Reference Class with custom field classes in R?

Question

I would like to use a custom reference class inside another reference class, but this code fails:

nameClass <- setRefClass(\"nameClass\", fields = list(first         


        

Answer 1

It seems that this is because you do not have a default constructor for your "nameClass":

nameClass$new()
Error in strsplit(char, "\\.") : 
  argument "char" is missing, with no default

If you modify your nameClass like this:

nameClass <- setRefClass("nameClass", fields = list(first = "character",
                                                    last = "character"),
                         methods = list(
                           initialize = function(s = NULL) {
                             if (!is.null(s) && nzchar(s)) {
                               chunks <- strsplit(s,"\\.")
                               first <<- chunks[[1]][1]
                               last <<- chunks[[1]][2]
                             }
                           },
                           show = function(){
                             cat("Special Name Class \n:")
                             cat("First Name:")
                             methods::show(first)
                             cat("Last Name:")
                             methods::show(last)
                           }
                         ))

Then:

nameClass$new()
Special Name Class 
:First Name:character(0)
Last Name:character(0)

and your personClass is now functional (yet the initialize method is quite odd):

personClass$new("tyler.durden")
Reference class object of class "personClass"
Field "fullname":
Special Name Class 
:First Name:[1] "\"tyler"
Last Name:[1] "durden\""
Field "occupation":
[1] "tyler.durden"