Macro warn_named 

macro_rules! warn_named {
    ($cmd:expr, $msg:expr $(,$val:expr)*) => { ... };
}

Prints out a warning message with a command name, like println!

Example

fn my_cd(action: &mut (), name: &str, args: &[&str]) -> zsh_module::MaybeError {
    if args.len() > 1 {
        zsh_module::warn_named!(name, "too much arguments!");
    }
    todo!()
}