[civilized]

This works, but only because you can tell which function you need to call using only the first argument.

A more compelling example for Julia would have to have two modes of operation where the first argument has the same type in both modes, but later arguments have different types.

[Cosi1125]

    setMethod(myfun, signature = c("integer", "character"), ...)
    setMethod(myfun, signature = c("list", "data.frame", "logical"), ...)
    setMethod(myfun, signature = "foo", ...)

This takes into account as many arguments as you wish.

[kkoncevicius]

True, but in R (at least in S3) it's probably avoided by design because of default parameters. A short example:

  genericfun.type1 <- function(x, sub=1) x - sub
  genericfun.type2 <- function(x, y)     sum(x, y)

The single case can be differentiated:

  genericfun(x)

But which function are we calling with:

  genericfun(x, y)

I don't know about Julia and how it solves this. Maybe by not allowing to pass nameless optional arguments.

[disgruntledphd2]

S4 can dispatch on multiple arguments, just like Julia (though it seems a lot more natural in Julia).