Slots of typ formula

Question

I am trying to use a slot of type formula. But formula isn't a basic datatype. What can I do to create a slot to store objects like formula. Or is it intentional to prohibit storing general S3 objects as slots? If it's intentional to use slots of type S4, how do I turn the S3 class formula into S4 class?

Answer 1

Seems to work for me:

setClass("form", representation(f="formula"))
myForm <- new("form",f=y~x)
myForm
An object of class "form"
Slot "f":
y ~ x

class(myForm@f)
[1] "formula"

Answer 2

Maybe it helps if you use named arguments in your call to new. S4 classes as slots are supported.

setClass(Class = "B", representation = representation(var1 = "character"))
setClass(Class = "A", representation = representation(var1 = "B"))
b<-new("B",var1="b")
a<-new("A",var1=b)

Answer 3

I would like to use a mechanism like

 class B{
    int varb=0;
 }

 class A{
     B classvar;
     A(B var) classvar=var;
 }


 b=new B();
 a=new A(b);

Currently I do it in this way

  setClass(Class = "A",
     representation = representation(var1 = "list")
     )

  setClass(Class = "B",
     representation = representation(var1 = "character")
     )
  b<-new("B","b")
  a<-new("A",list(b))

to save S4 object like a class variable.