Function bpaf::cargo_helper

pub fn cargo_helper<P, T>(cmd: &'static str, parser: P) -> impl Parser<T> where
    T: 'static,
    P: Parser<T>, 

Strip a command name if present at the front when used as a cargo command

When implementing a cargo subcommand parser needs to be able to skip the first argument which is always the same as the executable name without cargo- prefix. For example if executable name is cargo-cmd so first argument would be cmd. cargo_helper helps to support both invocations: with name present when used via cargo and without it when used locally.

Combinatoric usage

fn options() -> OptionParser<(u32, u32)> {
    let width = short('w').argument("PX").from_str::<u32>();
    let height = short('h').argument("PX").from_str::<u32>();
    let parser = construct!(width, height);
    cargo_helper("cmd", parser).to_options()
}

Derive usage

If you pass a cargo command name as a parameter to options annotation bpaf_derive would generate cargo_helper.

#[derive(Debug, Clone, Bpaf)]
#[bpaf(options("cmd"))]
struct Options {
    #[bpaf(short, argument("PX"))]
    width: u32,
    #[bpaf(short, argument("PX"))]
    height: u32,
}

fn main() {
   println!("{:?}", options().run());
}

Example

$ cargo cmd -w 3 -h 5
(3, 5)
$ cargo run --bin cargo-cmd -- -w 3 -h 5
(3, 5)