| // This file is part of ICU4X. For terms of use, please see the file |
| // called LICENSE at the top level of the ICU4X source tree |
| // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ). |
| |
| impl_tinystr_subtag!( |
| /// A key used in a list of [`Keywords`](super::Keywords). |
| /// |
| /// The key has to be a two ASCII alphanumerical characters long, with the first |
| /// character being alphanumeric, and the second being alphabetic. |
| /// |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use icu::locid::extensions::unicode::Key; |
| /// |
| /// assert!("ca".parse::<Key>().is_ok()); |
| /// ``` |
| Key, |
| extensions::unicode, |
| key, |
| extensions_unicode_key, |
| 2..=2, |
| s, |
| s.all_bytes()[0].is_ascii_alphanumeric() && s.all_bytes()[1].is_ascii_alphabetic(), |
| s.to_ascii_lowercase(), |
| (s.all_bytes()[0].is_ascii_lowercase() || s.all_bytes()[0].is_ascii_digit()) |
| && s.all_bytes()[1].is_ascii_lowercase(), |
| InvalidExtension, |
| ["ca", "8a"], |
| ["a", "a8", "abc"], |
| ); |