Change value in nested json dictionary

DictionaryKeyPathSet.swift

extension Dictionary where Key == String, Value == Any {
    @dynamicMemberLookup
    struct LookupPath {
        fileprivate let path: [String]
        
        subscript(dynamicMember member: String) -> LookupPath {
            LookupPath(path: path + [member])
        }
    }
    
    private mutating func _set(value: Any, path: [String]) throws {
        switch (path.first, path.dropFirst()) {
        case let (key?, []):
            self[key] = value
        case let (key?, rest):
            var sub = (self[key] as? [Key: Any]) ?? [:]
            try sub._set(value: value, path: Array(rest))
            self[key] = sub
        default:
            return
        }
    }
    
    mutating func set(value: Any, forPath path: KeyPath<LookupPath, LookupPath>) throws {
        try _set(value: value, path: LookupPath(path: [])[keyPath: path].path)
    }
}

// Example

var dictionary: [String: Any] = ["json": ["type": "order",
                                          "details": ["size": 5,
                                                      "additional": ["here": 1234]]]]

dictionary.set(value: true, forPath: \.json.details.additional.here)
// ["json": ["type": "order", "details": ["size": 5, "additional": ["here": true]]]]