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Our first Jane Street Tech Talk went really well! Thanks to everyone who came and made it a fun event.

UPDATE: We are full up. Tons of people signed up for the talk, and we’re now at the limit of what we feel like we can support in the space. Thanks for all the interest, and if you didn’t get into this one, don’t worry, we have more talks coming!

Spacetime is a new memory profiling facility for OCaml to help find space leaks and unwanted allocations. Whilst still a little rough around the edges, we’ve found it to be a very useful tool. Since there’s not much documentation for using spacetime beyond this readme, I’ve written a little intro to...

Ppx is a preprocessing system for OCaml where one maps over the OCaml abstract syntax tree (AST) to interpret some special syntax fragments to generate code.

I was recently invited to do the keynote at the Commercial Users of Functional Programming workshop, a 15-year-old gathering which is attached to ICFP, the primary academic functional programming conference.

Now that the interns have mostly gone back to school, it’s a good time to look back at what they did while they were here. We had a bumper crop – more than 30 dev interns between our London, New York and Hong Kong offices – and they worked on just about every corner of our code-base.

Recruiting talented people has always been challenging.

In the last few years, we’ve spent more and more effort working on developer tools, to the point where we now have a tools-and-compilers group devoted to the area, for which we’re actively hiring.

Earlier this year, we created a ppx_let, a PPX rewriter that introduces a syntax for working with monadic and applicative libraries like Command, Async, Result and Incremental. We’ve now amassed about six months of experience with it, and we’ve now seen enough to recommend it to a wider audience.

At Jane Street, we have always been heavy users of pre-processors, first with camlp4 and now ppx. Pre-processing makes the infrastructure a bit more complex, but it save us a lot of time by taking care of a lot of tedious boilerplate code and in some case makes the code a bit prettier.

We finally got a decent recording of one of my favorite talks. This one is about our Incremental library (which I wrote about here), and in particular about the story of how we got to the present, quite performant, implementation.

In my previous post I wrote about Flambda, which is the single biggest feature coming to OCaml in this release. In this post, I’ll review the other features of 4.03 that caught my eye.

OCaml 4.03 is branched and a first release candidate is imminent, so it seems like a good time to take stock of what’s coming.

In my last post, I gave some simple examples showing how you could use self adjusting computations, or SAC, as embodied by our Incremental library, to incrementalize the computation of virtual dom nodes. In this post, I’d like to discuss how we can extend this approach to more realistic scales, and ...