Thomas Letan's Blog - releases

Teaching Firefox About slack:// URLs

February 19, 2026

Teaching Firefox About `slack://` URLs

I’ve been using Slack at $WORK for the past 5 (!) years. I don't know why, but it looks like Firefox does not know what to do with the slack:// URLs out of the boxTry logging in Slack when your browser does not let Slack know authentication concluded successfully. The worst thing? Sometimes it works, sometimes it doesn’t. . It could be an issue on my side—wouldn’t be the first time!—but in case you are suffering from the same issue, I have found that I can provision my laptop with a so-called Firefox policy to fix this annoyance.

Caution

Firefox only supports a single policies.json file. If you happen to already have one installed at /usr/lib/firefox/distribution/policies.json, you will need to merge the policies manually.

{
  "policies": {
    "Handlers": {
      "schemes": {
        "slack": {
          "action": "useHelperApp",
          "ask": false,
          "path": "/usr/lib/firefox-slack-policy/open-slack"
        }
      }
    }
  }
}

This will only work if you also install the companion script open-slack.

#!/bin/sh
exec xdg-open "$@"

These two files together tell Firefox to use xdg-open in place of gio open. If I understand correctly, the latter needs an explicit entry in the mimeapps.list file to select an application to handle mimetypes it is not familiar with (like x-scheme-handler/slack) even if you have a .desktop file with the appropriate MimeType declaration. I have no idea why, especially considering that mimeinfo.cache correctly resolves x-scheme-handler/slack on my machine.

Anyway, now at least I can log in Slack without issue. I made a small AUR package of it, so if you are an ArchLinux user affected by this bug and without a pre-existing Firefox entreprise policy, feel free to install firefox-slack-policy and call it a day.

Introducing bepo-tsrn.nvim

May 23, 2024

Introducing `bepo-tsrn.nvim`

neovim releases

It is not much, but I have recently published on GitHub what can be considered my very first Neovim “plugin.”

bepo-tsrn.nvim is a zero-configuration, global plugin for Neovim which remaps default Neovim bindings for the Bépo keyboard layout. It started as a fork of bepo.nvim with two significant changes:

hjkl are remapped to tsrn instead of ctsr. hjkl as motion keys always had one great drawback in my opinion: they required me to shift my left hand whenever I wanted to use them. Well, no more!
bepo-tsrn.nvim is a global plugin, unconditionally loaded at startup without the need to explicitely load it. As a consequence, it is a very convenient way to get Bépo enabled in Neovim system-wide. Bonus point if you are using Archlinux, since I have added it to the Archlinux User Repository (AUR).

bepo-tsrn.nvim is released under the terms of the Apache-2.0 license (inherited from bepo.nvim ). Granted, this plugin targets a very small niche of users, but maybe you will find it as useful as I do!

Spatial Shell 6th Release Might Be the Charm

December 30, 2023

Spatial Shell 6th Release Might Be the Charm

spatial-shell releases

After a first call for testers that could have been more effective if only the building instructions listed in the README were correct , I am quite happy to announce the 6th release for Spatial Shell that, I believe, is pretty usable for someone who isn’t me.

What’s Spatial Shell Already?

In a nutshell, Spatial Shell implements a spatial model inspired by Material Shell for i3 and sway. Windows are organized in a grid whose rows are your workspace, and you can navigate this grid (by focusing neighbors windows), move the focused window around, decide how many window you want to see at most in every workspace, etc.

When I first discovered Material Shell in August 2022, I was pretty excited, but the fact that it is a GNOME extension prevented me from switching completely (besides, it was pretty unstable on my laptop for reasons. So when I discovered that Sway (my personal favorite window manager) could be controlled by a third-party program through a Unix socket , I started experimenting. It didn’t take long before I had a working prototype that fit most of my need , but it took a significant amount of time to turn this prototype into something really usable by anyone who isn’t me.

Here is a clunky showcase of what Spatial Shell can doYes, Scott Pilgrim Takes Off is an awesome show that you definitely need to watch. .

