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 - su

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.