Show HN: A Tiling Window Manager for Windows, Written in Janet

166 agentkilo 49 5/20/2025, 3:08:42 PM agent-kilo.github.io ↗

Hi HN!

I read[1] about Janet[2] some time ago, then immediately got impressed by the enthusiasm of its community, and by the language itself, so I started playing with it.

At the time I was searching for a tiling window manager for Windows, and unavoidably the idea of scratching my own itch with Janet got hold of me, so Jwno was born.

Simply put, Jwno is a keyboard-driven tiling window manager for Windows, scriptable with Janet. But since it has a complete Lisp runtime, and a thin wrapper library for Win32 APIs[3], you can certainly do much more with it.

I hope you'll enjoy playing with it as much as I enjoyed building it.

And yes, I use StumpWM on the Linux side, by the way.

[1]: https://ianthehenry.com/posts/why-janet/

[2]: https://janet-lang.org/

[3]: https://github.com/agent-kilo/jw32

Comments (49)

TeMPOraL · 13m ago

Long-time StumpWM user, before I switched back to Windows a few years ago. This is super-exciting to see, and I'm going to take it for a spin. It might just address my major frustrations with arranging windows and switching between them; my monitor seems just the right shape/resolution for the standard Windows splits to be suboptimal.

(Browsers, in particular, I use full-screen less and less. That annoying trend of squeezing everything into short lines "because readability" is just wasting too much screen space; zooming in makes everything too big, and I'm getting tired of writing userstyles or userscript to fix it for every other page I open, so I'm back to keeping 2 or 3 columns of windows running.)

Also, any excuse to use more Lisp is good in my book. Based on the screenshots, it looks stellar; if it works half as well as it comes across, I'll switch over instantly.

ang_cire · 4h ago

Custom windows shells (I know this is just a window manager, but still) in the year of our lord 2025? This takes me back to the days of installing bb4win and litestep in XP. I'm a kid again!

scbrg · 1h ago

flashback, 2001. I'm 25, sitting in the office with litestep installed (which honestly was the only alternative to Linux or resignation). My five years younger colleague steps up to my desk and says "hey, cool desktop!"

I start explaining, very carefully, like I'm talking to a child, that this is an alternative shell, which replaces the standard Windows Explorer et cetera, und so weiter... it's very complicated you know...

Guy says, "cool... hey, why don't you check out this URL?". I do. It's the litestep contributor page. His nick is on it. Near the top.

Ow.

insin · 3h ago

TIL bbLean [1] still works in Windows 11! Currently digging through my archives for my old BB4Win styles repository

[1] https://bb4win.sourceforge.net/bblean/

90s_dev · 2h ago

Wow, bb4win and bblean take me way back. In fact, they were a huge inspiration for my shells[1] feature, which are just userland programs that happen to be able to manage panels (windows).

[1] https://90s.dev/technical/architecture.html#shells

philsnow · 38m ago

Sloop manager for replacing progman.exe in windows 3.1, for me..

reddit_clone · 2h ago

>litestep

Brings back memories !

piskov · 1h ago

Oh shit yes: Rainlendar

Pfeil · 2h ago

I always disliked the chaos that happens quickly with application windows, and loved the idea of tiling. But none of them really worked for me practically until I found PaperWM around a year ago or so (gnome extension). It has few core shortcuts and feels more natural. Like you would really arrange applications directly on your desk. It does not limit itself by your screen width and has the nice default that a new window appears to the right of the current window (configurable). You seldomly have the need to re-arrange windows, because the default just fits 99% of all cases. In addition, you still have the comfort of gnome. No hacky config files just to get wifi working or so. For work we have OSX, and I am really missing it there (I am using rectangle there instead). https://github.com/paperwm/PaperWM?tab=readme-ov-file#usage

bsnnkv · 48m ago

Jwno can do this! https://agentkilo.itch.io/jwno/devlog/871672/scroll-jwno-scr...

pbohun · 5h ago

This is so cool! It's funny because open source devs are making Windows better while MS is actively making it worse. If MS removed all telemetry and AI (and restored win10 functions in context menus), I would probably move back to it.

I've recently started playing around with Janet, and it's a great language. I think it's inspired by Clojure and Lua, and somehow manages to be better than both (in my opinion).

agentkilo · 5h ago

> I think it's inspired by Clojure and Lua, and somehow manages to be better than both

This is exactly how I feel about Janet too. I don't think I have enough experience on Clojure or Lua to comment on them, but I got attracted to Janet almost immediately.

