laravel/system/package.php

<?php namespace System;

class Package {

	/**
	 * All of the loaded packages.
	 *
	 * @var array
	 */
	public static $loaded = array();

	/**
	 * Load a package or set of packages.
	 *
	 * @param  string|array  $packages
	 * @return void
	 */
	public static function load($packages)
	{
		foreach ((array) $packages as $package)
		{
			// Packages may have a bootstrap file, which commonly is used to register auto-loaders
			// and perform other initialization needed to use the package. If the package has a
			// bootstrapper, we will require it here.
			if ( ! array_key_exists($package, static::$loaded) and file_exists($path = PACKAGE_PATH.$package.'/bootstrap'.EXT))
			{
				require $path;
			}

			static::$loaded[] = $package;			
		}
	}

}