Embrace, Extend, Override

Object-Oriented Programming with S3 and R6 in R

Richie Cotton

Data Evangelist at DataCamp

thing_factory <- R6Class(
  "Thing",
  public = list(
    do_something = function() {
      message("the parent do_something method")
    }
  )
)

child_thing_factory <- R6Class(
  "ChildThing",
  inherit = thing_factory,

  public = list( 
    do_something = function() {
      message("the child do_something method")
    },

    do_something_else = function() {
      message("the child do_something_else method")


    }

  )

)

a_child_thing <- child_thing_factory$new()

a_child_thing$do_something()

the child do_something method

private$ accesses private fields

self$ accesses public methods in self

super$ accesses public methods in parent

child_thing_factory <- R6Class(
  "ChildThing",
  inherit = thing_factory,
  public = list(
    do_something = function() {
      message("the child do_something method")
    },
    do_something_else = function() {
      message("the child do_something_else method")

     self$do_something()

     super$do_something()

    }
  )
)

a_child_thing <- child_thing_factory$new()

a_child_thing$do_something_else()

the child do_something_else method
the child do_something method
the parent do_something method

Summary

Override by giving the same name
Extend by giving a new name
self$ accesses public methods in self
super$ accesses public methods in parent

Let's practice!

Object-Oriented Programming with S3 and R6 in R