Here you go smile
Use either //echo -s $alldifferent(a,b,c,d,e,f,,g) or /alldifferent a b c d e f g

Code:
alias alldifferent {
  ; $1 is first entry, $2 second etc
  ; only limitation is line length (about 900 characters)
  var %txt, %n = 1, %t = 0
  var %delim = $asc(Ø)
  var %r = $iif($isid,return,echo -s)
  while ( %n <= $0) {
    if ([ $ [ $+ [ $v1 ] ] ] == $null) {
      ; ignore all $null values
      inc %n    
      continue 
    }
    var %txt = $addtok(%txt,$v1,%delim)
    inc %t
    if ($numtok(%txt,%delim) < %t) {
      var %tok1 = $findtok(%txt, $ [ $+ [ %n ] ] ,%delim)
      var %tok2 = %n
      var %contents = $ [ $+ [ %n ] ]
      ; should give same result: 
      ; var %contents = $gettok(%txt,%tok1,%delim)
      %r Parameter %tok1 is the same as %tok2 $+(; contents are <,%contents,>.)
      return $false
    }
    inc %n
  }
  %r All parameters are unique...
  return $true
}