[Rd] group generics

From: Ross Boylan <ross_at_biostat.ucsf.edu>
Date: Tue, 24 Nov 2009 16:34:25 -0800


I have classes A and B, where B contains A. In the implementation of the group generic for B I would like to use the corresponding group generic for A. Is there a way to do that?

I would also appreciate any comments if what I'm trying to do seems like the wrong approach.

Here's a stripped down example:
setClass("A",

         representation=representation(xa="numeric")
         )

setMethod("Arith", signature(e1="numeric", e2="A"), function(e1, e2) {   new("A", ax=e1*e2_at_xa)
}

          )

setClass("B",

         representation=representation(xb="numeric"),
         contains=c("A")
         )

setMethod("Arith", signature(e1="numeric", e2="B"), function(e1, e2) {
	# the next line does not work right

  v <- selectMethod("callGeneric", signature=c("numeric", "A"))(e1, e2)   print(v)
  new("B", v, xb=e1*e2_at_xb)
}
)

Results:
> t1 <- new("B", new("A", xa=4), xb=2)
> t1

An object of class “B”
Slot "xb":
[1] 2

Slot "xa":
[1] 4

> 3*t1

Error in getGeneric(f, !optional) :
  no generic function found for "callGeneric"

Thanks.
Ross Boylan



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