Passing a Switch key is ignored if the Switch contains a flag

[natanrolnik]

Imagine the following scenario:

Switch(flag: "f", key: "force", usage: "Whether to force")

Surprisingly, calling my-tool do something -f has a different than my-tool do something --force. The former one works, while the latter fails.

However, if the switch is initialized with: Switch(flag: nil, key: "force", usage: "Whether to force"), without a flag, --force works.

This is due to a (what I understand as a) bug in the Switch <| function:

case let .arguments(arguments):
    var enabled = arguments.consume(key: option.key)

    if let flag = option.flag {
        enabled = arguments.consumeBoolean(flag: flag)
    }
    return .success(enabled)

You can see that, when a flag exists, it will always read try to read if the flag was passed, and this will override the value if the key was passed.

I've opened a PR with tests and the fix for them.

[mdiep]

Fixed by #96.