Static methods in R6 classes

Question

Is there a way to add static methods to R6 classes? For example, a function that can be called like

MyClass$method()

Instead of

myinstance <- MyClass$new()
myinstance$method()

Answer 1

I'm not an expert on R6 but since every R6 class is an environment, you can add anything you want to this environment.

Like:

MyClass$my_static_method <- function(x) { x + 2}
MyClass$my_static_method(1)
#[1] 3

But the method will not work on the instance of the class:

instance1 <- MyClass$new()
instance1$my_static_method(1)
# Error: attempt to apply non-function

You should be careful with the existing objects in the class environment. To see what is already defined use ls(MyClass)

Answer 2

I have used a workaround for the solution. You can access the methods without creating the instance by calling MyClass$public_methods$my_static_method(). To restrict the calls without the instance, I have made self as an argument in all of the methods.