protected function parseAssetDefinition($asset)
    {
        if (starts_with($asset, 'http://')) {
            return new HttpAsset($asset);
        } elseif (str_contains($asset, array('*', '?'))) {
            return new GlobAsset($this->absolutePath($asset));
        } else {
            return new FileAsset($this->absolutePath($asset));
        }
    }