l10n-psr-brainstorming.php

<?php

// Translator

interface Translator
{
    /**
     * @param array<mixed> $context
     */
    public function translate(string $message, array $context = [], ?LocalesPreferences $localesPreferences = null): string;
}

interface LocalesPreferences
{
    /**
     * @param array<Locale> $availableLocales
     */
    public function bestLocale(array $availableLocales): ?Locale;
}

// Translation catalog

interface LocalizableMessage
{
    public function localize(LocalesPreferences $localesPreferences): ?LocalizedMessage;
}

interface LocalizedMessage
{
    /**
     * @param array<mixed> $context
     */
    public function render(array $context): string;
}

interface TranslationCatalog
{
    public function fetch(string $message): ?LocalizableMessage;
}

// exemple

class MyTranslator implements Translator
{
    /**
     * @param callable(string $message): LocalizedMessage
     */
    public function __construct(
        private TranslationCatalog $catalog,
        private Closure $fallback,
        private LocalesPreferences $defaultLocalesPreferences
    ) {}

    /**
     * @param array<mixed> $context
     */
    public function translate(string $message, array $context = [], ?LocalesPreferences $localesPreferences = null): string
    {
        $localizableMessage = $this->catalog->fetch($message);

        $localizedMessage = $localizableMessage?->localize($localesPreferences ?? $this->defaultLocalesPreferences)
            ?: ($this->fallback)($message);

        return $localizedMessage->render($context);
    }
}

class MyLocalesPreferences implements LocalesPreferences
{
    /**
     * @param array<Locale> $availableLocales
     */
    public function bestLocale(array $availableLocales): ?Locale
    {
        return $availableLocales[array_rand($availableLocales, 1)] ?? null;
    }
}




class MyLocalizableMessage implements LocalizableMessage
{
    /** @var array<Locales> */
    private array $locales = [];

    /** SplObjectStorage<Locale,string> */
    private SplObjectStorage $messages;

    /**
     * @param array<array{locale:Locale,message:string}>
     */
    public function __construct(array $messages) {
        $this->messages = new SplObjectStorage();

        foreach ($messages as ["locale" => $locale, "message" => $message]) {
            $this->locales[] = $locale;
            $this->messages->attach($locale, $message);
        }
    }

    public function localize(LocalesPreferences $localesPreferences): ?LocalizedMessage {
        return $this->messages[$localesPreferences->bestLocale($this->locales)] ?? null;
    }
}

class MySprintfLocalizedMessage implements LocalizedMessage
{
    public function __construct(private string $localizedContent) {}

    /**
     * @param array<mixed> $context
     */
    public function render(array $context): string {
        return sprintf($this->localizedContent, ...$context);
    }
}

class MyTranslationCatalog implements TranslationCatalog
{
    /**
     * @param array<string,LocalizableMessage> $messages
     */
    public function __construct(private array $messages) {}

    public function fetch(string $message): ?LocalizableMessage {
        return $this->messages[$message] ?? null;
    }
}

$catalog = new MyTranslationCatalog([
    "Hello World!" => new MyLocalizableMessage([[
        "locale" => new Locale("fr"),
        "message" => new MySprintfLocalizedMessage("Bonjour, monde !"),
    ]]),
    "Hello %s!" => new MyLocalizableMessage([[
        "locale" => new Locale("fr"),
        "message" => new MySprintfLocalizedMessage("Bonjour, %s !"),
    ]]),
]);

global $translator;
$translator = new MyTranslator(
    $catalog,
    static fn (string $message) => new MySprintfLocalizedMessage($message),
    new MyLocalesPreferences(),
);

/**
 * @param array<mixed> $context
 */
function __(string $key, array $context = []): string
{
    global $translator;
    return $translator->translate($key, $context);
}

echo __("Hello %s!", ["John"]), PHP_EOL;
echo __("Good bye %s!", ["John"]), PHP_EOL;

// output:
// Bonjour, John !
// Good bye John!