Struct icu::locale::extensions::unicode::Keywords

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

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§

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impl Keywords

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pub const fn new() -> Keywords

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

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

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pub fn try_from_str(s: &str) -> Result<Keywords, ParseError>

A constructor which takes a str slice, parses it and produces a well-formed Keywords.

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pub fn try_from_utf8(code_units: &[u8]) -> Result<Keywords, ParseError>

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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());
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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")));
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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")));
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pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut Value>
where Key: Borrow<Q>, Q: Ord,

Returns a mutable reference to the Value corresponding to the Key.

Returns None if the key doesn’t exist or if the key has no value.

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

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

if let Some(value) = keywords.get_mut(&key!("ca")) {
    *value = value!("gregory");
}
assert_eq!(keywords.get(&key!("ca")), Some(&value!("gregory")));
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pub fn set(&mut self, key: Key, value: Value) -> Option<Value>

Sets the specified keyword, returning the old value if it already existed.

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

let mut loc: Locale = "und-u-hello-ca-buddhist-hc-h12"
    .parse()
    .expect("valid BCP-47 identifier");
let old_value = loc
    .extensions
    .unicode
    .keywords
    .set(key!("ca"), value!("japanese"));

assert_eq!(old_value, Some(value!("buddhist")));
assert_eq!(loc, "und-u-hello-ca-japanese-hc-h12".parse().unwrap());
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pub fn remove<Q>(&mut self, key: Q) -> Option<Value>
where Q: Borrow<Key>,

Removes the specified keyword, returning the old value if it existed.

§Examples
use icu::locale::extensions::unicode::key;
use icu::locale::Locale;

let mut loc: Locale = "und-u-hello-ca-buddhist-hc-h12"
    .parse()
    .expect("valid BCP-47 identifier");
loc.extensions.unicode.keywords.remove(key!("ca"));
assert_eq!(loc, "und-u-hello-hc-h12".parse().unwrap());
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pub fn clear(&mut self) -> Keywords

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());
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pub fn retain_by_key<F>(&mut self, predicate: F)
where F: FnMut(&Key) -> bool,

Retains a subset of keywords as specified by the predicate function.

§Examples
use icu::locale::extensions::unicode::key;
use icu::locale::Locale;

let mut loc: Locale = "und-u-ca-buddhist-hc-h12-ms-metric".parse().unwrap();

loc.extensions
    .unicode
    .keywords
    .retain_by_key(|&k| k == key!("hc"));
assert_eq!(loc, "und-u-hc-h12".parse().unwrap());

loc.extensions
    .unicode
    .keywords
    .retain_by_key(|&k| k == key!("ms"));
assert_eq!(loc, Locale::default());
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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);
}
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pub fn iter(&self) -> impl Iterator<Item = (&Key, &Value)>

Produce an ordered iterator over key-value pairs

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impl Keywords

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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§

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impl Clone for Keywords

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fn clone(&self) -> Keywords

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Keywords

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

Formats the value using the given formatter. Read more
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impl Default for Keywords

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fn default() -> Keywords

Returns the “default value” for a type. Read more
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impl Display for Keywords

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

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

Formats the value using the given formatter. Read more
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impl From<LiteMap<Key, Value, ShortBoxSlice<(Key, Value)>>> for Keywords

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

Converts to this type from the input type.
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impl FromIterator<(Key, Value)> for Keywords

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fn from_iter<I>(iter: I) -> Keywords
where I: IntoIterator<Item = (Key, Value)>,

Creates a value from an iterator. Read more
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impl FromStr for Keywords

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type Err = ParseError

The associated error which can be returned from parsing.
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fn from_str(s: &str) -> Result<Keywords, <Keywords as FromStr>::Err>

Parses a string s to return a value of this type. Read more
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impl Hash for Keywords

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for Keywords

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

This method returns an Ordering between self and other. Read more
1.21.0 · source§

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

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl PartialEq for Keywords

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

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

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

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

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

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

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.
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fn writeable_length_hint(&self) -> LengthHint

Returns a hint for the number of UTF-8 bytes that will be written to the sink. Read more
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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.
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fn write_to_string(&self) -> Cow<'_, str>

Creates a new String with the data from this Writeable. Like ToString, but smaller and faster. Read more
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impl Eq for Keywords

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impl StructuralPartialEq for Keywords

Auto Trait Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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where T: 'static,

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impl<T> MaybeSendSync for T
where T: Send + Sync,