Yaron Minsky
@yminsky.bsky.social
📤 1736
📥 289
📝 3008
Occasional OCaml programmer. Host of Signals and Threads
http://signalsandthreads.com
Another fun hiring spot at Jane Street: we're looking to hire some great hybrid writers-and-engineers. As we grow and do more, communication becomes ever more important, for both internal and external audiences.
www.janestreet.com/join-jane-st...
loading . . .
https://www.janestreet.com/join-jane-street/position/7604415002/
2 days ago
2
10
2
It's been a minute, but, time for another Signals and Threads, this one with Will Wilson about the testing tools he's building at
@antithesis.com
. And, in a bow to modernity, we have a video version of this one too!
youtu.be/F_LvzcdNH3Q?...
loading . . .
Why Testing Is Hard and How to Fix It
YouTube video by Jane Street
https://youtu.be/F_LvzcdNH3Q?si=CNyq8Lt0eT3c8piR
5 days ago
2
9
0
reposted by
Yaron Minsky
Ty Overby
15 days ago
A poor craftsman blames his tools. Wealthy craftsmen also blame their tools. Lots of tool-blaming going around.
0
23
4
I wonder if we're starting to hit a deflationary era in software engineering. For the first time, we're starting to talk about this in a planning context; it can make sense to put off some projects because we expect they'll be easier to achieve in the future than today.
19 days ago
1
7
0
reposted by
Yaron Minsky
Joe Cutler
about 1 month ago
Seems like a good time as any to say I'm: (1) moving to New York next week, where I'll: (2) be writing OxCaml at Jane Street! Excited to start the next thing :)
add a skeleton here at some point
2
54
1
reposted by
Yaron Minsky
New Ideas in Networked Systems
about 2 months ago
February 10th, and thus the inaugural edition of NINeS is just around the corner. You can participate from anywhere in the world, at times that are convenient to you. See
https://nines-conference.org/attend
for information on how you can participate. We hope to see you on Feb 10th!
loading . . .
Attending NINeS 2026
https://nines-conference.org/attend
0
6
6
My regular PSA that if you enjoy working on developer tools, then Jane Street is kind of an amazing place. Apply here! There's no special posting, so just apply for the Software Engineering role, and express your interests in dev-tools in a note.
janestreet.com/apply
3 months ago
0
17
2
We've had an exciting couple of weeks full of opportunities to teach people about the exciting (and mildly bewildering) features of OxCaml. And...we're looking to hire an experienced educator to help us in this work. Please share this with anyone you think might be a good fit!
5 months ago
1
18
4
I did anothr version of my "Saga of Mulicore OCaml" talk, but this time, nerve-wrackingly, the authors of the original paper were all there! Here's the link to the talk, which is found towards the end of the recording for the whole session.
t.co/FQTmsFWji0
5 months ago
1
24
4
Me too! (But Max knows more about it than I do.)
add a skeleton here at some point
5 months ago
0
4
0
reposted by
Yaron Minsky
Kit Eason
6 months ago
Most companies be like “We daren’t go functional, we might not be able to hire”. Jane Street be like “Hold. Our. Beer.”
add a skeleton here at some point
1
9
2
Excited to say that we're looking to hire someone to focus on OxCaml education! We're doing enough to change the language that we have a pretty big internal education task ahead of us, and we want to hire someone to focus on it! Please share this with others!
www.janestreet.com/join-jane-st...
loading . . .
OxCaml Educator :: Jane Street
Jane Street is a quantitative trading firm and liquidity provider with a unique focus on technology and collaborative problem solving.
https://www.janestreet.com/join-jane-street/position/6546786002/
6 months ago
1
17
9
A fun talk about...hacking OCaml. Basically, what you get when you supercollide a systems-y OCaml developer and a CTF.
www.youtube.com/watch?v=SV9V...
loading . . .
Hacking OCaml
YouTube video by Jane Street
https://www.youtube.com/watch?v=SV9Vna-Qgo8
6 months ago
0
19
4
reposted by
Yaron Minsky
Richard Primus
6 months ago
On Advisory Opinions, Sarah Isgur and David French speak with me about enumerated powers. The segment begins 43-44 minutes in, depending on format. This was a good conversation among people with different approaches to constitutional interpretation.
thedispatch.com/podcast/advi...
loading . . .
