Intl::Format::Unit

A module for formatting units in a localized manner

To use

use Intl::Format::Unit;

say format-unit 0,        :unit<length-meter>; # 0 m
say format-unit 1234,     :unit<length-meter>; # 53,425.21 m
say format-unit 53425.21, :unit<length-meter>; # 1,234 m

The sub format-unit takes the following arguments:

• quantityThe amount of the unit (a number).

• unitThe type of unit (e.g. meter, liter, etc).

• :languageThe language to use in formatting. Defaults to user-language.

• :lengthAny of long, short or narrow. Defaults to short.

• :caseThe grammatical case to use (normally only applicable with long length). Defaults to nominative

The units can be quite complex, even to the point of making no sense. Assuming English,

format-unit 12345.6789, :unit<solar-radius-cubic-yottaliter-per-pound-square-millimeter>;
# 12,345.6789 R☉⋅Yl³/lb⋅mm²

Supported units

The units that are generally supported by CLDR's validity/units.xml file. These have been curated a bit to have the following base units:

**g-force meter second arc-minute arc-second degree radian

          revolution acre hectare foot inch mile yard dunam karat
          gram liter mole percent permille permyriad permillion item
          portion gallon gallon-imperial bit byte century decade
          day day-person hour minute month month-person week week-person
          year year-person ampere ohm volt calorie foodcalorie joule
          watt-hour electronvolt therm-us british-thermal-unit pound-force newton
          hertz dot em pixel astronomical-unit fathom furlong light-year
          mile-scandinavian nautical-mile parsec point earth-radius solar-radius
          candela lumen lux solar-luminosity carat grain metric-ton ounce
          ounce-troy pound stone ton dalton earth-mass solar-mass watt
          horsepower atmosphere inch-ofhg bar meter-ofhg pascal
          ofhg knot celsius fahrenheit generic kelvin pound-force-foot
          newton-meter acre-foot bushel cup cup-metric dessert-spoon
          dessert-spoon-imperial drop dram jigger pinch quart-imperial
          fluid-ounce fluid-ounce-imperial pint pint-metric quart
          tablespoon teaspoon barrel**

All of these make take the following SI and SI-ish (˟) prefixes:

**yotta zetta exa peta tera giga mega kilo hecto deka

    deci centi  milli  micro  nano  pico  femto atto zepto yocto
    exbi˟ pebi˟ tebi˟ gibi˟ mebi˟  kibi˟**

Lastly, the following powers are supported:

square cubic

Using the above units, you can combine them in the following way:

• To prefix, attach directly: millimeter kiloliter

• To raise to a power, separate the power and the unit by a hyphen: square-foot, cubic-centimeter

• To multiple two units, separate by a hyphen: watt-hour

• To divide two units, separate by a hyphenated per: miles-per-hour.

These can combined in almost infinite complexity. The only restriction is that there may only be one -per- (subsequent ones, per TR 35, are ignored).

Also note that the rarer the combination of units that you get, the more likely that non-major languages may not have full support. For Latin-based languages, this might not look terrible, but for others, it means that the fallback versions (all Latin-script) may be inserted.

⚠ Warning

More so than other modules in the Intl namespace, this module should be considered experimental for the following reasons:

1. The method of selecting the unit is not intuitive and will likely be changed.

2. Composed units were only introduced in CLDR v.38 (early 2020) with support for two languages (French and German).As of v.38.1 (late 2020), this has not changed. Use caution when attempting to use these, as some languages may end up creating unexpected combinations (like saying liter per minutes instead of liters per minute). This should not affect the most simple units such as meter or liter or even common ones like kilometers per hour.

Dependencies

• Intl::CLDRHouses the data for calculating the counts

• Intl::UserLanguageDetermines the default language when not provided

• Intl::Format::NumberFormats the quantity as a decimal number

• Intl::Number::PluralDetermines the grammatical-ish number to select the correct pattern

Todo

• More tests files (especially for compound units)

Version History

• v0.2.0

  • Initial support for composed units

• v0.1.0

  • Initial version

License and Copyright

© 2020-2021 Matthew Stephen Stuckwisch. Licensed under the Artistic License 2.0.