For the interested viewers, I am using a forked version of sway called SwayFX to get these rounded corners and the dim effects on unfocused windows. The status bar is Waybar with a config you can try yourself if you are interested ! There is also a minimal i3blocks config available if you cannot use WaybarI fully intend to provide an example config as visually pleasing as the one for Waybar, but compatible with i3. .

To be clear, the UI part of Spatial Shell remains lacking to this day. My Waybar configuration works, but is pretty verbose and statically limited. For instance, it will only display the 8th first windows of a workspace. This is because Waybar does not allow one widget to generate multiple blocks. The same goes for the i3blocks configuration example. Also, they assume the availability of a font with iconsOn that matter, I love the Nerd Fonts project. .

Try It Yourself!

As of today, you can install Spatial Shell using the following methods:

By fetching the official binary builds for Linux x86_64 from the GitHub releases page
By installing the AUR package for Archlinux
By building directly from source

The README should be a good starting point. If it is lacking key pieces of information, do not hesitate to open an issue. At this point, I am willing to deal with documentation issue as bugs.

Besides its README, Spatial Shell is documented via manpages. For a list of available manpages, you can refer to man -k spatial. Spatial Shell definitely works with sway, and should work with i3 since the former is basically a drop-in replacement for the latter.

Conclusion

The journey from the initial idea up to this moment has definitely been an interesting one. At this point, Spatial Shell provides every feature I need. That being said, it does not mean there is nothing more to tell! I certainly hope this project will catch the eyes of some of you, and soon be used on computers I do not own by folks who are not me.

Contributions are obviously welcome! Typically, if you happen to piece together a neat status bar configuration, I am very interested.

What happened since December 2022?

May 18, 2023

What happened since December 2022?

emacs meta neovim releases spatial-shell

Initially, I started this “What happened” series as an exercise to publish more regularly on this website. Suffice to say, I haven’t done a particularly impressive job in that regard, which only means I have a lot of room for improvement.

Anyway, if the first few months of 2023 has been mostly $WORK focus, the same cannot be said for April and May. For one, I have started running again. But this is only the tip of the iceberg.

Spatial Shell got its first releases

Spatial Shell is probably my hobby project I am most excited about. The “call for testers” article I have published recently managed to catch the attention of a few folksYou want to hear a lesson I learned the hard way just after publishing it? Before calling for testers, it is better to be sure your project can actually be compiled easily by the potential volunteers . . The perspective to publish such a write-up was a very strong source of motivation for me to clean up a project I was using daily for several months now, and I am very satisfied with the result.

Mass adoption is still a distant horizon, but still, the project is now mainstream enough that it has already been mentioned in a random topic on the OCaml discourse by someone who isn’t me . 🎉

This led me to formally release a first version of Spatial Shell in the end of April, and a second today. For the first time, I have also published an Archlinux package , to make the life of potential early adopters even easier. Do not hesitate to upvote it so that it can find its way to the extra repository some day.

Goodbye Emacs! Remember me, Neovim?

In 2015, I started using Coq for my PhD thesis and at the time, there was no real support for (Neo)vimThe situation later improved. Nowadays, you can implement your theories using Coqtail , and Coq LSP will probably become a viable and interesting setup in a near future. . Everyone was using Proof General and Emacs, so I was left with little choice but to follow through. With only my courage and the good advice of a fellow “vimer” who had also made a similar journey , I started using Emacs.

Fast forward 8 years later, and my Emacs configuration has become a project of its own. Overall, I was pretty happy with my setup, but in the same time, I always remained a bit nostalgic of my Neovim days. This is probably why I decided to give this old friend a try when my company bought me a new laptop. I also used this as an opportunity to try out this LSP-thing everyone was talking about.

It has been a month now, and I do not plan to come back to my previous habits. There are still some few edges here and there, I still need to get my head around lua, but LSP is nice, and plugins like telescope are simply too beautiful.

That being said, there was one aspect of moving from Emacs to Neovim I had not anticipated: Org mode. Which constitutes a perfect transition to the next session.

