Kotlin 内联函数只有一个 return 语句

Question

我想使用内联函数返回函数外(跳过打印“之后”)。所以当我使用

inline fun test() {
    return
}

fun test1() {
    println("before")
    test()
    println("after")
}
test1()

输出是

before  
after

当我使用

inline fun test(callBack: () -> Unit) {
    callBack()
}

fun test1() {
    println("before")
    test {
        return
    }
    println("after")
}
test1()

输出是

before

所以我想知道为什么第一个内联函数中的 return 语句不起作用。为什么第一段代码不起作用？

Answer 1

根据文档:

(return) by default returns from the nearest enclosing function or anonymous function. -- returns-and-jumps

A return statement without a label always returns from the function declared with the fun keyword. -- anonymous-functions

实际上我会回答这个问题:为什么它在第二个例子中起作用？答案是:

In Kotlin, we can only use a normal, unqualified return to exit a named function or an anonymous function. This means that to exit a lambda, we have to use a label, and a bare return is forbidden inside a lambda, because a lambda cannot make the enclosing function return (...). But if the function the lambda is passed to is inlined, the return can be inlined as well, so it is allowed.-- non local returns