nimbme – Nim bare-metal environment | Hacker News Reader

nimbme – Nim bare-metal environment

github.com

Since Nim compiles to C, porting it to new platforms is surprisingly easy. I did it a few years ago for 16-bit DOS (OpenWatcom): https://github.com/Ronsor/Nim/tree/i086-and-watcom.

While there are several "OS in Nim" projects (https://github.com/khaledh/fusion is probably the most interesting), this same ability to run bare-metal and generate to C should, in theory, make it possible to write kernel modules in Nim for Linux/SomeBSD without any special permission slip / drama over integration (the way Rust suffers, for example). I haven't heard of anyone doing such modules, but it might be a fun project for someone to try.

Well, the C that Nim outputs isn't exactly human readable. Sure if you know what you're doing you might be able to follow along, but no sane maintainer would admit it into a C project.

It could help the build process a you can pre-compile to C and only use the C build system. And it allows you to run anywhere C can run (we use it for everything from servers to microcontrollers). But apart from that it's mostly an implementation detail.

My idea is not to submit the generated C any more than you submit C-compiler generated assembly, but to write directly in Nim. The niceness would mostly just be if you wanted to write some complex thing like a filesystem or driver in Nim with its templates & macros & user-defined operators and DSL building and all that goodness.

Being a module means it can be separately distributed - kernel maintainers don't need to admit them or even be aware of them. ZFS is not distributed in mainline Linux out of Oracle fears (though that module is popular enough some distros help out). This is more or less the key to any extensible system. The C backend is helpful here in that internal kernel APIs can rely heavily on things like the C preprocessor, not just object file outputs.

I think the main challenges would be "bindings for all the internal kernel APIs" and the ultimately limited ability &| extra work to make them Nimonic and adapting the "all set up for your C module" build process to ease a Nim build (as well as the generic in-kernel no-stdlib hassles). So, I imagine a 2- or 3-level/stage approach would be best - the background to make the Nim modules easy and then actual modules. { Linux itself, while the most popular free Unix, is also kind of a faster moving target. So, it would probably present an additional challenge of "tracking big shifts in internal APIs". }

Pleasantly surprised about the ease of porting to new platforms. Being able to inline assembly, nevermind call regular C functions (eg from an OEM SDK) is incredibly handy. I recently wrote a pure Nim implementation for the CH32V003 microcontroller https://github.com/snacsnoc/nim-on-ch32v003

Nim seems underrated. A nice balance of utility, longevity, speed, and coding niceness.

Happy to see it get more attention here - it really is versatile

I was active in the community for several years before getting too busy with other things. Good folks.

Happy to see more Nim projects on HN!

I don't know if AI code gen helped with this particular project, so please forgive my small tangent; Claude Code is surprisingly good at writing Nim. I just created a QuickJS + MicroPython wrapper in Nim with it last week, and it worked great!

Don't let "but the Rust/Go/Python/JavaScript/TypeScript community is bigger!" be the default argument. I see the same logic applied to LLM training data: more code means more training data, so you should only use popular languages. That reasoning suggests less mainstream languages are doomed in the AI era.

But the reality is, if a non-mainstream language is well-documented and mature (Nim's been around for nearly 20 years!), go for it. Modern AI code gen can help fill in the gaps.

tl;dr: If you want to use Nim, use Nim! It's fun, and now with AI, easier than before.

Is there a reasonably good IDE for Nim that provides debugging, specifically the full debugging experience (Nim code rather than C, breakpoints, inspect/modify values, etc.)? That's been the gating factor for me trying it. What's the present situation?

I'm using Claude Code... And then for manual review and editing, using Zed with Nim extensions: https://zed.dev/docs/languages/nim

Sorry, I don't really do debuggers... I mostly step through code interactively using a REPL (INim).

I ran into some problems with Zed and Nim which I eventually solved by enhancing the LSP’s settings. This might be useful for anyone interested https://blog.ameri.coffee/using-zed-for-nim-development

I see comments like this fairly often and in my entire career (I'm 53) I've never had to use a debugger. For inspection of values, I write small functions and unit tests or just output to stderr in debug modes set with env vars. I've always thought that the need to use a debugger was a code smell- too much cyclomatic complexity of single functions.

Have you ever used rr though?

https://github.com/rr-debugger/rr

it... goes backwards in time?

OK, THIS is interesting!

Does Nim not output the #line directives when compiling to C? That alone should help with the debugging experience.

Sure! Just compile with nim c --lineDir=on or drop `lineDir=on` in your $HOME/.config/nim/nim.cfg (or per project NimScript .nims or per file foo.nim.cfg or ...) and source-level debugging with gdb on Linux works..

mostly at the level of Nim source, although various things are likely to "leak through" like mangled names (though in fairness, lower-level assembly notions leak through in "C source level" debugging...).

Beware, though, that since around Spring 2024 this can make the tinycc/tcc backend infinite loop (but otherwise tcc can be a nice way to get fast development iteration).

Also recently Nim’s generated C code started using Itanium name mangling, which oddly has become the defacto name mangling method for C++ on Linux and other platforms.

Meaning you get pretty function names with generic types and all included with debuggers that support it. Works better with ldb as gdb seems to refuse to recognize it.

My experience has been the same. I have found it much easier to write good Nim and F# code with Claide Code, than say modern Python with type hints everywhere.

Both Nim and F# have strong types and strict compilers (arguably more strict in case of F#). These factors matter a lot more than how much code there is for the LLM to train on. And there probably is less ostensibly bad Nim and F# code out there than old Python code written by people who were not really developers, so the training data set is higher quality.

I agree, the code output for Nim with Claude and Gemini as well is pretty good. It misses some Nim idioms but generally does really well. Simple syntax with strong types helps both Nim and F#.

I used Claude 4 to generate SIMD versions of signed distance functions for both NEON and SSE2 and it all worked and compiled fine the first time aside from some minor import changes [1]. Gave me an almost 4x increase for many SDFs.

I also use Atlas, an alternative package manager for Nim [2], to clone deps into a local folder which lets Cursor grep and search the dependencies to add it to the context as needed.