Subcommands

You can nest commands. Let's take git for example

git has a command called stash. When you execute git stash, it stashes all the changes. But stash has further commands like, git stash pop, git stash list, etc.

Let's mimic the same behavior using CommandDotNet:

Subcommand as a property

[Command(Description = "Fake git application")]
public class Git
{
    // Properties decorated with the [SubCommand] attribute
    // will be registered as subcommands.
    [SubCommand]
    public Stash Stash {get;set;}

    [Command(Description = "Commits all staged changes")]
    public void Commit([Option(ShortName = "m")]string commitMessage)
    {
        Console.WriteLine("Commit successful");
    }
}

[Command(Description = "Stashes all changes when executed without any arguments")]
public class Stash
{
    [DefaultCommand]
    public void StashDefaultCommand()
    {
        Console.WriteLine($"changes stashed");
    }

    [Command(Description = "Applies last stashed changes")]
    public void Pop()
    {
        Console.WriteLine($"stash popped");
    }

    [Command(Description = "Lists all stashed changes")]
    public void List()
    {
        Console.WriteLine($"here's the list of stash");
    }
}

Notice the Stash property decorated with the [SubCommand] attribute.

The help will generate as:

Fake git application

Usage: git.exe [command] [options]

Commands:
  Commit  Commits all staged changes
  Stash   Stashes all changes when executed without any arguments

Use "git.exe [command] --help" for more information about a command.

Here's how the interaction looks like:

~
$ git.exe commit -m "some refactoring"

Commit successful

~
$ git.exe stash

changes stashed

~
$ git.exe stash --help

Stashes all changes when executed without any arguments

Usage: git.exe Stash [command] [options]

Commands:
  List  Lists all saved stashed changes
  Pop   Applies last stashed changes

~
$ git.exe stash pop

stash popped

Tip

See Nullable Reference Types for avoiding "Non-nullable property is uninitialized" warnings for subcommand properties

Subcommand as a nested class

The same git stash command could be modelled as a nested class.

[Command(Description = "Fake git application")]
public class Git
{
    [Command(Description = "Commits all staged changes")]
    public void Commit([Option(ShortName = "m")]string commitMessage)
    {
        Console.WriteLine("Commit successful");
    }

    // Nested classes decorated with the [SubCommand] attribute
    // will also be registered as subcommands.
    [SubCommand]
    [Command(Description = "Stashes all changes when executed without any arguments")]
    public class Stash
    {
        [DefaultCommand]
        public void StashDefaultCommand()
        {
            Console.WriteLine($"changes stashed");
        }

        [Command(Description = "Applies last stashed changes")]
        public void Pop()
        {
            Console.WriteLine($"stash popped");
        }

        [Command(Description = "Lists all stashed changes")]
        public void List()
        {
            Console.WriteLine($"here's the list of stash");
        }
    }
}