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Internationalization
Phabricator Contributor Documentation (Developer Guides)

Describes Phabricator translation and localization.

Overview

Phabricator partially supports internationalization, but many of the tools are missing or in a prototype state.

This document describes what tools exist today, how to add new translations, and how to use the translation tools to make a codebase translatable.

Adding a New Locale

To add a new locale, subclass PhutilLocale. This allows you to introduce a new locale, like "German" or "Klingon".

Once you've created a locale, applications can add translations for that locale.

For instructions on adding new classes, see Adding New Classes.

Adding Translations to Locale

To translate strings, subclass PhutilTranslation. Translations need to belong to a locale: the locale defines an available language, and each translation subclass provides strings for it.

Translations are separated from locales so that third-party applications can provide translations into different locales without needing to define those locales themselves.

For instructions on adding new classes, see Adding New Classes.

Writing Translatable Code

Strings are marked for translation with pht().

The pht() function takes a string (and possibly some parameters) and returns the translated version of that string in the current viewer's locale, if a translation is available.

If text strings will ultimately be read by humans, they should essentially always be wrapped in pht(). For example:

$dialog->appendParagraph(pht('This is an example.'));

This allows the code to return the correct Spanish or German or Russian version of the text, if the viewer is using Phabricator in one of those languages and a translation is available.

Using pht() properly so that strings are translatable can be tricky. Briefly, the major rules are:

  • Only pass static strings as the first parameter to pht().
  • Use parameters to create strings containing user names, object names, etc.
  • Translate full sentences, not sentence fragments.
  • Let the translation framework handle plural rules.
  • Use PhutilNumber for numbers.
  • Let the translation framework handle subject gender rules.
  • Translate all human-readable text, even exceptions and error messages.

See the next few sections for details on these rules.

Use Static Strings

The first parameter to pht() must always be a static string. Broadly, this means it should not contain variables or function or method calls (it's OK to split it across multiple lines and concatenate the parts together).

These are good:

pht('The night is dark.');
pht(
  'Two roads diverged in a yellow wood, '.
  'and sorry I could not travel both '.
  'and be one traveler, long I stood.');

These won't work (they might appear to work, but are wrong):

pht(some_function());
pht('The duck says, '.$quack);
pht($string);

The first argument must be a static string so it can be extracted by static analysis tools and dumped in a big file for translators. If it contains functions or variables, it can't be extracted, so translators won't be able to translate it.

Lint will warn you about problems with use of static strings in calls to pht().

Parameters

You can provide parameters to a translation string by using sprintf()-style patterns in the input string. For example:

pht('%s earned an award.', $actor);
pht('%s closed %s.', $actor, $task);

This is primarily appropriate for usernames, object names, counts, and untranslatable strings like URIs or instructions to run commands from the CLI.

Parameters normally should not be used to combine two pieces of translated text: see the next section for guidance.

Sentence Fragments

You should almost always pass the largest block of text to pht() that you can. Particularly, it's important to pass complete sentences, not try to build a translation by stringing together sentence fragments.

There are several reasons for this:

  • It gives translators more context, so they can be more confident they are producing a satisfying, natural-sounding translation which will make sense and sound good to native speakers.
  • In some languages, one fragment may need to translate differently depending on what the other fragment says.
  • In some languages, the most natural-sounding translation may change the order of words in the sentence.

For example, suppose we want to translate these sentence to give the user some instructions about how to use an interface:

Turn the switch to the right.

Turn the switch to the left.

Turn the dial to the right.

Turn the dial to the left.

Maybe we have a function like this:

function get_string($is_switch, $is_right) {
  // ...
}

One way to write the function body would be like this:

$what = $is_switch ? pht('switch') : pht('dial');
$dir = $is_right ? pht('right') : pht('left');

return pht('Turn the ').$what.pht(' to the ').$dir.pht('.');

This will work fine in English, but won't work well in other languages.

One problem with doing this is handling gendered nouns. Languages like Spanish have gendered nouns, where some nouns are "masculine" and others are "feminine". The gender of a noun affects which article (in English, the word "the" is an article) should be used with it.

In English, we say "the knob" and "the switch", but a Spanish speaker would say "la perilla" and "el interruptor", because the noun for "knob" in Spanish is feminine (so it is used with the article "la") while the noun for "switch" is masculine (so it is used with the article "el").

A Spanish speaker can not translate the string "Turn the" correctly without knowing which gender the noun has. Spanish has two translations for this string ("Gira el", "Gira la"), and the form depends on which noun is being used.

Another problem is that this reduces flexibility. Translating fragments like this locks translators into a specific word order, when rearranging the words might make the sentence sound much more natural to a native speaker.

For example, if the string read "The knob, to the right, turn it.", it would technically be English and most English readers would understand the meaning, but no native English speaker would speak or write like this.

