Plurals

What Are Plurals?

Plurals are a standardized way to deal with quantities. For example, English uses with 2 plurals: "one" (1) and "other" (0, 2, 3, ..).

If you have

{
  "items": "{{ count }} items"
}

this would produce "1 items", which is incorrect English.

This can be solved by defining 2 plural forms:

{
  "items_one": "{{ count }} item",
  "items_other": "{{ count }} items"
}

When providing the count to the t! macro, this will result in:

let i18n = use_i18n();

t!(i18n, items, count = || 0) // -> "0 items"
t!(i18n, items, count = || 1) // -> "1 item"
t!(i18n, items, count = || 4) // -> "4 items"

All items_* are merged into the single key items.

{{ count }} is a special variable when using plurals. Even if you don't interpolate it, you must supply it:

{
  "items_one": "one item",
  "items_other": "some items"
}

This will still require you to supply the count variable: t!(i18n, items, count = ...).

Why Bother?

Why bother, instead of just doing:

if item_count == 1 {
    t!(i18n, items_one)
} else {
    t!(i18n, items_other, count = move || item_count)
}

Because not all languages use the same plural rules.

For example, in French, 0 is considered singular, so this could produce "0 choses" instead of "0 chose", which is incorrect in French (with some exceptions — French has many of them).

Ordinal Plurals

What I described above are "cardinal" plurals, but they don’t work for cases like "1st place", "2nd place", etc.

The English language uses 4 ordinal plural forms, while French uses 2:

• one: "1st place", "21st place"
• two: "2nd place", "22nd place"
• few: "3rd place", "33rd place"
• other: "4th place", "5th place", "7th place"

And French:

• one: "1ère place"
• other: "2ème place", "21ème place"

You can use ordinal plurals by using the _ordinal suffix:

{
  "key_ordinal_one": "{{ count }}st place",
  "key_ordinal_two": "{{ count }}nd place",
  "key_ordinal_few": "{{ count }}rd place",
  "key_ordinal_other": "{{ count }}th place"
}

The _ordinal suffix is removed, in this example you access it with t!(i18n, key, count = ..)

How to Know Which to Use

There are online resources that help determine which plural rules to use, my personal favorite is the Unicode CLDR Charts.

What if I Need Multiple Counts?

If you need multiple counts, for example:

{
  "key": "{{ boys_count }} boys and {{ girls_count }} girls"
}

There isn't a way to represent this in a single key, you will need Foreign keys, which you can read about in a later chapter.

Activate the Feature

To use plurals in your translations, enable the "plurals" feature.