Working on Jwno also confirms my first impression on Janet: It's really a practical language. The tooling has some room for improvement, but the language itself can get things done - usually fast and easily.

cfiggers · 4h ago

Agreed on the need for better Janet tooling. I'm trying to be the change I wish to see with Janet LSP[0]. Issues and contributions are welcome!

[0] https://GitHub.com/CFiggers/janet-lsp

sph · 3h ago

How’s the REPL/interactive editing story? I feel weird using a Lisp that is not as interactive as Racket, Scheme or Common Lisp. Running scripts from the REPL ain’t the same thing as C-x C-e an expression on a live program

behnamoh · 40m ago

> I feel weird using a Lisp that is not as interactive as Racket, Scheme or Common Lisp

I think Racket and Scheme don't belong in there because neither has a REPL as powerful and "interactive" as Common Lisp REPL. They don't support images either (but Janet and CL do).

TeMPOraL · 27m ago

There's multiple dimensions you can slice and dice the Lisp family by. Images and REPL experience are two big ones, but they're almost orthogonal.

behnamoh · 5m ago

I didn't mean that Racket and Scheme aren't Lisp (they are!). I meant they don't have the images and REPL-driven development of Common Lisp.

pbohun · 4h ago

This is how I feel about Janet too, absolutely practical. So far it's been a breeze to write the little experiments I've done so far.

rich_sasha · 5h ago

I'm curious, did you find there were things that were easier to do because it's Janet/lisp-like language? Or you just fancied like using it (perfectly valid reason of course!).

I tried various lisp dialects, but I could never find the killer feature vs other languages I already use. And I can justify why I use these specific languages I do use, if that makes sense.

agentkilo · 4h ago

I find the REPL and interactive development workflow invaluable. A window manager is a long-running background service by nature, and has a lot of accumulated runtime states. The ability to peek inside and debug while the process keeps running helped me a lot when building Jwno.

I think Jwno's REPL module is so important, I specifically changed Jwno's architecture at one point to make it work.

behnamoh · 38m ago

> I find the REPL and interactive development workflow invaluable. A window manager is a long-running background service by nature, and has a lot of accumulated runtime states. The ability to peek inside and debug while the process keeps running helped me a lot when building Jwno.

Sure, but any particular reason you picked Janet over Common Lisp? They both support images, REPL, hot-code-reloading, etc.

iLemming · 2h ago

> I could never find the killer feature vs other languages I already use.

You're kidding or trolling? Structural editing and the REPL are the greatest features of Lisp. The ability to just grab any expression and move it around simplifies so many things when coding and refactoring. With the connected REPL you can eval anything on the spot, that turns the entire experience of coding into a video game — you don't need to wait for linter, linker, compiler — you just run things. You often don't even have to save anything. I suspect when you "tried various lisp dialects" maybe you didn't use structural editing and the connected REPL?

Often people confuse Lisp REPL with REPLs in other programming languages, e.g. Python, where usually you have to copy-n-paste chunks of code into it. Lisp's REPLs are different in the sense that every step in Read-Eval-Print-Loop is different — in Lisp, you typically eval things right where you type them, by sending whole expressions to the connected REPL, which could be remote. We (for example) run ours in a Kubernetes cluster, that allows us to experiment with pods, running queries against the "real" DB tables, testing services "live".

alpb · 2h ago

It's not a tiling manager but slightly related: I replicated Spectacle/Rectangle (macOS apps) on Windows a while ago to snap windows to edges/corners/two-thirds/one-thirds etc a while back. If you're interested: https://github.com/ahmetb/RectangleWin/blob/main/README.md

videogreg93 · 58m ago

I love Rectangle, will definetly check this out!

90s_dev · 5h ago

> You can implement custom commands and hooks to trigger. It's even possible to call native Win32 APIs in your own implementations. For example, to always move a Notepad window to the (100, 100) coordinates on your screen(s), using the low-level SetWindowPos function

Great job. Looks really interesting and useful. And a fun excuse to write Lisp.

I really appreciate it when APIs give you high-level functionality but keep the door open to lower-level APIs when you really need them.

iLemming · 2h ago

Whoa, very cool. I love WMs, I love Lisp, and I hate Windows. This seems to be a perfect "medicine" for my frustration with it.

aus10d · 4h ago

Janet looks really neat. And this project seems really cool. Windows DESPERATELY needs a more powerful built-in manager. It's ridiculous to use the mouse all the time.

