Binary relation closure

• 闭包

Binary relation closure的用法和样例：

例句

1. In our example above, notice how we referred to the closure member val.
   在上面的例子中，要注意我们是如何引用闭包变量的。
2. The set of reachable objects is the transitive closure of the root set under the points-to relation.
   可到达的对象集是指向关系下根集的传递闭包。