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Show HN: A backend agnostic Ruby framework for building reactive desktop apps

Show HN: A backend agnostic Ruby framework for building reactive desktop apps

22 comments

·May 9, 2025

For a year or two I've been building a UI library with the aim of making desktop applications fun and easy to write.

It is currently written in C/Ruby and uses a custom tree sitter grammar to describe templates.

Features include: composable UI components, template directives, event and prop handling, slots, styles and automation capabilities baked in.

One of the goals of the project is privileging easy to write custom components via a drawing API over providing a fixed set of components.

At the time of this writing it should install on Windows, Mac, and Linux, but sometimes it is hard to test the install on all platforms.

I'd love to hear any feedback or suggestions on the project. It is still in an early stage, but it would be great to hear thoughts.

Docs are here: https://hokusai.skinnyjames.net/ Repo is here: https://codeberg.org/skinnyjames/hokusai

Licensed under the PPL

viraptor

Could you add some information about licence? Currently I don't know what is it compatible with and it's not listed on OSI. So unless someone's up for reading lots of legalese, it's not easy to use/publish.

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xfalcox

This looks super cool, exactly what I've been wanting to create some useful widgets! Thanks for sharing!

zero-st4rs

Thanks! I'm really interested to hear how it "plays" for people. Would love updates if you use it.

az09mugen

Very cool project, and well thought with the choice of Raylib or SDL2. But since Raylib can compile to Android (https://github.com/raysan5/raylib/blob/master/examples/Makef...), do you think it could be difficult to add Android as a target platform ?

zero-st4rs

Interesting, for sure. I don't know much about Ruby on android (the resulting application will absolutely need a ruby interpreter) but I thought Windows would be a no-op and I got it working there, so who knows? :)

az09mugen

Ahah nice, I will definitively craft some GUIs for fun with your lib and make you some feedback. Thanks for this project !

jenadine

First time I hear about "copyfarleft license".

I wonder what that means in practice for such a library.

iraliaf

this is really cool, thanks for contributing to the ruby ecosystem!! Do you have any example sites? I couldn't find a reference on your overview

zero-st4rs

Yup! https://hokusai.skinnyjames.net has a guide with screenshots.

The repo itself has more examples.

whalesalad

How would you compare this to RubyMotion?

zero-st4rs

Great question. From what I understand of RubyMotion, it compiles directly to native, calling into Objective C APIs, and like DragonRuby the Ruby implementation is not MRI.

Since Hokusai uses MRI, one can pull in from that ecosystem of gems.

RubyMotion also appears to support (iOS, Android, OSX) whereas Hokusai intends to support OSX, Linux, and Windows.

Implementation-wise, the framework itself seems different. Looking at the following [RubyMotion app](https://github.com/HipByte/RubyMotionSamples/tree/master/ios...), the logic is spread out over separate files and it doesn't appear to have a templating language.

On the other hand, Hokusai UI components are just a class that inherits from Hokusai::Block, and are self contained blocks that can be stitched together.

Hokusai is more like Vue Single file components in this regard. Hokusai also doesn't make a distinction between a "component" and an "app", they are all just Blocks.

Does that answer your question?

dismalaf

Looks really cool. Just a curiosity though, why xmake instead of rake?

zero-st4rs

Good question! Most of the development build fetches and compiles C dependencies. xmake happens to be really good at this, especially considering xmake-repo.

Rake tasks don't have builtins for this iirc.

samiv

Cool.. I guess but I just wonder.. is writing the UIs in code an actual practice that people do these days?

I program (mostly) in C++ using Qt for my UIs and I just use the Qt Designer to visually drag and drop to build my UIs and the actual code gets generated by the tool.

Fast and simple.

sunrunner

As an end user, what's the licensing situation like with Qt? I was looking to build a cross-platform desktop application (down the rabbit hole...) and was frustrated with the number of options that were just a web view of some sort and some bindings to a JS/TS framework of your choice (I don't have one and don't really want to have to use one or bundle it with the application).

Qt looked interesting, particularly with the concise syntax afforted by QML and QtQuick, but the licensing was off-putting and even just getting access (for a non-commercial project for example) seemed to require an awkward sign-up and some kind of installer.

I crave the conciseness and simplicity of something like SwiftUI but the options for doing that in a cross-platform way seem limited.

samiv

It's double licensed. The Qt Company offers both a commercial and LGPL license but they do their best to bury and hide the LGPL option and use dark patterns to try to trick one to get the commercial license. They also want to push you towards getting an account with them for the installer.

That being said the packages (without online installer) are also available for direct download when you know where to look... [see link below]

If you're on Linux though the situation is much simpler since your distribution most likely already packages the Qt libs so you just use your package manager to install them and off you go...

Regardless, for anyone looking for a native portable toolkit, I don't really think there's anything that comes close to Qt in terms of functionality and tooling (like Qt Creator and Qt Designer) and once you get over the idiosyncrasies and quirks its really quite good (for the most part).

https://download.qt.io/official_releases/qt/

sunrunner

I'm on macOS a lot of the time so I did get to the installer part and immediately stopped as it felt like LGPL-licensed software should be accessible without needing an account, an installer (is it useful?) or anything except allowing the end user to access libraries and headers directly.

zero-st4rs

Pretty cool! I've heard a lot of good things about Qt.

teaearlgraycold

Most UIs are made with web technologies without WYSIWYG. And now quite a lot of UIs on desktop are made with web tech.

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