Website redesign, again

Did you notice this website has been revamping recently? The changes are actually deeper than “just” a redesign, to a point where I had to port all my write-ups to a different markup languageAre you starting to understand why “Org mode” was the perfect transition to move on to this section? .

Why, you ask? Well, it’s actually pretty simple: as time goes, I’ve grown lazier.

Let me give you some context. Until very recently, my website was built around the idea to have literate programming as a first-class citizen of my author tools. For instance, you can have a look at what used to be the literate program which was responsible for generating the website. Similarly, most of my write-ups about Coq were actually Coq documents. Literate programming is actually a very nice paradigm for authoring technical contents, because it gives you the tools to keep said contents accurate and up-to-date. In a nutshell, you cannot have a typo in one of your code snippets which would prevent it from compiling, because you actually compile the snippet and catch the typo when you try to generate your website. Or at least, it is what I used to do.

I decided to stop because, for all its benefits, this approach has one major drawback: it is hard to maintain. I had invested quite some time and efforts to keep my website sources under control, but it really was an everyday fight. There are some strange things which start happening when you fully commit to this, as I think I did. For instance, software dependencies tie your article together. Suddenly, you cannot talk about this new fancy feature of the latest Coq release without upgrading all your write-ups implemented as Coq documentsWell, in theory you can. Just have each Coq document specifies the Coq version it requires, and support this level of customization in your build toolchain. But then, your blog takes forever to build from a cold repository. .

That being said, most of the work had already been done. This website was a collection of literate programs, and I was pretty proud of the state of things. I could deal with the annoyancesLike using Coqdoc syntax to write my articles, for instance. I could write about how the Coqdoc syntax irks me for ages. . But then, as I explained in the previous section, I decided to move away from Emacs. The first time I tried to start a new write-up, it hit me.

I used to write most of my contents using Org mode. Org mode, also known as the Emacs markup language.

I know of at least one “Org plugin” for Neovim , but instead of giving it a try, I decided to use this opportunity to tackle my “maintenance problem” once and for all. I gave up on literate programming for this website. As a result, this website is now generated from Markdown files only (using markdown-it with many plugins). As a consequence, the generated HTML is way more “predictable.” This was enough to motivate me at giving a try at Soupault’s indexes , which are way more powerful than I anticipated. Now, this website has

Tags. Each write-up can be labeled with as many tags as I want, there is a page which lists all the tags used in the website, and each tag has its own page (for instance, the coq tag.
A RSS feed. It was actually one of the main features I really wanted to get with this revamp.
Automatically generated list of articles in the home page, for each series (see the Ltac series for instance). Before, I was publishing “curated indexes,” or put in other words: I was writing these indexes myself, by hand. And again, I’ve grown lazier.

It took me a week to go through this rework. Translating manually every write-up was tedious, to say the least, as was implementing the Lua plugins for Soupault since I have neither proficiency nor tooling to help me write Lua code. But I am very glad for the final result.

Also, I have invested in an Antidote license, so hopefully, this website will have fewer typos and English butchering as of now. A clean text, delivered with a nice and simple design, from a sane and maintainable Git repository .

Release of colorless-themes-0.2

February 15, 2020

Release of `colorless-themes-0.2`

releases

I have tagged and released a new version of colorless-themes . The motivation behind modifying the version number is an important breaking change regarding how the colorless-themes-make macro shall be used.

Before 0.2, the macro was calling deftheme and provide-theme itself. In practices, it meant the actual themes were not using these two functions themselves. It was working great in isolation, but it turns out many tools such as use-package or Peach Melpa (an auto-generated Emacs themes gallery) are relying on the presence of these functions to decide whether a file provides a theme or not. As of now, nordless-theme and lavenderless-theme have been updated accordingly, and they appear on Peach Melpa . Their loading can also be deferred using the :defer keyword of the use-package macro.

if you happen to be a user of colorless-themes, feel free to shoot an email! I would love to hear about your experience using a mostly colorless theme.