Adds a new `AsyncParsableCommand` protocol, which provides a
`static func main() async` entry point and can call through to the root
command's or a subcommand's asynchronous `run()` method. For this
asynchronous execution, the root command must conform to `AsyncParsableCommand`,
but its subcommands can be a mix of asynchronous and synchronous commands.
Due to an issue in Swift 5.5, you can only use `@main` on an
`AsyncParsableCommand` root command starting in Swift 5.6.
This change also includes a workaround for clients that are using Swift 5.5.
Declare a separate type that conforms to `AsyncMainProtocol` and add the `@main`
attribute to that type.
```
@main enum Main: AsyncMain {
typealias Command = <#command#>
}
```
* Add 'see help' messages to usage messages and the help screen
* Update tests for new help messages.
* Update guide examples with additional help messages
If a command cannot successfully run with zero arguments, print the error and the full help message instead of the short usage message.
This closes#134.
* Add built-in support for --version flag
* Test that command-defined --version overrides the built-in.
* Document the `version:` parameter in CommandConfiguration
* Include --version in the generated help.
* Add an API for converting an error to an exit code
* Make ExitCode more useful as a value type
* Update tests to use ExitCode values
* Typo fix
* Add a test for ExitCode.isSuccess
* Switch to just using ExitCode for tests
Kth
Nate Cook
Jake Petroules
Gonzalo RH
Alfredo Delli Bovi
John Mueller
Elliott Williams