The Oldest Constitutional Question | Interview: Richard Primus
Originalism through the lens of sola scriptura.
https://thedispatch.com/podcast/advisoryopinions/the-oldest-constitutional-question-interview-richard-primus/
0
3
2
reposted by
Yaron Minsky
Simmo Saan
6 months ago
They should know the difference between TeX and LaTeX, so they could hate Lamport less and Knuth more.
1
1
1
Clearly, the reason for the AI work is to build an AI capable of porting from Latex to Typst.
add a skeleton here at some point
6 months ago
0
12
1
reposted by
Yaron Minsky
a ton of crates
6 months ago
"we need a manhattan project for AI" no what we really need is a manhattan project for porting every math TeX package to Typst (and please start with mathpartir)
0
21
4
I've raised my kids well, I think.
6 months ago
3
42
2
A new episode of Signals and Threads just dropped! This one is an interview with Chris Lattner talking about Mojo, a new-ish language for GPU programming that's aiming to be an alternative to the CUDA stack.
signalsandthreads.com/why-ml-needs...
loading . . .
Signals and Threads Podcast
Listen in on Jane Street’s Ron Minsky as he has conversations with engineers working on everything from clock synchronization to reliable multicast, build systems to reconfigurable hardware. Get a pee...
https://signalsandthreads.com/why-ml-needs-a-new-programming-language/
7 months ago
2
27
4
This was a great talk from Will Crichton. I think Will's approach to approaching questions around language tooling and teaching is compelling, though I wonder how far the approach can scale!
youtu.be/R0dP-QR5wQo?...
loading . . .
https://youtu.be/R0dP-QR5wQo?si=ZKWUh9micZ7iUH_A
7 months ago
1
11
1
I just finished our yearly roundup of this year's intern projects, and it was a real bumper crop! Lots of fun projects, and some cameos from OxCaml...
blog.janestreet.com/wrought-2025/
loading . . .
What the interns have wrought, 2025 edition
Yet again, we’re at the end of our internship season, and so it’s time to summarize whatthe interns were up to!
https://blog.janestreet.com/wrought-2025/
7 months ago
2
8
1
Just ran across this old post from a former intern about Jane Street's approach to programming and code review. I thought it was a pretty accurate, and I think captures something important about how OCaml's design makes code review easier and more effective.
digitalfreepen.com/2017/01/07/j...
loading . . .
Learned at Jane Street - Practical functional programming and software engineering - Digital Freepen
This is the second of two blog posts on my Summer 2016 internship experience at Jane Street, focusing on the technica...
https://digitalfreepen.com/2017/01/07/jane-street-ocaml.html
7 months ago
1
12
2
reposted by
Yaron Minsky
Anil Madhavapeddy
8 months ago
This will remove so many unnecessary OCaml functors from our codebases. My rough rule of thumb is that if a functor is not applied more than once in a codebase, it doesn’t need to be a functor. Parameterised libraries lets us easily do one-shot reuse of existing modules in a different context.
add a skeleton here at some point
1
17
2
We've finally landed a full version internally (coming to an OxCaml near you soon!) of a new feature called parameterized libraries. It's basically an answer to a problem I first ran into 23 years ago. Here's a thread about it on the caml-list.
inbox.vuxu.org/caml-list/10...
loading . . .
[Caml-list] Functorizing large collections of modules - Yaron M. Minsky
https://inbox.vuxu.org/caml-list/
[email protected]
/
8 months ago
2
30
6
A new epsiode of Signals and Threads has just dropped: "The Thermodynamics of Trading". I got to talk to Dan Pontecorvo from our physical engineering team about the complex work that goes into our physical spaces to make the work we do at Jane Street possible.
signalsandthreads.com/the-thermody...
loading . . .
Signals and Threads Podcast
Listen in on Jane Street’s Ron Minsky as he has conversations with engineers working on everything from clock synchronization to reliable multicast, build systems to reconfigurable hardware. Get a pee...
https://signalsandthreads.com/the-thermodynamics-of-trading/
8 months ago
0
8
0
I had a lot of fun giving this talk in Singapore about the many-years-long saga of multicore OCaml, and in particular, the work over the least 2.5 years of getting it ready for production work within Jane Street's walls.
www.youtube.com/watch?v=XGGS...
loading . . .
