Macro clap::value_t_or_exit
source · [−]macro_rules! value_t_or_exit {
($m:ident, $v:expr, $t:ty) => { ... };
($m:ident.value_of($v:expr), $t:ty) => { ... };
}
Expand description
Convenience macro getting a typed value T
where T
implements std::str::FromStr
or
exiting upon error, instead of returning a Result
type.
NOTE: This macro is for backwards compatibility sake. Prefer
value_t!(/* ... */).unwrap_or_else(|e| e.exit())
Examples
let matches = App::new("myapp")
.arg_from_usage("[length] 'Set the length to use as a pos whole num, i.e. 20'")
.get_matches();
let len = value_t_or_exit!(matches.value_of("length"), u32);
let also_len = value_t_or_exit!(matches, "length", u32);
println!("{} + 2: {}", len, len + 2);