locale

BCP 47 locale-identifier parsing and manipulation via the JavaScript Intl.Locale. Parse a tag with optional extension subtags, query its components via info, list the calendars or collations the locale supports, and convert between maximal and minimal canonical forms.

Types

Builder

opaque </>

The configuration for a Locale. Constructed from a BCP 47 tag with optional per-component overrides.

pub opaque type Builder

Info

</>

A snapshot of a locale’s parsed components, returned by info. Components with no value for the locale are None.

pub type Info {
  Info(
    base_name: String,
    language: String,
    script: option.Option(String),
    region: option.Option(String),
    calendar: option.Option(String),
    case_first: option.Option(intl.CaseFirst),
    collation: option.Option(String),
    hour_cycle: option.Option(intl.HourCycle),
    numbering_system: option.Option(String),
    numeric: Bool,
  )
}

Constructors

```
Info(
  base_name: String,
  language: String,
  script: option.Option(String),
  region: option.Option(String),
  calendar: option.Option(String),
  case_first: option.Option(intl.CaseFirst),
  collation: option.Option(String),
  hour_cycle: option.Option(intl.HourCycle),
  numbering_system: option.Option(String),
  numeric: Bool,
)
```
Arguments

base_name

The BCP 47 base name — the language, script (if any), and region (if any) joined with hyphens, without extension subtags. For "en-US-u-ca-gregory", this is "en-US".

language

The language subtag (e.g., "en").

script

The script subtag (e.g., "Latn", "Hans").

region

The region subtag (e.g., "US", "CN").

calendar

The preferred calendar identifier (e.g., "gregory", "chinese").

case_first

The preferred case-first ordering.

collation

The preferred collation identifier (e.g., "phonebk", "pinyin").

hour_cycle

The preferred hour cycle.

numbering_system

The preferred numbering-system identifier (e.g., "latn", "arab").

numeric

Whether numeric collation is preferred — digit runs compared as numbers rather than character by character.

Locale

</>

A parsed BCP 47 locale identifier with optional extension subtags.

See Intl.Locale on MDN.

pub type Locale

TextDirection

</>

The dominant writing direction of a locale’s primary script. Returned by text_direction.

pub type TextDirection {
  Ltr
  Rtl
}

Constructors

```
Ltr
```
Left-to-right (Latin, Cyrillic, etc.).
```
Rtl
```
Right-to-left (Arabic, Hebrew, etc.).

WeekInfo

</>

Locale-specific calendar-week information, returned by week_info. first_day and entries of weekend use ISO 8601 day-of-week numbering — Monday is 1, Sunday is 7.

pub type WeekInfo {
  WeekInfo(first_day: Int, weekend: List(Int))
}

Constructors

WeekInfo(first_day: Int, weekend: List(Int))

Values

build

</>

pub fn build(builder: Builder) -> Result(Locale, Nil)

Constructs a Locale from the configured builder. Returns Error(Nil) if the tag or any override is structurally invalid.

calendars

</>

pub fn calendars(locale: Locale) -> List(String)

The calendars supported by the locale, in preference order.

collations

</>

pub fn collations(locale: Locale) -> List(String)

The collations supported by the locale, in preference order.

hour_cycles

</>

pub fn hour_cycles(locale: Locale) -> List(intl.HourCycle)

The hour cycles supported by the locale, in preference order.

info

</>

pub fn info(locale: Locale) -> Info

Returns a snapshot of the locale’s parsed components. See Info.

maximize

</>

pub fn maximize(locale: Locale) -> Locale

Returns a locale with all subtags filled in to canonical maximal form per the Unicode Likely Subtags algorithm (e.g., "en" becomes "en-Latn-US").

minimize

</>

pub fn minimize(locale: Locale) -> Locale

Returns a locale with redundant subtags removed per the Unicode Likely Subtags algorithm (e.g., "en-Latn-US" becomes "en").

new

</>

pub fn new(tag: String) -> Builder

Creates a Builder for the given BCP 47 locale tag (e.g., "en-US", "zh-Hans-CN").

numbering_systems

</>

pub fn numbering_systems(locale: Locale) -> List(String)

The numbering systems supported by the locale, in preference order.

text_direction

</>

pub fn text_direction(locale: Locale) -> TextDirection

The dominant writing direction of the locale’s primary script.

time_zones

</>

pub fn time_zones(locale: Locale) -> Result(List(String), Nil)

The IANA time zones associated with the locale’s region. Returns Error(Nil) when the locale has no region subtag.

to_string

</>

pub fn to_string(locale: Locale) -> String

The canonical BCP 47 string representation of the locale, including any extension subtags.

week_info

</>

pub fn week_info(locale: Locale) -> WeekInfo

Locale-specific calendar-week information.

with_calendar

</>

pub fn with_calendar(
  builder: Builder,
  calendar: String,
) -> Builder

Overrides the calendar identifier (e.g., "gregory", "chinese").

with_case_first

</>

pub fn with_case_first(
  builder: Builder,
  case_first: intl.CaseFirst,
) -> Builder

Overrides the case-first preference.

with_collation

</>

pub fn with_collation(
  builder: Builder,
  collation: String,
) -> Builder

Overrides the collation identifier (e.g., "phonebk", "pinyin").

with_hour_cycle

</>

pub fn with_hour_cycle(
  builder: Builder,
  hour_cycle: intl.HourCycle,
) -> Builder

Overrides the preferred hour cycle.

with_language

</>

pub fn with_language(
  builder: Builder,
  language: String,
) -> Builder

Overrides the language subtag (e.g., "en", "fr").

with_numbering_system

</>

pub fn with_numbering_system(
  builder: Builder,
  numbering_system: String,
) -> Builder

Overrides the numbering-system identifier (e.g., "latn", "arab").

with_numeric

</>

pub fn with_numeric(builder: Builder, numeric: Bool) -> Builder

Overrides whether numeric collation is preferred (digit runs compared as numbers rather than character by character).

with_region

</>

pub fn with_region(builder: Builder, region: String) -> Builder

Overrides the region subtag (e.g., "US", "CN").

with_script

</>

pub fn with_script(builder: Builder, script: String) -> Builder

Overrides the script subtag (e.g., "Latn", "Hans").

Constructors

Arguments

Constructors

Constructors