AppRegistry.php

<?php  // vim: ts=4 sts=4 sw=4

class AppRegistry
{
    private static $instance;
    private        $registry = array( );

    static function instance ( )
    {
        if ( !isset(self::$instance) ) {
            self::$instance = new self( );
        }

        return self::$instance;
    }

    private function __construct ( ) { }

    function get ($key)
    {
        return array_key_exists($key, $this->registry)
             ? $this->registry[$key]
             : null;
    }

    function set ($key, $value)
    {
        $this->registry[$key] = $value;

        return $value;
    }
}