function yy_reduce($yyruleno)
    {
        //int $yygoto;                     /* The next state */
        //int $yyact;                      /* The next action */
        //mixed $yygotominor;        /* The LHS of the rule reduced */
        //SQLParser_yyStackEntry $yymsp;            /* The top of the parser's stack */
        //int $yysize;                     /* Amount to pop the stack */
        $yymsp = $this->yystack[$this->yyidx];
        if (self::$yyTraceFILE && $yyruleno >= 0 
              && $yyruleno < count(self::$yyRuleName)) {
            fprintf(self::$yyTraceFILE, "%sReduce (%d) [%s].\n",
                self::$yyTracePrompt, $yyruleno,
                self::$yyRuleName[$yyruleno]);
        }

        $this->_retvalue = $yy_lefthand_side = null;
        if (array_key_exists($yyruleno, self::$yyReduceMap)) {
            // call the action
            $this->_retvalue = null;
            $this->{'yy_r' . self::$yyReduceMap[$yyruleno]}();
            $yy_lefthand_side = $this->_retvalue;
        }
        $yygoto = self::$yyRuleInfo[$yyruleno]['lhs'];
        $yysize = self::$yyRuleInfo[$yyruleno]['rhs'];
        $this->yyidx -= $yysize;
        for ($i = $yysize; $i; $i--) {
            // pop all of the right-hand side parameters
            array_pop($this->yystack);
        }
        $yyact = $this->yy_find_reduce_action($this->yystack[$this->yyidx]->stateno, $yygoto);
        if ($yyact < self::YYNSTATE) {
            /* If we are not debugging and the reduce action popped at least
            ** one element off the stack, then we can push the new element back
            ** onto the stack here, and skip the stack overflow test in yy_shift().
            ** That gives a significant speed improvement. */
            if (!self::$yyTraceFILE && $yysize) {
                $this->yyidx++;
                $x = new SQLParser_yyStackEntry;
                $x->stateno = $yyact;
                $x->major = $yygoto;
                $x->minor = $yy_lefthand_side;
                $this->yystack[$this->yyidx] = $x;
            } else {
                $this->yy_shift($yyact, $yygoto, $yy_lefthand_side);
            }
        } elseif ($yyact == self::YYNSTATE + self::YYNRULE + 1) {
            $this->yy_accept();
        }
    }