| // 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 [`Fields`](super::Fields). |
| /// |
| /// The key has to be a two ASCII characters long, with the first |
| /// character being alphabetic, and the second being a number. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use icu::locid::extensions::transform::Key; |
| /// |
| /// let key1: Key = "k0".parse().expect("Failed to parse a Key."); |
| /// |
| /// assert_eq!(key1.as_str(), "k0"); |
| /// ``` |
| Key, |
| extensions::transform, |
| key, |
| extensions_transform_key, |
| 2..=2, |
| s, |
| s.all_bytes()[0].is_ascii_alphabetic() && s.all_bytes()[1].is_ascii_digit(), |
| s.to_ascii_lowercase(), |
| s.all_bytes()[0].is_ascii_lowercase() && s.all_bytes()[1].is_ascii_digit(), |
| InvalidExtension, |
| ["k0"], |
| ["", "k", "0k", "k12"], |
| ); |