更改 R6 class 的 subclass 中的初始化方法

Change initialize method in subclass of an R6 class

假设我有一个 R6 class Person:

library(R6)

Person <- R6Class("Person",
  public = list(name = NA, hair = NA,
                initialize = function(name, hair) {
                  self$name <- name
                  self$hair <- hair
                  self$greet()
                },
                greet = function() {
                  cat("Hello, my name is ", self$name, ".\n", sep = "")
                })
)

如果我想创建一个 subclass,其 initialize 方法除了向 self 添加一个变量外应该是相同的,我该怎么做?
我尝试了以下方法:

PersonWithSurname <- R6Class("PersonWithSurname",
  inherit = Person,
  public = list(surname = NA,
                initialize = function(name, surname, hair) {
                  Person$new(name, hair)
                  self$surname <- surname
                })
)

然而,当我创建 class PersonWithSurname 的新实例时,字段 namehairNA,即默认值 class Person.

PersonWithSurname$new("John", "Doe", "brown")
Hello, my name is John.
<PersonWithSurname>
   Inherits from: <Person>
   Public:
     clone: function (deep = FALSE) 
     greet: function () 
     hair: NA
     initialize: function (name, surname, hair) 
     name: NA
     surname: Doe

Python 中,我将执行以下操作:

class Person(object):
  def __init__(self, name, hair):
    self.name = name
    self.hair = hair
    self.greet()

  def greet(self):
    print "Hello, my name is " + self.name

class PersonWithSurname(Person):
  def __init__(self, name, surname, hair):
    Person.__init__(self, name, hair)
    self.surname = surname

R6 在这方面与 Python 非常相似;也就是说,您只需在 super 对象上调用 initialize

PersonWithSurname <- R6Class("PersonWithSurname",
  inherit = Person,
  public = list(surname = NA,
                initialize = function(name, surname, hair) {
                  super$initialize(name, hair)
                  self$surname <- surname
                })
)