icu 2.0.0-beta2

ICU4X: International Components for Unicode, written in Rust
Documentation 
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// 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 ).

use icu::{
    calendar::Date,
    datetime::{fieldsets, DateTimeFormatter},
    locale::locale,
    time::{
        zone::{IanaParser, TimeZoneVariant, UtcOffset, UtcOffsetCalculator},
        Time, ZonedDateTime,
    },
};

fn main() -> Result<(), Box<dyn core::error::Error>> {
    let ts: jiff::Timestamp = "2024-09-10T23:37:20.123456789Z".parse()?;
    let zoned: jiff::Zoned = ts.in_tz("Asia/Tokyo")?;

    // Convert to ICU types
    let date = Date::try_new_iso(
        i32::from(zoned.year()),
        zoned.month().unsigned_abs(),
        zoned.day().unsigned_abs(),
    )?;

    let time = Time::try_new(
        zoned.hour().unsigned_abs(),
        zoned.minute().unsigned_abs(),
        zoned.second().unsigned_abs(),
        u32::from(zoned.millisecond().unsigned_abs()) * 1_000_000
            + u32::from(zoned.microsecond().unsigned_abs()) * 1_000
            + u32::from(zoned.nanosecond().unsigned_abs()),
    )?;

    let zone =
        // Parse IANA ID into ICU time zone
        IanaParser::new().parse(zoned.time_zone().iana_name().unwrap_or_default())
        // In ICU's model, a time zone has a fixed offset, as that's required for formatting
        .with_offset(UtcOffset::try_from_seconds(zoned.offset().seconds()).ok())
        // Display names might change over time for a given zone (e.g. it might change from Eastern Time to
        // Central Time), so the ICU timezone needs a reference date and time.
        .at_time((date, time))
        // And finally, the zone variant is also required for formatting
        // TODO(jiff#258): Jiff does not currently guarantee rearguard semantics
        .with_zone_variant(TimeZoneVariant::from_rearguard_isdst(zoned.time_zone().to_offset_info(zoned.timestamp()).dst().is_dst()));

    let zoned_date_time = ZonedDateTime { date, time, zone };

    // Alternatively, the ICU ZonedDateTime can be parsed from a serialized IXDTF string.
    assert_eq!(
        ZonedDateTime::try_from_str(
            &zoned.to_string(),
            icu::calendar::Iso,
            IanaParser::new(),
            &UtcOffsetCalculator::new()
        )
        .unwrap(),
        zoned_date_time
    );

    // Preferences for an English formatter using the Japanese calendar
    let prefs = locale!("en-GB-u-ca-japanese").into();

    // A medium-length year-month-day-time-specific-zone formatter
    let formatter = DateTimeFormatter::try_new(
        prefs,
        fieldsets::YMDT::medium().zone(fieldsets::zone::SpecificLong),
    )?;

    println!("{}", formatter.format(&zoned_date_time)); // 11 Sept 6 Reiwa, 08:37:20 Japan Standard Time

    Ok(())
}