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.
I can’t really think of anything that’s less frustrating than sh and ticks all your boxes. You can try TCL but it’s bound to be a shit show.
It was painful to use two decades ago.
Perl is a step up in terms of developer comfort, but it’s at the same time too big and too awkward to use.
OP is on OpenWRT (a router distro), and Alpine. Those distros don't come with very much by default, and perl is not a core dependency for any of their default tools. Neither is python.
Based on the way the cosmo project has statically linked builds of python, but not perl, I'm guessing it's more difficult to create a statically linked perl. This means that it's more difficult to put perl on a system where it isn't already there, and that system doesn't have a package manager*, than python or other options.
*or the the user doesn't want to use a package manager. OP said they just want to copy a binary around. Can you do that with perl?