Enum icu_datetime::options::YearStyle

#[non_exhaustive]
pub enum YearStyle {
    Auto,
    Full,
    Always,
}

A specification of how to render the year and the era.

Examples

use icu::calendar::Date;
use icu::calendar::Gregorian;
use icu::datetime::fieldsets::YMD;
use icu::datetime::options::YearStyle;
use icu::datetime::FixedCalendarDateTimeFormatter;
use icu::locale::locale;
use writeable::assert_writeable_eq;

let formatter = FixedCalendarDateTimeFormatter::<Gregorian, _>::try_new(
    locale!("en-US").into(),
    YMD::short().with_year_style(YearStyle::Auto),
)
.unwrap();

// Era displayed when needed for disambiguation,
// such as years before year 0 and small year numbers:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(-1000, 1, 1).unwrap()),
    "1/1/1001 BC"
);
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(77, 1, 1).unwrap()),
    "1/1/77 AD"
);
// Era elided for modern years:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(1900, 1, 1).unwrap()),
    "1/1/1900"
);
// Era and century both elided for nearby years:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(2025, 1, 1).unwrap()),
    "1/1/25"
);

let formatter = FixedCalendarDateTimeFormatter::<Gregorian, _>::try_new(
    locale!("en-US").into(),
    YMD::short().with_year_style(YearStyle::Full),
)
.unwrap();

// Era still displayed in cases with ambiguity:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(-1000, 1, 1).unwrap()),
    "1/1/1001 BC"
);
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(77, 1, 1).unwrap()),
    "1/1/77 AD"
);
// Era elided for modern years:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(1900, 1, 1).unwrap()),
    "1/1/1900"
);
// But now we always get a full-precision year:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(2025, 1, 1).unwrap()),
    "1/1/2025"
);

let formatter = FixedCalendarDateTimeFormatter::<Gregorian, _>::try_new(
    locale!("en-US").into(),
    YMD::short().with_year_style(YearStyle::Always),
)
.unwrap();

// Era still displayed in cases with ambiguity:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(-1000, 1, 1).unwrap()),
    "1/1/1001 BC"
);
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(77, 1, 1).unwrap()),
    "1/1/77 AD"
);
// But now it is shown even on modern years:
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(1900, 1, 1).unwrap()),
    "1/1/1900 AD"
);
assert_writeable_eq!(
    formatter.format(&Date::try_new_gregorian(2025, 1, 1).unwrap()),
    "1/1/2025 AD"
);

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Auto

Display the century and/or era when needed to disambiguate the year, based on locale preferences.

This is the default option.

Examples:

• 1000 BC
• 77 AD
• 1900
• '24

Full

Always display the century, and display the era when needed to disambiguate the year, based on locale preferences.

Examples:

• 1000 BC
• 77 AD
• 1900
• 2024

Always

Always display the century and era.

Examples:

• 1000 BC
• 77 AD
• 1900 AD
• 2024 AD

Trait Implementations

impl Clone for YearStyle

fn clone(&self) -> YearStyle

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for YearStyle

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for YearStyle

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for YearStyle

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl IntoOption<YearStyle> for YearStyle

fn into_option(self) -> Option<Self>

Return self as an Option<T>

impl PartialEq for YearStyle

fn eq(&self, other: &YearStyle) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for YearStyle

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for YearStyle

impl Eq for YearStyle

impl StructuralPartialEq for YearStyle