Enum icu_casemap::titlecase::LeadingAdjustment

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

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)

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.

None

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

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

ToCased

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

Trait Implementations

impl Clone for LeadingAdjustment

fn clone(&self) -> LeadingAdjustment

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LeadingAdjustment

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

Formats the value using the given formatter.

impl Default for LeadingAdjustment

fn default() -> LeadingAdjustment

Returns the “default value” for a type.

impl Hash for LeadingAdjustment

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 PartialEq for LeadingAdjustment

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for LeadingAdjustment

impl Eq for LeadingAdjustment

impl StructuralEq for LeadingAdjustment

impl StructuralPartialEq for LeadingAdjustment