Macro attribute

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

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

Examples

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

assert_eq!(
  icu_locale_core::extensions::unicode::attribute!("foo12"),
  "foo12".parse::<icu_locale_core::extensions::unicode::Attribute>().unwrap()
);

Invalid input is a compile failure:

icu_locale_core::extensions::unicode::attribute!("no");