[Rd] help with S4 objects: trying to use a "link-glm" as a class in an object definition

[Paul Bailey]

Hi,

I'm trying to make a new S4 object with a slot for a "link-glm" object. R doesn't like me have a slot of class "link-glm"

> class(make.link("probit"))
[1] "link-glm"
> setClass("a",representation(item="link-glm"))
[1] "a"
Warning message:
undefined slot classes in definition of "a": item(class "link-glm") 
> fa <- function() {
+   new("a",item=make.link("probit"))
+ }> 
> fa()
Error in validObject(.Object) : 
  invalid class "a" object: undefined class for slot "item" ("link-glm")

# and a link-glm looks like a list to me, so I thought I would tell R it is a list and see what happens

> setClass("b",representation(item="list"))
[1] "b"
> fb <- function() {
+   new("b",item=make.link("probit"))
+ }
> fb()
Error in validObject(.Object) : 
  invalid class "b" object: invalid object for slot "item" in class "b": got class "link-glm", should be or extend class "list"

Any advice?

Regards,
Paul Bailey
Ph.D. candidate
Department of Economics
University of Maryland

###### raw code #####
setClass("a",representation(item="link-glm"))
fa <- function() {
  new("a",item=make.link("probit"))
}
fa()
setClass("b",representation(item="list"))
fb <- function() {
  new("b",item=make.link("probit"))
}
fb()
###########