Performs a uniform random permutation on the given elements.

Examples:
//var %x = 0 | while (%x < 3) { echo -a $randomPermutation(a,b,v,d,t) | inc %x }
b t a v d
d t b v a
d a b t v

/*
Performs a uniform random permutation to the given parameters.
*/
alias randomPermutation {
  var %length $0
  if (%length < 1) {
    return $iif($v1 < 0, $null, $1)
  }
  var %elements $1-
  var %index 1
  while (%index < %length) {
    var %newIndex $rand(%index, %length)
    if (%index == %newIndex) {
      continue
    }
    var %token $gettok(%elements, %index, 32)
    var %newToken $gettok(%elements, %newIndex, 32)

    ; todo implement a $swaptok function
    %elements = $remtok(%elements, %token, 1, 32)
    %elements = $remtok(%elements, %newToken, 1, 32)

    %elements = $instok(%elements, %newToken, %index, 32)
    %elements = $instok(%elements, %token, %newIndex, 32)

    inc %index
  }
  return %elements
}