Underscore.php puts all its functions into the Underscore Namespace, so it requires at least PHP 5.3.0.

• No Support for timer based functions (delay, debounce, defer,...) as they make no sense in a synchronous environment, such as Requests to PHP
• _() is __(), because _() is already taken by the gettext Extension
• include() is includes(), because include is a reserverd word in PHP

Everything you need for using Underscore.php is contained in the file underscore.php in the projects repository. Just put this file somewhere in your path and include the file in your code with require_once "underscore.php". All functions are in contained in the Underscore Namespace. You may want to alias this Namespace to _, by calling use Underscore as _;. Calls to functions then will look like this: $result = _\first(array(1, 2, 3));.

Underscore.php is MIT licensed. Please see the included LICENSE.txt.