iced-counter2 VS Slint

The iced package requires the messages to implement the Debug, Clone, and Send traits, none of which are available for closures. I was able to implement something similar to your example[0] but it only supports plain function pointers for the callbacks. The compiler wasn't able to derive a sufficiently general Debug trait for the function pointer due to an issue with the lifetime of the argument, so I had to implement that myself as well.

Incidentally, as long as there are situations where only function pointers can be used and not closures it would be really nice to have some support for anonymous function pointers in Rust (with the fn type and not just the Fn trait) so that one could write e.g. "Message(fn |c| c.value += 1)" instead of "Message({ fn f(c: &mut Counter) { c.value += 1 } f })". Or just infer the fn type for "closures" which don't actually close over any variables without the need for an extra keyword.

[0] https://github.com/nybble41/iced-counter2/blob/master/src/ma...

As an anecdote, the three top contributors to sixtyfps are ex-Qt people. I think it is not anecdotal that there is at least some degree of overlap and competition between Rust and C++, and that this is a market that surely The Qt Company is watching.

SixtyFPS (https://sixtyfps.io/) is in progress for Rust, but it is still early days. It also does not technically use a native toolkit (it uses Qt), but I believe that might be on roadmap. For traditional GUI apps, I think the lack of a table or tree widget is the most limiting for the time being. They have stated they intend to remedy that.

The most promising GUI hasn't been posted here, SixtyFPS. It's in it's early stages and not FOSS, but it's built by some ex-QT cats and has a lot of potential.

People have been recommending https://sixtyfps.io/ to me.

There is already a project to make a Qt like GUI toolkit in Rust: https://sixtyfps.io/ It is really similar to Qt https://sixtyfps.io/releases/0.1.5/docs/rust/sixtyfps/index.html

People are doing that too. https://sixtyfps.io/ is basically a Qt clone in Rust, actually developed by previous Qt developers.

spdlog, a pretty useful and more and more commonly used logging library for C++.\ SixtyFPS, an emerging GUI library for Rust, but you can use it in multiple languages. It uses OpenGL or Qt currently as backend (well, it's a new library and they wanted two from the get-go to make sure their abstractions are done right/well enough). They started a company this year for it too.

Just so some are not aware, there's a new project called sixtyfps by some people who were in the Qt world for long. I didn't take a deep dive into it but it looks promising.