The OCaml Planet

The OCaml community participated in the December 2024 round of [Outreachy internships](https://www.outreachy.org). One intern worked on a tool for diffing OCaml APIs. This meeting was an opportunity for our intern to present their work and for ...

Explanation of our learnings from attempting to build all Dune packages in opam-repository using Dune package management.

OCaml is famous for allow you to do a lot of things like modules. Like really a lot! Advanced features like functors, aside, it’s really common to either alias module names to something shorter or localize open Module_name to a smaller scope:

In my previous article I mentioned that OCaml’s Stdlib leaves a lot to be desire when it comes to regular expressions. One thing I didn’t discuss back then was that the problem is somewhat mitigated by the excellent module Scanf, which makes it easy to parse structured data.

One of the things that bothered me initially in OCaml was the poor support for working in regular expressions in the standard library. Technically speaking, there’s no support for them at all!

Jane Street is a trading firm that uses a variety of high-performance systems built in OCaml to provide liquidity to financial markets worldwide. Over the last couple of years, we have started developing major extensions to OCaml’s type system, with the primary goal of making OCaml a better language for writing high-performance systems. In this talk, we will attempt to provide a developer's-eye view of these changes. We’ll cover two major directions of innovation: first, the addition of modal types to OCaml, which opens up a variety of ambitious features, like memory-safe stack-allocation; type-level tracking of effects, and data-race freedom guarantees for multicore code. The second is the addition of a kind system to OCaml, which provides more control over the representation of memory, in particular allowing for structured data to be represented in a cache-and-prefetch-friendly tabular form. Together, these features pull together some of the most important features for writing high performance code in Rust, while maintaining the relative simplicity of programming in OCaml. In all of this, we will focus less on the type theory, and more on how these features are surfaced to users, the practical problems that they help us solve, and the place in the design space of programming languages that this leaves us in.