code: function fileScope(filename) {
      filename = path.resolve('', filename || '');
      var result = scopes[filename];
      if (!result) {
        result = create({
          clean: clean,
          removeList: removeList,
          excludeList: excludeList,
          rootScope: rootScope,
          filename: filename,
          argv: argv,
          scopes: scopes,
          processors: processors,
          variants: variants,
          cacheKeys: cacheKeys,
          tags: tags
        });
      }
      return result;
    }
docs: 获取一个文件的作用域
  
  @param {string} filename 对应文件名
  @return {jdistsScope} 返回文件对应的作用域