[R] Aliases for arguments in a function

[Richard M. Heiberger]

foo <- function(arg1, this, that) {
  if (missing(this) && !missing(that)) this <- that
  if(this < 0) stop("this must be positive")
  return(arg1/this)
}

foo(arg1=5, this=10)

foo(arg1=5, that=10)