Configurable Internationalization with Twig

This is a hack to get Twig's native internationalization extension to work with other translation systems than PHP's native gettext extension. That way, you can use other implementation, such as gettext/gettext or even your own one, provided a function is available to perform translations for singular strings, and another one for plural strings.

Installation

If you are using composer, installation is as easy as requiring this package:

composer require jaimeperez/twig-configurable-i18n

If you are not using composer, you will need to manually include all (four) source files in this project from your script, and make sure you have the twig/extension package installed as well.

Usage

Using this extension is extremely simple, and won't require you to modify your code or existing templates, but just a couple of modifications to the PHP scripts where you want internationalization.

First, create aliases for two classes so that the ones defined in this extension override the default ones:

use JaimePerez\TwigConfigurableI18n\Twig\Environment as Twig_Environment;
use JaimePerez\TwigConfigurableI18n\Twig\Extensions\Extension\I18n as Twig_Extensions_Extension_I18n;

The first line allows you to redefine the twig environment class, so that you can keep the configuration options you pass to the constructor. The second line installs this extension instead of the native one. Your code will use now this extension without further modifications, and PHP's native gettext will continue to be used.

Now, you are ready to configure the extension to use different translation functions. You will do that by passing options to the Twig environment class you have just imported:

$twig = new Twig_Environment($loader, array(
    'translation_function' => 'translate',
    'translation_function_plural' => 'translate_plural'
));

These are the only two supported options. translation_function lets you specify a function that is capable to translate strings in singular, being equivalent to gettext(). On the other hand, translate_function_plural lets you specify a function to handle the translation of strings in plural. This one is equivalent to ngettext().

You are all set. Twig will use the translate() and translate_plural() functions you have just specified, instead of the native gettext() and ngettext() functions. Of course, you will need to specify some functions that actually exist, but that depends on what implementation of gettext you want to use. If, for example, you plan to use Oscar Otero's pure-PHP implementation gettext/gettext, you can do the following:

use \Gettext\Translator as Translator;

...

$this->translator = new Translator();
$this->translator->register();

...

$twig = new Twig_Environment($loader, array(
    'translation_function' => '__',
    'translation_function_plural' => 'n__'
));