Struct icu_datetime::TypedDateFormatter

pub struct TypedDateFormatter<C>(_, _);

TypedDateFormatter is a formatter capable of formatting dates from a calendar selected at compile time. For the difference between this and DateFormatter, please read the crate root docs.

When constructed, it uses data from the data provider, selected locale and provided options to collect all data necessary to format any dates into that locale.

For that reason, one should think of the process of formatting a date in two steps - first, a computational heavy construction of TypedDateFormatter, and then fast formatting of DateInput data using the instance.

Examples

use icu::calendar::{Date, Gregorian};
use icu::datetime::{options::length, TypedDateFormatter};
use icu::locid::locale;

let provider = icu_testdata::get_provider();

let df = TypedDateFormatter::<Gregorian>::try_new_with_buffer_provider(&provider, &locale!("en").into(), length::Date::Full)
    .expect("Failed to create TypedDateFormatter instance.");

let date = Date::new_gregorian_date(2020, 9, 1)
    .expect("Failed to construct Date.");

assert_eq!(df.format_to_string(&date), "Tuesday, September 1, 2020");

This model replicates that of ICU and ECMA402.

Implementations

impl<C: CldrCalendar> TypedDateFormatter<C>

pub fn try_new_unstable<D>(
    data_provider: &D,
    locale: &DataLocale,
    length: Date
) -> Result<Self, DateTimeFormatterError> where
    D: DataProvider<<C as CldrCalendar>::DateSymbolsV1Marker> + DataProvider<<C as CldrCalendar>::DateLengthsV1Marker> + DataProvider<DecimalSymbolsV1Marker> + DataProvider<OrdinalV1Marker> + DataProvider<WeekDataV1Marker> + ?Sized, 

Constructor that takes a selected locale, reference to a data provider and a list of options, then collects all data necessary to format date and time values into the given locale.

Examples

use icu::calendar::Gregorian;
use icu::datetime::{options::length, TypedDateFormatter};
use icu::locid::locale;

let provider = icu_testdata::get_provider();

TypedDateFormatter::<Gregorian>::try_new_with_buffer_provider(&provider, &locale!("en").into(), length::Date::Full)
    .unwrap();

pub fn try_new_with_any_provider(
    provider: &impl AnyProvider + ?Sized,
    locale: &DataLocale,
    length: Date
) -> Result<Self, DateTimeFormatterError>

Create a new instance using an AnyProvider.

See also: Self::try_new_unstable

pub fn try_new_with_buffer_provider(
    provider: &impl BufferProvider + ?Sized,
    locale: &DataLocale,
    length: Date
) -> Result<Self, DateTimeFormatterError>

Create a new instance using a BufferProvider. Enabled with the "serde" feature.

See also: Self::try_new_unstable

pub fn format<'l, T>(&'l self, value: &T) -> FormattedDateTime<'l> where
    T: DateInput<Calendar = C>, 

Takes a DateTimeInput implementer and returns an instance of a FormattedDateTime that contains all information necessary to display a formatted date and operate on it.

Examples

use icu::calendar::{Date, Gregorian};
use icu::datetime::{options::length, TypedDateFormatter};
use writeable::assert_writeable_eq;
let df = TypedDateFormatter::<Gregorian>::try_new_with_buffer_provider(&provider, &locale.into(), length::Date::Full)
    .expect("Failed to create TypedDateFormatter instance.");

let date = Date::new_gregorian_date(2020, 9, 1)
    .expect("Failed to construct Date.");

assert_writeable_eq!(df.format(&date), "Tuesday, September 1, 2020");

At the moment, there’s little value in using that over one of the other format methods, but FormattedDateTime will grow with methods for iterating over fields, extracting information about formatted date and so on.

pub fn format_to_write(
    &self,
    w: &mut impl Write,
    value: &impl DateInput<Calendar = C>
) -> Result

Takes a mutable reference to anything that implements Write trait and a DateTimeInput implementer and populates the buffer with a formatted value.

Examples

use icu::calendar::{Date, Gregorian};
use icu::datetime::{options::length, TypedDateFormatter};
let df = TypedDateFormatter::<Gregorian>::try_new_with_buffer_provider(&provider, &locale.into(), length::Date::Short)
    .expect("Failed to create TypedDateFormatter instance.");

let date = Date::new_gregorian_date(2020, 9, 1)
    .expect("Failed to construct Date.");

let mut buffer = String::new();
df.format_to_write(&mut buffer, &date)
    .expect("Failed to write to a buffer.");

assert_eq!(buffer, "9/1/20");

pub fn format_to_string(&self, value: &impl DateInput<Calendar = C>) -> String

Takes a DateTimeInput implementer and returns it formatted as a string.

Examples

use icu::calendar::{Date, Gregorian};
use icu::datetime::{options::length, TypedDateFormatter};
let df = TypedDateFormatter::<Gregorian>::try_new_with_buffer_provider(&provider, &locale.into(), length::Date::Short)
    .expect("Failed to create TypedDateTimeFormatter instance.");

let date = Date::new_gregorian_date(2020, 9, 1)
    .expect("Failed to construct Date.");

assert_eq!(df.format_to_string(&date), "9/1/20");