Enum icu_casemap::titlecase::LeadingAdjustment

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#[non_exhaustive]
pub enum LeadingAdjustment { None, Auto, ToCased, }
Expand description

Where to start casing the string.

TitlecaseMapper by default performs “leading adjustment”, where it searches for the first “relevant” character in the string before initializing the actual titlecasing. For example, it will skip punctuation at the beginning of a string, allowing for strings like 'twas or «hello» to be appropriately titlecased.

Opinions on exactly what is a “relevant” character may differ. In “adjust to cased” mode the first cased character is considered “relevant”, whereas in the “auto” mode, it is the first character that is a letter, number, symbol, or private use character. This means that the strings 49ers and «丰(abc)» will titlecase in “adjust to cased” mode to 49Ers and «丰(Abc)», whereas in the “auto” mode they stay unchanged. This difference largely matters for things that mix numbers and letters, or mix writing systems, within a single segment.

§Examples

use icu::casemap::titlecase::{LeadingAdjustment, TitlecaseOptions};
use icu::casemap::TitlecaseMapper;
use icu::locid::langid;

let cm = TitlecaseMapper::new();
let root = langid!("und");

let default_options = Default::default(); // head adjustment set to Auto
let mut no_adjust: TitlecaseOptions = Default::default();
let mut adjust_to_cased: TitlecaseOptions = Default::default();
no_adjust.leading_adjustment = LeadingAdjustment::None;
adjust_to_cased.leading_adjustment = LeadingAdjustment::ToCased;

// Exhibits leading adjustment when set:
assert_eq!(
    cm.titlecase_segment_to_string("«hello»", &root, default_options),
    "«Hello»"
);
assert_eq!(
    cm.titlecase_segment_to_string("«hello»", &root, adjust_to_cased),
    "«Hello»"
);
assert_eq!(
    cm.titlecase_segment_to_string("«hello»", &root, no_adjust),
    "«hello»"
);

// Only changed in adjust-to-cased mode:
assert_eq!(
    cm.titlecase_segment_to_string("丰(abc)", &root, default_options),
    "丰(abc)"
);
assert_eq!(
    cm.titlecase_segment_to_string("丰(abc)", &root, adjust_to_cased),
    "丰(Abc)"
);
assert_eq!(
    cm.titlecase_segment_to_string("丰(abc)", &root, no_adjust),
    "丰(abc)"
);

// Only changed in adjust-to-cased mode:
assert_eq!(
    cm.titlecase_segment_to_string("49ers", &root, default_options),
    "49ers"
);
assert_eq!(
    cm.titlecase_segment_to_string("49ers", &root, adjust_to_cased),
    "49Ers"
);
assert_eq!(
    cm.titlecase_segment_to_string("49ers", &root, no_adjust),
    "49ers"
);

Variants (Non-exhaustive)§

This enum is marked as non-exhaustive
Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.
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None

Start titlecasing immediately, even if the character is not one that is relevant for casing (“’twixt” -> “’twixt”, “twixt” -> “Twixt”)

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Auto

Adjust the string to the first relevant character before beginning to apply casing (“’twixt” -> “’Twixt”). “Relevant” character is picked by best available algorithm, by default will adjust to first letter, number, symbol, or private use character, but if no data is available (e.g. this API is being called via CaseMapper::titlecase_segment_with_only_case_data()), then may be equivalent to “adjust to cased”.

This is the default

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ToCased

Adjust the string to the first cased character before beginning to apply casing (“’twixt” -> “’Twixt”)

Trait Implementations§

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impl Clone for LeadingAdjustment

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fn clone(&self) -> LeadingAdjustment

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 LeadingAdjustment

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

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

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fn default() -> LeadingAdjustment

Returns the “default value” for a type. Read more
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impl Hash for LeadingAdjustment

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

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 PartialEq for LeadingAdjustment

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fn eq(&self, other: &LeadingAdjustment) -> 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 Copy for LeadingAdjustment

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impl Eq for LeadingAdjustment

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impl StructuralPartialEq for LeadingAdjustment

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> 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, 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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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T