Struct Collator

pub struct Collator {
    pub tailoring: Tailoring,
    pub shifting: bool,
    pub tiebreak: bool,
    /* private fields */
}

The Collator struct is the entry point for this library’s API. It defines the options to be used in collation. The method collate will then compare two string references (or byte slices) according to the selected options, and return an Ordering value.

You can choose between two tables of character weights: DUCET and CLDR. With the CLDR table, there is a further choice of locale tailoring. The Root locale represents the table in its unmodified form. The ArabicScript locale shifts the weights of Arabic-script letters so that they sort before the Latin script; and the ArabicInterleaved locale mixes the two scripts, so that, e.g., alif sorts between A and B, and bā’ between B and C. Further locales will be added over time.

You can also choose between two approaches to the handling of variable-weight characters: “non-ignorable” and “shifted.” Finally, you can select whether to use byte-value comparison as a tiebreaker when two strings produce identical Unicode Collation Algorithm sort keys.

The default for Collator is to use the CLDR table with the Root locale; to use the “shifted” approach for variable-weight characters; and to break ties with byte-value comparison. This should be a good starting point for collation in many languages.

Fields

tailoring: Tailoring

The table of weights to be used: DUCET or CLDR (with a choice of locale for the latter)

shifting: bool

The approach to handling variable-weight characters: “non-ignorable” (i.e., false) or “shifted” (i.e., true)

tiebreak: bool

Whether to use byte-value comparison as a tiebreaker when two strings produce identical Unicode Collation Algorithm sort keys

Implementations

impl Collator

pub fn new(tailoring: Tailoring, shifting: bool, tiebreak: bool) -> Self

Create a new Collator with the specified options. NB: it is also possible to call Collator::default().

pub fn collate<T: AsRef<[u8]> + Eq + Ord + ?Sized>( &mut self, a: &T, b: &T, ) -> Ordering

This is the primary method in the library. It accepts as arguments two string references or byte slices; compares them using the options chosen; and returns an Ordering value. This is designed to be passed to the sort_by (or sort_unstable_by) function in the standard library. Simple usage might look like the following…

use feruca::Collator;

let mut collator = Collator::default();

let mut names = ["Peng", "Peña", "Ernie", "Émile"];
names.sort_unstable_by(|a, b| collator.collate(a, b));

let expected = ["Émile", "Ernie", "Peña", "Peng"];
assert_eq!(names, expected);

Trait Implementations

impl Clone for Collator

fn clone(&self) -> Collator

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Collator

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

Formats the value using the given formatter.

impl Default for Collator

fn default() -> Self

Returns the “default value” for a type.

impl Hash for Collator

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 Collator

fn cmp(&self, other: &Collator) -> 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 Collator

fn eq(&self, other: &Collator) -> 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 Collator

fn partial_cmp(&self, other: &Collator) -> 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 Eq for Collator

impl StructuralPartialEq for Collator