Macro subtag

macro_rules! subtag {
    ($string:literal) => { ... };
}

A macro allowing for compile-time construction of valid Subtag subtags.

Examples

Parsing errors don’t have to be handled at runtime:

assert_eq!(
  icu_locid::extensions::private::subtag!("foo12"),
  "foo12".parse::<icu_locid::extensions::private::Subtag>().unwrap()
);

Invalid input is a compile failure:

icu_locid::extensions::private::subtag!("toolooong");