Something

alias mass {
  if ($me isop $chan) {
    if ($1 isin +vvoice) { set %prefix $+(+,$str(v,$modespl)) | goto start }
    if ($1 isin -vdevoice) { set %prefix $+(-,$str(v,$modespl)) }
    if ($1 isin +oop) { set %prefix $+(+,$str(o,$modespl)) | goto start }
    if ($1 isin -odeop) { set %prefix $+(-,$str(o,$modespl)) }
    :start
    set %massing $nick($chan,0)
    while (%massing) {
      if ($nick($chan,%massing) != $me) { set %mass1 %mass1 $nick($chan,%massing) }
      if ($gettok(%mass1,0,32) = $modespl) { mode $chan %prefix %mass1 | unset %mass1 }
      dec %massing
    }
    mode $chan %prefix %mass1 | unset %mass1 
  }
  else { echo -a *** Error you're not an op on $chan *** }
}