However, some languages have different subject-verb order rules or colloquialisms, and a word order which transliterates like this may sound more natural to a native speaker. By translating fragments instead of complete sentences, you lock translators into English word order.

Finally, the last fragment is just a period. If a translator is presented with this string in an interface without much context, they have no hope of guessing how it is used in the software (it could be an end-of-sentence marker, or a decimal point, or a date separator, or a currency separator, all of which have very different translations in many locales). It will also conflict with all other translations of the same string in the codebase, so even if they are given context they can't translate it without technical problems.

To avoid these issues, provide complete sentences for translation. This almost always takes the form of writing out alternatives in full. This is a good way to implement the example function:

if ($is_switch) {
  if ($is_right) {
    return pht('Turn the switch to the right.');
  } else {
    return pht('Turn the switch to the left.');
  }
} else {
  if ($is_right) {
    return pht('Turn the dial to the right.');
  } else {
    return pht('Turn the dial to the left.');
  }
}

Although this is more verbose, translators can now get genders correct, rearrange word order, and have far more context when translating. This enables better, natural-sounding translations which are more satisfying to native speakers.

Singular and Plural

Different languages have various rules for plural nouns.

In English there are usually two plural noun forms: for one thing, and any other number of things. For example, we say that one chair is a "chair" and any other number of chairs are "chairs": "0 chairs", "1 chair", "2 chairs", etc.

In other languages, there are different (and, in some cases, more) plural forms. For example, in Czech, there are separate forms for "one", "several", and "many".

Because plural noun rules depend on the language, you should not write code which hard-codes English rules. For example, this won't translate well:

if ($count == 1) {
  return pht('This will take an hour.');
} else {
  return pht('This will take hours.');
}

This code is hard-coding the English rule for plural nouns. In languages like Czech, the correct word for "hours" may be different if the count is 2 or 15, but a translator won't be able to provide the correct translation if the string is written like this.

Instead, pass a generic string to the translation engine which includes the number of objects, and let it handle plural nouns. This is the correct way to write the translation:

return pht('This will take %s hour(s).', new PhutilNumber($count));

If you now load the web UI, you'll see "hour(s)" literally in the UI. To fix this so the translation sounds better in English, provide translations for this string in the PhabricatorUSEnglishTranslation file:

'This will take %s hour(s).' => array(
  'This will take an hour.',
  'This will take hours.',
),

The string will then sound natural in English, but non-English translators will also be able to produce a natural translation.

Note that the translations don't actually include the number in this case. The number is being passed from the code, but that just lets the translation engine get the rules right: the number does not need to appear in the final translations shown to the user.

Using PhutilNumber

When translating numbers, you should almost always use %s and wrap the count or number in new PhutilNumber($count). For example:

pht('You have %s experience point(s).', new PhutilNumber($xp));

This will let the translation engine handle plural noun rules correctly, and also format large numbers correctly in a locale-aware way with proper unit and decimal separators (for example, 1000000 may be printed as "1,000,000", with commas for readability).

The exception to this rule is IDs which should not be written with unit separators. For example, this is correct for an object ID:

pht('This diff has ID %d.', $diff->getID());

Male and Female

Different languages also use different words for talking about subjects who are male, female or have an unknown gender. In English this is mostly just pronouns (like "he" and "she") but there are more complex rules in other languages, and languages like Czech also require verb agreement.

When a parameter refers to a gendered person, pass an object which implements PhutilPerson to pht() so translators can provide gendered translation variants.

pht('%s wrote', $actor);

Translators will create these translations:

// English translation
'%s wrote';

// Czech translation
array('%s napsal', '%s napsala');

(You usually don't need to worry very much about this rule, it is difficult to get wrong in standard code.)

Exceptions and Errors

You should translate all human-readable text, even exceptions and error messages. This is primarily a rule of convenience which is straightforward and easy to follow, not a technical rule.

Some exceptions and error messages don't technically need to be translated, as they will never be shown to a user, but many exceptions and error messages are (or will become) user-facing on some way. When writing a message, there is often no clear and objective way to determine which type of message you are writing. Rather than try to distinguish which are which, we simply translate all human-readable text. This rule is unambiguous and easy to follow.

In cases where similar error or exception text is often repeated, it is probably appropriate to define an exception for that category of error rather than write the text out repeatedly, anyway. Two examples are PhutilInvalidStateException and PhutilMethodNotImplementedException, which mostly exist to produce a consistent message about a common error state in a convenient way.

There are a handful of error strings in the codebase which may be used before the translation framework is loaded, or may be used during handling other errors, possibly raised from within the translation framework. This handful of special cases are left untranslated to prevent fatals and cycles in the error handler.

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