在我的代码中，计算由每个AST结点自己执行，但我们可能也将使用一个树遍历器来遍历每个结点，基于它的类型来执行。

In my code the evaluation is performed by each AST node itself, but we may use also a tree walker to walk each node and execute it based on its type.

youdao

接着是一匹活马勇敢地与水搏击。但我们担心，洪水的力量将使它上岸之前就筋疲力尽了。

Bravely exhausted Next came a horse, swimming bravely, but we were afraid that the strength of the current would prevent its landing anywhere before it became exhausted.

youdao

但我知道我将使它通过，如果你等我。

But I know I will make it through, if you wait for me.

youdao