icu_locid/subtags/variant.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!(
/// A variant subtag (examples: `"macos"`, `"posix"`, `"1996"` etc.)
///
/// [`Variant`] represents a Unicode base language code conformant to the
/// [`unicode_variant_id`] field of the Language and Locale Identifier.
///
/// # Examples
///
/// ```
/// use icu::locid::subtags::Variant;
///
/// let variant: Variant =
/// "macos".parse().expect("Failed to parse a variant subtag.");
/// ```
///
/// [`unicode_variant_id`]: https://unicode.org/reports/tr35/#unicode_variant_id
Variant,
subtags,
variant,
subtags_variant,
4..=8,
s,
s.is_ascii_alphanumeric() && (s.len() != 4 || s.all_bytes()[0].is_ascii_digit()),
s.to_ascii_lowercase(),
s.is_ascii_lowercase()
&& s.is_ascii_alphanumeric()
&& (s.len() != 4 || s.all_bytes()[0].is_ascii_digit()),
InvalidSubtag,
["posix", "1996"],
["yes"],
);