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## Module cargo_example_derive

Source
Available on crate feature `unstable-doc` only.
Expand description

## §Example: cargo subcommand (Derive API)

    use clap::Parser;

    #[derive(Parser)] // requires `derive` feature
    #[command(name = "cargo")]
    #[command(bin_name = "cargo")]
    #[command(styles = CLAP_STYLING)]
    enum CargoCli {
        ExampleDerive(ExampleDeriveArgs),
    }

    // See also `clap_cargo::style::CLAP_STYLING`
    pub const CLAP_STYLING: clap::builder::styling::Styles = clap::builder::styling::Styles::styled()
        .header(clap_cargo::style::HEADER)
        .usage(clap_cargo::style::USAGE)
        .literal(clap_cargo::style::LITERAL)
        .placeholder(clap_cargo::style::PLACEHOLDER)
        .error(clap_cargo::style::ERROR)
        .valid(clap_cargo::style::VALID)
        .invalid(clap_cargo::style::INVALID);

    #[derive(clap::Args)]
    #[command(version, about, long_about = None)]
    struct ExampleDeriveArgs {
        #[arg(long)]
        manifest_path: Option<std::path::PathBuf>,
    }

    fn main() {
        let CargoCli::ExampleDerive(args) = CargoCli::parse();
        println!("{:?}", args.manifest_path);
    }

For more on creating a custom subcommand, see the cargo book. The crate `clap-cargo` can help in mimicking cargo’s interface.

The help looks like:

    $ cargo-example-derive --help
    Usage: cargo <COMMAND>

    Commands:
      example-derive  A simple to use, efficient, and full-featured Command Line Argument Parser
      help            Print this message or the help of the given subcommand(s)

    Options:
      -h, --help  Print help

    $ cargo-example-derive example-derive --help
    A simple to use, efficient, and full-featured Command Line Argument Parser

    Usage: cargo example-derive [OPTIONS]

    Options:
          --manifest-path <MANIFEST_PATH>
      -h, --help                           Print help
      -V, --version                        Print version

Then to directly invoke the command, run:

    $ cargo-example-derive example-derive
    None

    $ cargo-example-derive example-derive --manifest-path Cargo.toml
    Some("Cargo.toml")