README

Polyglot.php is a tiny I18n helper library written in PHP, which is based entirely on the Polyglot.js Airbnb's I18n javascript library.

The reason behind the decision to replicate the Airbnb's javascript library was to have a small, but yet powerful library, for developers to use the same way of internationalizing their PHP back-ends as they do in the front-end apps.

Polylglot doesn’t perform any translation; it simply gives you a way to manage translated phrases from your server-side PHP application.

Installation

install with composer:

$ composer require m1sh0u/polyglot-php

Running the tests

Clone the repo, run composer update --prefer-dist --dev, and composer test, or composer test-win for windows.

Usage

Instantiation

First, create an instance of the Polyglot class, which you will use for translation.

$polyglot = new Polyglot();

Polyglot is class-based so you can maintain different sets of phrases at the same time, possibly in different locales.

See Options Overview for information about the options array you can choose to pass to new Polyglot.

Translation

Tell Polyglot what to say by simply giving it a phrases key-value pair, where the key is the canonical name of the phrase and the value is the already-translated string.

$polyglot->extend([
  "hello" => "Hello"
]);

$polyglot->t("hello");
=> "Hello"

You can also pass a mapping at instantiation, using the key phrases:

$polyglot = new Polyglot(['phrases' => ["hello" => "Hello"]]);

Polyglot doesn’t do the translation for you. It’s up to you to give it the proper phrases for the user’s locale.

Interpolation

Polyglot->t() also provides interpolation. Pass an array with key-value pairs of interpolation arguments as the second parameter.

$polyglot->extend([
  "hello_name" => "Hola, %{name}."
]);

$polyglot->t("hello_name", ["name" => "DeNiro"]);
=> "Hola, DeNiro."

Polyglot also supports nested phrase objects.

$polyglot->extend([
  "nav" => [
    "hello" => "Hello",
    "hello_name" => "Hello, %{name}",
    "sidebar" => [
      "welcome" => "Welcome"
    ]
  ]
]);

$polyglot->t("nav.sidebar.welcome");
=> "Welcome"

The substitution variable syntax is customizable.

$polyglot = new Polyglot({
  "phrases" => [
    "hello_name" => "Hola {{name}}"
  ],
  "interpolation" => ["prefix" => "{{", "suffix" => "}}"]
});

$polyglot->t("hello_name", ["name" => "DeNiro"]);
=> "Hola, DeNiro."

Pluralization

For pluralization to work properly, you need to tell Polyglot what the current locale is. You can use $polyglot->locale("fr") to set the locale to, for example, French. This method is also a getter:

$polyglot->locale()
=> "fr"

You can also pass this in during instantiation.

$polyglot = new Polyglot(["locale" => "fr"]);

Currently, the only thing that Polyglot uses this locale setting for is pluralization.

Polyglot provides a very basic pattern for providing pluralization based on a single string that contains all plural forms for a given phrase. Because various languages have different nominal forms for zero, one, and multiple, and because the noun can be before or after the count, we have to be overly explicit about the possible phrases.

To get a pluralized phrase, still use $polyglot->t() but use a specially-formatted phrase string that separates the plural forms by the delimiter ||||, or four vertical pipe characters.

For pluralizing "car" in English, Polyglot assumes you have a phrase of the form:

$polyglot->extend([
  "num_cars" => "%{smart_count} car |||| %{smart_count} cars",
]);

In English (and German, Spanish, Italian, and a few others) there are only two plural forms: singular and not-singular.

Some languages get a bit more complicated. In Czech, there are three separate forms: 1, 2 through 4, and 5 and up. Russian is even more involved.

$polyglot = new Polyglot(["locale" => "cs"]); // Czech
$polyglot->extend([
  "num_foxes" => "Mám %{smart_count} lišku |||| Mám %{smart_count} lišky |||| Mám %{smart_count} lišek"
])

$polyglot->t() will choose the appropriate phrase based on the provided smart_count option, whose value is a number.

$polyglot->t("num_cars", ["smart_count" => 0]);
=> "0 cars"

$polyglot->t("num_cars", ["smart_count" => 1]);
=> "1 car"

$polyglot->t("num_cars", ["smart_count" => 2]);
=> "2 cars"

As a shortcut, you can also pass a number to the second parameter:

$polyglot->t("num_cars", 2);
=> "2 cars"

Custom plural rules

If needed, one can replace the existing plural rules or specify new custom plural rules for certain locales. The custom plural rules must be objects which implements Polyglot\Pluralization\Rules\RuleInterface. They will be passed to the Polyglot pluralRules option as a key-value pair where the key is the locale and the value is the custom rule object.

