Overloading + operator and incompatibility exception

I tried to overload the + operator and ran into incompatibility issues. Even though the + function is a generic S3 function, it seems to treat both arguments (similar to multiple dispatch), not just the left argument, like other generic S3 functions (see "Ops" groups at http: // www .inside-r.org / r-doc / base / summary ). So, if two different + functions are defined for the arguments, R will issue a warning and fall back to + for the two numeric values.

Here's an example:

myType1 <- function(obj) {
  structure(obj, class = "myType1")
} # function myType1

`+.myType1` <- function(obj1, obj2) {
  return(obj1)
} # function +.myType1

myType2 <- function(obj) {
  structure(obj, class = "myType2")
} # function myType2

`+.myType2` <- function(obj1, obj2) {
  return(obj2)
} # function +.myType2

myType1("A") + 1 # this works, use defined types seem to have precedence
myType1("A") + myType2(1) # this doesn't

      

        
        
        
      

    

Is there a way to get around this problem? I know S4 methods support multiple dispatch. Would using S4 help me avoid this problem even if an S3 + method is defined for one of the arguments?

Thank you so much in advance.

Regards, Junghoon Lee