OCaml Hacking Session in Belgium -- 1-2 July

Hi everyone.

I’m glad to announce and invite you to the first OCaml/Reason (Compiler) Hacking
Session in Belgium which will be the first week-end of July (1-2 July) in my
appartment (yes, in my appartment for the moment. I hope I will have
a bigger place later). The registration are opened here[2]. The full location
will be given later. If you have any problem to come, we can find a solution if
you come in Brussels, don’t worry about that. For info, you have to take
the train from Brussels to come and it lasts 1 hour. I will take you to the

The event is opened 24/24 and the entire week-end. You can come the
entire week-end or only one day or few hours. If you want to stay to sleep, I
can host around 5 people (just take a sleeping bag). Just tell me if you come.

Thanks OCamlLabs for offering OCaml stickers to all participants!

Motivation of the event.

I wrote an article on my blog[1] some weeks ago about the idea of organizing some
hacking events (specially about OCaml/Reason) in Belgium.
Since last year, I learnt and had some interesting experiences in the OCaml
community and I’m still more and more interested in collaborating and meeting other
OCaml developers I speak with on Twitter and GitHub or by email.

The main purpose of this event is to meet other people sharing the same
interests than me and sharing cultures and knowledge.


The subjects of this first event will be very large and will depend on coming
people. The only thing I would like to keep in mind is hacking. Hack
for me is discovering and understanding new subjects and build something new or
fix some issues. I hope other hackers like me, with the same mindset, will be
interested in this event and will come.

The (non-exhaustive) list of subjects is:

  • hack on OCaml compiler. It can be fix some junior issues
    (https://caml.inria.fr/mantis/my_view_page.php), understand the type system,
    improve it, learn how type systems work, improve front-end, propose some
    useful syntactic sugar, etc.

  • hack on Reason front-end compiler. Reason changes the syntax of OCaml by
    giving a syntax more friendly to people coming from other
    languages like JavaScript. Reason community also builds very interesting tools
    to interact with React or JavaScript world.

  • hack Ocsigen. Ocsigen is a very interesting web framework and maybe the most
    advanced web framework in terms of new ideas and concepts. The core team is
    very small and doesn’t have a lot of time to develop a lot of new features. As
    there are not a lot of core developers, Ocsigen lacks some useful features
    present in most web framework. The documentation and the website must be
    updated and lots of issues must be fixed.

  • hack on opam. opam is the main and the most used package manager for OCaml.
    The release of opam 2.0 is coming soon and we can look after some last issues.

  • hack on Mirage. In the world of unikernels, Mirage becomes popular and a
    subject I would like to learn.

About me

I will be able to help in the first three subjects.

  • About the OCaml compiler, I work at INRIA for some months and I built typing and subtyping
    algorithms based on the type system DOT for first-class modules in OCaml. I
    think I will able to help for the type system and the front end. About multicore
    or ASM code generation, I’m not an expert and don’t have a deep knowledge about
  • About the Reason front-end compiler. I have some experience in lexing and
  • About the Ocsigen project, I worked on Ocsigen Start for several months and had
    some experience in Eliom.

About the two last, I don’t have any hacking knowledge (I never use Mirage, but
it’s on my TODO list).

About drinks and foods.

I think drinks and food will be offered, to be confirmed depending on the
number of participants (don’t trust the article on my blog). A special beer will be offered to all
participants (We are in Belgium, it’s mandatory =)).


You can register on the Eventbrite link. Please register if you are only sure to come.
If you have a better solution than Eventbrite, tell me (I don’t think Eventbrite is a good solution but I’m not an expert). The event is entirely free. If Eventbrite asks you to pay something, refuse and contact me.

About next events.

I really want to create a community in Belgium around functional programming and specially about OCaml and Reason. I would like to create more hacking sessions. If you want to contribute or help to the organization of such event (by hosting for example), contact me.
I hope some institutions or companies will be interested in such events.

[1] https://blog.danny-willems.be/ocamlreason-compiler-hacking-sessions-first-announcement/
[2] https://www.eventbrite.fr/e/billets-ocaml-hacking-session-belgium-35217611825


This is exciting news! Would love to participate. Can you share some details about location, so I can plan my trip (I plan to come from Netherlands).


Hi! Very exciting you come. I will send you by email when the registration is done (just for a question of confidentiality, I don’t want to see my address on the Internet).

EDIT: I saw your registration. I sent you an email with complete information and how to come.

@dannywillems This sounds excellent! Would you consider using the OCaml Labs compiler hacking wiki to log activity at the session - as @gasche did for the recent MIT event? The wiki is still rather compiler-focussed, but as discussed in the other thread, we are looking to broaden the scope and add other OCaml projects and tasks. Having a range of tasks in one place would be really helpful :slight_smile:

@gemmag Yes we will. In the next few days/weeks, I will gather all information and make a small wiki. Maybe it would be better to have only one wiki for all OCaml Hacking Session.

@dannywillems it would be nice to have all the hacking sessions on one wiki if possible – see the temporary page that @gasche created for his, and you are also welcome to create one like that on the ocamllabs one. We can rearrange all these things into a more systematic whole after your event :slight_smile:

I just created a new topic to broadly discuss how we collect contribution ideas and hackaton organization tips, and an issue on the compiler-hacking wiki to discuss its structure (I made changes today). Let’s move there to discuss non-Belgium-specific concerns.