如何声明Swift中的计算属性“抛出”？ [英] How do I declare that a computed property 'throws' in Swift?

问题描述

class SomeClass {
  var someProperty: Int {
    throw Err("SNAFU")
  }
}

对于上述代码，快速二进制文件抱怨未处理错误，因为未将包围函数声明为 throws。

For code like the above, the swift binary complains 'error is not handled because the enclosing function is not declared 'throws'.

如何在上面声明 someProperty为 throws？

How do I declare that 'someProperty' 'throws' in the above?

class SomeClass {
  var someProperty throws: Int {
  }
}

和

class SomeClass {
  var someProperty: throws Int {
  }
}

和

class SomeClass {
  var someProperty: Int throws {
  }
}

似乎不起作用。

推荐答案

Swift 5的更新：仍然如此

Update for Swift 5: This is still not possible.

从Swift 3开始：

As of Swift 3:

您不能从计算属性中抛出。如果要抛出，必须使用一个函数。 末尾的语言参考的声明部分 Swift编程语言仅将抛出（和 rethrows ）列为函数和初始化程序声明的关键字。

You cannot throw from a computed property. You must use a function if you want to throw. The Declarations section of the Language Reference part at the end of The Swift Programming Language only lists throws (and rethrows) as a keyword for function and initializer declarations.

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