procs VS nimkernel

Some terminals probably scroll sideways, but this `st` program seems to require running to completion. So, ^C does not give you any report at all.

While it does RSS not Proportional Set Size (PSS) { arguably parsing /proc/PID/smaps_rollup should be added } and does not integrate program launch with tracking or use netlink to track making kids, an alternative that might interest some is a scrolling terminal kind of log report out of the Nim https://github.com/c-blake/procs .

    pd -pBHd1 -f "%N %R %< %> %J %a" $(pf firefox)

I don't know about all your other questions, but the https://github.com/c-blake/cligen CLI framework seems much lower effort / ceremony than even Rust's `argh` and is just about as old as `clap` (both started 8 years ago in 2015).

There are over 50 CLI utilities at https://github.com/c-blake/bu, many of which do something novel rather than just "re-doing ls/find/cat with a twist". While they are really more an "ls/ps construction toolkits" with some default configs to get people going, I think https://github.com/c-blake/lc and https://github.com/c-blake/procs are nicer than Rust alternatives. I mention these since you seem interested in such tools.

Since `ps` is featuring prominently here, folks might be interested in https://github.com/c-blake/procs which is a color ps (Linux-only right now). It has a more canonical CLI since it is based upon https://github.com/c-blake/cligen. It actually does subcommands, too (display, find, scrollsys) and so it can replace pgrep, pkill, ps, etc., etc.

> 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/

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).