function acttab_action($lookahead, $action)
    {
        if ($this->nLookahead === 0) {
            $this->aLookahead = array();
            $this->mxLookahead = $lookahead;
            $this->mnLookahead = $lookahead;
            $this->mnAction = $action;
        } else {
            if ($this->mxLookahead < $lookahead) {
                $this->mxLookahead = $lookahead;
            }
            if ($this->mnLookahead > $lookahead) {
                $this->mnLookahead = $lookahead;
                $this->mnAction = $action;
            }
        }
        $this->aLookahead[$this->nLookahead] = array(
            'lookahead' => $lookahead,
            'action' => $action);
        $this->nLookahead++;
    }