Install lua interpreter on demand

[gustavo-hms]

The fzf plugin for vim has a handy feature: it can automatically install a version of the fzf binary on the user's machine, freeing the user of the burden of dealing with the plugin dependency and making it works out of the box.

The lua interpreter is very tiny (around 300 Kb in a 64 bits Linux machine) and can be downloaded much faster than fzf, almost unnoticeably. So, it would be nice if Luar could detect that a lua interpreter is missing and automatically installs one. This has the potential to make people less worried about publishing Kakoune plugins written using Luar.

It could be something in the following lines:

• on ModuleLoaded, a script would check if a lua executable is available. If so, nothing happens;
• if, on the other hand, a lua executable could not be found, download a tar file from here, unpack it in a predetermined location and set a hidden option to inform the lua command to use the custom binary instead of relying on a system installation.
• optionally, allow the user to set an option informing Luar to not download the interpreter automatically.

[catdevnull]

I think it would be nicer if auto-downloading would be opt-in as some people may not like downloading binaries to their devices without their interaction.

Also, they may want to install it from a package manager instead.

[gustavo-hms]

Hi, @catdevnull !

Yeah, the idea is to have an option you can set to disable that behaviour.

[catdevnull]

Yes, I saw, what I meant is that instead you might want to do the reverse: add an option to enable downloading of Lua.

This is similar to what vim-plug does: https://github.com/junegunn/vim-plug/wiki/tips#automatic-installation

It's also what fzf.vim does; you have to call fzf#install for it to install the binary.

Just a suggestion though!

[gustavo-hms]

I see...

Ok, I agree with you. When this feature finally get an implementation, it won't be the default behaviour.