Chris Rybicki

I started a software research company

notes.eatonphil.com/2026-02-25-i...

🤲 Boston TS Club needs your help! We're out of a venue space and are on the lookout for one who can host our monthly meetups.

If you work at or know of a company who wants to support the local web development & JavaScript/TypeScript community, please let us know. 💙

the ideal class to me would be a survey like class that each day takes one topic and looks at it cross sectionally, like

"How do languages across research/industry approach X?"

where every day X could be subtyping, GC, async, metaprogramming, etc

and each class you read 2-3 papers in advance

Syntax design and type inference and data flow analysis and JITs and so on are also interesting but I could understand wanting to keep them for a compiler class?

Mmm I see.

I guess by rare features I'm thinking of fancy types of polymorphism, linear/affine types, refinement types, gradual typing... (rare should probably be in quotes)

Providing more student exposure to languages with useful-but-rare semantic properties would be appealing to me. And intros to model/proof checking languages.

To bridge the gap between software implementations and their corresponding designs / formal models? (thinking of eg Dafny)

HEARTBREAKING: This Woman Thought Her PR Was Already Merged

Are words basically just pointers to concepts? 🤔

screenshot of the beginning of the blog post, black text over plain white background. It begins with a bad joke, "Did you know that in programming, threads have been locking in before it was cool?"

New blog post!

Writing mutexes from scratch in Go

rybicki.io/blog/2026/01...

TIL reentrant locks are considered harmful?

These are locks that are OK to call .acquire() on by the same thread more than once. For example, Java provides ReentrantLock out of the box in java.util.concurrent.locks.

But they aren't available in Go:

groups.google.com/g/golang-nut...

"The best time to start training a policy was 20 episodes ago. The second best time is now." -Chinese proverb

GitHub - Chriscbr/advent-of-code-2025 Contribute to Chriscbr/advent-of-code-2025 development by creating an account on GitHub.

advent of code 2025 here I come!

embarrassingly I've never completed all 25 days in a single year. but this time, there's only 12 days of puzzles so I think I have a fighting chance!

I'm also going to try using Haskell (language I barely know)!

github.com/Chriscbr/adv...

Announcing Unison 1.0 After years of engineering, design, and community collaboration, we're excited to release Unison 1.0. This version delivers a refined programming workflow and a mature toolchain. Join us as we celebrate this milestone and look ahead to the future of Unison.

🎉 Unison 1.0 has landed!

After years of engineering, design, and community collaboration, we’re excited to announce this milestone!

Spread the word!

Huge congrats to the Unison team for launching 1.0 of their language. Really ambitious vision! 🎉

I'll have to try it out some more (maybe for Advent of Code? 👀). Curious to see where it gets adopted in production.

www.unison-lang.org/unison-1-0/

sui generis (adj.) - unique; in a class by itself

photo of NYC subway times display, where the orange M line is shaped like a pumpkin instead of a circle, and faded ghosts overlay

nice Halloween touches NYC!

To that end, using AI seems like a great solution!

As a human there might not be a finite list of criteria for what makes a puzzle interesting. But if I give the model enough positive and negative examples, there's a chance (but not guarantee) it might pick up on some patterns.

This is a good starting point, but depending on the puzzle type, your artifacts might still feel very randomly generated, so you might still need a human curation process.

Many puzzles are like constraint-satisfaction problems (CSPs). One strategy I tried was to generate puzzles at random and rank them to:

- minimize the # of constraints, since elegant puzzles have fewer moving parts
- maximize the search tree complexity, so mentally finding the solution feels hard

In college I used to hack around with writing code to generate grid-based pencil and paper puzzles like Sudoku, Numberlink, etc. So I love this stuff.

Teaching a computer to solve puzzles is straightforward once you have the algorithm down. But how do you make it generate puzzles that feel "human"?

DeepMind's AI Learns To Create Original Chess Puzzles, Praised By GMs In a new study, researchers from Google DeepMind have created an AI system that is capable of generating creative chess puzzles, some of which impressed experts in chess compositions.

www.chess.com/news/view/ai...

Really cool results! In most game-like domains, the focus of AI is on maximizing win rate or score etc., but measuring the "novelty" of objects like puzzles turns out to be quite hard because it requires human taste, in a sense.

I am looking for a full-time job.

Being independent in open source for 3.5+ years has been wonderful. I've gotten done most of the high-level goals I wanted to, and miss having people & structure around me.

If you know of a role for a staff-level TypeScript+web developer, let me know! 🙂

Slack thread in #all-water-cooler: this past weekend some friends invited me to watch the first game of the world series, in part so i could learn how to watch baseball. they kept recommending a slide deck which explained how the game worked, made by "some rando on the internet". this is what they shared with me: https://slim.computer/assets/teaching/ baseball.pdf at first i thought maybe this deck was made by some other person who happened to call themselves "slim lim". but after a few slides i was convinced it was made by our own @sliminal and eerie. 28 :slim: reacts

I'm delivering tremendous value in the enterprise Slack

Saw an article about the AWS outage analogize the DynamoDB endpoint of AWS as "the digital phone book of the internet". This feels like the same as calling mitochondria the powerhouse of the cell, no?

Dining philosophers problem - Wikipedia

I only just now realized concurrency algorithms are called "starvation free" because the most famous concurrency problems/algorithms are about feeding people:

en.wikipedia.org/wiki/Dining_...

en.wikipedia.org/wiki/Lamport...

Andrej Karpathy shown mid-speech, caption underneath saying "it's over"

Copy-pasting from Stack Overflow was the OG vibecoding.

Two other aspects that make EarPods feel more shareable:

1. They're cheap - it's low risk if they're damaged
2. They don't have sensors detecting if they're in your ears or not. Most apps pause music if you take an AirPod out of your ear. Great for solo use, not for sharing

Apple's wired EarPods are worse than AirPods Pro in most ways - the audio is less clear, they leak more sound to others, they're not noise cancelling, etc.

And yet, something about the wired, rubber tip-less design makes them feel more shareable.