[usrusr]

The difference I think is that Dart is a dependency they have already accepted on the level of "we'll maintain it if necessary" (probably in the form of the intra-Google equivalent of an acqui-hire, I wouldn't even be surprise if Dart/Flutter were already reporting to Fuchsia, while publicly still appearing as equal peers), whereas Rust is a big scary NIH.

And still the decision on Rust reads very much like a "we'd love to extend the scope of the time is right" whereas the dismissal of Go is surprisingly brutal, almost reads as if there was a cold civil war going on between the two garbage collected Google languages and Fuchsia people feel need to to demonstrate loyalty to their Darters. Might even just mirror an equal dismissal regarding server side Dart.

[dodobirdlord]

> Might even just mirror an equal dismissal regarding server side Dart.

That'd be my guess. Given the nature of Flutter and its co-development with Dart it's not surprising that Fuchsia prioritizes it. After all, you need to implement the UI in something. Meanwhile I have literally never heard of a UI implemented in Go, and outside of the UI I can see why they don't want to use garbage collected languages in their OS.

[masklinn]

> I have literally never heard of a UI implemented in Go

I expect it has the same issue as UI in Rust: UI is one of the domain where OO inheritance is most convenient and most deeply embedded. So langages which don’t do inheritance are hard sells.

Newer “declarative” UI frameworks less so but they’re probably not mature enough conceptually that you’d want to bet your OS’s core UI system on them, right now they’d be used as an overlay on the core stateful UI system (see bodil’s vgtk for example).

[anthonybullard]

Flutter is a declarative UI framework in Dart, and is the core system UI for Fuchsia. Shallow inheritance is used extensively there

[pjmlp]

There are a couple of them, including some books, but yeah there are better alternatives out there.