[R] callNextMethod with dots argument

[Kiên Kiêu]

Hi,

I met a problem when invoking callNextMethod within a method associated 
with a generic function taking ... as an argument.

Here is the code

setClass("Aparent",representation(x="numeric",y="numeric"))
setClass("Achild",contains="Aparent")

setGeneric("do",def=function(a,...) standardGeneric("do"))
setMethod("do",signature(a="Aparent"),
           function(a,msg) {
             print("do Aparent")
           })
setMethod("do",signature(a="Achild"),
           function(a,msg)  {
             print("do Achild")
             callNextMethod()
           })

myA <- new("Achild")
buf <- do(a=myA)               # works
buf <- do(a=myA,msg="bonjour") # error

The last call yields the following error message:

Error in callNextMethod() :
   in processing 'callNextMethod', found a '...' in the matched call, 
but no corresponding '...' argument

which I do not understand. Replacing "..." by "msg" in setGeneric makes 
it work. But I don't like this limitation so much (unless I understand it).

Regards.

Kien