Hi,

I am implementing a class that inherits from two other classes (see the example below). And just wanted to ask whether it is possible to specify which show() method will be used (A or B) when calling the new show() method associated with class C.

I am aware that the call to callNextMethod() results in the call to the first inherited method.

setClass(
  "A",slots = c(slot1 = "character")
)

setMethod(
  f = "show",
  signature = "A",
  definition = function(.Object) {
    print("Show class A")
  }
)

setClass(
  "B",slots = c(slot1 = "character")
)

setMethod(
  f = "show",
  signature = "B",
  definition = function(.Object) {
    print("Show class B")
  }
)

setClass(
  "C",slots = c(slot1 = "character"),contains = c("A","B")
)

setMethod(
  f = "show",
  signature = "C",
  definition = function(.Object) {
    callNextMethod()
  }
)

new("C")

Questions about package development should be on the bioc-devel mailing list.

I'd say no, there is no way to influence the way method dispatch works. There are a number of hacks that one could imagine, e.g., using selectMethod() to choose your desired method, and calling that instead of callNextMethod(), but probably the answer is somewhere else, either in class redesign or code refactoring (e.g., creating a helper function that does that you would like to share between methods).