The Saga of Multicore OCaml
YouTube video by Jane Street
https://www.youtube.com/watch?v=XGGSPpk1IB0
8 months ago
0
46
10
reposted by
Yaron Minsky
Thomas Gazagnaire
8 months ago
My approach so far is to treat AI code assistants as an extension of “a large team with communication challenges working on the same codebase.” You need better tools to clean up the local optima that individual agents get stuck in. See prune and merlint:
discuss.ocaml.org/t/ann-new-to...
loading . . .
[ANN] new tools to keep your projects clean (after AI, or just after yourself)
Hi all, I’ve been experimenting with AI code assistants lately. They’re surprisingly good at generating new code but it’s not very good at remembering things: it’s like having a steady stream of good...
https://discuss.ocaml.org/t/ann-new-tools-to-keep-your-projects-clean-after-ai-or-just-after-yourself/
0
2
1
Yet another small OCaml/OxCaml diff has been squished! Polymorphic parameters has just gotten merged upstream:
github.com/ocaml/ocaml/...
There's more to go (include functor, for example:
github.com/ocaml/RFCs/p...
), but it's nice to see more progress in this space.
loading . . .
Polymorphic Parameters by voodoos · Pull Request #13806 · ocaml/ocaml
This upstreaming PR adds the possibility to have function parameters with polymorphic types in the language. This work was originally done by @lpw25 in Jane Street's fork of the compiler with e...
https://github.com/ocaml/ocaml/pull/13806
8 months ago
1
29
7
We're starting to think about how to evolve OCaml to be a more effective language for agentic programming. One intuition here is that agents change what's important in 2 ways: - the toil of writing matters less - the ease of understanding and verifying matters more đź§µ1/3
8 months ago
5
19
3
We're starting to think about how to evolve OCaml to be a more effective language for agentic programming. One intuition here is that agents change what's important in 2 ways: - the toil of writing matters less - the ease of understanding and verifying matters more đź§µ1/3
8 months ago
1
2
0
reposted by
Yaron Minsky
Anil Madhavapeddy
8 months ago
Some fun OCaml GC projects here with
@sadiq.toao.com
and
@kcsrk.info
if any students are looking for projects involving programming languages
toao.com/blog/ocaml-0...
loading . . .
Last three months in OCaml (July 2025) - Sadiq Jaffer
https://toao.com/blog/ocaml-0725
1
17
6
reposted by
Yaron Minsky
Kiran
9 months ago
PSA! Please share around! Due to a limited number of submissions, we're extending the OCaml Workshop deadline by a week to July 10th AoE! Functional programmers! Heed my call! We need your submissions!!
add a skeleton here at some point
0
12
12
A gem from Stephen Dolan, which proposes replacing the "generational hypothesis" that drives the design of generational GCs with a notion of lifetime dispersion as measured by the gini coefficient. Nice to see economics playing a role here!
dl.acm.org/doi/pdf/10.1...
9 months ago
1
34
7
reposted by
Yaron Minsky
Ty Overby
9 months ago
Something I predict will happen soon is using LLMs to port large test suites from one language / framework to another. Imagine starting a graphics or networking project and having hundreds of thousands of test cases already implemented!
1
12
2
reposted by
Yaron Minsky
Sam Westrick
9 months ago
taking a go at oxcaml today first attempt: let's try a parallel reduction. Idea is to compute the "sum" of [f(lo), ..., f(hi-1)] in parallel, combining via some associative function g (and corresponding zero element, z).
1
32
5
reposted by
Yaron Minsky
Sam Tobin-Hochstadt
9 months ago
Over the 10 days, I wrote a new Racket library for "expect testing", a style that
@yminsky.bsky.social
has advocated for in OCaml.
github.com/samth/recspe...
As an experiment, I built it entirely with Codex (the OpenAI async AI programming tool). I have some thoughts.
1
22
5
A thing that people may not realize is how new some of the OxCaml extensions are. We are on the verge of rolling our very first data race free parallel program into production. Almost no one at Jane Street knows how to use this stuff yet!
