从Swift 4获取字符串新的密钥路径语法？ [英] Getting string from Swift 4 new key path syntax?

问题描述

如何从字符串值 rel =noreferrer> Swift 4智能密钥路径 语法（例如， \Foo.bar ）？在这一点上，我对任何方式都很好奇，如果它很复杂并不重要。

How can you get a string value from Swift 4 smart keypaths syntax (e.g., \Foo.bar)? At this point I'm curious about any way at all, does not matter if it's complicated.

我喜欢类型信息与智能密钥路径相关联的想法。但并非所有API和第三方都在那里。

I like the idea of type information being associated with smart key path. But not all APIs and 3rd parties are there yet.

通过 #keyPath（编译时验证）获取属性名字符串的旧方法）。使用Swift 4来使用 #keyPath（）你必须将属性声明为 @objc ，这是我的意思d喜欢避免。

There's old way of getting string for property name with compile-time validation by #keyPath(). With Swift 4 to use #keyPath() you have to declare a property as @objc, which is something I'd prefer to avoid.

推荐答案

对于Objective-C类的Objective-C属性，可以使用 _kvcKeyPathString property 得到它。

For Objective-C properties on Objective-C classes, you can use the _kvcKeyPathString property to get it.

但是，Swift键路径可能没有String等价物。它是Swift键路径的既定目标，它们不要求字段名称包含在可执行文件中。关键路径可能表示为要获取的字段偏移序列，或者可以表示要调用对象的闭包。

However, Swift key paths may not have String equivalents. It is a stated objective of Swift key paths that they do not require field names to be included in the executable. It's possible that a key path could be represented as a sequence of offsets of fields to get, or closures to call on an object.

当然，这与您的直接冲突自己的目标是避免声明属性 @objc 。我相信没有内置工具可以做你想做的事。

Of course, this directly conflicts with your own objective of avoiding to declare properties @objc. I believe that there is no built-in facility to do what you want to do.

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