1

KeyPath is PowerFull.
but, i needs keypath("") like #keypath("")

can it, i ease json-parsing like

struct a{
init(json : Dictionary<String,Any>){
for (key,value) in json{
self[keypath : key] = value
}
}
struct b : a{}
struct c : a{}

struct b,c is auto-mapping at jsonData.
can it?

2

For now the keypath concept is entirely static, meaning that you cannot translate a keypath to a string or a string to a keypath.

Have you looked at the Codable concepts for reading and writing to json?
Codable is extremely powerful and let’s you encode to and decode from json with very little code.

3

I also hit this problem, I expected this to work:

let dict = NSMutableDictionary(object: "value1", forKey: NSString("key"))
dict.observe(keyPath:KeyPath("key")) { (dict, change) in // compilation error
    print("changed")
}
dict.setObject("value2", forKey: NSString("key"))

'KeyPath<Root, Value>' cannot be constructed because it has no accessible initializers

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