library(R6)
library(methods)
library(microbenchmark)

make_class4 <- function() {
  cl <- setClass("num_with_id", slots = c(id = "character"),
                 contains = "numeric")
  setGeneric("getId", function(x) stop("Not implemented"))
  setMethod("getId", c("num_with_id"), function(x) x@id)
  cl
}

num_with_id4 <- make_class4()

make_instance4 <- function() {
  num_with_id4(1:3, id = "An Example")
}

instance4 <- make_instance4()

call_method4 <- function() {
  getId(instance4)
}

## -----------------------------

make_class6 <- function() {
  R6Class(
    "num_with_id6",
    cloneable = FALSE,
    public = list(
      data = NULL,
      id = NULL,
      initialize = function(data, id) {
        self$id <- id
        self$data <- data
      },
      getId = function() self$id
    )
  )
}

num_with_id6 <- make_class6()

make_instance6 <- function() {
  num_with_id6$new(1:3, id = "An Example")
}

instance6 <- make_instance6()

call_method6 <- function() {
  instance6$getId()
}

## ------------------------------

microbenchmark(make_class4(), make_class6(), times = 1000)

#> Unit: microseconds
#>           expr      min       lq       mean    median        uq       max neval
#>  make_class4() 3782.930 4036.894 4736.39757 4246.9235 4976.1090 56461.682  1000
#>  make_class6()   57.062   68.655   92.39163   90.3715  102.6475  1969.083  1000

microbenchmark(make_instance4(), make_instance6(), times = 1000)

#> Unit: microseconds
#>              expr     min       lq      mean   median      uq      max neval
#>  make_instance4() 163.115 172.9755 186.44686 178.0685 184.335 1304.314  1000
#>  make_instance6()  27.697  32.5685  39.62562  39.4375  43.698 1008.130  1000

microbenchmark(call_method4(), call_method6(), times = 1000)

#> Unit: microseconds
#>            expr   min     lq     mean median     uq    max neval
#>  call_method4() 7.360 7.9530 8.571229 8.2580 8.6625 53.650  1000
#>  call_method6() 2.257 2.4325 2.748578 2.6395 2.8375 19.556  1000