https://xvw.lol/articles.xml English articles YOCaml 2025-10-28T00:00:00Z xvw, Xavier Van de Woestyne https://xvw.lol https://xvw.lol/en/articles/notion-coffee.html 2025-10-28T00:00:00Z

This article is a reinterpretation of an [article](https://github.com/xvw/planet/blob/master/content/posts/notion-cafe.org) I wrote in 2021 on my [former site](https://github.com/xvw/planet). I tried to focus on the essentials, and it outlines the set of [Notion](https://www.notion.so/about) pages I created to index my coffee consumption and attempt to build an intuition about understanding my tastes. In general, I think that building a _knowledge base_ is a good practice when trying to explore a discipline. Being far from an expert in both coffee and Notion, it’s likely that much of what I describe in this article may seem naïve! To sum up, this article will present how I set up an infrastructure to index the coffees I taste, with the goal of providing precise metrics to help characterize my preferences, using the Notion tool, while also sharing some techniques and tricks I learned during the creation of this system.

https://xvw.lol/en/articles/why-ocaml.html 2025-08-13T00:00:00Z

I started using the [OCaml](https://ocaml.org) language regularly around 2012, and since then, my interest and enthusiasm for this language have only grown. It has become my preferred choice for almost all my personal projects, and it has also influenced my professional choices. Since 2014, I have been actively participating in public conferences dedicated to programming and software development, where I often express my enthusiasm for OCaml in ways that may be a bit over the top (but always passionate). This has earned me, in a friendly way, the nickname _OCaml evangelist_ — a title that, I admit, I find very flattering. Moreover, I’m not alone in thinking this. Despite the common misconception that OCaml wouldn’t be a pragmatic choice for industry, major companies such as [Meta](https://engineering.fb.com/?s=ocaml), [Microsoft](https://www.microsoft.com/en-us/research/project/slam/?from=https://research.microsoft.com/en-us/projects/slam/&type=exact), [Ahref](https://tech.ahrefs.com/tagged/ocaml), [Tarides](https://tarides.com), [OCamlPro](https://ocamlpro.com/), [Bloomberg](https://www.bloomberg.com/company?s=ocaml), [Docker](https://github.com/moby/vpnkit), [Janestreet](https://www.janestreet.com/technology/), [Citrix](https://xapi-project.github.io/), [Tezos](https://tezos.com), and [many others](https://ocaml.org/industrial-users) actively use it.

https://xvw.lol/en/articles/tetra-master.html 2025-07-02T00:00:00Z

_Tetra Master_ is the optional card game in **Final Fantasy IX**. At first glance, it seems similar to _Triple Triad_ — the card game from Final Fantasy VIII. And while you can develop a general intuition for how to win, especially if you have strong cards, after playing over a hundred matches, I had to admit something: just playing the game and reading all the _in-game_ tutorials wasn’t enough to truly understand the rules. Eventually, I gave in and started looking things up to figure out what I was missing. The complete absence of **any actual rules** — whether in the game or the manual — left me utterly frustrated, which is what led me to write this article, illustrated in OCaml.

https://xvw.lol/en/articles/modules-import.html 2025-06-30T00:00:00Z

The [OCaml](https://ocaml.org) module system can be intimidating, and it typically involves the use of many keywords—for example, `open` and `include`, which allow importing definitions into a module. Since version OCaml `4.08`, the `open` primitive has been *generalized* to allow the opening of **arbitrary module expressions**. In this article, we’ll explore how to use this generalization to reproduce a common practice in other languages, what I somewhat pompously call _import strategies_, to describe patterns like `import {a, b as c} from K`, without relying on a (_sub-_)language dedicated specifically to importing.

https://xvw.lol/en/articles/oop-refl.html 2025-06-29T00:00:00Z

**Guarded methods** allow attaching **constraints** to the receiver (`self`) **only for certain methods**, thus allowing these methods to be called only if the receiver satisfies these constraints (these _guards_). [OCaml](https://ocaml.org) does not syntactically allow defining this kind of method _directly_. In this note, we will see how to encode them using a **type equality witness**.