Rasthor · 3h ago

One of the later PowerToys updates makes the first few steps in the right direction with "fancy zones". It's not strictly native windows, but still developed by Microsoft and adds keyboard shortcuts for all its utilities

TeMPOraL · 24m ago

PowerToys seems to be making two step forward, one step backwards, and then makes a leap in a random off-axis direction. Every time an update comes, I feel both joy and worry - I expect to see some new cool thing (and possibly even useful to me), but I also worry about bloat and random performance degradations. I haven't bothered with measuring and quantifying it properly, but I do feel PowerToys got heavier and slower over the last 2 years.

Ironically, 90% of use I get from them is remapping Caps Lock to CTRL. Which I historically did with AutoHotkey, which was much lighter, but then there's the 10% of the time I need something else from PowerToys...

nemomarx · 17m ago

Even lighter than autohotkey is remapping on the hardware of the keyboard. There's a lot of open source firmware options for that now in the custom scene

behnamoh · 41m ago

> Windows DESPERATELY needs a more powerful built-in manager. It's ridiculous to use the mouse all the time.

And yet, I find Windows window management far more advanced than macOS. It's ridiculous that up until recently, macOS didn't even have basic max-size functionality w/o reaching for 3rd party apps.

pona-a · 5h ago

What kinds of automation are possible with having a scripting language inside your WM, rather than Sway-style IPC? I heard the new Windows WMs were where most pure workflow advances happen, so I wonder if they can be replicated on Linux.

packetlost · 5h ago

This might be the coolest project I've seen using Janet yet!

bsnnkv · 5h ago

Jwno is great, agentkilo is kind, Lisp is magic :)

agentkilo · 5h ago

Thanks for the kind words! It means a lot coming from you :)

pjerem · 5h ago

Oh ! That looks cool :)

agentkilo · 5h ago

Thanks :)

roxolotl · 4h ago

Tangential but I’ve been writing a lot of Janet recently using Joy[0], web framework, to build a small web app. Would love to hear what you learned about Janet from doing this work and how you feel about the language afterwards.

The one thing I’ve noticed is that it seems like Janet had a burst of interest 2020-2022 but it has since slowed down. Would love to see it become popular again. The main reason I’m using it is because I like how it’s both powerful and lightweight. I’d use clojure but I don’t want Java. I’m tempted to also try Common Lisp but so far Janet has been great.

[0]: https://github.com/joy-framework/joy

agentkilo · 4h ago

I think Janet is quite...liberal? It's a practical language, but doesn't force a specific paradigm on you. There're "escape hatches" in different levels of the language, and I like that.

Maybe the most "opinionated" things in Janet are the ev stuff and fibers. I think they're done right though, you just need to be careful with the event loop when embedding Janet.

nicce · 4h ago

How it compares with Lua?

behnamoh · 42m ago

If you like Janet and Lua, might as well try Fennel, which was made by the creator of Janet.

giraffe_lady · 2h ago

Strictly better unless you need an extremely small runtime rather than a very small one, or are exposing a scripting API to users who will recoil from prefix notation.

77pt77 · 3h ago

This one actually has real arrays (mutable and immutable)

MisterKent · 3h ago

How does it compare to komorebi? I've been using it for about 5 months with great success. I'm a Hyprland user when I'm on my personal machine, but for windows Komorebi has let me keep my muscle memory and workflow largely intact.

agentkilo · 3h ago

I think these are the most obvious differences between the two:

* By default, Komorebi uses dynamic tiling, while Jwno uses manual tiling.

* Komorebi has workspaces, Jwno works with Windows native virtual desktops instead.

* Komorebi uses IPC and native system command line to send commands, while Jwno usually operates all by itself.

There are definitely other details that are important to you, but these are the things that immediately came to my mind. I don't run Hyprland so can't really comment on that.

piskov · 5h ago

Just in case someone new is looking, komorebi is great:

https://github.com/LGUG2Z/komorebi

bsnnkv · 5h ago

komorebi dev here - Jwno is awesome and I highly recommend people give it a try (especially people who enjoy writing Lisp!)

The Windows tiling window manager development scene is a very kind, relaxed and collaborative space where we all take inspiration from and support each other

TeMPOraL · 9m ago

That is amazing and I hope it'll continue to be so :).

The Linux scene isn't bad either (or at least it wasn't 4+ years ago when I was into this); I've used StumpWM as a daily driver for many years, and while it was definitely niche, I still saw friendly exchange of ideas and experiences with people using and/or contributing to dwm, i3, and ratpoison.

(Then there's EXWM, but I never really mustered the courage necessary to try it.)

agentkilo · 5h ago

Definitely! I got great inspirations from both of the Komorebi and GlazeWM communities. People who like tidy desktops are definitely nice people :)

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Show HN: A Tiling Window Manager for Windows, Written in Janet

Comments (49)