[PHP] A common use method of factory pattern

<?php
class test{
	public $x=1;
	public $setting;
	//负责生成其他对象的类或方法,这就是工厂模式
	public function getSetting(){
		if(!$this->setting){
			$this->setting=new Setting();
		}
		return $this->setting;
	}
}
class Setting{
	public function __construct(){
		echo 1111;
	}
}
$test=new test();
$setting=$test->getSetting();
$setting2=$test->getSetting();

//判断两个对象是否是同一个对象
var_dump($setting===$setting2);
//看编号,也能看出来
var_dump($setting);
var_dump($setting2);

//属性中有减号的处理
$name="x-b";
$test->$name=2;

var_dump($test);

//$test->x-b;//直接使用上面的属性,会被认为是一个减号
/*
报错:
PHP Notice:  Use of undefined constant b - assumed &#39;b&#39; in D:\phpServer\WWW\test\
test.php on line 11

Notice: Use of undefined constant b - assumed &#39;b&#39; in D:\phpServer\WWW\test\test.
php on line 11

*/

echo $test->{&#39;x-b&#39;}; //这种属性里面有-的这样包一下