swift - 如何处理未捕获的异常

Question

如果使用 NSSetUncaughtExceptionHandler，它只处理 objective-C 运行时错误。 https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_Functions/index.html#//apple_ref/c/func/NSSetUncaughtExceptionHandler

NSSetUncaughtExceptionHandler 可以捕获异常:

var a: NSArray = [""]
println(a[2])

但是NSSetUncaughtExceptionHandler无法捕获异常:

var a = [""]
println(a[2])

How swift deal with non-objective-C runtime errors(swift runtime errors)??

Answer 1

如果您希望处理超出索引的异常，那么您始终可以验证索引项

extension Collection {
    /// Returns the element at the specified index if it is within bounds, otherwise nil.
    public subscript (safe index: Index) -> Element? {
      return indices.contains(index) ? self[index] : nil
    }
}