axiom VS awesome-nim

I'm creating a hobby operating system in Nim (early stages). After an initial attempt[0] I decided to start over[1] and document my journey in building it[2]. The focus for me is on learning low-level systems programming and enjoying the journey, rather than building something production ready.

[0] https://github.com/khaledh/axiom

[1] https://github.com/khaledh/fusion

[2] https://0xc0ffee.netlify.app/osdev/01-intro.html

> kernel developers do not allow third party runtimes in the kernel. Even meager Rust's "panic" runtime is a contentious

Much in Linux is contentious :-) which is why the module system is nice. A kernel module for C code requires no permission from Linux-core unless you need it distributed with the kernel (which, yes, might be required for "credibility" - but critically also might not). It may require many decls to access various kernel APIs, but those can be (semi-)automated or just done as-needed. So, Linux kernel policy is not so relevant (at best) which is what I meant by "no special support" (admittedly brief). Kernel coding is always a bit trickier, and you may need to build up some support code to make integration nice, though as well as decl generators.

> Can one disable runtime in Nim completely -- no GC, no exceptions?

To answer your question, and as discussed elsewhere in this subthread, Nim has many options for memory management.. only stdlib seq/string really needs automatic methods. One can disable the runtime completely via os:standalone and statically check that no exceptions are raised with Nim's effect system (and there are also both setjmp & goto based exception impls which may/may not be workable in Linux/BSD kernel module settings). As "proof more by example", a few people have written OS kernels in Nim recently[1,2] and there was another toy kernel long ago[3].

People have also written OS kernels in Go which "has a GC and runtime".[4] So, I acknowledge it's not quite the same example, but I also see no fundamental blockers for kernel modules.

[1] https://github.com/khaledh/axiom

[2] https://prosepoetrycode.potterpcs.net/2023/01/a-barebones-ke...

[3] https://github.com/dom96/nimkernel

[4] https://github.com/mit-pdos/biscuit/

I gave Rust a few chances, and always came out hating its complexity. I needed a systems programming language to develop a hobby OS[1], and Nim hit the sweet spot of being very ergonomic, optional GC, and great interop with C. I can drop down to assembly any time I want, or write a piece of C code to do something exotic, but the rest of the system is pure Nim. It's also quite fast.

[1] https://github.com/khaledh/axiom

I've used both to work on a hobby OS project (Nim[1], Zig[2]). I very much prefer Nim. Code is succinct, elegant, and lets you focus on your core logic rather than fighting the language.

Zig is nice and I like its optionals support and error handling approach. But I was put off by its noisy syntax, e.g. !?[]u8 to represent an error union of an optional pointer to a many-pointer of uint8. Also having to prepare and weave allocators throughout most of the code that needs to dynamically allocate (which is most of the code) gets in the way of the main logic. Even little things like string concatenation or formatting becomes a chore. Zig also doesn't have dynamic dispatch, which makes polymorphic code hard to write; you have to work around it through some form of duck typing. In the end I realized that Zig is not for me.

[1] https://github.com/khaledh/axiom

Niceness is subjective, but Nim is just as valid an addition to that group. Nim compiles to C and has had an --os=standalone mode for like 10 years from its git history, and as mentioned else-thread (https://news.ycombinator.com/item?id=36506087) can be used for Linux kernel modules. Multiple people have written "stub OSes" in it (https://github.com/dom96/nimkernel & further along https://github.com/khaledh/axiom).

While it can use clang as a backend, Nim does not rely upon LLVM support like Zig or Rust (pre-gcc-rust working). Use on embedded devices is fairly popular: https://forum.nim-lang.org/search?q=embedded (or web search).

Latency-wise, for a time, video game programming was a perceived "adoption niche" or maybe "hook" for Nim and games often have stringent frame rendering deadlines. If you are interested in video games, you might appreciate https://github.com/shish/rosettaboy which covers all but Ada in your list with Nim being fastest (on one CPU/version/compiler/etc). Note, however, that cross-PL comparisons are often done by those with much "porting energy" but limited familiarity with any but a few of the PLs. A better way to view it is that "Nim responds well to optimization effort" (like C/Ada/C++/Rust/Zig).

If anyone is interested, I have a couple of implementations of booting under UEFI and getting a bunch of info about the system (don't expect a functioning system, they just boot and dump some info):

Nim: https://github.com/khaledh/axiom

Zig: https://github.com/khaledh/axiom-zig (this one goes into depth in disassembling ACPI DSDT bytecode)

I wasn't ready to share it yet, but here it goes[1]. It's at a very early stage, but should give you an idea of how to get things up and running under Nim.

I didn't avoid malloc. I provided a simple bump pointer based heap to get things going. Later I'll have to separate things into a UEFI bootloader and a proper kernel image, each with its own allocator (the bootloader will use UEFI memory allocation services, and the kernel will have its own heap).

[1] https://github.com/khaledh/axiom

Ones that have not been mentioned so far:

nlvm is an unofficial LLVM backend: https://github.com/arnetheduck/nlvm

npeg lets you write PEGs inline in almost normal PEG notation: https://github.com/zevv/npeg

futhark provides for much more automatic C interop: https://github.com/PMunch/futhark

nimpy allows calling Python code from Nim and vice versa: https://github.com/yglukhov/nimpy

questionable provides a lot of syntax sugar surrounding Option/Result types: https://github.com/codex-storage/questionable

ratel is a framework for embedded programming: https://github.com/PMunch/ratel

cps allows arbitrary procedure rewriting to continuation passing style: https://github.com/nim-works/cps

chronos is an alternative async/await backend: https://github.com/status-im/nim-chronos

zero-functional fixes some inefficiencies when chaining list operations: https://github.com/zero-functional/zero-functional

owlkettle is a declarative macro-oriented library for GTK: https://github.com/can-lehmann/owlkettle

A longer list can be found at https://github.com/ringabout/awesome-nim.

Hasznos cuccok hozzá: https://github.com/ringabout/awesome-nim

Ecosystem-wise - a brief subset of Nim packages:

    https://github.com/ringabout/awesome-nim

One can, of course, go much further than simply distinct number types: https://github.com/ringabout/awesome-nim#science

(Unchained seems maybe the most featureful of those units packages.)

> This is useful for compiler programmers, or maybe also those writing source code analyzers/optimizers, but is that it?

It is also useful for anyone wanting to implement language-level features as simple libraries. Someone else brought up Nim here: it's a great example of what can be done with metaprogramming (and in a non-Lisp language) as it intentionally sticks to a small-but-extendable-core design.

There's macro-based libraries that implement the following, with all the elegance of a compiler feature: traits, interfaces, classes, typeclasses, contracts, Result types, HTML (and other) DSLs, syntax sugar for a variety of things (notably anonymous functions `=>` and Option types `?`), pattern matching (now in the compiler), method cascading, async/await, and more that I'm forgetting.

https://github.com/ringabout/awesome-nim#language-features

Just under their table of contents, they say that "This list is fairly outdated." and point you to https://github.com/xflywind/awesome-nim - and that repo seems to have recent updates.

Thanks for making these, I actually had no idea these existed! I don't "need" them now but seeing these gives me ideas for projects and makes future things easier.

I wish discovery of community libraries was higher, I'm constantly discovering libraries that do amazing things 'hidden' away. I know there's https://nimble.directory/ and https://github.com/xflywind/awesome-nim but most of the time I end up using a search engine for something specific if I think of it.

awesome-nim: https://github.com/xflywind/awesome-nim