The next two lines use pattern matching to pick off the values required to enforce this rule when the returned function is actually executed.

接下来两行用模式匹配摘出实施规则所必需的数据。

youdao

Now look at the search function. This function USES one of the most powerful features of Scala, its pattern matching.

现在参看搜索函数，这个函数使用一个功能最强大的scala特性：模式匹配。

youdao

Pattern matching is used to evaluate the arguments to the function, so if you supply a tuple with three elements to the mathexp() function, the pattern matching will fail.

使用模式匹配评估函数的参数，所以如果把包含三个元素的元组提供给 mathexp() 函数，模式匹配会失败。

youdao