9 months ago
2
26
3
reposted by
Yaron Minsky
Brendan Zab
9 months ago
The memory management aside, I’m really excited about the stuff already in the process of being upstreamed, like labelled tuples, polymorphic parameters and include functor. Those will be really handy to have!
0
2
1
reposted by
Yaron Minsky
Sam Westrick
9 months ago
OxCaml SIMD primitives are looking really nice 👀 > [unboxed vector values] are passed between functions in XMM registers, stored in structures as flat data, … > Within a function, all SIMD vectors live in floating-point registers or 16-byte aligned stack slots.
oxcaml.org/documentatio...
loading . . .
OxCaml | SIMD | Intro
https://oxcaml.org/documentation/simd/intro/
0
15
4
And here's a blog post, announcing the release!
blog.janestreet.com/introducing-...
loading . . .
Introducing OxCaml
At Jane Street, we’ve been actively making improvements to OCaml for a long time. Over thelast few years, we’ve started to build some fairly ambitious extens...
https://blog.janestreet.com/introducing-oxcaml/
9 months ago
0
55
19
I'm pleased to announce OxCaml! OxCaml is Jane Street's branch of OCaml. We've given it a new name and a snazzy logo, and done a bunch of work to make it easy for people to try.
9 months ago
5
107
43
Fun talk preparation trick: use Claude Code to create HTML animations for complex diagrams I want. Talk it through, explain in English, maybe even share a snapshot of a hand-draw diagram to get it going. It takes some babysitting, but the results are better than what I would have gotten on my own.
9 months ago
1
24
1
I was recently reminded of this old post, highlighting how broken IEEE NaNs are. Really, ML and its descendents had the right idea here, and everything else is kinda broken.
blog.janestreet.com/making-somet...
loading . . .
Making something out of nothing (or, why None is better than NaN and NULL)
Null is a pervasive concept in computing. Virtually all programming languageshave a way of expressing nothing, nullity, no answer. But handling nullscorrectl...
https://blog.janestreet.com/making-something-out-of-nothing-or-why-none-is-better-than-nan-and-null/
9 months ago
2
11
0
reposted by
Yaron Minsky
KC Sivaramakrishnan
10 months ago
Using uniqueness mode for improving behavioural types:
kcsrk.info/ocaml/modes/...
loading . . .
Uniqueness for Behavioural Types · KC Sivaramakrishnan
https://kcsrk.info/ocaml/modes/2025/05/29/uniqueness_and_behavioural_types/
3
15
7
A new Signals and Threads just dropped, with
@ianthehenry.bsky.social
! This one is about building tools for traders, but it also has some fun dives into Ian's personal projects, including
bauble.studio
and
janet.guide
. Anyway, more here:
signalsandthreads.com/building-too...
loading . . .
Bauble
https://bauble.studio
10 months ago
1
24
7
I'm curious if anyone could summarize for me the state of evidence on the utility of type systems in reducing software faults. I'm aware of and even the source of some of the anecdotal evidence, but I'm curious if there's anything even vaguely methodologically rigorous.
10 months ago
5
18
1
Wild stuff.
add a skeleton here at some point
10 months ago
0
8
2
The other great thing about AI-assisted programming in OCaml is expect tests. They give you a great way of making the behavior of your program visible, both to you, and to the AI. It provides a valuable feedback loop that the AI can leverage in all sorts of flexible ways.
10 months ago
0
5
0
I've been talking with
@avsm.bsky.social
about this, and he makes a cool point about OCaml and AI-assisted programming. Which is that OCaml's beautiful interface language gives you a nice way to interact with an agent: first make mli's, then write implementations.
10 months ago
2
9
0
A periodic reminder: Jane Street is hiring front-end devs!
janestreet.com/join-jane-st...
It's a different flavor of front-end work than you might see elsewhere, but it's great if you love UIs, FP, and type systems that are ergonomic and reliably help you get things right.
loading . . .
Front End Software Engineer :: Jane Street
Jane Street is a quantitative trading firm and liquidity provider with a unique focus on technology and collaborative problem solving.
https://janestreet.com/join-jane-street/position/6184529002/
10 months ago
1
9
3
Load more
feeds!
log in