Investigate the options of migrating to some library for parsing cmd line args

[psfinaki]

The original parser was written long time ago, since then a bunch of libraries for arg parsing popped up, we can try switching to some.

Some libs I know of: Argu, CommandLineParser.

[baronfel]

If at all possible I'd advocate for System.CommandLine - we're trying to standardize on it across the board. It powers the dotnet CLI and has a broad range of functionality, including support for tab-completions and trimmability built-in

[psfinaki]

No objections from my side - haven't used it but definitely heard some good words about it.
The only argument for Argu would be that it's F# native and I think @dsyme was contributing to that so might have extra insight.

[vzarytovskii]

If anything, I'd vote for not using anything 3rd-party, it will inevitably be painful to support it, System.CommandLine sounds OK to me, our feedback will be beneficial for them too.
@jonsequitur CC as you may be interested in it.

[dsyme]

I think we should not do this. What is there works, is stable, and whatever else we use will have some weird compat problems. Plus the Fable version of the F# compiler would need an implementation of that library.

In general this last point means there is a structural advantage in fully F#-implemented functionality internalized in FSharp.Compiler.Service, with very low dependency base for that component. We can't always avoid dependencies - and reusing other libraries is good sometimes - but it's a major factor to take into account. There just has to be a really compelling customer-facing reason to take a new dependency.

[dsyme]

I'll close, as I think in balance we shouldn't do it, for reasons described above.