rust-orphan-rules VS embassy

Well, unless someone comes up with better, compatible rules, the orpan rules are gonna stick around.

Additionally there are other issues with rust currently. Compile time code (ala constexpr) is not up to par with C++20 (not really close). The const generic aren't as powerful as C++20 which added non primitive non type template parameters (though with you stuck with C++14, it actually is significantly better than what you have, again, if you're going to use C++, just use 20). Generics accepting closures is a bit more of an ordeal in rust, compared to C++. Also C++'s Duck Typed templates allow for some uncharacteristically strong typing compared to what is expressible in Rust generics currently. Now, duck typed templates do have major downsides, for example the entire feature of concepts is completely irrelevant in rust, but required for sane DTT type bounds, but they also have major upsides. Rust currently doesn't have "negative trait bounds", basically "This objected does not implement this trait, or std::enable_if> or the equivalent concepts implementation. Rust also doesn't have trait specializations, basically template specialization. Do note all features I've talked about to this point have nightly options, they just are at various stages of being stable/complete. Another issue is the orphan rule, though this is kind of a problem in C++ too in some respects, and that's unlikely to change drastically, since there are legitimate reasons for it's existence. For a lot of code none of these things are big deals, others they are, which is why you find inconsistent feed back on these issues.

Not that simple... hence why Orphan rule is still in-place. The struct wrapper was implemented in Rust as a temporary safe work-around. However, they are making progress on a solution: https://github.com/Ixrec/rust-orphan-rules/issues/1

That's still not an entirely complete explanation because there's more nuanced situations which aren't completely foreign but are foreign enough that if allowed, two crates could write the same impls. Some of the definitions are still unofficial as far as am I'm aware. For the best reference I’ve seen so far see this for more details.

In our crate the compiler doesn't know when calling MyTrait methods on MyStruct whether to use the implementation defined in crate 3 or crate 4! Rust has a set of orphan rules to prevent this situation from happening.

Sadly because of the rusts orphan rule you cannot implement a Trait on a Type where you do not own one or the other. So, apart from upstream contributions your only options are either a new Trait or a new Type.

If anyone is looking for additional background about orphan rules, check out https://github.com/Ixrec/rust-orphan-rules

thanks. looked that up. for the curious: https://embassy.dev/

Running the Embassy RP2040 USB CDC ACM serial example takes about 5 seconds on a Pico.

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

Async solves different problems, you can, for instance, have just a single-threaded CPU and still have a nice API if you have async-await. It might not be so cool at a higher level as Go's approach of channels and threads, but it's cool in embedded, read this:

https://github.com/embassy-rs/embassy?tab=readme-ov-file#rus...

"Rust's async/await allows for unprecedently easy and efficient multitasking in embedded systems. Tasks get transformed at compile time into state machines that get run cooperatively. It requires no dynamic memory allocation, and runs on a single stack, so no per-task stack size tuning is required. It obsoletes the need for a traditional RTOS with kernel context switching, and is faster and smaller than one!"

I'm just toying with Raspberry Pi Pico and it's pretty nice.

Go and Rust have different use cases, the async-await is nice at a low level.

I have not yet dipped by toes in the Rust waters, but reading about the embassy project is actually what piqued my curiosity about using C++ coroutines in embedded. Are you familiar with the project or have you found it lacking?

I think I get the basics (shoutout to the Rust Embedded Working Group!), and I've started looking for the stack I'd be using. I think Embassy is really amazing, as well as the work of the ESP team -- hats off.

> }

And this is how to do it using embassy, which is an async framework for embedded in rust:

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

> not good for embedded

embassy begs to differ

https://embassy.dev/

async/await is really just a syntax for building state machines in a way that resembles regular code. It's compiled down to the same code that you would write by hand anyway (early on it had some bloat in state size but I think it's all fixed now).

And embedded has a lot of state machines!

You can run multiple executors at different interrupt priority levels (with multiple tasks per executor), which allows tasks on the higher priority executor to interrupt other tasks. Here's an example https://github.com/embassy-rs/embassy/blob/main/examples/nrf...