I've been looking around for a scripting language that:
- has a cli interpreter
- is a "general purpose" language (yes, awk is touring complete but no way I'm using that except for manipulating text)
- allows to write in a functional style (ie. it has functions like map, fold, etc and allows to pass functions around as arguments)
- has a small disk footprint
- has decent documentation (doesn't need to be great: I can figure out most things, but I don't want to have to look at the interpter source code to do so)
- has a simple/straightforward setup (ideally, it should be a single executable that I can just copy to a remote system, use to run a script and then delete)
Do you know of something that would fit the bill?
Here's a use case (the one I run into today, but this is a recurring thing for me).
For my homelab I need (well, want) to generate a luhn mod n check digit (it's for my provisioning scripts to generate synchting device ids from their certificates).
I couldn't find ready-made utilities for this and I might actually need might a variation of the "official" algorithm (IIUC syncthing had a bug in their initial implementation and decided to run with it).
I don't have python (or even bash) available in all my systems, and so my goto language for script is usually sh (yes, posix sh), which in all honestly is quite frustrating for manipulating data.
Among others, I run stuff on alpine and openwrt.
I don't need to run these scripts everywhere (strictly speaking, I don't need the homlab at all), but I was wondering if there's something that I can adopt as a default goto solution without having to worry about how each system is packaged/configured.
As for python, I doubt the full version would fit in my router plus as said I don't want to deal with libraries/virtualenvs/... and (in the future) with which distro comes with python3 vs pyton4 (2 vs 3 was enough). Openwrt does have smaller python packages, but then I would be using different implementations on different systems: again something I'd rather not deal with.
As for perl, it would be small enough, but I find it a bit archaic/esoteric (prejudice, I know), plus again I don't want to deal with how every distro decides to package the different things (eg. openwrt has some 40+ packages for perl - if I were doing serious development that would be ok, but I don't want to worry about that for just some scripts).
Sounds like you want MicroPython. It’s definitely available on OpenWrt and AlpineLinux and has a very small footprint.
If you don’t like Python, have a look at Lua/luajit.
You've defined yourself into an impossible bind: you want something extremely portable, universal but with a small disk imprint, and you want it to be general purpose and versatile.
The problem is that to be universal and general purpose, you need a lot of libraries to interact with whatever type of systems you might have it on (and the peculiarities of each), and you need libraries that do whatever type of interactions with those systems that you specify.
E.g. under-the-hood, python's
open("<filename>", 'r')is a systemcall to the kernel. But is that Linux? BSD? Windows NT? Android? Mach?What if you want your script to run a CLI command in a subshell? Should it call "cmd"? or "sh"? or "powershell"? Okay, okay, now all you need it to do is show the contents of a file... But is the command "cat" or "type" or "Get-FileContents"?
Or maybe you want to do more than simple read/write to files and string operations. Want to have graphics? That's a library. Want serialization for data? That's a library. Want to read from spreadsheets? That's a library. Want to parse XML? That's a library.
So you're looking at a single binary that's several GBs in size, either as a standalone or a self-extracting installer.
Okay, maybe you'll only ever need a small subset of libraries (basic arithmetic, string manipulation, and file ops, all on standard glibc gnu systems ofc), so it's not really "general purpose" anymore. So you find one that's small, but it doesn't completely fit your use case (for example, it can't parse uci config files); you find another that does what you need it to, but also way too much and has a huge footprint; you find that perfect medium and it has a small, niche userbase... so the documentation is meager and it's not easy to learn.
At this point you realize that any language that's both easy to learn and powerful enough to manage all instances of some vague notion of "computer" will necessarily evolve to being general purpose. And being general purpose requires dependencies. And dependencies reduce portability.
At this point your options are: make your own language and interpreter that does exactly what you want and nothing more (so all the dependencies can be compiled in), or decide which criteria you are willing to compromise on.
Is compiling scripts an option? Aka compiling them in C, C++, Rust, whatever for your router on another machine, and copying and executing those binaries on your router?