Added json option to env command

[zaucy]

Main motivation for this PR is to make the nushell experience better (#463). Taken from one of the suggestions in the comments I added a --json option.

fnm env --json | from json | load-env
let-env PATH = ($env.PATH | prepend ($env.FNM_MULTISHELL_PATH + "/bin"))

[changeset-bot]

🦋 Changeset detected

Latest commit: 456093f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
fnm	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[Schniz]

I'm having some refactoring questions/suggestions here that I would love to know your input on. But on the other side, I wonder: should we have a support for --shell=nu[shell]? the json implementation can allow implementing this on userland easier, but maybe we should bake this knowledge into fnm and test it properly to make other features like use-on-cd work?

[Schniz]

We should probably make it broader, so --output=json is preferable. --output=json conflicts with --shell=ANY which can be declared with #[clap(conflicts_with = "shell")]

That being said, --shell=... is practically --output=..., right? so maybe we can leverage --shell= to be used as --shell=json? Kinda ugly naming but does not break and does not introduce another API complexity?

[zaucy]

Ah I didn't know about conflicts_with. Thanks!

Haha I almost did --shell=json. Maybe deprecating --shell and replace it with --output? That reads well in my head.

fnm env --output=bash

Then for compatbility sake just have --shell map to --output? Is there an option for that in clap?

[Schniz]

ah and by the way, thanks for stepping up and making a PR. I really appreciate your contribution. It's not something I take for granted 🙏

[zaucy]

Thanks for the review and improvement suggestions! I'll be honest my decision making was mainly driven by my lack of experience with rust haha.

I 100% agree adding nushell to the --shell option would be much better. I initially went down that route, but got a little stuck with functions such as to_clap_shell since nushell wasn't part of the result enum. I figured the json way was less intrusive in the codebase as a first step considering my lack of rust experience.

[Schniz]

re: to_clap_shell:

• it's currently not returning Option<Shell> but I think we should do that, in the meantime we can panic like we do in WinCmd:

  fnm/src/shell/windows_cmd/mod.rs

  Lines 8 to 11 in c85ff97

  	fn to_clap_shell(&self) -> clap_complete::Shell {
  	// TODO: move to Option
  	panic!("Shell completion is not supported for Windows Command Prompt. Maybe try using PowerShell for a better experience?");
  	}

• we can also link to this issue: Auto-generated completion scripts add NuShell support clap-rs/clap#2778

(off topic, I'm using lists on github any time I want to link to an issue just to have the nice formatting they do on lists. FORMATTING ISSUES EVERYWHERE IN GITHUB WEN)

[Schniz]

my decision making was mainly driven by my lack of experience with rust

I built fnm in Rust when I had zero experience in Rust, I want to refactor so much of the current code but I have no time 😜 you're doing good 🙏

[Schniz]

@zaucy I took the liberty to fix conflicts so I'll merge this finally. Sorry it took so long.

[zaucy]

Ayy! Love that