here's a #blog post reprising one I'd written earlier, about recursion and trampolines, which is now #python centric! johnazariah.github.io/2026/03/04/t...

I've finally put together the blog post accompanying a lecture that @neeldhara.bsky.social invited me to give over a year ago - which happened about a year after @shriram.bsky.social got us to start thinking about it :) Eventual consistency, I guess. :) johnazariah.github.io/2026/02/08/o...

My #FsAdvent 2025: "Froggy Tree House" 🐸 A fun little series about building a game DSL in #fsharp. Frogs jumping. Flies getting eaten. Normal stuff. (Part 6 is called "Code as Model" but that's probably not important :)) johnazariah.github.io/2025/12/12/t... /cc: @sergeytihon.com