ON $*:TEXT:/^[!@.]dv \S+/Si:#:{
  if ($2 == $null) {
    mode $chan -v $nick 
  }
  else {
    if ($2 != $null) && ($nick isop $chan) || ($address($nick,2) == $address($me,2)) {
    mode $chan -v $2 }
  }
}

Doesn't work for single?