Something

alias cbans {
  .enable #cbans
  mode $active b
}
#cbans off
raw *:*:{
  if ($numeric == 367) {
    if (~c:* !iswm $3) set %bs %bs $3
    if ($numtok(%bs,32) == $modespl) {
      echo -a %bs
      mode $active $+(-,$str(b,$modespl)) %bs
      unset %bs
    }
  }
  elseif ($numeric == 368) {
    if (%bs) mode $active $+(-,$str(b,$numtok(%bs,32))) %bs
    .disable #cbans
  }
}
#cbans end