Let's define a custom plural rule for romanian language:

use Polyglot\Pluralization\Rules\RuleInterface;

class RomanianRule implements RuleInterface
{
    public function decide(int $n): int
    {
        return $n !== 1 ? 1 : 0;
    }
}

Now you can pass it to the Polyglot options to be used whenever the ro locale is used for pluralization:

$polyglot = new Polyglot([
    'phrases' => ['num_cars' => '%{smart_count} mașină |||| %{smart_count} mașini'],
    'locale' => 'ro',
    'pluralRules' => ['ro' => new RomanianRule()]
]);

$polyglot->t('num_cars', 1)
=> 1 mașină
$polyglot->t('num_cars', 6)
=> 6 mașini

Public Instance Methods

Polyglot->t($key, $interpolationOptions)

The most-used method. Provide a key, and t() will return the phrase.

$polyglot->t("hello");
=> "Hello"

The phrase value is provided first by a call to $polyglot->extend() or $polyglot->replace().

Pass in an object as the second argument to perform interpolation.

$polyglot->t("hello_name", ["name" => "Spike"]);
=> "Hello, Spike"

Pass a number as the second argument as a shortcut to smart_count:

// same as: $polyglot->t("car", ["smart_count" => 2]);
$polyglot->t("car", 2);
=> "2 cars"

If you like, you can provide a default value in case the phrase is missing. Use the special option key "_" to specify a default.

$polyglot->t("i_like_to_write_in_language", [
  "_" => "I like to write in %{language}.",
  "language" => "JavaScript"
]);
=> "I like to write in JavaScript."

Polyglot->extend($phrases)

Use extend to tell Polyglot how to translate a given key.

$polyglot->extend([
  "hello" => "Hello",
  "hello_name" => "Hello, %{name}"
]);

The key can be any string. Feel free to call extend multiple times; it will override any phrases with the same key, but leave existing phrases untouched.

Polyglot->unset($keyOrArray)

Use unset to selectively remove keys from a polyglot instance. unset accepts one argument: either a single string key, or an array whose keys are string keys, and whose values are ignored unless they are nested arrays (in the same format).

Example:

$polyglot->unset('some_key');
$polyglot->unset([
  'hello' => 'Hello',
  'hello_name' => 'Hello, %{name}',
  'foo' => [
    'bar' => 'This phrase’s key is "foo.bar"'
  ]
]);

Polyglot->locale(?$localeToSet)

Get or set the locale (also can be set using the constructor option, which is used only for pluralization. If a truthy value is provided, it will set the locale. Afterwards, it will return it.

Polyglot->clear()

Clears all phrases. Useful for special cases, such as freeing up memory if you have lots of phrases but no longer need to perform any translation. Also used internally by replace.

Polyglot->replace($phrases)

Completely replace the existing phrases with a new set of phrases. Normally, just use extend to add more phrases, but under certain circumstances, you may want to make sure no old phrases are lying around.

Polyglot->has($key)

Returns true if the key does exist in the provided phrases, otherwise it will return false.

Polyglot->phrases()

Returns all the phrases.

Polyglot->transformPhrase($phrase[, $substitutions[, $locale[, $tokenRegex]]])

Takes a phrase string and transforms it by choosing the correct plural form and interpolating it. This method is used internally by t.
The correct plural form is selected if $substitutions['smart_count'] is set.
You can pass in a number instead of an array as $substitutions as a shortcut for smart_count.
You should pass in a third argument, the locale, to specify the correct plural type. It defaults to 'en' which has 2 plural forms.
You should pass in a forth argument, to specify the interpolation token regex. It defaults to ~%{(.*?)}~. Note: the regex delimiter ~ is included by default.

Options Overview

new Polyglot accepts a number of options:

phrases: a key/value map of translated phrases.
locale: a string describing the locale (language and region) of the translation, to apply pluralization rules. see Pluralization
delimiter: the delimiter used for pluralization. The default delimiter is ||||. see Pluralization
allowMissing: a boolean to control whether missing keys in a t call are allowed. If false, by default, a missing key is returned and a warning is issued.
onMissingKey: if allowMissing is true, and this option is a function, then it will be called instead of the default functionality. Arguments passed to it are $key, $options, $locale, $tokenRegex and Polyglot $polyglot. The return of this function will be used as a translation fallback when $polyglot->t('missing.key') is called (hint: return the key).
interpolation: an array to change the substitution syntax for interpolation by setting the prefix and suffix fields.
pluralRules: replace or add new plural rules for certain locales by providing a key-value pair where the key is the locale and the value is the plural rule object implementing Polyglot\Pluralization\Rules\RuleInterface

Related projects

Polyglot.js: Polyglot.js is a tiny I18n helper library written in JavaScript, made to work both in the browser and in CommonJS environments (Node). It provides a simple solution for interpolation and pluralization, based off of Airbnb’s experience adding I18n functionality to its Backbone.js and Node apps.

m1sh0u / polyglot-php

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