So they don t conflict with other names in enclosing or nested scopes ,使它們不會(huì)與包含或嵌入宏的范圍中的其他名稱沖突。
At any time during execution , there are at least three nested scopes whose namespaces are directly accessible : the innermost scope , which is searched first , contains the local names ; the namespaces of any enclosing functions , which are searched starting with the nearest enclosing scope ; the middle scope , searched next , contains the current module ' s global names ; and the outermost scope ( searched last ) is the namespace containing built - in names 每次執(zhí)行時(shí),至少有三個(gè)命名空間可以直接訪問的作用域嵌套在一起:包含局部命名的使用域在最里面,首先被搜索;其次搜索的是中層的作用域,這里包含了同級(jí)的函數(shù);最后搜索最外面的作用域,它包含內(nèi)置命名。