icu_locid/extensions/unicode/attribute.rs
// 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!(
/// An attribute used in a set of [`Attributes`](super::Attributes).
///
/// An attribute has to be a sequence of alphanumerical characters no
/// shorter than three and no longer than eight characters.
///
///
/// # Examples
///
/// ```
/// use icu::locid::extensions::unicode::{attribute, Attribute};
///
/// let attr: Attribute =
/// "buddhist".parse().expect("Failed to parse an Attribute.");
///
/// assert_eq!(attr, attribute!("buddhist"));
/// ```
Attribute,
extensions::unicode,
attribute,
extensions_unicode_attribute,
3..=8,
s,
s.is_ascii_alphanumeric(),
s.to_ascii_lowercase(),
s.is_ascii_alphanumeric() && s.is_ascii_lowercase(),
InvalidExtension,
["foo12"],
["no", "toolooong"],
);