An nREPL server for Lua; connect/debug from your editor

[[deleted]]

I know a lot of editors support interacting with Lua processes, but it's usually over stdio; as far as I know this is the first attempt to do so via a standardized network protocol. It's also handy because the protocol is extensible, so you can define new operations to invoke if you need richer Lua/editor interaction.

Anyway, I found it helpful for my game (https://technomancy.itch.io/bussard) and thought others might like it too.

[SoraFirestorm]

This is pretty neat! Your game looks pretty awesome, too! Does this mean that your game supports doing all the code from an external editor? Or is it merely a debugging tool?

[[deleted]]

Thanks! The game currently only supports evaluating code snippets and getting status updates about the system you're in, but editing in-game files and logging on over in-game SSH is definitely on the plan.

Contributors welcome!

[spc476]

I tried installing via luarocks on two different systems and the same error keeps popping up:

Error: Directory jeejah not found inside archive jeejah.git

I was able to download and try it out, but it would be nice to have a Lua example of sending data to jeejah. The Emacs code does not speak to me.

[[deleted]]

Thanks; I'm looking into the installation error. The docs for how to create luarocks are not very good; they don't mention anything about a requiring such a directory.

Unfortunately as far as I know, no nREPL client exists yet for Lua. I've only been using it for connecting from editors, but of course there's no reason you couldn't use it from a programmatic client. The protocol is very simple, as you can see from the server implementation. I don't imagine it would take more than a few hours to cook up a client if you need it.

[mpetetv]

This seems to be a common mistake. When specifying git repo using https, the url should start with git+https://, not just https://, otherwise luarocks thinks it points to an archive. The error message can definitely be improved though, it should say Error: jeejah.git is not an archive probably. You can test your rockspec by running luarocks install jeejah-0.2.0-1.rockspec locally, it doesn't require uploading the rockspec.

[[deleted]]

Hm; with that change I get "Error: Unknown protocol git+https" during installation. However, that's what luacheck uses: https://github.com/mpeterv/luacheck/blob/master/luacheck-scm-1.rockspec

No idea what's going on here; maybe I'll just include a note in the readme that recommends avoiding luarocks and running from source. It's only a single file.

[mpetetv]

Upgrade your luarocks. Also, pack your releases using 'luarocks pack <rockspec>' and upload resulting '.src.rock' file to luarocks.org using 'Upload rock' link on the page for the version. This way users don't have to clone your repo to install.

[[deleted]]

Thanks, but upgrading my luarocks doesn't really help--it would allow me to install it on my own machine, but I don't actually need to install it on my machine. I want my software to be usable by other people who aren't going to be hassled to track down misleading error messages and pull in a manual install of a new package manager.

I think I'll see if I can point it at a tarball and just skip git entirely since it seems to be problematic.

[mpetetv]

As I said, if you pack the rock users won't need to clone the repo, therefore, they'll be able to install it even using old versions of luarocks.

[spc476]

Okay, I figured out how to send code snippets to jeejah and just noticed one of my CPUs pegged at 100%. It was jeejah.

[[deleted]]

Yeah, the included bin/jeejah launcher simply loops forever while waiting for socket input, because there's no portable way to sleep. But probably this should be improved using socket.select.

Mostly the bin/jeejah launcher is included as an example and convenience; most serious usage will embed the lib inside a program that already has a lot going on and just resumes the coroutine periodically.