Struct Keywords

pub struct Keywords(/* private fields */);

A list of Key-Value pairs representing functional information about locale’s internationalization preferences.

Here are examples of fields used in Unicode:

• hc - Hour Cycle (h11, h12, h23, h24)
• ca - Calendar (buddhist, gregory, …)
• fw - First Day Of the Week (sun, mon, sat, …)

You can find the full list in Unicode BCP 47 U Extension section of LDML.

Examples

Manually build up a Keywords object:

use icu::locale::extensions::unicode::{key, value, Keywords};

let keywords = [(key!("hc"), value!("h23"))]
    .into_iter()
    .collect::<Keywords>();

assert_eq!(&keywords.to_string(), "hc-h23");

Access a Keywords object from a Locale:

use icu::locale::{
    extensions::unicode::{key, value},
    Locale,
};

let loc: Locale = "und-u-hc-h23-kc-true".parse().expect("Valid BCP-47");

assert_eq!(loc.extensions.unicode.keywords.get(&key!("ca")), None);
assert_eq!(
    loc.extensions.unicode.keywords.get(&key!("hc")),
    Some(&value!("h23"))
);
assert_eq!(
    loc.extensions.unicode.keywords.get(&key!("kc")),
    Some(&value!("true"))
);

assert_eq!(loc.extensions.unicode.keywords.to_string(), "hc-h23-kc");

Implementations

impl Keywords

pub const fn new() -> Self

Returns a new empty list of key-value pairs. Same as default(), but is const.

Examples

use icu::locale::extensions::unicode::Keywords;

assert_eq!(Keywords::new(), Keywords::default());

pub const fn new_single(key: Key, value: Value) -> Self

Create a new list of key-value pairs having exactly one pair, callable in a const context.

pub fn is_empty(&self) -> bool

Returns true if there are no keywords.

Examples

use icu::locale::locale;
use icu::locale::Locale;

let loc1 = Locale::try_from_str("und-t-h0-hybrid").unwrap();
let loc2 = locale!("und-u-ca-buddhist");

assert!(loc1.extensions.unicode.keywords.is_empty());
assert!(!loc2.extensions.unicode.keywords.is_empty());

pub fn contains_key<Q>(&self, key: &Q) -> bool

where Key: Borrow<Q>, Q: Ord,

Returns true if the list contains a Value for the specified Key.

Examples

use icu::locale::extensions::unicode::{key, value, Keywords};

let keywords = [(key!("ca"), value!("gregory"))]
    .into_iter()
    .collect::<Keywords>();

assert!(&keywords.contains_key(&key!("ca")));

pub fn get<Q>(&self, key: &Q) -> Option<&Value>

where Key: Borrow<Q>, Q: Ord,

Returns a reference to the Value corresponding to the Key.

Examples

use icu::locale::extensions::unicode::{key, value, Keywords};

let keywords = [(key!("ca"), value!("buddhist"))]
    .into_iter()
    .collect::<Keywords>();

assert_eq!(keywords.get(&key!("ca")), Some(&value!("buddhist")));

pub fn clear(&mut self) -> Self

Clears all Unicode extension keywords, leaving Unicode attributes.

Returns the old Unicode extension keywords.

Examples

use icu::locale::Locale;

let mut loc: Locale = "und-u-hello-ca-buddhist-hc-h12".parse().unwrap();
loc.extensions.unicode.keywords.clear();
assert_eq!(loc, "und-u-hello".parse().unwrap());

pub fn strict_cmp(&self, other: &[u8]) -> Ordering

Compare this Keywords with BCP-47 bytes.

The return value is equivalent to what would happen if you first converted this Keywords to a BCP-47 string and then performed a byte comparison.

This function is case-sensitive and results in a total order, so it is appropriate for binary search. The only argument producing Ordering::Equal is self.to_string().

Examples

use icu::locale::Locale;
use std::cmp::Ordering;

let bcp47_strings: &[&str] =
    &["ca-hebrew", "ca-japanese", "ca-japanese-nu-latn", "nu-latn"];

for ab in bcp47_strings.windows(2) {
    let a = ab[0];
    let b = ab[1];
    assert!(a.cmp(b) == Ordering::Less);
    let a_kwds = format!("und-u-{}", a)
        .parse::<Locale>()
        .unwrap()
        .extensions
        .unicode
        .keywords;
    assert!(a_kwds.strict_cmp(a.as_bytes()) == Ordering::Equal);
    assert!(a_kwds.strict_cmp(b.as_bytes()) == Ordering::Less);
}

pub fn iter(&self) -> impl Iterator<Item = (&Key, &Value)>

Produce an ordered iterator over key-value pairs

impl Keywords

pub fn to_string(&self) -> String

Converts the given value to a String.

Under the hood, this uses an efficient [Writeable] implementation. However, in order to avoid allocating a string, it is more efficient to use [Writeable] directly.

Trait Implementations

impl Clone for Keywords

fn clone(&self) -> Keywords

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Keywords

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

Formats the value using the given formatter.

impl Default for Keywords

fn default() -> Keywords

Returns the “default value” for a type.

impl Display for Keywords

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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

Formats the value using the given formatter.

impl From<LiteMap<Key, Value, ShortBoxSlice<(Key, Value)>>> for Keywords

fn from(map: LiteMap<Key, Value, ShortBoxSlice<(Key, Value)>>) -> Self

Converts to this type from the input type.

impl Hash for Keywords

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 Ord for Keywords

fn cmp(&self, other: &Keywords) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Keywords

fn eq(&self, other: &Keywords) -> 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 PartialOrd for Keywords

fn partial_cmp(&self, other: &Keywords) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Writeable for Keywords

fn write_to<W: Write + ?Sized>(&self, sink: &mut W) -> Result

Writes a string to the given sink. Errors from the sink are bubbled up. The default implementation delegates to write_to_parts, and discards any Part annotations.

fn writeable_length_hint(&self) -> LengthHint

Returns a hint for the number of UTF-8 bytes that will be written to the sink.

fn write_to_parts<S>(&self, sink: &mut S) -> Result<(), Error>

where S: PartsWrite + ?Sized,

Write bytes and Part annotations to the given sink. Errors from the sink are bubbled up. The default implementation delegates to write_to, and doesn’t produce any Part annotations.

fn write_to_string(&self) -> Cow<'_, str>

Creates a new String with the data from this Writeable. Like ToString, but smaller and faster.

impl Eq for Keywords

impl StructuralPartialEq for Keywords