The easiest way to internationalize PHP software is by using array files and using those strings in templates, such as <h1><?=$TRANS['title_about_page']?></h1>. This is, however, hardly a recommended way for serious projects, as it poses some maintenance issues along the road - some might appear in the very beginning, such as pluralization. So, please, don’t try this if your project will contain more than a couple of pages. 对于 PHP 软件来首，实现国际化的最简单的方式是使用数组键值对应的方式如 <h1><?=$TRANS['title_about_page']?></h1>，不过在比较正经的项目中，不建议这么做。因为会随着项目代码慢慢变多，维护的难度将会增加，尤其会阻碍后续本地化实施。

The most classic way and often taken as reference for i18n and l10n is a Unix tool called gettext. It dates back to 1995 and is still a complete implementation for translating software. It is pretty easy to get running, while it still sports powerful supporting tools. It’s about Gettext we will be talking here. Also, to help you not get messy over the command-line, we will be presenting a great GUI application that can be used to easily update your l10n source files.

其他工具

There are common libraries used that support Gettext and other implementations of i18n. Some of them may seem easier to install or sport additional features or i18n file formats. In this document, we focus on the tools provided with the PHP core, but here we list others for completion:

oscarotero/Gettext: Gettext support with an OO interface; includes improved helper functions, powerful extractors for several file formats (some of them not supported natively by the gettextcommand), and can also export to other formats besides .mo/.pofiles. Can be useful if you need to integrate your translation files into other parts of the system, like a JavaScript interface.

symfony/translation: supports a lot of different formats, but recommends using verbose XLIFF’s. Doesn’t include helper functions nor a built-in extractor, but supports placeholders using strtr() internally.

zend/i18n: supports array and INI files, or Gettext formats. Implements a caching layer to save you from reading the filesystem every time. It also includes view helpers, and locale-aware input filters and validators. However, it has no message extractor.

Other frameworks also include i18n modules, but those are not available outside of their codebases: - Laravel supports basic array files, has no automatic extractor but includes a @lang helper for template files. - Yiisupports array, Gettext, and database-based translation, and includes a messages extractor. It is backed by the Intl extension, available since PHP 5.3, and based on the ICU project; this enables Yii to run powerful replacements, like spelling out numbers, formatting dates, times, intervals, currency, and ordinals.

If you decide to go for one of the libraries that provide no extractors, you may want to use the gettext formats, so you can use the original gettext toolchain (including Poedit) as described in the rest of the chapter.