bandicoot (version 1.0.0)

super: Get the parent class (the next class based on the method resolution order)

Description

This function gets the parent class or the next class based on the method resolution order. This is useful when one wants to access the overwritten parent class method or the overwritten parent class attribute.

Usage

super(self_name = "self", mro_current_name = "..mro_current..", where = NULL)

Value

A bandicoot object which is an environment.

Arguments

self_name

Character. The name of the self reference.

mro_current_name

Character. The name of the variable storing the current class. This is used to determine the next class.

where

Environment/Character. The target environment to search for the parent class. If where == NULL, the parent environment of self will be used. If a character value is provided, the package with the same name will be used.

Details

Note that this function assumes the parent class can be found in the parent environment of the current object. If one wants to find the parent class from a package, it needs to be specified via the where argument.

Examples

# Define class O
O <- new_class(class_name = "O")
register_method(O, foo = function() {
  print("Calling class O `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
})

# Define class F
F <- new_class(O, class_name = "F")
register_method(F, foo = function() {
  print("Calling class F `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# Define class E
E <- new_class(O, class_name = "E")
register_method(E, foo = function() {
  print("Calling class E `foo` method")
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# Define class D
D <- new_class(O, class_name = "D")
register_method(D, foo = function() {
  print("Calling class D `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# Define class C
C <- new_class(D, F, class_name = "C")
register_method(C, foo = function() {
  print("Calling class C `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# Define class B
B <- new_class(E, D, class_name = "B")
register_method(B, foo = function() {
  print("Calling class B `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# Define class A
A <- new_class(B, C, class_name = "A")
register_method(A, foo = function() {
  print("Calling class A `foo` method")
  print(paste0("Self is ", self$my_name))
  print(paste0("Next class is ", super()$..type..))
  use_method(self, super()$foo)()
})

# To understand why the order is A, B, E, C, D, F, O,
# please check [https://www.python.org/download/releases/2.3/mro/].
a <- A$instantiate()
a$my_name <- "a"
a$foo()