Crate icu::datetime

source ·
Expand description

Formatting date and time.

This module is published as its own crate (icu_datetime) and as part of the icu crate. See the latter for more details on the ICU4X project.

FixedCalendarDateTimeFormatter and DateTimeFormatter are the main types of the component. They accepts a set of arguments which allow it to collect necessary data from the data provider, and once instantiated, can be used to quickly format any date and time provided. There are variants of these types that can format greater or fewer components.

These formatters work with types from the calendar module, like Date, DateTime, and Time, and timezone::TimeZoneInfo, however other types may be used provided they implement the traits from the input module.

Each instance of a date-related formatter is associated with a particular Calendar. The “Typed” vs untyped formatter distinction is to help with this. For example, if you know at compile time that you will only be formatting Gregorian dates, you can use FixedCalendarDateTimeFormatter<Gregorian> and the APIs will make sure that only Gregorian DateTimes are used with the calendar. On the other hand, if you want to be able to select the calendar at runtime, you can use neo::DateTimeFormatter with the calendar specified in the locale, and use it with DateTime<AnyCalendar> (see AnyCalendar). These formatters still require dates associated with the appropriate calendar (though they will convert ISO dates to the calendar if provided), they just do not force the programmer to pick the calendar at compile time.

§Examples

use icu::calendar::{DateTime, Gregorian};
use icu::datetime::fieldset::YMDT;
use icu::datetime::{DateTimeFormatter, FixedCalendarDateTimeFormatter};
use icu::locale::{locale, Locale};
use writeable::assert_try_writeable_eq;

// You can work with a formatter that can select the calendar at runtime:
let locale = Locale::try_from_str("en-u-ca-gregory").unwrap();
let dtf = DateTimeFormatter::try_new(&locale.into(), YMDT::medium().hm())
    .expect("should successfully create DateTimeFormatter instance");

// Or one that selects a calendar at compile time:
let typed_dtf = FixedCalendarDateTimeFormatter::<Gregorian, _>::try_new(
    &locale!("en").into(),
    YMDT::medium().hm(),
)
.expect(
    "should successfully create FixedCalendarDateTimeFormatter instance",
);

let typed_date =
    DateTime::try_new_gregorian(2020, 9, 12, 12, 34, 28).unwrap();
// prefer using ISO dates with DateTimeFormatter
let date = typed_date.to_iso();

let formatted_date = dtf.convert_and_format(&date);
let typed_formatted_date = typed_dtf.format(&typed_date);

assert_try_writeable_eq!(formatted_date, "Sep 12, 2020, 12:34 PM");
assert_try_writeable_eq!(typed_formatted_date, "Sep 12, 2020, 12:34 PM");

Modules§

  • fields
    Enums representing the fields in a date pattern, including the field’s type, length and symbol.
  • fieldset
    All available field sets for datetime formatting.
  • input
    A collection of utilities for representing and working with dates as an input to formatting operations.
  • neo_pattern
    Temporary module for neo datetime patterns
  • neo_skeleton
    Temporary module for neo datetime skeletons (Semantic Skeleta)
  • options
    DateTimeFormatterOptions is a bag of options which, together with Locale, defines how dates will be formatted.
  • provider
    🚧 [Unstable] Data provider struct definitions for this ICU4X component.
  • scaffold
    Scaffolding traits and types for the datetime crate.

Structs§

Enums§