protected function _parseExtensionDef($target)
    {
        $paths = array();
        if (!empty($target['paths'])) {
            $paths = array_map(array($this, '_replacePathConstants'), (array)$target['paths']);
        }
        $target['paths'] = $paths;
        if (!empty($target['cachePath'])) {
            $path = $this->_replacePathConstants($target['cachePath']);
            $target['cachePath'] = rtrim($path, '/') . '/';
        }
        return $target;
    }