/**
 * 计算工作日天数结束日期
 * 作者：beyonder@163.com
 * 吐槽一下，一开始低估了这个算法的复杂性，用了两天时间，真的不容易，写好的算法必须要沉一下心来理清逻辑才能写出来，虽然写得还不是很完美，但在这小佩服一下自己。
 * startDate:开始日期
 * days:天数
 * holidays:法定节假日字符串
 * workDays:调休上班日字符串
 * return:到期日期（不含）
 */
function getWorkingEndDate($startDate,$days,$holidays,$workDays)
{
    //开始日期
    $startDate = strtotime($startDate);
    $daysnum=0;
    $num=0;
    //法定节假日数组
    $holiDays=explode(",",$holidays);
    //调休工作日数组
    $workDays=explode(",",$workDays);
    //法定节假日
    $holiday=0;
    //周末
    $weekday=0;
    //调休工作日
    $workday=0;
    //循环daysnum
    while(($daysnum)<intval($days)){
        //临时日期
        $tempdate=$startDate+$num*(60*60*24);
        //周末天数
        if(date("N", $tempdate) == 6 || date("N", $tempdate) == 7)
            $weekday++;
        //周末天数遇到法定节假日减去周末天数
        if(in_array(date('Y-m-d',$tempdate),$holiDays)&&(date("N", $tempdate) == 6 || date("N", $tempdate) == 7))
            $weekday--;
        //法定节假日天数
        if(in_array(date('Y-m-d',$tempdate),$holiDays))
            $holiday++;
        //法定调休工作日
        if(in_array(date('Y-m-d',$tempdate),$workDays))
            $workday++;
        //循环自增
        $num++;
        //天数=循环天数+工作日-节假日-周末
        $daysnum=$num+$workday-$holiday-$weekday;
    }
    //最后计算天数正好与之前计算相反
    //天数=需要的工作日-法定调休工作日+法定节假日+周末天数
    $daysnum=$days-$workday+$holiday+$weekday;
    //返回
    return date("Y-m-d H:i:s",$startDate+$daysnum*(60*60*24));
}


/**
 * 计算两日期之间的工作日天数
 * 作者：beyonder@163.com
 * startDate:开始日期
 * endDate:结束日期
 * holidays:法定节假日
 * workDays:调休上班日
 */
function getWorkingDays($startDate, $endDate, $holidays,$workDays)
{
    $endDate = strtotime($endDate);
    $startDate = strtotime($startDate);
    $days = ($endDate - $startDate) / 86400 + 1;
    $no_full_weeks = floor($days / 7);
    $no_remaining_days = fmod($days, 7);
    $the_first_day_of_week = date("N", $startDate);
    $the_last_day_of_week = date("N", $endDate);
    if ($the_first_day_of_week <= $the_last_day_of_week) {
        if ($the_first_day_of_week <= 6 && 6 <= $the_last_day_of_week) $no_remaining_days--;
        if ($the_first_day_of_week <= 7 && 7 <= $the_last_day_of_week) $no_remaining_days--;
    } else {
        if ($the_first_day_of_week == 7) {
            $no_remaining_days--;
            if ($the_last_day_of_week == 6) {
                $no_remaining_days--;
            }
        } else {
            $no_remaining_days -= 2;
        }
    }
    $workingDays = $no_full_weeks * 5;
    if ($no_remaining_days > 0) {
        $workingDays += $no_remaining_days;
    }
    //法定休息日计算
    $holidays=explode(",",$holidays);
    for($i=0;$i<count($holidays);$i++){
        $time_stamp = strtotime($holidays[$i]);
        if ($startDate <= $time_stamp && $time_stamp <= $endDate && date("N", $time_stamp) != 6 && date("N", $time_stamp) != 7)
            $workingDays--;
    }
    //调休工作日调整
    $workDays=explode(",",$workDays);
    for($i=0;$i<count($workDays);$i++){
        $time_stamp = strtotime($workDays[$i]);
        if ($startDate <= $time_stamp && $time_stamp <= $endDate && (date("N", $time_stamp) == 6 || date("N", $time_stamp) == 7))
            $workingDays++;
    }
    return $workingDays;
}

简单的闭包（匿名函数）

function test_closure($name, Closure $clo){
    echo 'Hello {$name} ';
    $clo();
}

test_closure('Lily', function() {
    echo ' you are like...';
});

class A 
{
    private static $_instance = null;
    
    private function __construct(){}
    
    private function __clone(){}
    
    public static function getInstance()
    {
        if(! (self::$_instance instanceof self)){
            self::$_instance = new self();
        }
        return self::$_instance;
    }
}

$obj = A::getInstance();

记录下：

self 在本类中使用，只代表类本身。
$this 只有将类实例化以后才存在，指向类的实例。
static 当类中使用此关键字定义属性与方法时，在调用它时只要用类别::调用，因为它只属于类而非实例。

关于后期静态绑定，如下：

https://github.com/tuyuwei/SensitiveWord