[bla3]

I think that might be true of the language committee, but there's presumably a huge crowd of people with existing c++ code bases that would like to have a different path forward than just hoping that the committee changes priorities.

[pjmlp]

That is what many of us have done moving into managed languages, with native libraries when required to do so.

The remaining people driving where the language goes have other priorities in mind like reflection.

The profiles that were supposed to be so much better than the Safe C++ proposal, none of them made it into C++26, and it remains to be seen if we ever will see a sensible preview implementation for C++29.

[tialaramex]

C++ 26 doesn't have the technology, but it wouldn't matter anyway because what's crucial about Rust isn't the technology it's the culture.

If WG21 were handling Rust instead f64 would implement Ord, and people would just write unsafe blocks with no explanation in the implementation of supposedly "safe" functions. Rust's technology doesn't care but their culture does.

Beyond that though, the profiles idea is dead in the water because it doesn't deliver composition. Rust's safety composes. Jim's safe Activity crate, Sarah's safe Animals crate and Dave's safe Networking crate compose to let me work with a safe IPv6-capable juggling donkey even though Jim, Sarah and Save have never met and had no idea I would try that.

A hypothetical C++ 29 type safe Activity module, combined with a thread safe Animals module, and a resource leak safe Networking module doesn't even get you something that will definitely work, let alone deliver any particular safety.

[justcuriousab]

> If WG21 were handling Rust instead f64 would implement Ord, and people would just write unsafe blocks with no explanation in the implementation of supposedly "safe" functions. Rust's technology doesn't care but their culture does.

But Rust allows pattern matching on floats.

https://play.rust-lang.org/?version=stable&mode=debug&editio...

Rust Zulip is C++ WG21 confirmed?

[tialaramex]

I'm sure you think this was somehow succinctly making your point, but I can't see any connection at all, so if you did have an actual point you're going to need to explain it.

[justcuriousab]

Float matching in Rust is not supported due to correctness concerns, but due to historical accidents and backwards compatibility.

https://github.com/rust-lang/rust/issues/41620#issuecomment-...

https://github.com/rust-lang/rust/pull/84045#issuecomment-82...

[tialaramex]

OK? I don't see how that's connected? It's not controversial that f32 and f64 are partially ordered, the problem in C++ is that the difference between "Partially Ordered" and "Totally Ordered" is semantic not syntactic in their language and all semantic mistakes are just IFNDR so it's a footgun.

[pjmlp]

Yeah, that sums it all quite nicely, see contracts proposal as a good example of that.