swap(x, y)

#
# Example in a new empty environment:
#
local({
  x <- 0:9
  y <- 10:19
  print(x)
  print(y)
  swap(x[1], y[2])
  print(x)
  print(y)
})
#
# Sanity check with a bubble sort:
#
bubble.sort <- function(tab, n = length(tab)){
  i <- 1
  while(i < n){
    if(tab[i + 1] < tab[i]){
      swap(tab[i], tab[i+1])
      i <- 1
    } else {
      i <- i+1
    }
  }
  return(tab)
}
set.seed(1)
x <- rnorm(10)
stopifnot(identical(sort(x), bubble.sort(x)))