digging.swift

extension Dictionary { 
  subscript(digging first: Key, rest: AnyHashable...) -> Any? {
    return self[digging: first, rest[0..<rest.endIndex]]
  }
  
  subscript(digging first: Key, rest: ArraySlice<AnyHashable>) -> Any? {
    let v = self[first]
    
    guard let firstOfRest = rest.first else {
      return v
    }
    
    let dict = v as? [AnyHashable: Any]
    return dict?[digging: firstOfRest, rest.dropFirst()]
  }
}