Add completer for tox 4

[samuelallan72]

Add completions for https://tox.wiki/ (based on tox 4.13)

[samuelallan72]

Hi @rsteube , I'm interested in adding support for tox and happy to work on it. I've done some digging into the codebase and started a very basic PoC here. Would you be interested in this feature? I may need some guidance during the process, as this would be the first time working with the project or these Go libraries.

[rsteube]

Probably best to use the parser here to create the initial command structure: https://github.com/carapace-sh/carapace-bin/tree/master/cmd/carapace-parse

I need to update the docs for it but see the first minute for how it works: https://asciinema.org/a/466859

Store the help output (if available) or https://tox.wiki/en/latest/cli_interface.html of a command (root or subcommand) in a text file.

Prepare it a bit for parsing (something like this):
-s, --long shorthand singlespace longhand 2+ space then description
-v, --value VALUE same but accepts a value (single space and some text)
--longonly only longhand
-s only shorthand

It can handle some variants, but it's just a simple regex.

cat root.txt | carapace-parse -n tox -s "tox root command" > root.go
cat sub.txt | carapace-parse -n sub -p root -s "subcommand of root" > sub.go
cat susbsub2.txt | carapace-parse -n sub2 -p sub -s "subcommand of sub" > sub_sub2.go

[samuelallan72]

Thanks for your tip about carapace-parse! 😄 That's jumpstarted it. I also applied your suggestions. Still a work in progress though.

[samuelallan72]

@rsteube the completer should be complete now, and ready for review. :)

[rsteube]

• common.go

Files in cmd generally represent a (sub)command.
Moved functions to root.go for consistency since they are small enough.
In another case I've put these in a common subfolder (alternative).

• snake_case

Go uses camelCase.

• verbose/quiet

Cobra has Count for this kind of flags.

• Common Flags

Seems these are used in every command.
Cobra has PersistentFlags which passes them on to subcommands.
It also hides them for subcommands when they are already set on the parent.

• Files / Folder

File completion is explicit in Carapace and needs to be set.
So there is no fallback as shells normally do.
The venv folder name is arbitrary, but it can be an absolute path so folder completion is still beneficial.

• discover, f, m

This is a weird (bad) pattern in some python commands where flags can consume multiple arguments.
I've got basic support for it with Nargs.

• StyleF(style.ForKeyword)

No need for this, but highlights positive/negative/arbitrary keywords (like true/false) in colors.

• PreInvoke

This changes the workdir for all actions based on the workdir flag value.
(Assuming this is what the flag is meant for)

[rsteube]

Made some minor changes. Just open an issue/pr if I botched something.

Thanks!

[samuelallan72]

Thanks for your feedback and the merge! 😁