Can one set up groups of options that "shadow" each other?

Related Projects ArgumentParser
1

Once you get past very simple CLIs, it is common to have conflicting options, especially flags.

Here is how ls handles it:

The -1, -C, -x, and -l options all override each other; the last one specified
determines the format used.

The -c, -u, and -U options all override each other; the last one specified
determines the file time used.

Here is rm

The -f option overrides any previous -i options.

The -i option overrides any previous -f options.

I haven't figured out how to do this in Argument Parser. Am I missing something?

2

You might want to look into Custom Enumerable Flags. It lets you support non-binary Flags.

This should reimplement the rm command’s -f,-i and -I flags with Swift Argument Parser

enum PromptMode {
    case never
    case always
    case once
    case unassigned
}

extension PromptMode: EnumerableFlag {
    static func name(for value: Self) -> NameSpecification {
        switch value {
        case .never:  return [.customShort("f"),.customLong("force")]
        case .once:   return .customShort("I")
        case .always: return .customShort("i")
        default:      return [] // No Flags for internal modes
        }
    }
    
    static func help(for value: Self) -> ArgumentHelp? {
        switch value {
        case .never:  return "ignore nonexistent files, never prompt"
        case .once:   return "prompt once before removing more than three files or when removing recursively"
        case .always: return "prompt before every removal"
        default:      return .init("This is an internal mode and has no flags", visibility: .private)
        }
    }
}

You can put it in your ParsableCommand with

@Flag(exclusivity: .chooseLast)
var promptMode: PromptMode = .unassigned
2 Likes
3

Thanks. Especially for writing out the example.