What OO features are you thinking of that Rust doesn't have?
Traits give you the ability to model typical GUI OO hierarchies, e.g.:
trait Widget {
fn layout(&mut self, constraints: Constraints);
fn paint(&self, ctx: &mut PaintCtx);
fn handle_event(&mut self, event: Event);
}
struct Button { ... }
struct Label { ... }
impl Widget for Button { ... }
impl Widget for Label { ... }
let mut widgets: Vec<Box<dyn Widget>> = Vec::new();
Implementation inheritance can be achieved with good old shared functions that take trait arguments, like this: fn paint_if_visible<W>(widget: &W, ctx: &mut PaintCtx)
where
W: HasBounds + HasVisibility,
{
if widget.is_visible() {
ctx.paint_rect(widget.bounds());
}
}
You can also define default methods at the trait level.This all ends up being much more precise, clear, and strongly typed than the typical OO inheritance model, while still following a similar overall structure.
You can see real world examples of this kind of thing in the various GUI toolkits for Rust, like Iced, gpui, egui, Dioxus, etc.
