Add jlx

[davidanthoff]

This could be similar to npx, i.e. to run Julia applications. I haven't thought much about it, but I think my main scenario would be something like:

jlx Foo

would automatically install a package called Foo from the general registry, and then run some well defined entry point (say Foo.main).

[johnnychen94]

https://github.com/Roger-luo/IonCLI.jl has a full set of such features that you might be interested to get inspiration from. But I think it's better to solve JuliaLang/Pkg.jl#1962 first before we actually work on this.

[Roger-luo]

I personally would prefer this to be separated from juliaup implementation, I have been thinking about how to install CLIs, I find for Julia it would be much easier if we can assume there is a Julia locally for various reasons (e.g we can have deamon process to reduce latency if we are able to assume there is a Julia available, and this type of CLI needs to understand more Julia specific things such as dependencies). And this is now possible with juliaup.

I think with juliaup we will be able to simplify the logic in a manager like Ion by letting it depends on an actual Julia compiler instead of trying to ship a compiled binary, and get updated by juliaup (similar to cargo to rustup). so I'm now rewriting IonCLI here https://github.com/Roger-luo/Ion.jl/ to make use of this assumption, I'm happy to chat if anyone is interested in this direction