Swift DictionaryKeyPath

DictionaryKeyPath.swift

public struct DictionaryKey {
    public typealias Path = WritableKeyPath<Self, Self>

    public var keys: [String]

    public init(keys: [String] = []) {
        self.keys = keys
    }

    public subscript(key: String) -> Self {
        get {
            var keys = keys
            keys.append(key)
            return Self(keys: keys)
        }
        set {
            keys = newValue.keys
        }
    }
}

var b: DictionaryKey.Path = \.["b"]["c"]
print(b) // \DictionaryKey.<computed 0x0000000103a7d330 (DictionaryKey)>.<computed 0x0000000103a7d330 (DictionaryKey)>

print(DictionaryKey()[keyPath: b].keys) // ["b", "c"]