pub struct CollatorOptions { pub strength: Option<Strength>, pub alternate_handling: Option<AlternateHandling>, pub case_first: Option<CaseFirst>, pub max_variable: Option<MaxVariable>, pub case_level: Option<CaseLevel>, pub numeric: Option<Numeric>, pub backward_second_level: Option<BackwardSecondLevel>, }
Expand description

Options settable by the user of the API.

See the spec.

The setters take an Option so that None can be used to go back to default.


Examples for using the different options below can be found in the crate-level docs.


This is the BCP47 key ks. The default is Strength::Tertiary.

Alternate Handling

This is the BCP47 key ka. Note that AlternateHandling::ShiftTrimmed and AlternateHandling::Blanked are unimplemented. The default is AlternateHandling::NonIgnorable, except for Thai, whose default is AlternateHandling::Shifted.

Case Level

See the spec. This is the BCP47 key kc. The default is false (off).

Case First

See the spec. This is the BCP47 key kf. Three possibilities: CaseFirst::Off (default, except for Danish and Maltese), CaseFirst::Lower, and CaseFirst::Upper (default for Danish and Maltese).

Backward second level

Compare the second level in backward order. This is the BCP47 key kb. kb is prohibited by ECMA 402. The default is false (off), except for Canadian French.


This is the BCP47 key kn. When set to true (on), any sequence of decimal digits (General_Category = Nd) is sorted at a primary level according to the numeric value. The default is false (off).

Unsupported BCP47 options

Reordering (BCP47 kr) currently cannot be set via the API and is implied by the locale of the collation. kr is probihibited by ECMA 402.

Normalization is always enabled and cannot be turned off. Therefore, there is no option corresponding to BCP47 kk. kk is prohibited by ECMA 402.

Hiragana quaternary handling is part of the strength for the Japanese tailoring. The BCP47 key kh is unsupported. kh is deprecated and prohibited by ECMA 402.

Variable top (BCP47 vt) is unsupported (use Max Variable instead). vt is deprecated and prohibited by ECMA 402.

Fields (Non-exhaustive)

This struct is marked as non-exhaustive
Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.
strength: Option<Strength>

User-specified strength collation option.

alternate_handling: Option<AlternateHandling>

User-specified alternate handling collation option.

case_first: Option<CaseFirst>

User-specified case first collation option.

max_variable: Option<MaxVariable>

User-specified max variable collation option.

case_level: Option<CaseLevel>

User-specified case level collation option.

numeric: Option<Numeric>

User-specified numeric collation option.

backward_second_level: Option<BackwardSecondLevel>

User-specified backward second level collation option.


Create a new CollatorOptions with the defaults.

Trait Implementations

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