Cldr Units version 3.0.0

Summary

• New unit creation including rational numbers

• Base unit calculation

• New unit preferences

• New conversion engine

Breaking changes

• Cldr.Unit.new/2 is now Cldr.Unit/{2, 3} and it returns a standard {:ok, unit} tuple on success. Use Cldr.Unit.new!/{2,3} if you want to retain the previous behaviour.

• Removed Cldr.Unit.unit_tree/0

• Removed Cldr.Unit.units/1

• Removed Cldr.Unit.compatible_units/2

• Removed Cldr.Unit.best_match/1

• Removed Cldr.Unit.jaro_match/1

• Removed Cldr.Unit.unit_category_map/0 (replaced with Cldr.Unit.base_unit_category_map/0)

Deprecations

• Deprecate Cldr.Unit.unit_categories/0 in favour of Cldr.Unit.known_unit_categories/0 to be consistent across CLDR.

Enhancements

• Incorporate CLDR's unit conversion data into the new conversion engine

• Unit values may now be rational numbers. Conversion data and the results of conversions are executed and retained as rationals. New units can be created with integer, float, Decimal or rational numbers. Conversion to floats is done only when the unit is output via Cldr.Unit.to_string/3 or explicitly through the new function Cldr.Unit.ratio_to_float/1

• Add an option :usage to Cldr.Unit.new/{2,3}. This defines an expected usage for a given unit that will be applied during localization. The default is :default. See Cldr.Unit.unit_category_map/0 for what usage is defined for a unit category.

• Add Cldr.Unit.known_measurement_sytems/0 to return the known measurement systems

• Add Cldr.Unit.Conversion.preferred_units/3 that returns a list of preferred units for a given unit. This makes it straight forward to take a unit and convert it to the units preferred by the user for a given unit type, locale and use case.

• Add Cldr.Unit.base_category_map/0 that maps base units to their unit categories. For example, map mile_per_hour to :speed or kilogram_square_meter_per_cubic_second_ampere to :voltage. Base units are derived from a unit name and are not normally the concern of the consumer of ex_cldr_units.