I was profiling the Symfony Demo app, and I realized that json_decode() took a lot of time to execute:

The reason is that Intl data is provided as JSON files (see https://github.com/symfony/symfony/tree/master/src/Symfony/Component/Intl/Resources/data).

Would it make sense to transform that data into PHP (using var_export()) to avoid parsing it and to get free caching thanks to OPCache? By the way, Intl already provides a reader and writer of this data for PHP, so we could use it (see https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Intl/Data/Bundle/Reader/PhpBundleReader.php).