R参考类别作为参考类别的字段 [英] R reference classes as a field of a reference class

问题描述

我想将参考类传递给参考类构造函数，并将传递的参考类分配为字段.但是，当我运行下面的代码时，我不明白为什么会收到错误消息.我的问题是:

I would like to pass a reference class to a reference class constructor, and assign the passed reference class as a field. However, when I run the code below, I don't understand why I get an error. My questions are:

1)请有人可以解释一下为什么会发生此错误:

1) Please can someone kindly explain why this error is occurring:

> a <- ClassA&new()
Error in .getClassFromCache(Class, where) : 
  argument "Class" is missing, with no default
> b <- ClassB$new(a)
Error in .Object$initialize(...) : object 'a' not found

2)我已经将 class.a.container 声明为列表"类，但是我希望这是一个参考类.我需要在这里放置什么而不是列表"?

2) I have declared class.a.container as class "list", however I want this to be a reference class. What do I need to put here instead of "list" ?

ClassA <- setRefClass(
  "ClassA",

  fields = list(myVar = "numeric"),

  methods = list(
    someMethod = function(){
      print("hi")
    }
  )
)

ClassB <- setRefClass(
  "ClassB",

  fields = list(class.a.container = "list"),

  methods = list(
    initialize = function(class.a){
      class.a.container <<- class.a
  })
)

a <- ClassA&new()
b <- ClassB$new(a)

推荐答案

您会觉得很傻，至少当我注意到问题时才这样做.从环境类项目中提取的内容中，您有一个&"符号.

Y'er gonna feel kind of silly, at least I did when I noticed the problem. You have an ampersand insead of a dollar-sign in the extraction from the envirnment-class-item.

a <- ClassA$new(myVar=1)
a$someMethod(2)
#[1] "hi

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