Subcommand with no additional arguments?

[kartikynwa]

I am trying to create a program that's supposed to work like this:

$ ./app copy "some text"

$ ./app paste
some text

The paste subcommand is not supposed to take any arguments. But I can't figure out from the docs whether it is possible.

I tried something like this:

// ...

#[derive(FromArgs, PartialEq, Debug)]
#[argh(subcommand)]
enum Subcommand {
    Copy(SubcommandCopy),
    Paste(SubcommandPaste),
}

// ....

#[derive(FromArgs, PartialEq, Debug)]
/// Second subcommand.
#[argh(subcommand)]
struct SubcommandPaste {};

But this doesn't work because SubcommandPaste cannot be an empty or unit struct.

Any pointers are appreciated. Thank you.

[kartikynwa]

Actually, this works:

use argh::FromArgs;

#[derive(FromArgs, PartialEq, Debug)]
/// Top-level command.
pub struct Args {
    #[argh(subcommand)]
    pub nested: Subcommand,
}

#[derive(FromArgs, PartialEq, Debug)]
#[argh(subcommand)]
pub enum Subcommand {
    Copy(SubcommandCopy),
    Paste(SubcommandPaste),
}

#[derive(FromArgs, PartialEq, Debug)]
/// copy command
#[argh(subcommand, name = "copy")]
pub struct SubcommandCopy {
    #[argh(positional)]
    /// the text to be stored
    pub input: String,
}

#[derive(FromArgs, PartialEq, Debug)]
#[argh(subcommand, name = "paste")]
/// paste command
pub struct SubcommandPaste {}