class moodle_exception extends Exception {
    public $errorcode;
    public $module;
    public $a;
    public $link;
    public $debuginfo;

    /**
     * Constructor
     * @param string $errorcode The name of the string from error.php to print
     * @param string $module name of module
     * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
     * @param object $a Extra words and phrases that might be required in the error string
     * @param string $debuginfo optional debugging information
     */
    function __construct($errorcode, $module='', $link='', $a=NULL, $debuginfo=null) {
        if (empty($module) || $module == 'moodle' || $module == 'core') {
            $module = 'error';
        }

        $this->errorcode = $errorcode;
        $this->module    = $module;
        $this->link      = $link;
        $this->a         = $a;
        $this->debuginfo = $debuginfo;

        if (get_string_manager()->string_exists($errorcode, $module)) {
            $message = get_string($errorcode, $module, $a);
        } else {
            $message = $module . '/' . $errorcode;
        }

        parent::__construct($message, 0);
    }
}