Locale Formatting

The world-locale provides formatting capabilities for country codes and locale-specific operations.

Country Formatting

Countries implement the world.format.Formatter trait:

import world.locale.country.Country

val uk = Country.GB
uk.format  // "GB"

The default format uses the ISO 3166-1 alpha-2 code.

Custom Country Formatting

Implement custom formatters for different display requirements:

import world.locale.country.Country
import world.format.Formatter

// Full name formatter
given Formatter[Country] with
  extension (country: Country)
    def format: String = country.name

val usa = Country.US
usa.format  // "United States of America"

// Alpha-3 formatter
given Formatter[Country] with
  extension (country: Country)
    def format: String = country.alpha3

val japan = Country.JP
japan.format  // "JPN"

Note that providing multiple given instances in the same scope will cause ambiguity. Structure your code to have only one Formatter instance in scope at a time, or use explicit formatter parameters.

Locale-Aware Formatting Patterns

For applications requiring locale-specific formatting (numbers, dates, currencies), consider:

1. Java Interoperability: Use java.text.NumberFormat with locale support (JVM only)
2. Custom Implementations: Implement locale-specific formatters using world.format.Formatter
3. External Libraries: Consider libraries like scala-java-time for date/time formatting

Example: Locale-Aware Number Formatting

import world.locale.country.Country
import java.text.NumberFormat
import java.util.Locale

def formatNumber(value: Double, country: Country): String =
  val locale = country.alpha2 match
    case "GB" => Locale.UK
    case "US" => Locale.US
    case "FR" => Locale.FRANCE
    case code => new Locale("", code)
  
  val formatter = NumberFormat.getInstance(locale)
  formatter.format(value)

formatNumber(1234.56, Country.GB)  // "1,234.56"
formatNumber(1234.56, Country.FR)  // "1 234,56"

Future Enhancements

Future releases may include:

• Built-in locale-aware number formatting
• Date and time formatting with locale rules
• Collation and sorting support
• Language code support
• Currency formatting (see Money module for currency-specific formatting)

API Reference

See world.locale.format for formatting-related types and functions.