protected function prepareVariables(array $variables)
    {
        // My kingdom for a generator.
        $ret = [];
        foreach ($variables as $name => $val) {
            if ($this->showItem($name)) {
                $fname = '$' . $name;
                $ret[$fname] = [
                    'name'  => $fname,
                    'style' => \in_array($name, self::$specialNames) ? self::IS_PRIVATE : self::IS_PUBLIC,
                    'value' => $this->presentRef($val),
                ];
            }
        }

        return $ret;
    }