[Discussion] Rust integration in Nuttx

[rushabhvg]

As a part of GSOC 2024, I wish to integrate Rust into Nuttx. For that, a new coding standard for Rust programming language will be required and there's no mention of it anywhere. Before writing any rust code, a coding standard would be required. Please give your inputs. I was able to find C coding standards at: C Coding Standard

[rushabhvg]

@xiaoxiang781216 @anchao @raiden00pl Please give your suggestions.

[xiaoxiang781216]

NuttX doesn't support Rust yet, that's why no Rust coding standard exist in official document. As far as I know, Rust defines an official coding standard, so I would suggest that NuttX follow this style too. @patacongo @acassis what do you thinking?

[ppisa]

I think that it would worth to discuss Rust on NuttX with @lupyuen https://lupyuen.github.io/ . I have seen lot of useful information on his site.

[lupyuen]

Yep sure let's have a chat. I'm more into Rust Apps for NuttX, not so much Rust Kernel for NuttX. But let's talk :-)

(Linux Kernel Rust might be a good model to adopt)

[rushabhvg]

Hello @lupyuen then maybe I can start with Rust Apps for Nuttx? How should we communicate?

[lupyuen]

@rushabhvg Let's discuss over email: luppy@appkaki.com. I'm in Singapore (GMT+8) so my response may be slow. Thanks :-)

[acassis]

NuttX doesn't support Rust yet, that's why no Rust coding standard exist in official document. As far as I know, Rust defines an official coding standard, so I would suggest that NuttX follow this style too. @patacongo @acassis what do you thinking?

@xiaoxiang781216 you mean for Rust applications or Rust code used on kernel right? I think it makes sense because Rust developer could feel uncomfortable reading/write Rust code using NuttX Coding Style

[TimJTi]

Is this a suggestion that NuttX RTOS itself will move from C to Rust? Or a mix of the two? Sorry if it's a dumb question but I know nothing about rust other than what's on my car...

[patacongo]

I would think that a mix of the two could be a maintenance problem.

[acassis]

Is this a suggestion that NuttX RTOS itself will move from C to Rust? Or a mix of the two? Sorry if it's a dumb question but I know nothing about rust other than what's on my car...

I thought exactly that when I read Xiang comments at first time, but no, he was just saying: let Rust code to use Rust coding style, that makes sense. But as Greg commented we need to figure out how to improve the maintenance to have two coding styles. Maybe just having CI checker for .c and .rs is enough, not sure

[TimJTi]

Is this a suggestion that NuttX RTOS itself will move from C to Rust? Or a mix of the two? Sorry if it's a dumb question but I know nothing about rust other than what's on my car...

I thought exactly that when I read Xiang comments at first time, but no, he was just saying: let Rust code to use Rust coding style, that makes sense. But as Greg commented we need to figure out how to improve the maintenance to have two coding styles. Maybe just having CI checker for .c and .rs is enough, not sure

Where would Rust code be used - approved to be used - though?

[patacongo]

Where would Rust code be used - approved to be used - though?

It is somewhat less concerning if restricted to architecture- or board- specific logic as Alan suggested in an dev email.

Any use of use of Rust in the OS must have the support of the NuttX community. Not just the small group of people with special interests in this issue.

[cederom]

Hello @rushabhvg and thank you for your interest in NuttX RTOS :-) My suggestions for the workplan in 5 simple steps is presented below :-)

1. Limit Rust use for APPLICATIONS ONLY and NOT THE KERNEL.
2. Work on application layer just like other programming languages do in NuttX (i.e. existing Basic code or new ZigLang apps created by @lupyuen).
3. Work out optional setup that will allow porting and running Rust applications on NuttX. Use most generic and well known Rust tool set for integration like [1].
4. Create and/or Port some demo applications including peripherals use cases (i.e. UART, SPI, I2C, graphical display, audio, input, network). Note that applications should only use existing underlying RTOS drivers (i.e. Arch + Board setup with devfs+ioctl interface) and not their own drivers that would interfere with existing RTOS drivers.
5. Create documentation on how to setup local environment for Rust build, how to setup NuttX to work with Rust, how to build a firmware with NuttX and example Rust applications, how to port new Rust applications to NuttX (including KConfig, Makefile, etc).

[1] https://github.com/rust-embedded/awesome-embedded-rust

[rushabhvg]

Okay @cederom I will follow this worklplan. ANd, work with @lupyuen .

[lupyuen]

Hi All: @rushabhvg couldn't register on the NuttX Mailing List to read our thoughts about Rust. Any idea how we can troubleshoot this? Thanks :-)