First Rust+GObject coding session

Last Wednesday, Nicholas Matsakis from Rust/Mozilla and I sat down on a video chat to start getting our hands dirty on moving ahead with making Rust a part of the GNOME ecosystem.

While there are two efforts to produce GNOME bindings for Rust, gi-rust and gtk-rs, however none of them provided the means to emit GObject subclases so we decided to tackle this problem.

During the first half of the session we reviewed how GObjects are created from C, I used Vala’s output to illustrate how this is done. We didn’t dive on too much detail on how properties and signals are emitted nor interfaces, however we focused on detail on how to inherit from a GObject.

After that we went ahead and wrote what, probably, is the first piece of Rust code that emits a GObject in this playground repo. Nothing too fancy, but a starting point to get us somewhere.

The next step is to figure out how to take this and turn it into something that a Rust developer would find Rust-like. One of the options we’re exploring is to use Rust macros and try something like this:

gobject!{
  class Foo : Bar {
    fn method_a () -> u8 {
      ...
    }
  }
}

The other alternative would be to decorate structs, traits and whatnot, but this would be a bit more cumbersome. Turns out that Rust’s macro system is quite powerful and allows you to define a custom syntax.

That’s the progress so far, the next step would be to try to start implementing some bits and pieces for the macro and see how far we can get. I’d like to thank Mozilla and Nicholas specially for the amount of attention and effort they are putting into this, I must say I’m quite excited and looking forward to make progress on this effort.

Stay tuned, and if you’d like to help don’t hesitate to reach out to us!